Saturday, 23 June 2012

EHX 73 Rams Head Big Muff

Another request, there you go Vince! :o)   From a 1974 Electro Harmonix ad:

This fine distortion device is high on sustain and low on distortion.  It is designed for the guitarist who wants his axe to sing like a hummingbird, with sweet violin-like sustaining sound.  The sustain control allows you to optimize long sustain with a hint of harmonic distortion.  Jimi Hendrix relied on the Big Muff for his smooth, mellow, supple Electric Lady sound.








BUY A KIT

145 comments:

  1. Excellent mate! thanks!. Had to order some 1n5817's.. but I'll make the majority of it up tomorrow... switch too!! you read my mind ;o)

    ReplyDelete
    Replies
    1. You don't absolutely need the 1N5817s. It's just for polarity protection so if you're not bothered just take the supply straight to row 9 on either the left or right hand side. Or you could use a 1N4001 if you want but there will be more of a voltage drop.

      Delete
    2. Hmm this is where my OCD kicks in as his HAS to be as it is in the layout lol... I'll do it without and I can always throw one in when they arrive ;o)

      Delete
    3. We if you're worried about authenticity, they were very unlikely to use 1N5817s when this was produced, I just included that one because it would be preferable now because you get a lower voltage drop out of schottky diodes. They'd have been more likely to use a 1N4001 or maybe none at all because the details of any supply related components wasn't shown in the schematic I used.

      Delete
    4. Check this post out and tailor your muff to what you want. Thanks to lvlark for the fantastic vero!
      http://www.diystompboxes.com/smfforum/index.php?topic=88048.0

      Delete
  2. I cant comment on the layout, but here is a spreadsheet with the component values for 12 different flavors of big muff, based on the kit rae schematics.
    http://img812.imageshack.us/img812/4306/muffvariantsbig.png (original source: http://www.flickr.com/photos/thetonyballs)
    If you get bored you can socket some of the more tone-critical components and make your own mutant muff.

    ReplyDelete
  3. Verified.

    This is what you get when you go to bed at 10 o'clock at saturday evening and wake up at 7 :)

    Works and is just as boring as 73 ram's head is supposed to be :) Other reason why this didn't impress me at all was the fact that i happened to test out the Green Russian first...

    For those a bit more exotic components, i used two 2nF ceramics in parallel to get 4nF and for those 7K5 i just put in 5K1 and 2K4 in series. For transistors i just put in four 2N5089s.. Works ok, but i think i might experiment with some much lower hfe transistors on this soon. If that would give out some more cream.
    +m

    ReplyDelete
    Replies
    1. Excellent, nice one. 300 here we come! :o)

      Delete
    2. hello
      you followed an order to place the transistor hfe?

      Delete
    3. Look for something around 650-700hfe for all transistors

      Delete
  4. Finished this this morning and have just been jamming with drummer and bassist with it and lord yes! THIS was the muff I've been wanting! I made the green russian too and to me that was just another fat muff.. nothing special.. This however has far more grit and teeth to it.. great for palm muting stoner riffs!... It also gently blends into glorious feedback as the note slowly dies out. This is staying ;o)

    Cheers Mark.

    ReplyDelete
    Replies
    1. Good stuff. Well you two have had a very productive day while I've been sat watching Scooby Doo 2 with my daughter. Brain is numb! :o)

      Delete
    2. Haha... my son has been running around the rehearsal room in a spiderman suit with ear defenders on!... He'll either grow to love the guitar or hate it!

      Delete
  5. The DPDT is on-off-on right?

    ReplyDelete
  6. If I want to build this without the switch, would I just hook up the Sw1 wire to Tone 3?

    ReplyDelete
    Replies
    1. Just omit the switch and Sw1 wire, that leaves everything stock. It may still be worth socketing the 4n cap though, then you can increase it slightly if it's a bit too scooped, or even reduce it slightly if you want it more scooped. At least then you'll have the ability to fine tune it to your own tastes even without the switch.

      Delete
  7. Built the pedal and left out the sw1 wire. Pedal works great but seems to be very loud compared to when bypassed. Is this normal for this pedal? If so any thoughts on how to lower the overall output.

    ReplyDelete
    Replies
    1. Very loud where in the volume control? I've got a couple of Muffs which are at unity at around 10 o'clock and so at half way they seem very loud.

      Delete
    2. Ok. Then it's nothing I did wrong. I'm used to tubescreamers, ect., where you turn them up to 3 oclock to get unity. 10 oclock is where is was getting unity so it must be the way that pedal it. Thanks

      Delete
  8. I don't suppose anyone has an idea of which components control bass and treble? fancy having a play with it some more...

    ReplyDelete
    Replies
    1. Tone section has these five comps round the tone pot:
      Caps: 4n, 100n and 10n
      resistors: 22K and 39K

      Other place to go would probably be 10µ+47K filter at the input..
      +m

      Delete
    2. You can also increase the size of the 100n blocking caps to "cut out" some of bass all together.

      Delete
  9. If I wanted to make the clipping in stage 2? switchable, would I put the wires from?

    ReplyDelete
    Replies
    1. In the second stage or the second clipping stage (actually the third stage)?

      Delete
  10. second clipping stage :) thanks for the super quick replies!

    ReplyDelete
    Replies
    1. Take out the diodes and if you imagine a 2 position on/on DPDT switch like this:

      1----4
      2----5
      3----6

      Solder the diode pair between 1 and 4, then take a wire from 2 to the the row below the Tone 2 wire (that the bottom of the 100n from Q3 base is connected to). Then connect 5 to the Sw1 lug on the cap switch. 3 and 6 remain unconnected.

      Delete
  11. ok got it wired up, now I get bypassed signal, and when i turn it on it will hum if I touch the board. I have continuity between the input jack switch and board.but not between the input and output of the board. I tooke some pictures, maybe I'm missing something.. http://a8.sphotos.ak.fbcdn.net/hphotos-ak-ash3/523244_10151153724743988_656796009_n.jpg

    http://a2.sphotos.ak.fbcdn.net/hphotos-ak-prn1/534387_10151153724978988_940420139_n.jpg

    http://a5.sphotos.ak.fbcdn.net/hphotos-ak-prn1/557524_10151153725318988_244667940_n.jpg

    ReplyDelete
  12. Finished another one and I'm getting really weak/starved gain/sustain. Tried loads of transistors etc. Just wondered if there were any obvious components around the gain stage that I could swap as I suspect yet another dodgy component.

    ReplyDelete
    Replies
    1. It's not just round the gain stages though, it could be anywhere. Are there any components in common with the Rah? Just wondering if you've got a dodgy batch of something.

      Delete
    2. Hmmm not really sure, It could be loads of them then, Oh well, back to scratch!

      Delete
    3. Check the voltages first mate, that'll give a better idea than just listening to the results

      Delete
    4. Here we go;

      Q1 = e,0.04 b,0.64 c,3.93

      Q2 = e,0 b,0 c,8.64

      Q3 = e,0 b,0.59 c,6.32

      Q4 = e,1.15 b,1.63 c,4.52

      Delete
    5. Q2 looks like a problem to me, no way it should have 8.64V on the collector with a 12K resistor. Check around there mate.

      Delete
    6. You have something slightly wrong in there. FSB thread: http://www.freestompboxes.org/viewtopic.php?f=19&t=2925&start=40

      Seems to me like Q2 base would need to be around 0,5V, so if you have a bridge somewhere that grounds it, that could be the cause of your behaviour. So. Check all the connections, traces and cuts around and near Q2 base for starters. You could also check if that transistor measures correctly on your DMM...
      +m

      Delete
    7. Ok, nice one. I'll have look tomorrow

      Cheers mate ;)

      Delete
    8. And thanks Miro for the link, Well I've knifed it, all components are exact so I guess theres failure somewhere and rather than waste further parts by switching I may as well rebuild.. arrghh! these are the times this hobby tests me ;)

      Delete
  13. Well, I got this one finished!

    Q1 is mpsa18, q2-3 are 4401, and q4 is 5088.
    d1 and d2 are 3mm blue leds
    and I made d3-d4 switchable between 4 914's or 2 2n7000.
    This. thing. sounds. HUGE.
    I also swapped output cap to 1u and input to .18
    And have the switch set up for scooped, boosted, and really boosted. with a 10n and 33n.
    Any other mods Ya'll think would work well?

    ReplyDelete
  14. Just a question, not very related to the effect circuit itself but...... do you know where to buy this kind of knobs?, round with a little pointer and not being original MXR's at 3 euro each if possible :P

    ReplyDelete
    Replies
    1. Check Musikding and Banzai. Both offer those cheaper than 3€. Ebay wasn't very helpful as it offered only beaded(?) knobs.
      +m

      Delete
    2. Thanks Miro, you're right. I always tend to forget Banzai and Musikding whenever I look at their s&h costs, or when they take 3 weeks in sending your order because they always have some item in backorder. Not to mention when they totally mistake your components :P

      BR!

      Delete
    3. :) You're right. But they are only people too, and both have pretty nice staff to take care the issues that comes along with shipping the wrong stuff. Shouldn't happen that often as it does but i'm still a customer...
      +m

      Delete
    4. Hi,

      I did find these kind of knobs on https://www.mammothelectronics.com/ (Oklahoma), cheaper than in many other webs. Very low international s&h using First Class mail if you buy knobs, trannies, and other little components.

      Let's say that 6 knobs + s&h have been finally 6,40 euros. Ordered on Nov 14 and received today. I think is a good alternative to get knobs and small components without being ripped off with s&h and high prices. Will get more stuff from them for sure.

      BR

      Delete
  15. I want to build this as my first pedal and I am ordering the kit from Bitsbox. I am also going to order all other neccessary parts at bitsbox.
    I already figured that I buy the 16/02 cables. My only problem is I really don't know which 1/4 Jack sockets to buy( mono/stero, switched/unswitched, open?) and which ABS Box I should buy. The Kit says (Stripboard 64x95mm wich is 24*36 holes or something like that) but there is only a 18*17 holes stripboard needed.
    The original size of 261x96x150mm seems kind of oversized and also isn't available.
    I also don't know which power supply I should get.

    ReplyDelete
    Replies
    1. If you intend to use a battery as well as a DC adapter then you'll need 1 x stereo and 1 x mono sockets. If you're not bothered about the battery then 2 x mono sockets will do.

      Yes only 18x17 holes are needed, but Bitsbox of course have to provide the next size up in their standard stripboard which in this case is 24x36. You will need to cut it down to size, and you will be left with a bit over which you could make a couple of extra pedals out of.

      ABS boxes won't offering any shielding against noise and so especially for something like this I would prefer not to use one. But if you do want ABS box it would fit in an EN002, or opt for the EN003 if you want plenty of room. For alumnium go for the EN012, or the EN013 again if you want plenty of space to make the installation and offboard easier.

      The kit comes with a DC adapter, if you're looking at buying a power supply for it then you want one that is 9VDC, centre negative, and depending what other pedals you may want to power from the same supply, I would think 100mA would be plenty for this pedal.

      Delete
  16. Hi, I am not sure if I understood everything correctly and wanted to ask if someone could spare the time and look over the complete circuit. I just want to know if it works before I start soldering everything together.

    I found two guides for the footswitch but since I don't use the LED I am not 100% sure if I changed everything correctly. Also I wanted to ask if there is any difference in the performance between those.

    https://dl.dropbox.com/u/8160918/schaltung.png
    guide by beavisaudio (I think this is correct)

    https://dl.dropbox.com/u/8160918/schaltung2.png
    guide by lvlark (not shure if this is correct since I use one pin less)

    ReplyDelete
    Replies
    1. You have both correct. My helper sheet shows you how the switches connect (at the bottom of it...): http://mirosol.kapsi.fi/varasto/boxes_other/pots_switches.png

      So.. Beavis way is just easier to percieve as upper side is for bypass and lower for effect, while the other (the way i do it) takes input to two lugs. Both ways give you exatly the same results.

      You could use 2PDT stompswitch here. With 3PDT you're wasting one pole :)

      And your wiring plans seem solid too.
      +m

      Delete
    2. Thank you mirosol for taking a look at the circuit. The helper sheet is really useful. I hope I get the time to complete it tomorrow. Hope the circuit board works. First time soldering :D

      Delete
    3. As a little tip, you could use a knife to clean the strip gaps of the board - so that your chance of unwanted solder bridges is minimized.
      +m

      Delete
    4. After some problems it works now :) Althouth I get noise when I am not playing. Could this be because I don't use an aluminium case?

      Delete
    5. Very possibly, a metal box shields out a lot of noise. Try shielding the inside of the box with aluminium foil all round, and ground it.

      Delete
  17. I am getting loads of hum. I used your offboard wiring diagram. I jumpered the ground at the top of the board to the ground at the bottom. Could that be the problem? How should I connect those two board grounds? Thanks!

    ReplyDelete
    Replies
    1. They also need to be taken to a point of ground. Solder another wire to a free hole on either the top or bottom row, and solder the other end to the input or output socket sleeves. That will ground the board properly.

      Delete
    2. great, thanks! I was 0-3 today...this was humming, a vibrato just won't work (I've built it a few times but today it just won't work), and I'm out of 1uf capacitors so I couldn't finish a compressor...oh well, tomorrow will be better.

      Delete
  18. On the switch when it says "tone 3" is that straight to the pot or to where the board says "tone 3" thanks. I redid the grounding and still get tons on hum. Hmm?

    ReplyDelete
    Replies
    1. Also I used a 1n5818 instead of a 1n5817. Would that change anything. I may go back and try a 1n4001.

      Delete
    2. You can connect it to either. Basically they all need connecting together so you can daisy chain from one to the next. And no problem using the 1N5818 or 1N5817, or even a 1N4001 if you like.

      As far as the humming goes, have you connected both the top and bottom rows to ground?

      Delete
    3. Yeah I grounded the bottom to the dc ground like in you diagram, and tried the top to in out and dc. I'm baffled. But it'll work out eventually.

      Delete
    4. You need to ground them both. I've built these with a black wire jumping from bottom row to the top row - that way you'll need just one ground connection for the board.
      +m

      Delete
    5. Yeah, that's how I did it. I've done a number of other builds with the same grounding scheme. For some reason this one is humming like crazy. I'll track it down. Thanks!

      Delete
    6. I'll test it today, but I think it was the smallest solder bridge I've ever seen. What a mess! thanks guys, you're the best...I needed another hobby like a hole in my head, but it's a blast.

      Delete
    7. Ok, sorry to keep clogging up the comments. I went over the board and wiring at least 10 times and it's still getting a load of hum when I'm not playing...with HBs and single coils. Is this just a noisy circuit? Could it be a bad component (i swapped the transistors to see and no change)? would better shielding and shielded in/out cable help? This one has me baffled?

      Delete
  19. Hi,

    I've just built this pedal. Everything works and it sounds great, except for a high pitched whine when the pedal is turned on.

    I've tried the usual things, scoring between tracks to remove bridges, reflowing the solder and I've triple checked the layout and wiring, but cannot get rid of the noise.

    What would people recommend as the next step to diagnose the problem?
    Thanks in advance

    Nick

    ReplyDelete
    Replies
    1. Many of the BMP circuits are prone to whine. Sometimes some transistors just do that. You could try upping the 470pFs for 560pF. That should tame it down.

      Another thing i'd suggest, would be checking the filter cap - the 100µ electrolytic.
      +m

      Delete
    2. Thanks for the advice mirosol.
      The caps seem to be behaving as they should on the meter, I did change a few out with no success though.

      The transistors seem to to test ok too but I'm not really very familiar with those or if you can say for sure they are not dudd

      Just in case anyone can put a finger on the problem from the noise (it is quite distinctive really) here is a sample

      http://conditionalcomment.co.uk/downloads/whine.mp3

      I reckon my next step will be to try some new transistors...

      Nick

      Delete
    3. What voltages are you getting at all the transistor pins? That's usually a good guide to where the problem is

      Delete
    4. Now that doesn't sound like the whine i know from BMP circuits... That's more like a full on oscillation.

      Yup. Measure voltages and post them.
      +m

      Delete
    5. cheers lvlark, that is interesting. 3 of them show e=0 b=0.6 and c=3.9 and the fourth is e=1.1 b=1.6 c=4.5

      Am I right to assume that the last one could be the culprit?!

      Delete
    6. Q4 base should be about 2.5v and E about 1.9. The rest (Q1 to Q3) E should NOT be 0, a low 0.03 or so would be correct.

      BR

      Delete
    7. ok. putting the meter on the correct resolution, q1 to q3 do indeed show E = 0.03.
      Q4 B = 1.66 and E = 1.19

      So Q4 still looks suspect to me...
      Cheers, Nick

      Delete
  20. Well, effect ready. I've used Mark's layout, but with slightly different values, as I wanted to build the first "Violet" (V.2 Rev 4) that you can get on http://www.bigmuffpage.com/Big_Muff_Pi_versions_schematics_part1.html
    (You can get nearly ALL big muff versions there).

    I've built it without diode and without filtering cap. While with battery works awesome, with power supply is a unbearable noisy box, so I had to add the filtering cap, but did it on the DC jack, not on the board, so, it just operates when pluged to the power supply.

    For what I could read about, this effect did not have protection diode, nor filtering cap.... nor DC Jack. So, I have to tell that while its sound is just unbeliable when used with battery, with power supply, is still a bit noisy, and the filtering cap CHANGES / affects the tone, so I believe, this is a clear candidate to be always powered with battery and forget about the PS.

    http://www.facebook.com/photo.php?fbid=437052366366617&set=a.404470492958138.93220.404417189630135&type=1&theater

    BR

    ReplyDelete
    Replies
    1. I'm planning on building this too, but I want it to be as loud and noisy as possible. What did you mean you built it without diode and filtering cap? Which parts in the tagboard were those? Thanks!

      Delete
    2. Remove Dx and move the 9V wire down 2 rows. Remove the 100uf cap on the bottom right of the layout. You can also remove the link beside that cap.

      Delete
    3. Thanks, Ciaran! I appreciate the help!

      Delete
  21. Hi Mark, just build the Muff from the kit, then I had a look back at this page and realized there is an almost completely schematic posted.... I'm a bit confused. What happened with the old one? Should I start from scratch again? Thanks !

    ReplyDelete
    Replies
    1. Don't worry,

      Schematic is exactly the same with the only difference of an added column inserted in the middle with the only function of joing the upper an lower roll getting a full ground line without having to put together 2 wires outboard. This column gets too all the cuts that were previously placed at some other places.

      But don't worry, the schematics have no change.

      BR

      Delete
    2. Yes, sorry about that. I updated about 10 Big Muff layouts on here so that the board didn't require 2 ground connections just to make the builds a bit easier. Both layouts will work fine and as Javi said it was simply an extra column to add a ground link.

      Delete
  22. Hi Guys and thanks, yes, in the morning I had a "fresh" look over a cup of coffee and saw for myself that basically the schematic is unchanged :)
    Sorry for the rush and thanks again.
    The Muff is a miracle, if you are interested you might check that link for a sound sample:

    https://soundcloud.com/darth_jabs/big-muff-rams-head-gibson-lp

    and here comes the sexy casing :))):

    http://imageshack.us/a/img829/9099/img0935xr.jpg

    ReplyDelete
    Replies
    1. Excellent stuff, thanks for the pic and sample

      Delete
  23. I started this today as my first build. I have no electronics background at all (although I am trying), so please forgive my stupidness.

    On the circuit diagram posted above, there are a number of red dots. Are these the 'breaks'. And if so, how does one break them? I know you can get a tool for it. But I more mean where should I place the break?

    Thanks in advance
    SCott

    ReplyDelete
    Replies

    1. No stupidity to speak of. You just need to learn the ropes.

      The red dots are indeed breaks and they are nothing more than cuts in copper so that copper strip continuity is completely broken. You can do this anywhich way you see fit (scoring with a sharp blade, scraping it off etc) but to me the easiest way is to use a drillbit for metal and start drilling a hole on top of the existing one until the copper is gone. In my case it means that the bit goes in only halfway through although I've seen people drill holes all the way through.

      Delete
    2. Thank you for your speedy reply Goran!

      That makes sense. I just wasn't sure if i have to break the copper/board in between the holes to completely break the circuit or not!

      Thanks
      Scott

      Delete
    3. Same thing. On my first ever vero build I scored two lines in between holes and chiseled out the bit of copper between the lines.
      Needless to say this took me forever to do the cuts. On my second build I switched to drillbits and that's my method of choice ever since. I used to do it by hand (twisting the bit between the fingers) but that works well only if the bit is very sharp, if not it can get very tiring very soon.
      Now, if the cut count is low I do it with an electric screwdriver with a drillbit attachment, if the count is high I break out my drill press.
      Many ways to skin a cat...

      Delete
  24. Ok, almost finished this. Down to 2 having only 2 components left which I cant seem to see on the diagram above. For some reason I have an extra 10nF polybox instead of a needed 100nF polybox and the other thing is a 3.9nF ceramic disc. I dont see that listed on the diagram above either...

    thanks in advance.
    Scott

    ReplyDelete
  25. hey mate i believe you have overlooked the capacitors on the switch, have a look on the layout. Also you have used the 4n7 box cap on the board in place of the 4n cap where bitsbox has supplied the ceramic 3.9nf for this one so swap that one with the 4n7 and use that on the switch.

    ReplyDelete
  26. On another note just finished this one tonight, it is nice, i think i like it more than the triangle so far it really does have great sustain but i'm not sold...i might try the p-19 next or the sovtek, thanks for the layout

    ReplyDelete
  27. Hello,

    Nearly finished the kit purchased from Bitsbox but i'm confused that I have 5 x 100nF polybox caps and 2 x 100nF film caps. How do I know which is the best place to put the two types?

    Thanks Si

    ReplyDelete
    Replies
    1. Figured it out. The box caps only span 3 tracks when the film caps can cover more!

      Delete
  28. Hey guys,

    Love the site, lots of great builds on here. Before I found this site I found Harald's site over at sabrotone. I built up his Ram's Head BMP and I dig it, but I noticed that on this layout a mids switch is included. I've been comparing the two layouts, trying to figure out how I would add the mid switch to my BMP and frankly, I'm confused...could any of you help me? I'm thinking I only need to locate where to connect sw1 to the stripboard.

    Here is the layout I used: http://www.sabrotone.com/wp-content/uploads/2010/04/Big-Muff.Pi-Rams-Head.gif

    Thanks a ton guys!

    Jacob

    ReplyDelete
    Replies
    1. Usually we do not offer support for Harald's layouts.... :)

      Take the switch wires to H21 and J21.
      +m

      Delete
    2. Wow thanks for the fast response!

      So in essence, I would run one of the wires to tone 3 (since H21 goes to tone 3) and the other wire goes to J21 on the board, correct?

      Thanks for the help, I really appreciate it!

      Jacob

      Delete
    3. Exactly. The switch only adds caps in parallel to 3n9 (which in original units is 4n). That cap is basically responsible for mids.
      +m

      Delete
    4. Worked like charm, thanks a ton! I get volume increase when I switch to flat or boost, but I expect that's normal, considering the switch adds mids back in.

      Sounds awesome, it's a very interesting flavor with the mids added back in. Definitely a useful, worthwhile modification. Thanks again!

      Delete
  29. just made the board hooked it on the test rig and it sounds awesome i put in some bc547's i had laying around.
    [URL=http://imageshack.us/photo/my-images/401/lchf.jpg/][IMG]http://imageshack.us/a/img401/8007/lchf.jpg[/IMG][/URL]

    Uploaded with [URL=http://imageshack.us]ImageShack.us[/URL]

    ReplyDelete
  30. Funny shit... maybe the 25th Big Muff that I build, but first one with this layout. Well it works, but is unusable: more noise that signal!

    Voltages on all trannies are ok but noise is unbearable, even when I plugged the test probe, as soon as the board gets 9v, you get the same noise...... without getting the probe pin near the board.

    I'll have to triple check this lil' bastard, never han an issue of this kind with any pedal,

    ReplyDelete
  31. Hi.
    I bought a kit and assembled it, but... doesn't work for me.
    Clean sound low-pass filter like...

    [URL=https://imageshack.com/i/mj8ohjj][IMG]http://imagizer.imageshack.us/v2/800x600q90/811/8ohj.jpg[/IMG][/URL][URL=https://imageshack.com/i/go3knij][IMG]http://imagizer.imageshack.us/v2/800x600q90/600/3kni.jpg[/IMG][/URL][URL=https://imageshack.com/i/n6ksupj][IMG]http://imagizer.imageshack.us/v2/800x600q90/834/ksup.jpg[/IMG][/URL]

    ReplyDelete
    Replies
    1. I hope I didn't fail... Seems to me that I correctly assembled everything, also the POT links...
      Anyone can help me?
      Thanks a lot

      Delete
    2. Measure the voltages between all the transistor pins and ground and post the results here. That always gives a good indication where the problem starts.

      Delete
    3. This comment has been removed by the author.

      Delete
    4. This comment has been removed by the author.

      Delete
  32. Ok, measured and something strange appears also to me... Some value is 0
    Level 9V battery for the test is 7.93

    Q4 E-ground 0.39V
    Q4 B-ground 0.91V
    Q4 C-ground 6.18V
    Q4 E-C 5.77V

    Q3 E-ground 0.00V
    Q3 B-ground 0.53V
    Q3 C-ground 6.18V
    Q3 E-C 6.17V

    Q2 E-ground 0.00V
    Q2 B-ground 0.54V
    Q2 C-ground 6.23V
    Q2 E-C 6.22V

    Q1 E-ground 0.00V
    Q1 B-ground 0.54V
    Q1 C-ground 6.31V
    Q1 E-C 6.30V

    Is it normal that some value is 0? Seems like some transistor has broken?

    Which values should have all these parameters?
    Thanks a lot

    ReplyDelete
    Replies
    1. Hi.
      Is it possible that on your pocture the transistors are inverted? -> http://www.onsemi.com/pub_link/Collateral/BC550C-D.PDF
      Thanks again for an answer. Doesn't still work for me :(

      Delete
    2. Yes if you used BC550's then they will need rotating 180 degrees. When multiple options are mentioned in any of these layouts you need to check the pinouts of the transistors you're using match those shown in the layout. The orientation matches the 2N5089 but not the BC550.

      Delete
    3. Right. You have to rotate 180 degrees in order to use BC550, and in my opinion, these are the best sounding trannies in a Ram's Head.

      BR

      Delete
    4. Yes, in the kit I have the BC550 C version.
      It works, IT WORKS! Sound is AMAZING!!! Thank a lot for it, I am in love with it.
      It sounds better than my BYOC Muff.
      I saw on ebay some expensive 2N5133. Does the sound change a lot with them?

      Delete
    5. I honestly wouldn't bother with the 2N5133's on eBay. All the ones I've seen on there have been low gain and so not ideal for a muff. Unless you can get him to tell you the hfe of them all first I'd steer clear.

      Delete
    6. In a Big Muff, the model of trannie that youuse is not relevant sound wise, anything between 300-800 will do the trick. BC550C is great choice because they're low noise transistors, not because they sound "the best".

      I've built lots of Big Muffs with many different trannie models, and it really doesn't matter which one you use, but with the 550's you'll get a noticeable less noisy pedal.

      J.

      Delete
    7. Thanks again. This helps. In fact the sound is clear and noise is irrilevant than the other muffs.
      Thanks again for this great service. Is a dream.
      Cheers
      Riccardo

      Delete
  33. Hello there, is there any problem if i use 1N4148 instead of 1N914?

    ReplyDelete
    Replies
    1. No problem, they're essentially the same diode.

      Delete
    2. No. Those are basically the same diode, so you can definitely use 1N4148.
      +m

      Delete
  34. This comment has been removed by the author.

    ReplyDelete
    Replies
    1. OK i found it its perfect and it sounds awesome!!!

      Delete
  35. I'd like some help with the ammount of output volume. I build this 10 days before and the sound is the gr8. I'm had the original one and in my opinion it sound much better than the original with more headroom. he only thing is that when i have it on my pedal train the volume is about in the half of the other pedals on my board. So i want to change something in order to have more output volume. I am thinking change the volume pot or change a value of some caps but i am not sure for what i need to do.

    ReplyDelete
    Replies
    1. You should be getting plenty of volume from this so if it's quiet I think you're going to find you have a poor joint or connection somewhere. Re-flow your soldering including the pots and if that doesn't cure it just post the transistor pin voltages to see if that suggests something else. I do think the voltages will be ok though, the vast majority of times with a build that is quieter than expected is because of a connection somewhere.

      Delete
  36. I connected tone1 and tone2 as in figure and the tone 3 both to the switch and to the board (and of course the other side of the switch to sw1, but It seems that the tone pot is bypassed, in fact when I rotate it, no changes in sound. Any idea?
    I made several of this pedals in past but this is the first time that it happens.
    I checked twice links, cuts and solders but everything seems fine. Thanks

    ReplyDelete
  37. Hi,
    My measurements are:
    Q1 C = 8.39 B = 0.01 E = 0.01
    Q4 C = 8.60 B = 0.04 E = 0.01
    Q2 C = 6.76 B = 0.56 E = 0.02
    Q3 C = 6.73 B = 0.57 E = 0.02
    ...which appears to suggest too much voltage going to Q1 and Q4 agreed?

    ReplyDelete
    Replies
    1. Your voltages are totally wrong. These are the typical ones:

      Q1: C: 4.98V B: 0.65V E: 0.06V
      Q2: C: 4.42V B: 0.67V E: 0.06V
      Q3: C: 4.32V B: 0.62V E: 0.06V
      Q4: C: 4.10V B: 1.54V E: 1.02V

      There's something really wrong on your +9v rail and / or nearby area.

      J.

      Delete
    2. Thanks for confirmation. Can't see where I've gone wrong, but will look again..

      Delete
  38. Just to confirm I got this finished and working great, very smooth and authentic sounding to my ears. More so than the Black Russian I have. Very good indeed..

    ReplyDelete
  39. I just finished this build changing just few values using kitrae website to get a violet version. It sounds great.
    Very big thanks to Ivlark, mirosol and all of you for the info and the time you give here.

    ReplyDelete
  40. Would BC550's work? I can't get any 550Cs..

    ReplyDelete
    Replies
    1. Any silicon NPN will do. You may find you have your own preference based on individual gain of each transistor, but it's certainly worth experimenting to see what you think.

      Delete
    2. Excellent fuzz pedal !M manthanks for this great layout :)

      Delete
  41. Hi guys, someone know which box can I use? From an image in the comments I see a 1590B,
    is it right? And is there a way to know the measure(mm) of the board knownking the number of the holes?
    Thanks in advance,
    Alessandro

    ReplyDelete
    Replies
    1. You can fit up to 22 holes wide into a 1590B. 23 if you file all the edges down. This layout will fit no problem.

      Delete
  42. Hi, I've just finished this project using Bc550 c transistors.
    Tone is good but the volume is way too loud compared to the bypass signal.
    These are measurements:
    Q1 C=4.03 B=0.64 C=0.04
    Q2 C=4.03 B=0.64 C=0.04
    Q3 C=4.00 B=0.64 C=0.04
    Q4 C=4.67 B=1.68 C=1.20

    Thanks!

    ReplyDelete
  43. No Ram's Head. It's Ram's Head Violet

    ReplyDelete
  44. I´ve just built this to Rams Head "violet" specs. Used 4 random bc550c transistors.
    It sounds just classy, with a perfect balance in all frequencies.
    Being a hiwatt dr-103 and strat owner, I managed to nail EXACTLY the same guitar tone of this pink floyd live video: https://www.youtube.com/watch?v=xMrhRqK4iig (7:05mnts).
    It sounds much better powered by a battery without using the 100uf filtering cap.

    ReplyDelete
    Replies
    1. Unity level at about 1 o´clock, so near to perfection.

      Delete
  45. Hi I am new to building pedals, I am currently building a big muff rams head pedal, please could somebody indicate where the 2 Off 100nF Polyester Film Caps. should be fitted as there are 7 100nF Caps shown on the diagram.
    Many Thanks.
    Paul.

    ReplyDelete
    Replies
    1. don't bother with this...use them where ever you feel like.look for where they fit better from space perspective maybe. in theory maybe there are some places in the schem that you should use different types of caps like input-output caps or power supply filtering caps, but for a muff i really don't think that it matters

      Delete
    2. Many thanks for your speedy reply and advice.
      Best Regards,
      Paul.

      Delete
  46. I build this today but changed the transistors. Q1=2N5088, Q2=2N2222A, Q3=2N2222A, Q4=2N5088.
    This change made it a bit lower gain, but for some reason this sounds a lot more Ram's Head to me... Maybe I'm wrong... but MAN! do I dig this!

    ReplyDelete
  47. Hi everyone,

    I have 2 problems with this Big Muff.

    1: the volume is insanely loud compared to the bypassed sound. I am clueless here, it's not a big of a problem but I'd like to solve it if possible.

    2: Tone control (I built this with a switch)
    Well on this one, tone doesn't work like it should.
    When I turn the tone pot there are barely any changes until the end of the pot.

    When I was testing this circuit, I built it without the switch and the tone was working fine.

    Here's what did:
    I took both "Tone 3" and "SW1" from the PCB and soldered to the switch, leaving the Tone 3 lug on the pot empty.

    Did I make a mistake here? Should I have soldered Tone 3 from pot to the switch?

    Thank you :)

    ReplyDelete
    Replies
    1. Hey man. I can tell you the big muff is a massively loud pedal, on most of mine unity volume is about 10-11 o'clock, so I'm not sure where yours is to make a suggestion if you've got a mistake or not.

      As for the tone control you have it wired wrong. You should have a wire that goes from lug 3 of the tone pot to the place marked tone 3 on the board and a second wire from lug 3 of the tone pot to the switch lug marked tone 3. Then you should have a wire that runs from sw1 on the board to the lug on the switch marked sw1. Fix that and you should have a working tone control.

      Delete
    2. Hi Zach,

      I get unity around 11-12 o'clock, can't tell for sure since I haven't put on pot caps yet, but my guess is that the volume control is fine, since you stated that muff's are loud.

      As for the tone, I wired it the way you said, it works great now, I got all components from Tayda, except resistors which I got them as a kit from eBay.

      This was my first serious build (first build was a fuzzface BC108 on a board I etched, big mistake), as well and my first build on a vero board, and to my surprise it worked from the first try which made me quite happy considering that I am a newbie :)

      I've put everything into a 1590b enclosure, it barely fit, but I've managed to get it all in :)

      Thanks for the help mate :)

      Delete
  48. This comment has been removed by the author.

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

    ReplyDelete
  50. Hi,
    Newbie question alert! (first pedal build/time with vero board)
    I just wanted to check, when making the links, is it only between the blue points or all tracks in-between?

    The reason I ask is that there are cuts in the middle of some of the links, is this because its easier to make the full link then ‘break’ it at the indicated points or does the link simply jump over the cuts? 


    ReplyDelete
    Replies
    1. First off welcome. Secondly, if this is your first build I would build on vero something simpler then a big muff. Less components means less can go wrong, and easier to debug and learn if something does. I would also read the build guide, tab at the top of the page and understand what's being done in the guide before I would even attempt to build any board no matter how simple or complex.

      But, to answer you questions. Wires on the board that goes between different tracks on the board are your jumpers, and the red squares are cuts, so if you see a jumper from one position to another as well as cuts in line with it then typically the jumper will go over those cuts. There is a little caveat, there are build that have places where you will have 2 jumpers in one hole, double jumpers, that will be marked on the board.

      Delete
    2. Hi Zach, no problem, I have read through the build guide and now completed the pedal with some success.

      The only small issue I have is with the sustain pot where it only appears to only kick in properly for the last 10% or so of the pot (so 50k to 100k of the supplied log pot), below that it seems to cut the sound of the pedal altogether. I figured that it could well be down to my transistor values as they are generally a tad smaller than 'JaviCap's' values listed above (apart from Q4 which are larger), who claims his are right. Mine are:

      Q1 c = 3.39v b = 0.60v e = 40.00mv
      Q2 c = 3.62v b = 0.60v e = 19.70mv
      Q3 c = 4.00v b = 0.63v e = 37.90mv
      Q4 c = 4.70v b = 1.75v e = 1.1670v

      Do you think that this could be the source of the issue or are my voltages close enough to allow the pedal to perform fine?

      I recorded a demo video to illustrate the issue: https://youtu.be/zHyA_xqA1cE

      Any ideas for where I should look next would be great. I'll build one of the less complicated pedals for my second build haha!

      Delete