Sunday, 29 January 2012

Proco Rat




And a slightly more compact layout




Video of Geiri's build:

237 comments:

  1. This comment has been removed by the author.

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  2. Hi matey. I used analogguru's schematic:

    http://analogguru.an.ohost.de/193/schematics/Proco_TheRat-1986.gif

    I don't know if that is what most people would want, I get a bit lost with the Rat versions as well! :o)

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  3. What transistor is used? or if any, what would you suggest to keep with the original RAT?

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  4. I've just started building this and have noticed the 1u's. I have 1uf's but they're radial types and there is no indication to the orientation on the layout?

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    Replies
    1. The one under the opamp is negative to ground :o), the one on the right is negative to volume 3.

      Delete
  5. Well no luck with this one :( I get a clean signal but silence when the effect is selected....

    Not sure where the ground wire from the Volume should go but i just prodded it against the in and out jack ground but all i get are loud pops, no effect? Must be a fault in the circuit? (my fault that is)

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    1. The ground wire from the volume goes to any point of ground (which should all be connected together).

      What IC and JFET have you used, and you have used 47 and 560 ohm resistors, not 47K and/or 560K?

      Post a high res front and back pic if you can and I'll have a look.

      Delete
  6. Yep, used 47R and 560R resistors

    The IC is an LM308 and the JFET is a 2N5458

    Pictures: http://s1170.photobucket.com/albums/r534/vince371/Rat/

    Thanks

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    Replies
    1. You're missing 6 cuts mate:

      http://i76.photobucket.com/albums/j6/IvIark_2006/DIY/Debug/Vince_Rat_Back.jpg

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  7. Hahaaa! what a dumbass!! I really do apologise... back in the corner I go!

    Thanks mate, I'll get back to it later and sort it :)

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  8. Well goddamn! the little rodent works!! I forgot how good these things sound... takes me back to 80's metal days! it's a keeper! so you can verify this one... great pedal!

    Thanks for the help.

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  9. Excellent, thanks for verifying!

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  10. Hi, I gave this to a friend to rehearse with and he said he was getting 'whistling noises at different frequencies? Even when the pedal was off but it's ok at my 'bedroom' levels? any ideas?

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    Replies
    1. I haven't heard that one before about a Rat so don't know what could be the cause. You could try increasing the 100U power supply filter cap to something like 220u, but to be honest I would expect 100u to be big enough anyway. Have you tried it with your amp turned up to higher levels?

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  11. Yep, it's fine with mine, well it's bloody fantastic to be honest! I personally think he may have had other interference, maybe daisy power supply issues etc... I just thought it may be a mischievous LM308? picking up and amplifying noise?

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  12. There could be noise from the supply, although there are measures included like the filter cap and supply currentl limiting resistor which are there to minimize that. Some people do just have dirty supplies though and dirt pedals will always be the first thing affected by it. The IC is another possibility, if you've socketed it you should try swapping that just to see if it does solve it.

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  13. I'll try another IC then. I have no lm308's left but I do have some LM741 and LM386, either of them be ok?

    But then he did say the noise was present even when the pedal was turned off? surely that would mean it's a signal issue not a circuit one?

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    Replies
    1. Definitely not the LM386, and the LM741 doesn't have the compensation between pins 1 and 8 that the LM308 has. It may still work though, albeit not as well as the LM308.

      But I didn't notice you said the noise was still there in bypass, so that pretty much makes the IC thing irrelevant. How did you wire the switch?

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  14. The switch! that crossed my mind too as I've only recently started wiring it to the Skreddy method which I understand grounds it in bypass. So I guess rewire the switch and see if thats it...

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    Replies
    1. Yes it grounds the effect input and so stops any signal getting into the circuit.

      Delete
  15. Update:

    Rewired switch, When pedal is on but unplugged from the guitar and turn the gain past about 3'clock you get a siren effect (higher pitched when increasing the gain to full)

    Not an issue for me but just though I'd reference it as a point of possible interest.

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  16. Sent you an email but not sure they're reaching you. Made another of these but am having issues. I get continuity from DC up til pin 7 on the IC which reads 047??

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  17. I've just noticed that the layout cuts and links don't match? but the one I printed off a while ago do?

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    Replies
    1. That is so weird. That was an old error but I corrected the layout and posted the new one. I wonder if blogspot have reverted to an old version for some reasons?

      In terms of the difference it doesn't actually matter, the same connections and cuts are made, just further along the board.

      Your JFET voltages look fine, and your opamp voltages don't look too far away. Do me a favour and measure the pins with the distortion pot at minimum, and then again at maximum and tell me the numbers

      Delete
    2. Maximum;

      IC;

      1 = 8.12
      2 = 4.46
      3 = 2.18
      4 & 5 = 0.00
      6 = 4.46
      7 = 8.90
      8 = 4.69

      JFet;

      D = 8.90
      s = 1.47
      G = 0.00

      Minimum

      IC;

      1 = 8.00
      2 = 1.60
      3 = 2.16
      4 & 5 = 0.00
      6 = 8.16
      7 = 8.91
      8 = 8.66

      JFet;

      D = 8.91
      S = 1.47
      G = 0.00

      I have checked diode and no bridges :(

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    3. Oh crap.. minimum and maximum are wrong way around. sorry.

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    4. I Build 2 of these Rats And i dont get any big differents in Pin 2 and 8 its almost the same from min to max Distortion
      And i got this high pitch tone when its bypassed..( and unplugged..)
      Anyone got any advice ...Whats wrong ??

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    5. My figures are :

      Max Distortion

      1 8;40
      2 4,52
      3 4,09
      4 -5 = 0
      6 4,52
      7 9,06
      8 4,37

      D = 9,06
      S = 1,77
      G = 0

      Min Distortion

      1 8,43
      2 4,53
      3 4,10
      4 - 5 = 0
      6 4,53
      7 9,09
      8 4,58


      D = 9,09
      S = 1,71
      G = 0

      The rat is working ..The 3 knobs are working it sounds very good And when i play on my tube Amp ( Carlbro Top 100 - 1975 Made in England ) it dont have this high pitch tone
      but when i put it in front of my tranni amp i has ????
      I´m Gettin grey hair....
      Is there Anyone out there that has any advice ???

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    6. Can you take a front and back pic so I can check everything over. We know the layout is verified so if there's isn't any physical connection errors, then there must be a problem with a component.

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    7. I´m working on the 3. version.. When it is finnished i´ll be back...
      A big thanx for your support And A Great blog

      Where can i mail the pictures to ?

      My 1 M resistors reads , when measured ,878 k Ohm is that a problem

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    8. Mail the pics to guitarfx@hotmail.co.uk or post them to somewhere like Photobucket and post the links here.

      878K is low but I'm not sure whether it would cause the problems you mention. The squealing in bypass is a strange one, and suggests a problem with the switch or grounding rather than the circuit.

      Delete
    9. When I unplug the input cord and max the distortion I get a high pithed noise which changes as I decrease the distortion. Not a problem as I don't unplug but thought I'd mention it as may be of interest to the issue STAALHAAR is having (Mine is a tube amp also)

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    10. Thanks for chipping in mate. Do you wire your switches with the conventional true bypass wiring or a mehod like the one in my offboard wiring guide which grounds the effect input during bypass? You shouldn't get that kind of noise with my method.

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    11. I wire them the skreddy way which I think is the same way as your offboard wiring. I've just had a play with it, When the input cable is unplugged I get high pitched noise starting at around 2 0'clock on the distortion sweep. The pitch lowers as the sweep reaches the end. It is louder when the filter is at min and quiter on full. The filter doesn't change the pitch.

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    12. I should add this only happens when the effect is engaged.

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    13. I think Me and " Vince " are having the same kind of Noises or high pitch tones.. mine if affected by dialing the distortion knob and the Ruetz Mod knob both have influence on the high pitch tones or noises

      I´ll get back when i got version #3 ready for testing

      And Thanx to Vince for Joining

      Delete
    14. What Vince describes does happen sometimes, especially with distortion pedals. If the effect is engaged and you take the input cable out of the effect, then a connection to the amp is left hanging, in the same way that taking the cable out of your guitar when it's still connected to the amp give you noise and feedback.

      It shouldn't happen in bypass though, and you shouldn't get ground noise if you use the Skreddy method of wiring, because the effect input is grounded.

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    15. I got version # 3 up and running and its making the same noises or high pitch tones

      Ít still sounds awesome... And I´M building a version with four different kind of Diodes To switch between

      + The Ruetz Mod

      Red Led - 1N 914 - 1448 - And a Pair of Germanium ( 1N34 A or 1N 270 ( MXR )

      I´m wiring the Switch the " Skreddy way " Thanx to Melx



      I changed battery in my multimeter ( and thats the reason the 1 M resistor reads 878 K Ohm ) now it reads 970 K Ohm
      ( the battery was down to 6 Volts )

      Anybody Seen MELX Lately ??

      Thanx for the Advice ....Keep on Rocking

      Delete
  18. Heres a couple of pics in a last ditched attempt before it hits the bin.

    http://imageshack.us/f/841/dsc001361e.jpg/

    http://imageshack.us/f/213/dsc00135uc.jpg/

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    1. Well your soldering looks good, the cuts look good, values that I can see look good and the component positions look good. So that suggests a faulty component. The only thing I would say is that your voltages at pin 3 don't look right, it should be around 4v ish at minimum and 2v ish at maximum. Check the soldering of the components round there, the 1K resistor and 1n cap. Along with the soldering around the feedback loop, and so the 100p cap, distortion pot and the 560R/4u7 and 47R/2u2.

      If you do decide to ditch it, don't just bin it. Snip out all of the components first and measure them. Then if you come across a problem part it may help you in the future (and give you a prompt to check the rest of the batch).

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    2. Just noticed this:

      http://i76.photobucket.com/albums/j6/IvIark_2006/DIY/dsc001361e_check.jpg

      Are you sure there isn't a bridge there? It looks very close.
      That is the input cap and 2u2 in the feedback loop which makes sense with what I said above.

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    3. Just re flowed the solder again, no change etc etc... I haven't the patience to test all that lol... A couple of pokes and prods and in the bin you go! I'll build it again in a while and see what happens...

      Thanks anyway.

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    4. I noticed that too Mark, I took a hack saw to all the breaks to separate them but didn't seem to make a change :(

      Delete
  19. Remade it Mark and it fired up first time... I must of made an error somewhere but the time (and frustration) it was taking to debug, I could and did make another :o)

    I did it from your updated layout so I guess it's re verified lol

    Piccy for that scrapbook
    http://img706.imageshack.us/img706/6820/dsc00134axb.jpg

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    1. OK cheers for that. I reckon you had a faulty component because everything else looked good. I suppose it makes sense to measure the components before soldering just to make sure you don't have any faulty parts, but admit I'm mostly too lazy. I'm going to make more of an effort to do it in future because when I'm verifying something if I know the components are fine then the fault has to be mine, either in the layout or build. I wouldn't be happy with a high parts count build like a Klon or something, if a fault turned out to be a dodgy electrolytic after I'd spent hours trying to fault find the layout and build.

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    2. I agree, I think I'll make an effort to do some testing. As I plan to do the 'Kings of the Britians' next, I think that would be a good place to start as the parts are more than usual.. Do you know of a good guide on how to test components? As I'm new to the multimeter, it all looks greek to me.

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    3. Can it test capacitors? For resistors just put it in the appropriate range for ohms based on the value you're testing. If your meter can't test caps then something like this is invaluable:

      http://www.ebay.co.uk/itm/260841152985

      That's isn't exactly the same as mine but looking at the layout it seems to be the latest version of the same. It's actually really good, I've got a much more expensive meter and it's crap at measuring pf values, whereas this does it fine.

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    4. I can feel the laziness creeping in again.. Thanks mate, I'll take a look :o)

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  20. I'm on a mod mission... I don't suppose you have a mod version of this in your library? I know sabro has done one but I much prefer your layouts... I'll be moving on to the MXR Dist+ next... ;o)

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    Replies
    1. There are a few popular mods mate, I'll dig out my info and look at how things will need adapting.

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    2. Nice, Didn't know there were a few, I've only seen a diode clipping switch which looks pretty good.

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  21. Hmm.. Is it normal for a rat to squeal (or oscillate with some settings) with LM741, LM301 and TL071?
    +m

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    Replies
    1. Mine only squeals when the input cable is unplugged and the distortion on max, other than that all mine have been fine.

      I have only ever used the LM308 in this for the record.

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    2. The oscillation range changed between all different opamps. So i guess it's in the LM741. Actually LM741 sounds pretty mean. I'm not sure if i'm going to change it :) Well. We'll see, this is not for me, but for a friend.

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    3. I recently had the same issue with the Purple plexi. I must of sat and tried different LM386's for about 20 mins until I found one that didn't squeal. Never happened to me before with the plexi, I'm sure a gremlin gets a build once and a while.

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    4. Now that i've checked, the LM308 is pretty expensive opamp for such an inferior spec. A few sellers on eBay offer some in 10 packs for about 80 us cents a piece.. General stores like mouser or elfa don't have them at all, while Musikding and Banzai have unreasonable prices.

      Squeeling remains with all three i mentioned above. Any other suggestions in addition to normal substitutes, like LM741, LM301, LF351, TL081 and TL071?
      +m

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    5. I think Mark is better equipt to answer that. Good luck though, I know how annoying these things can be.

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    6. The only one that could be a realistic substitute out of the ones you've listed is the LM301. None of the others have the compensation between pins 1 and 8. But the LM301 has a "Balance" pin 5 which isn't in the LM308 and so I don't know whether that is something that needs to be taken into consideration, and maybe requires other components. I'd try an LM308, NE5534 or OP07CP (or similar comparable IC) in there and see if it makes a difference.

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    7. http://en.wikipedia.org/wiki/Proco_Rat

      Wikipedia article states that "Other op-amps that people try include the NE5535A, NE5534AP LM741 and TL071 FET-OP."

      I could try NE5534, which i think i have (can't remember and can't check 'cause i'm at work). Like i said, LM741 sounds really mean in a good way, but it oscillates, apparently due to that missing compensation in the specs.

      Which makes me think.. If one used something like 390pF cap instead of that 30pF, it should in theory reduce the oscillation. This is all just speculation and based on nothing but a guess :) If that mellows it, i might think about switch, with 30pF for "Osc mode" and 390pF for "Classic mode". I'll let you know :)
      +m

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    8. :) or i could just order a batch of LM308s.
      +m

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    9. I won't do anything. Pin 8 has no connection in an LM741

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    10. Oh. I completely missed that. I knew it, but didn't think it through :)
      +m

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    11. If Proco have used an LM741 or TL071 then they must have made some modification to the circuit, and I haven't come across a schematic showing anything other than the usual LM308. I'd be interested to know what the mods might be though

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    12. Just finished this build and while it sounds great, it oscillates unfortunately - the pitch can be changed with the gain knob. I've read pretty much all that's out there regarding this and it seems that I either need to increase the compensation cap (I already upped the 30pf cap to 100pf - little to no difference) or try other opamps (got an OP07 in there currently). Can anyone provide any suggestions? Should I try going beyond 100pf? I understand the OP07 slew rate is faster, so a larger value cap should help, but it doesn't seem to have in this case - can trying different opamps resolve this issue? I don't have any spares to experiment with, so just trying to make a gameplan at the moment.

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    13. I think OP07's "trim" doesn't act in the same manner as LM308's compensation as the chips are nothing like each other on the inside. In my experience only opamp suitable for Rat is LM308.
      +m

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    14. The OP07 doesn't have external compensation between pins 1 and 8 so the cap won't be doing anything. Proco have used the OP07 in Rats (not sure if the current one has one) but I suspect the circuit will be changed slightly. It shows a Trim function between pins 1 and 8 and so is looking for resistance, maybe adding a little trimmer there and seeing what it does will be a worthwhile experiment.

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    15. Just got some 308's from Smallbear and I'm having the same issue. Have tried a few in the socket and they all have the same oscillating effect I mentioned earlier with the OP07. What is going on here? I haven't changed the circuit it any way and it seems to otherwise work without issue. Compensation cap increase? Could there be a problem with some part/wire being in too close proximity to something else? Last question - should gain at 0 have the effect of completely muted output? This isn't my first build and it wasn't particularly difficult - I did take my time and have checked and re-checked all aspects of the build. Stuck :p

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    16. Steve

      My Landgraff MO'D ( which, I understand is a modded RAT ) did the squeal like you are describing, wherein the squeal changed frequency when gain knob was twisted. This was in bypass mode for mine, which you didn't mention. I wasn't grounding my input from the board when bypass was selected. As soon as I did that, the pitch changing squeal was gone. And now I make sure I add that little jumper in all my builds. Go back and read the comments from the MO'D for more details.

      If yours is doing it while the effect is engaged, then ignore this. I have a clay jones OD, which is one of my favorite ODs from here, that does the squeal in higher gain settings, and haven't been able to fix it. Luckily, I prefer the lower gain settings anyway, so it's not a dealbreaker.

      Delete
    17. Sorry - the details about grounding the board input in bypass were actually in the son of clay jones comments...

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    18. Thanks, Tinker - that's exactly it - when bypassed and controlled by the position of the gain knob. I had to experiment as I was using a different wiring diagram (http://www.beavisaudio.com/techpages/StompboxWiring/) but I finally got it to bypass without noise! Thanks for bringing this to my attention!

      Perhaps Mark/Miro can add a note about this in the post for future builders.

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  22. Came home and sticked the NE5534P to the socket. Now it squeals like Vince said. With Dist pot at maximum. Although. I can's say if the LM741 didn't work as good as NE5534. Actually without any modifications that may be an viable, or at least worth a try option. And one could then drop that 30p and one link..
    +m

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  23. http://mirosol.kapsi.fi/varasto/boxes/Rotta.jpg

    It has NE5534 inside, but i've ordered a batch of LM308s.. So i'll try those out once i get them. NE5534 works just fine, but it squeels a bit easily.
    +m

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  24. i built this one last night( using the enclosure from my disappointing Retro Fuzz build). i didn't have any LM308N's yet (they'll be here later today) but it works perfectly with LM741's, LM301N's, and my favorite so far is a TL071CP. to me, it sounds a little more 'tubey with the TL071 (and it has less noise). i have absolutely NO oscillation issues at any setting . i made it stock as per the vero, but socketed the input, output and tone caps, the 560R & 47R resistors in the drive circuit, and i also socketed the clipping diodes. and since i'm using it for bass, i raised the values of the input and output caps to allow more low end thru the circuit, slightly changed the values of the drive circuit reistors, and am running 1N270 Germanium diodes instead of the 1N4148's. (i tried red leds, green leds, blue leds, yellow leds, and the 1N270's sound the best to me, even though it loses some level with them.


    to make it even better suited for bass, i also added a blend control (split'n'blend) and am currently adding a Tillman FET (clean)booster so when the split'n'blend's balance control is in the center positon, the pedal will be at unity gain.

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    Replies
    1. Whoa, you're Bassface looks real pro quality! Thumbs up, man. What caps did you decide to go with? I'm building mine for bass, too, and would like to retain as much low end as possible without having to do a clean blend.

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  25. BTW, here's some pics of it. with all of the mods to it, i', very pleased with it:

    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/BassFace/BASSFACE-OD-fuzz-01.jpg

    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/BassFace/BASSFACE-OD-fuzz-02.jpg

    and here's a quick soundclip of it:

    http://soundcloud.com/johnk_10/dryrot

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  26. I think you miss a component ?!
    C13 10n
    Need to be connected to 100uF and the ground...

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    Replies
    1. i guess that it depends on which schematic the vero is based on (there are lots of versions of it). i've seen them both with and witout the 10n cap.

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    2. I seem to recall Mark doing this from a 1984 (ish) scheme. I may be wrong but it just rings a bell. I've had a few rats, pedals that is, in the past and this is deffo a RAT ;o)

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    3. Mark's first comment on this post says: "I used analogguru's schematic: http://analogguru.an.ohost.de/193/schematics/Proco_TheRat-1986.gif"

      But that 10n seems to be part of the power filtering (is not on the signal path), so omitting that could have been a conscious decision.

      Without that this still sounds 1:1 with original '84 or so...

      If someone wants to make this verbatim, then the 10n cap can be added in parallel with 100µ filter cap. But like i said, that won't change the tone.
      +m

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  27. Perfect, I've made this animal, sounds awesome! But is it normal to don't have sound when distortion (gain) is on 0 position? (no clean boost position).

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    Replies
    1. Yes, normal. Mine is the same.

      My filter was in reverse too?? Can't remember it being like that.. my memory isn't what it was...

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    2. I thought the filter is supposed to be "in reverse", as it adds more filtering when turned clockwise...
      +m

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    3. Sorry, brain freeze... yes it meant to be ''in reverse''

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  28. So for the Ruetz mod, would one remove the 47R and 560R to the left of the OP-amp? And then to make it a Turbo rat, would one just replace the diodes with any LED?

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    Replies
    1. I thought the Ruetz mod was just replacing the 47R with a trimmer (or switch if you just want to switch it in and out of the circuit)

      Delete
    2. If I wanted to replace D2 with an LED, are there any specific things I need to pay attention to about the LED? I know different colors/brightness' have different voltage barriers. Do you perhaps know if I choose a lower voltage one it'll yield less distortion, or something like that?

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    3. The higher the forward voltage of the LED, the less it will distort. So red LEDs (typical forward voltage 1.7V) will distort and compress more than blue ones (typical forward voltage 4.5V) for instance.

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  29. Anybody? I really want to build a rat!

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    Replies
    1. Well it's got the same pinouts so you don't have to twist legs or anything, but the chances are it will need to be biased differently. So yes use it, but consider socketing the 10K source resistor so you can change values if it doesn't bias correctly. Or even better, solder a 20K trimmer in there and you'll get it going after a bit of easy tweaking.

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  30. :D !!

    I have some 5457, perhaps that would be a better fit?? Same pinout as well. If I wanted to make the clipping diodes switchable, I would just run from the top of D1, for the bottom of D2, correct? Forgve my constant harrasing, I'm still learning. :D

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    Replies
    1. "I have some 5457, perhaps that would be a better fit??"

      IMO, yes.

      Delete
  31. Thanks for that quick reply john, much appreciated. I'll save the j201 for my preamp builds.

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  32. I think I'm right on the clipping, as it would need a connection at the cap there and to ground, we'll see! haha

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  33. Hi folks, this is my first shot at building a stompbox from this site and I'm having a bash at building this pedal but have noticed that my IC is an OP07E as opposed to the OP07CP (listed in one of the posts in this thread as a suitable replacement for the LM308). Does the difference in the letters (OP07E vs OP07CP) mean my OP07E chip is unsuitable for this task? I know literally nothing a about ICs so any help would be great. Cheers

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  34. Got it working, sounds amazing, Now, correct me if I'm wrong here, but I'm fairly sure you could get a 3130EZ to work in this circuit without the squeal/oscillation with a larger compensation cap, like 100p, This seems to be what bjorn did with the dyna red, or am I way off with this?

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    Replies
    1. Yes the 3130 should work in this, as should the NE5534. But some people swear that the Rat doesn't sound like a Rat without the LM308 so it's probably a case of swapping and seeing what you think.

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  35. Without changing the compensation cap, it hows like a banshee! lol. Another great layout mark!

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  36. This comment has been removed by the author.

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  37. Hi again, I've had a second shot at building the Rat after a failed attempt earlier in the week. I hooked the board up to my breakout box to test it but am still only getting the clean/bypassed signal and silence when I engage the effect.

    I'm using a 2N5458 as specified in the diagram, but I've had to substitute the IC for an OP07CP as I don't have an LM308, the OP07 was listed as a suitable alternative for the 308 in one of the posts above. I also had to sub the 30pF cap for a 33pF one and the 3n3 for a 4n7 as I didn't have any caps in those exact values, so I used the nearest thing I had. I can't imagine the cap values would change anything too drastically but thought I'd include all my changes/substitutions for the sake of completeness.

    I notice that there is a ground wire coming off the board and a ground wire coming from Vol 1, I have soldered the wire from Vol 1 to the ground rail; that's right....right?

    Here's a link to the set of pics I took as I was building it,
    http://imageshack.us/g/1/9909836/ <-- the board is 21 columns wide, rather than the specified 20, so don't let that throw you off.

    Any advice would be great as I'm getting a bit frustrated now....IvIark? Mirosol? Anyone? cheers in advance

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    Replies
    1. You've built it mirrored right to left, why have you done that? It can't work like that with an opamp effect because they pin numbers aren't vertically symmetrical like with a transistor.

      Delete
  38. AH ok, misinterpreted the diagram. noob mistake, my bad thanks for the help. Will post again once I've done another. cheers

    ReplyDelete
    Replies
    1. yup, I forgot to flip the diagram of the copper side. Silly me :-S

      Delete
    2. Finished the board yesterday and hooked it up to my breakout box. Works a treat, just need to hook it up to a proper amp to give it a test rather than the nasty little solid state 10w I have on my desk. Next stop, boxing up. Thanks Mark!

      Delete
  39. What's the best way to wire the links? On the build guide they're shown going under the IC, but I can't seem to make that fit too well?

    ReplyDelete
    Replies
    1. Use the discarded cut offs from resistors. Then you don't have to do anything special like cut wires to length, and the links are very thin which should easily allow ICs to go over the top. You will find it even easier if you use IC sockets because they have a small gap underneath which allows links to be present, whilst still allowing the socket to sit flat to the board.

      Delete
    2. Ah, I see. I'll give it a go when I get back. Thanks for the reply, I look forward to putting it all together!

      Delete
    3. Just finished this up (Waiting for parts and Christmas slowed me down!) and it sounds great. Played it through a Twin with a Strat and an SG, and it turned it into a monster.

      Onto the next one!

      Delete
  40. I had a go at making this, but I am getting no sound when engaged.

    I don't think it's the offboard wiring as I have double checked that according to a few 3PDT wiring diagrams. Also the LED works fine as does bypass.

    I did find a bad looking solder joint so I fixed that,, as well as made sure I had no continuity between strips. I have front and back pics here:

    http://i143.photobucket.com/albums/r154/ritchieiommi/20121222_173222.jpg

    http://i143.photobucket.com/albums/r154/ritchieiommi/20121222_173033.jpg

    Also despite how it looks that blue wire on the bottom left is not bridging, I check with the meter.

    IC, FET and Diodes are exactly the same as what is listed in the diagram.
    If someone could help me that'd be awesome.

    ReplyDelete
    Replies
    1. Good morning.

      For starters, you're missing one 4µ7 altogeher. Also, i would desolder all the wires, clean those up and take them through the holes. Soldering them to strip surface is one of the suspects.
      +m

      Delete
    2. Sorry, the images are oriented strangely.

      I have fixed it, here are the new links:

      http://i143.photobucket.com/albums/r154/ritchieiommi/20121222_173222-1.jpg

      http://i143.photobucket.com/albums/r154/ritchieiommi/20121222_173033-1.jpg

      Delete
    3. Well, that's embarrasing. What a stupid mistake haha.

      Thanks mirosol, I'll put in the second 4u7 in soon and let you know how it goes.

      Also I have no idea why I didn't think to put them through the holes in the first place :S I'll be doing that in future for sure.

      Delete
    4. I can also see that your iron runs a bit too hot and burns the board. I've had some occasions there solder must have flowed inside the board fiber layers - making in unrepairable.

      If you have the parts, i think a slow, careful rebuild wouldn't be that bad of an option..

      But basically missing that 4µ7 prevents the signal from getting in to clipping and filter stages - so it just stays amplified at the IC pin 6 and that 1K resistor.

      Hope you can get it running...
      +m

      Delete
  41. Yeah the iron is way too hot. When I put the capacitor in I actually managed to take the copper off the board; so had to re-bridge it with a resistor leg. I did have a less powerful iron but it recently stopped working, maybe I should get another. Is there any you can recommend that isn't too expensive?

    I put the 4u7 capacitor in and unfortunately, I still have nothing. I'm thinking starting over again is a plan too, I'll have to buy new parts but at least the LM308 is socketed so won't have to spend the money on another one of those.

    Thanks for all your help with this.

    ReplyDelete
    Replies
    1. If you are in europe, musikding has very cheap analog controllable soldering station...
      +m

      Delete
    2. Nah I'm in Australia. I ended up buying myself a good soldering station though, and a guy from work has offered to help me with my soldering after Christmas. I'll let you know how my second attempt goes.

      Delete
  42. I just noticed in the comments some voltage readings on the IC and JFET, so I thought I'd read mine. I did this by putting the negative lead on my multimeter on the sleeve of the output jack, then touched each of the pins with the positive lead; I got very different results to the other two people:


    Maximum distortion:

    IC:

    1 = 8.45
    2 = 8.24
    3 = 4.65
    4 = 0.00
    5 = 9.11
    6 = 9.37
    7 = 8.74
    8 = 0.00

    JFet;

    D = 9.36
    s = 1.63
    G = 0.00

    Minimum distortion:

    IC:

    1 = 8.47
    2 = 8.74
    3 = 4.67
    4 = 0.00
    5 = 9.12
    6 = 9.36
    7 = 8.74
    8 = 0.00

    JFet:

    D = 9.37
    S = 1.63
    G = 0.00

    Does this indicate a faulty IC or have I done something stupid?

    ReplyDelete
    Replies
    1. Well I'm an idiot, I got the pin order wrong, it's actually:

      Maximum distortion:

      IC:

      1 = 8.45
      2 = 8.24
      3 = 4.65
      4 = 0.00
      5 = 0.00
      6 = 8.74
      7 = 9.37
      8 = 9.11

      JFet;

      D = 9.36
      s = 1.63
      G = 0.00

      Minimum distortion:

      IC:

      1 = 8.47
      2 = 8.74
      3 = 4.67
      4 = 0.00
      5 = 0.00
      6 = 8.74
      7 = 9.36
      8 = 9.12

      JFet:

      D = 9.37
      S = 1.63
      G = 0.00

      I think that makes a bit more sense, but still is a bit different.

      Delete
  43. I've built this and it works...however the volume output is very quiet. At max volume its probably about 20% of the volume when the pedal is bypassed. I have tried changing the orientation of the transistor and it actually makes no difference to the sound, and also tried another transistor - a clue for anyone? Any ideas what might be up? Cheers.

    ReplyDelete
    Replies
    1. Tiny solder bridge somewhere would be my first guess. Part of the signal could get dumped to ground. You should also triple check all the component positions, links and cuts.
      +m

      Delete
    2. You were right, i thought i had them all but after triple checking again i found a tiny bridge and it roared into life. Thanks +m!

      Delete
  44. This is an interesting document about all the RAT version, seems to be the "real" correct layout! Will be great to add to the collection!

    http://www.aronnelson.com/gallery/main.php/v/diyuser/GGBB/Multi-RAT.png.html?g2_imageViewsIndex=1

    ReplyDelete
  45. was doing some research on ic substitutes for this and ran accross
    http://www.diystompboxes.com/smfforum/index.php?action=printpage;topic=33493.0

    "If you do use a TL071, omit that 30pF cap between Pin 1 & 8. The TL071 is internally compensated, and that cap on that the LM308 requires isn't required with the TL071. And, IIRC, the cap that is internal to the TL071 is around 30pF as well. I think it was 27pF."

    so if i undertand this correctly if you use the tl071 eliminate the 30 pf cap and the link betwean 9,2 and 9,3. Does this sound right

    ReplyDelete
    Replies
    1. Yes, most single opamps have internal compensation. As you say the LM308 has it between pins 1 and 8, the NE5534 has it between pins 5 and 8.

      Delete
  46. Just finished two boards.. And as a hint, someone may want to have linear pot for filter - and swap lugs 1 & 3 with each other. Better and more conventional tone control. Still a classic. And a good one.
    +m

    ReplyDelete
  47. hi folks. ive been using the Rat i built from this project for a little while, but just now when i got it out for a jam i noticed i dont get any clean sound at all. the pedal is great when it's switched on but i get no sound when i click it back to clean. can anyone shed some light on this please? cheers

    ReplyDelete
    Replies
    1. Problem sorted. I'm not sure what was causing the problem but I insulated the back of the pots and repositioned the board so it couldn't touch the case. I also noticed that the tip section of the jack socket on the input was bent outta shape meaning there wasn't the best contact between jack and socket. Gigged it the other day and it stood up to the task rather well :)

      Delete
  48. Hello! I've just finished this project and it sounds really well except for a really big problem with the overall noise when I'm not playing. When the distortion pot is at its maximum level, this noise is unbearable.
    A strange thing I noticed is that when I'm using a sound device (for example an mp3 or my cellphone) instead of an instrument, I don't have this noise problem.

    Do you think it can be solved using an accurately-shielded patch cord? Would it make any difference if I replaced the LM308 with a TL072?
    I also replaced the 2N5458 with the 2SK30A. Do you think it has something to do?

    Thank you very much for this wonderful page for diyers ^^.

    ReplyDelete
    Replies
    1. I also have to add that it makes that destroying sound when there is nothing connected to it. O.o

      Delete
  49. Hi mates,

    I've just built this effect. I did it just to A/B it with my original modern production Rat2 with LM308.

    Had no idea of boxin' it, but after tryin' both.... The tone is very similar in both, but while the modern gets really harsh on highs, this one sounds much more mellow and smooth, really loved it.

    So I have now to fit it in a 1590A, really great sounding effect.

    By the way, just to tell you that Filter wires are swapped, in the RAT lows -> CW, Highs CCW.

    BR

    ReplyDelete
  50. Hi guys,

    I've built mine all to spec, but its really quiet.
    Ivedone a few tests and everything seems fine and not dodgy soldering.

    Any ideas? maybe the JFET is the problem?

    ReplyDelete
  51. I'm really stuck with this. When bypassed everything sounds fine but when I enable the effect I get dead silence.

    I read the voltages of the IC and the JFET. This was done by connecting the negative lead to the enclosure. The power supply is a standard adapter that has the negative soldered to the ground. The input is still a stereo jack because that's all I had but the ring is not connected to anything. The results are here:

    Power Supply: 9.13

    Maximum

    IC:

    1 = 8.37
    2 = 4.55
    3 = 2.20
    4 & 5 = 0.00
    6 = 4.91 (gradually built up to this)
    7 = 9.11
    8 = 4.80

    JFet:

    D = 9.10
    s = 1.43
    G = 0.00

    Minimum

    IC:

    1 = 8.37
    2 = 4.54
    3 = 2.20
    4 & 5 = 0.00
    6 = 4.54
    7 = 9.11
    8 = 4.61

    JFet:

    D = 9.11
    S = 1.43
    G = 0.00


    I also have photos here:

    https://www.dropbox.com/s/hhyo7aex4bc4mis/20131014_185810.jpg

    https://www.dropbox.com/s/ztj35z1uzo8bta9/20131014_192549.jpg

    Sorry about the terrible quality of the second picture, I could not get it to focus.

    ReplyDelete
    Replies
    1. I would take a knife or hacksaw and run it in between the tracks to separate any possible bridges. And is the 100uf (far right) the correct way around? hard to see in the pic. I'd also socket the jfet/transistors next time around.

      Delete
    2. You're right. That capacitor was in backwards haha. But I still have the same problem. I have used a knife in each of the tracks and I can't find any bridges with my multimeter.

      Also I have noticed that I do in fact have sound but it is -very- quiet. As in I need to crank the master volume on a 30w valve amp to hear even a slight bit of sound with the distortion and volume of the pedal at full.

      Also I will use sockets in future, thanks for the tip.

      Delete
    3. Hi Nathan, when I first built mine it was quiet then I realised I was using a 2n5088 by mistake, swapped this for a 2N5458 and worked a treat!

      Delete
    4. Thanks for the tip but the transistor is a 2N5458. I actually had another look last night and noticed that I've had the 100uf cap connected to the source of the JFET instead of the drain. I'm going to guess that is my problem. When I get a chance to fix that I'll update here.

      Delete
    5. Well I replaced that capacitor with a new one. It is the right way round and in the right holes now but the effect is still quiet. It comes through clearly enough, but at full volume on the pedal you have to crank the master volume all the way to hear it. I have triple checked for bridges across tracks but cant find any, I have cut between the tracks using a knife anyway to make sure.

      I have redone the voltages and the results are very similar. I'm going to try an audio probe next, but does anyone have any idea what my problem could be?

      Delete
  52. Any idea how to mod this to have a Gate?

    I have read that the Big Muff Deluxe Gate mod was replacing the resistor connect Ground to the Q with a pot, so in this case the 1M resistor. - Think it would work?

    Thanks,
    Steve

    ReplyDelete
  53. If I wanted to add the overdrive mod, such as this:

    http://www.beavisaudio.com/projects/FKR/images/MightierMouse.gif

    How would I wire it up, to add the option of Diodes, MOSFET, and LED as 3 separate choices?

    ReplyDelete
  54. This comment has been removed by the author.

    ReplyDelete
  55. Is it cool to use a LM308AN?

    xoxo,
    Upthepunxx!

    ReplyDelete
    Replies
    1. That's ok (probably you figured it out yourself too already...)

      Delete
  56. Built it today. Really nice, worked first time, thanks for the layout Mark. Some notes:

    1) LM308, OP07 work just fine. OP07 has a bit tighter sound, but less distortion while LM308 is a bit looser but fuzzier. TL071 squealed like a dying pig. Maybe it could be healed by removing the 30pF compensation cap, but I didn't bother since I have LM308 and OP07 both.

    2) Lowering the 3n3 to 2n2 gave me better tone (Filter) range, but don't overdo it, 1n is already too harsh I think.

    3) The output buffer can be any JFET, you don't need to change the 10k source resistor (it can actually be anything from about 5k to 50k, maybe even more). I even tried a BJT and that worked too, though the level dropped to an unusable level. Probably it would be possible to find a good emitter resistor value if you wanted to go for BJTs instead of using your precious JFET reserves. I had a J111 lying around that I couldn't use for anything else anyways.

    4) If you find that it does not have enough bass (maybe if you are a bass player, for guitar I find it too bassy actually...) you can increase the 2u2 on the left, the 4u7 on the left (next to the 30pF cap) and the 22n on the right (over the clipping diodes)

    ReplyDelete
  57. Here's a link to current production National Semiconductor LM308N. Texas Instruments owns National Semiconductor but still makes parts. You can get 10 for 6.95US with free shipping on Ebay.

    http://m.ebay.ca/itm/251336843370?nav=SEARCH&sbk=1

    ReplyDelete
  58. Actually they're not current production, sorry. Texas Instruments bought National Semiconductor and has discontinued their product line. These are listed as 'obsolete'. I guess there's some old stock kicking around on ebay.

    ReplyDelete
    Replies
    1. Many places still have LM308N in stock, but they're quite expensive, where I live I can get them for about 2 USD per piece. Another option could be OP07, I've found almost no difference between the two in the Rat circuit. They are about 0,5 USD where I live, that is much more acceptable. And I think OP07 is still produced too.

      Delete
  59. I just built this today based on your layout. I used a TL070 with a 100pf comp cap. Great layout if worked perfectly on the first test without any troubleshooting. It sounds amazingly clean and crisp however it's a little under unity. I'm not certain if my opamp choice is to blame for the level drop of if I should just try out an lpb1 booster before or after the proco. I may replace the transistor just to see if I got a dark one.

    ReplyDelete
  60. I was made this project but I dont hear filter.tone is on this same level.Im used 1uF but electrolitic capacitors (orginally is ceramic).My question: do I must change this two electrolitic for ceramics and then is ok with the tone? thanks from sławek

    ReplyDelete
    Replies
    1. Same problem over here... i do like it's sound but some tone control would be nice...

      Delete
  61. First build in a long time, seem to have hit a wall. No signal, at all.

    IC voltages:

    1. 0,92
    2.0,20
    3. 0
    4. 0
    5. 0
    6, 4,47
    7. 8,74
    8. 0,01

    Fet Voltages:

    D: 8,74
    S: 1,31
    G: 0

    Pics from both sides of the board:

    https://db.tt/pCTlwPGt

    https://db.tt/Y6ZOeXVV

    Thanks in advance for any and all help. sorry for the congested board, I failed to mention that metalfoil resistors would be fine...

    ReplyDelete
  62. hey guys. can i replace the 2n5458 with a j310 ?
    thanks in advance

    ReplyDelete
    Replies
    1. Hi Roy.
      I'm not familiar with that part number and i couldn't find any reference of J301 being a JFET. Are you sure it's J301?
      +m

      Delete
    2. hi miro! roy said j310!
      i haven't seen that too. but it seems it would be ok. pretty much the same general characteristics (from a quick look)

      Delete
    3. Yes I've got some J310's too, there's just about the only Fairchild JFET you can still buy in decent quantity from dpi4parts on eBay. With it just being a buffer it should work fine without having to tweak anything.

      Delete
    4. My bad. :)

      What's more interesting, ONsemi lists J310 as active.
      http://www.onsemi.com/PowerSolutions/product.do?id=J310
      I guess i'll wait for the next payday and source enough. They don't need to be as high gain as J201, but if they perform even remotely close i think our problems for building trimmered JFET overdrives are gone - for now.
      +m

      Delete
    5. thanks for the response everybody :)
      i finished building the thing but now i can't seem to locate any of the 20 j310 i ordered a while back. what i do have is a bunch of other transistors.
      can u think of any popular ones that would sound similar ?

      Delete
    6. It's just an buffer at the output, so any JFET will work just fine. Just mind the pinout.
      +m

      Delete
    7. i have used a j201.
      the sound im getting is very low volume clean sound with the volume knob at min or max position with no sound in between.
      no apparent change while moving the filter or gain knob.

      if i wont be able to fix this it will be my third failed build in a row :(
      could it be the transistor or should i look somewhere else ?

      Delete
    8. IMO, you must have an error in your build somewhere.

      Delete
    9. Sounds like volume pot's sweeper is grounded. My bet is on a short where there shouldn't be one.
      +m

      Delete
    10. finally i was able to repair everything and its working now.
      i used a 2n5457 transistor and it really sounds awesome.
      thanks :D

      Delete
  63. Hi I have just built the Rat and it sounds great except I have a high frequency sound when the distortion is set over 75% and the effect is off so the only thing you guys have been able to do to stop it is switch ICs?
    https://www.dropbox.com/sc/b3wrxqld98aqevm/AABeU0Ndhuql0fOIA1BWwnjra

    ReplyDelete
    Replies
    1. Try increasing the value of the 100p cap and see if that tames it enough. Maybe socket it so you can try 220p and then up it if necessary

      Delete
  64. You're hearing the high frequency in the bypass signal? Are you using input grounded true bypass switching?

    ReplyDelete
  65. I noticed the frequency started when the gain pot was at about 22 or 23 k so i figured a paralell resistance for 100k and jumped a 27k resistor between the gain pot I get a little less gain but it is plenty distorted and the high frequency is gone I had four other 308s and they all gave me the3 same scenario btw what did you think of the custom air brush job?
    https://www.dropbox.com/s/90w2of3usjyevmf/2014-09-11%2004.10.38.jpg?dl=0

    ReplyDelete
  66. Just about to start building this project but I notice that the "slightly more compact" layout includes a 47u capacitor not found on the top layout. Is it supposed to be missing? Does it have any sonic impact on the build? Thanks!

    ReplyDelete
    Replies
    1. It's a filter cap for vref which was only 1u in the original layout. I have increased it to a value we see more commonly for a cap in that position and that should do the job better, but use either value if you prefer.

      Delete
    2. Just finished the "less compact" version (my very first vero build) and it worked like a charm...well, truth be told, it didn't work on the FIRST try but I'm 99% sure that's because my vero was shorting on the case or pots due to the tight vertical squeeze. I put some electrical tape over my pots and everything worked in full Rat glory. Thanks for posting and for answering my original questions. I can hardly wait to tackle the NPN silicon Tone Bender now! One quick question if I may...does it make sense for me to be finding "unity" at about 12:00 on the Volume knob? I'm OK with that but just wondered if I might be supposed to get more volume out of this thing with the volume knob below 12:00 than I currently do...

      Delete
  67. thank u very much for the lay out and the detailed replies to the comments .. just built me one with odd mods . loving it .. cherio
    hitech

    ReplyDelete
  68. I built mine using tl071, j201. Works fine, no squeeling at all. If youre using tl071 omit the 30p and the link at 9.2 to 9.3. Use a trimmer to adjust the jfet, I used a 25k.
    Build it right and use good wires to yhe pots and theres no squeel ;)

    Cheers Mortua

    ReplyDelete
  69. Succesfully built this one, and I'd recommend using a voltage doubler if you want the opamp clipping to be reduced a bit, that helps getting a more precise distortion, not so much into fuzz anymore. Use a switch if you want to move from 9V to 18V at will.
    I'd also recommend socketing the 47R and 560R resistors from pin2 of the LM308: removing the 47R is the Ruetz mod, playing with the value of the resistor will let you shift the mid bump. I have left it stock. Replacing the 560R with something closer to 330R will shift the high pass from 60Hz to 100Hz, which will refill the low end a bit, without being muddy. Kind of like a little "humpf" that is kind of missing with the stock value, useful, I dare say, if you are not using your pedal through a 4x12 cabinet... ^^ I had a 360R at hand and it did the job perfectly fir me. :)

    ReplyDelete
  70. Is it possible that u provide a part list for complete newbys like me ?

    kind regards,
    jelle

    ReplyDelete
  71. No sound is coming through, my voltages are really high on both the ic and the transistor and the gain isn't affecting them. Should I keep looking for an unwanted bridge?

    ReplyDelete
  72. Verified!
    I'm using a j201 on the output section. Volume reaches unity at about 7 of 10.
    Had an old can of uA308HC laying about, so I used it instead of the lmXXXN package.
    The diodes are Ge with a Vf of 0.17v. It clips early and it clips often. I was thinking about dropping something 0.4ish on one side or the other, see if the distortion is nice or awful (it'll be one or the other, I'm sure).
    I love the sound when the filter is about 5 or 6 and the dist is lowish (like this thing has "lowish") and the vol is cranked.

    Is there anything specifically that can be done about the noise? I know it's a high gain circuit and noise happens, but it hisses. The hiss drops out when I start playing, but the guitar/pedal/amp circuit is prone to hissing and oscillation. The oscillation is nice, actually, but the hissing is kinda annoying.

    ReplyDelete
  73. Hi!

    First timer... build the board because the kit I've got didn't work with the Ruetz Mod. Guess what? I built the board and it works... but not the ruetz mod. Making me CRAZY. Maybe someone can help me to solve this as I tried pretty much everything.

    Just using a spst switch to cut the 47R + it's cap. What I get is a clean sound. I did mod it with a 3p4t for more diode options and that works flawlessly.... also tried the ruetz without the Multi Rat Mod.

    The only difference to the Vero Schematic is Q1 which is a 2n5457... tried another IC to see if my opamp is bad but it's not and as mentioned... the ruetz didn't work with another board... what the hell am I doing wrong :)?

    ReplyDelete
    Replies
    1. when you swapped IC's are you using another single opamp, not a dual? also, did you swap IC's or the FET, 2n5457? how did you wiring the switch? did you move one end of the 47R resistor and cap to add the wire to the switch, and take the middle lug of the switch and attach it to the place where the cap and resistor should have ended? you may have wired the switch wrong.

      Delete
  74. Hey Zach, thanks for getting back.

    I use the lm308n and a 2n5457. The transistor is from the old board and will be replaced by another one today.

    I doubt the switch was wired the wrong way (on off switch with only two lugs). I used sockets with the 47R to test if the ruetz mod works. When I pulled the leg of the resistor that is connected to the opamp I had the same result as when I used the switch in off position: clean guitar sound and the pots don't react much.

    Wiring for the switch: 47R is connected to the outer lug. Resistor is then connected with a wire to the second row from bottom that connects to the cap. Middle lug is connected via wire to the row that connects to the opamp. Testing it with a dmm it does what it's supposed to do.

    ReplyDelete
    Replies
    1. well i did some research on the ruetz mod and here's what i found out.

      "Cutting the 47 ohm/2.2uf pair out of the circuit means that the gain and frequency response of the circuit is determined solely by the 560 ohm/4.7uf pair. This lowers the overall gain of the circuit, but also smooths out the overall frequency respone of the circuit: the amount of gain is flat across low-end to high-end. "

      that makes me think it should be much cleaner then when the resistor/cap are in the circuit. it it completely clean signal when you remove them from the circuit? how does it sound when the resistor is in the circuit like normal?

      i found a few videos on youtube that have rats with this mod, and they do have lower gain, but the controls do affect the signal and it's not completely clean.

      Delete
    2. It's more like a total bypass. When I still had my old board kit in it with the ruetz mod installed, I was shaking it and it actually worked for a second. I thought it might be a bad part or something. But it's strange the problem translated to the vero layout. It works flawlessly besides this so I start to think the box itself might be the problem... i that's possible at all? Maybe the wiring of the bypass switch could be a problem? I really don't know.

      Delete
    3. I connected the bypass switch like in the offboard wiring guide and it didn't help.

      Delete
    4. Rewired the switch like in the offboard wiring guide. Didn't help though. Controlled all my soldering for bridges or lose parts. Seems to be absolutely fine. The only part I couldn't replace it's the transistor as I don't have a replacement.

      Delete
    5. Rewired the switch like in the offboard wiring guide. Didn't help though. Controlled all my soldering for bridges or lose parts. Seems to be absolutely fine. The only part I couldn't replace it's the transistor as I don't have a replacement.

      Delete
    6. something is really off. if you giggled the board and it worked, that leads me to believe you've got a bad solder joint at one of the wires. can you take good pictures and post them so i can take a look?

      Delete
  75. Sure thing: https://www.dropbox.com/sh/xyh69vpw87l7cep/AADQ_Sx9D2UFXkVAN0Laz4Q4a?dl=0

    Please don't mind the extras in there. I added a rotary switch for diode switching and a high/lowpassfilter. They don't affect the ruetz mod as it didn't work when I took all the mods out either.

    ReplyDelete
  76. Oh and the shaking was with the old board. Not the new vero one.

    ReplyDelete
  77. I'm such an idiot. I found the problem. I wired the 4,7uf cap wrong. Stupid me. Working now. THANKS for your support, Zach.

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    Replies
    1. lol. no problem buddy, glad you were able to get it working. shit like that happens all the time.

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    2. Now I need to get that lpf to work correctly. It does work, but as soon as it's connected to the board I will lose some highs. I hope to make it transparent when it's turned all the way up. Where could I get support with that?

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    3. that's actually how a low pass filter works. what it does is cut the frequencies at a certain frequency and allows the lows to pass through. a high pass filter is the opposite, it cuts the frequencies at a certain frequency and allows the highs to pass through.

      what you can do if you're not happy with the frequencies that gets cuts you can raise either the resistor to capacitor values in the filter. by changing these values you'll also affect the amount of gain you'll get. so for instance if you raise the resistor, you may want to lower the cap to keep the gain about the same.

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  78. Zach, I think I didn't explain myself well enough. I use a variable lpf and hpf with their own pot. The hpf works flawlessly. As soon as I install the lpf the high frequencies will drop a little with the pot turned all the way up. I want it to sound like the stock Rat when the pot is turned all the way to the right and shift the high cut by turning the pot to the left. I'm using a 10k pot with a 15nf cap tied to ground. As I said it does work but I can't dial in the stock sound anymore.

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