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Sunday, 13 July 2014

Idiotbox Blowerbox


There are few manufacturers that raise an interest to simply go and get the original. I have no idea who the person behind Idiotbox is, but his designs, workmanship and artwork do please me to some degree. Plus his pricing seems to be on solid ground too. This one sounds particularly good. It has some wild distortion/fuzz tones for both, guitar and a bass...

This layout was originally based on a traced schematic by p.eat on FSB. That schematic had a few errors, which johnk helped to sort out. For this layout, i've subbed the parallel polarity protection for a series one and replaced the 10K JFET drain resistor with a 20K trimmer. This way you won't be able to kill your board with a reverse polarity and you'll be able to get everything you can out from that J201. JFET has also a 1M resistor path from gate to ground. This resistor isn't present in the original, but it will keep the JFET operation stable and it will not affect the sound.

A word about the original:
 The Idiotbox Blower Box Bass Distortion was designed with recreating the classic tone of Blacky from the early Voivod albums. It does everything from a mild grind to full-on massive distortion. It's awesome and you should have one...






BUY A KIT
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107 comments:

  1. onthetundra13 July 2014 at 18:35

    No cuts under the IC?

    ReplyDelete
  2. Unknown14 July 2014 at 03:26

    as the rat pro co, can i use LM741 ?
    keep on rockin'

    nico

    ReplyDelete
    Replies
    1. mirosol14 July 2014 at 08:03

      Nope. Not as a direct, drop-in replacement. LM308 has compensation between pins 1&8.
      http://www.ti.com/lit/ds/symlink/lm308-n.pdf
      Which LM741 doesn't have.
      http://www.ti.com/lit/ds/symlink/lm741.pdf
      In that configuration just about every other single opamp will squeel like a pig if tried on instead of the correct LM308.
      +m

      Delete
    2. Anonymous14 July 2014 at 10:19

      a 741 should work, but you'll need to take out the 30pf capacitor between pins 1 and 8.

      Delete
    3. Unknown14 July 2014 at 20:06

      ok, just like the rat
      thanks to both
      keep on rockin'

      Delete
  3. Brengos1914 July 2014 at 06:25

    hey mirosol, do you have another simple overdrive layout for bass?

    ReplyDelete
    Replies
    1. mirosol14 July 2014 at 07:53

      http://tagboardeffects.blogspot.fi/search/label/Bass
      +m

      Delete
  4. johnk14 July 2014 at 12:03

    I built this vero today and it's not working properly. I just traced my original one and i'll give it another try tomorrow.

    ReplyDelete
    Replies
    1. mirosol14 July 2014 at 14:40

      Don't bother just yet. I'll put this on hold until i get to redraw it later tonight. Original schematic has a number of errors, but one of them is preventing the circuit from working. There's no decoupling after the IC output, which means that the clippers kill the IC operation. Thanks for your trace John.
      Like i said, i'll be redrawing this in a few hours.
      +m

      Delete
    2. johnk14 July 2014 at 16:16

      I just relocated a couple of parts and added the extra 10u cap and it's working now.

      Delete
    3. mirosol14 July 2014 at 16:48

      Just got back to my laptop and grabbed the updated schematic. I'll start to tweak things around. I'm still going to leave that gate to ground resistor in place :)
      +m

      Delete
    4. johnk14 July 2014 at 17:00

      yep, that's what I did too.

      Delete
  5. johnk14 July 2014 at 17:10

    BTW, you can verify it now. it sounds identical to the original.

    ReplyDelete
    Replies
    1. mirosol14 July 2014 at 17:16

      Just updated it with added coupling cap. Otherwise it was already pretty much spot on. I'll tag it now too. Thanks John.
      +m

      Delete
  6. pearl blues14 July 2014 at 18:38

    Hi I'm sorry my comment has nothing to do with this post, but I wonder if anybody can help me solve a problem I have with my pedal board?... The problem is that my Wah, Univibe clone and Phase 90 suffer a dramatic loss of volume. This problem first occurred when I built my Si Fuzz Face clone, so I assumed it was and impedance miss-match, so I added a Klon buffer to the input of the fuzz. This sorted the problem for a little while but it soon came back. I've tried several different things but the problem keeps coming back. If I take the fuzz off the board altogether and replace it with my TS 808 clone or my Throbak Fuzz Haze the problem still occurs (although neither of these pedals caused me any problems before). Also if I unplug all the pedals and put them back together, the problem goes away for a little while.

    This is my pedal chain:

    >Maxon compressor > Wah > Univibe > Phase 90 > Maxon chorus > DIY Fuzz Face > DIY LPB 1 >

    All these are powered by a Carl Martin Pro Power. Any help or tips will be much appreciated. Joe

    ReplyDelete
    Replies
    1. johnk14 July 2014 at 18:55

      it sounds like you have a bad cable, a bad (cold) ground in one of the pedals, or a dirty jack somewhere to me.

      Delete
    2. pearl blues14 July 2014 at 19:11

      I don't think that's what it is, but will check...

      Delete
    3. mirosol14 July 2014 at 20:00

      Measure the power supply outputs. Play for a while and measure again.
      +m

      Delete
    4. pearl blues14 July 2014 at 20:47

      It did occur to me it might be something to do with the power supply, but how do I measure the outputs? I have a multimetre, where would I put the terminals?

      Delete
    5. mirosol14 July 2014 at 21:34

      Set the meter for DC voltage and point the leads to center and sleeve of those outputs.
      +m

      Delete
    6. pearl blues15 July 2014 at 18:43

      Hi, I've been running my pedal board for most of the day and the voltages of the eight power outputs are between 9.20v and 9.44v. The problem I mentioned above hasn't occurred at all today (sod's law!), but as soon as it does I'll post the new voltages if they change...

      Delete
    7. mirosol15 July 2014 at 20:31

      That doesn't quite confirm it yet :) If and when the issue appears again, measurethe voltages then. Even the best power supplies may die. And about 90% of all pedal issues i've seen are more or less power supply related. Quickest way to kill a supply is to have a tiny short in one pedal.
      +m

      Delete
    8. pearl blues16 July 2014 at 12:58

      The problem happened again this morning so I was able to measure the voltages on all eight power outputs:

      Output..................1 2 3 4 5 6 7 8

      Volt. before...........9.29 9.20 9.33 9.21 9.44 9.35 9.35 9.33

      Volt. with...............9.30 9.20 9.33 9.24 9.44 9.36 9.33 9.34
      problem

      There only seems to be a very slight fluctuation, but the volume on my Phaser, Wah and Univibe drops quite dramatically, and it is always these three pedals. Thanks for your help so far, do these readings indicate anything to you?

      Delete
    9. IvIark16 July 2014 at 13:24

      If you've got over 9V on every pin then something is extremely wrong with the build and it doesn't even give any clue as to where the problem may arise. Take a close up front and back pic of the board and also one that includes the offboard components so we can see how it is wired up.

      Delete
    10. mirosol16 July 2014 at 14:27

      Hehee Mark. This is totally off topic help thread about pearl blues' pedalboard and power supply :) I guess i should have mentioned that the question would have been better placed in the forum :)

      To pearl blues - nope. Voltages seem to be fine. I guess you should try to omit one of those three and see if the behavior comes back.. If not, then another.. Once you know which pedal does it, it may be easier to pinpoint the cause...
      +m

      Delete
    11. IvIark16 July 2014 at 14:43

      Ha ha right, I should have read back further, I couldn't work out how the hell you could get 9V on every pin! :o)

      Delete
    12. pearl blues16 July 2014 at 18:17

      Apologies for putting my comment in the wrong place, I only realized there was a separate forum from mirosol's comment above.

      I've tried every combination of the pedals that I can think of, even taking some off the board, but the problem remains. So I've gone back over the FF I built (this is what started the problem) and have found I used a 100k for the volume instead of a 500k. Not sure if such a small mistake would cause the problems I've had, but I'll put the right pot in and see what happens... Thanks for your help, at least a potential power source problem has been eliminated. Joe

      Delete
    13. mirosol16 July 2014 at 19:49

      Does the problem go away when the FF isn't in the chain?

      You could post the question to the forum too. I bet you could get more comments/suggestions/solutions out of it...
      +m

      Delete
    14. pearl blues16 July 2014 at 20:50

      No, but it only started happening when I built and started using this pedal. Initially if I put my ts808 in it's place the problem would go away, but now it happens whatever pedal is there, it comes and goes...

      Delete
  7. Anonymous15 July 2014 at 15:47

    Thanks for the layout chaps, this is an AWESOME effect. I'm planning to put a 47kΩ resistor across the gain pot (switchable) for a 'low gain' mode too…

    ReplyDelete
    Replies
    1. mirosol15 July 2014 at 16:56

      Since you're at it, you could also take the clippers on a switch :)
      +m

      Delete
    2. Unknown15 July 2014 at 23:55

      Down that road, madness lies...

      Delete
    3. Zach16 July 2014 at 04:52

      that sounds like an awesome idea. how are you adding the low gain switch? are you going to use a dtdp on-on switch, and have one side be the resistor, the middle is in and out to the pot, and the other is blank? i was thinking about trying to add a low gain option, but wasn't sure if what's in my head make sense and will work.

      Delete
    4. Anonymous16 July 2014 at 16:14

      I've got lug 1 of the gain pot to the board as directed, then the wire from the board that should go to lugs 2&3 go to one of the centre lugs on the DPDT switch, the other centre lug goes to lugs 2&3 of the pot. the bottom 2 lugs have a 22kΩ resistor across them, and the other two are shorted together. I've replaced the Gain pot with a 22kΩ pot, so that the switch alters the range from 0Ω to 22kΩ, then 22kΩ to 44kΩ.

      Basically you're using the switch to double the resistance (by wiring them in series), and therefor the gain in the feedback loop of the opamp.

      Delete
    5. Alex19 July 2014 at 08:47

      The guy builds everything in his home garage.
      They sound great and they are really cheap.
      If wish there were more schematics around.
      You can find more infos here:
      http://idiotboxeffects.bigcartel.com/

      Delete
  8. mirosol22 July 2014 at 16:26

    Built one today. Yup. Definitely better with a bass. As a bass rat, a winner.
    +m

    ReplyDelete
  9. johnk31 August 2014 at 17:35

    I just finished etching the enclosure for mine today:

    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/Idiotbox/BBoxclone-01.jpg

    ReplyDelete
  10. 2liveis2die7 September 2014 at 20:00

    This comment has been removed by the author.

    ReplyDelete
  11. 2liveis2die7 September 2014 at 20:04

    Are the polarised capacitors displayed correctly in the strip board diagram, I've bought the linked kit and I don't want to destroy them.

    ReplyDelete
  12. Natxo19 December 2014 at 19:49

    What kind of capacitors are the red ones in the schematic? Are they film radial? I've a bunch of mylar ones, can I use them?, Thank you

    ReplyDelete
    Replies
    1. mirosol19 December 2014 at 22:26

      We use the red ones to depict the Panasonic brand metal film poly caps. It's just a habit.. There's nothing wrong with green mylars, so use those if you have 'em.
      +m

      Delete
    2. Natxo20 December 2014 at 11:19

      I'll will try with the greenies then. Thank you.

      I've been trying to figure out where the out is, but I'm such a noob and I didn't find the vol2 nor the output. ty again.

      Delete
    3. mirosol20 December 2014 at 16:10

      I've made a promise i would never do this again, but here we go.
      You see the Volume 1 and Volume 3 points on the board? Those connect to volume pot's lugs 1 and 3 respectively. There is still the middle lug, the lug 2. You take a wire and solder one end of it to this middle lug. The other end of that wire is your output. All this equals to "Volume 2 to output".
      +m

      Delete
    4. Natxo22 December 2014 at 18:18

      Thank you. I promise to that I'll 'try' not to make silly questions. I've read the "offboard" article and everything is more clear to me.

      Delete
  13. fd5 January 2015 at 20:51

    is the schematic available?

    ReplyDelete
  14. Unknown12 February 2015 at 21:47

    I'm assuming the blue circles are double bridges in a sense? Hence the "double link" on the right of the layout?

    ReplyDelete
  15. Unknown8 March 2015 at 18:57

    Hi, I've just built this but I'm having a problem.

    The bass and treble controls aren't affecting the sound at all. I've checked over my wiring of the pots several times, and the wires are definitely in the right place on the board and definitely going to the correct lugs on the pots, the pots are also definitely reverse log 100k.

    Any idea what could be causing the problem?

    Thank you

    ReplyDelete
    Replies
    1. Unknown8 March 2015 at 19:03

      The output also seems really low, the volume and gain have to be on full for the output to be the same as when the effect is bypassed, and even then it's not still not quite as loud as when it is bypassed..

      Delete
    2. johnk8 March 2015 at 19:13

      you MUST have an error somewhere. the treble and bass controls are very effective and it has plenty of output

      Delete
    3. Unknown8 March 2015 at 19:45

      I know, from the videos I've seen on the pedal the tone controls seem really responsive so I know I've gone wrong somewhere.. Just a matter of finding where.. I only asked in case there might've been some where obvious that could cause the problems I'm encountering.

      I'll continue to search, I'm going to check the trim pot incase I have it oriented the wrong way..

      Cheers for the reply though, has gotten rid of any doubt in my mind about the output of the pedal, was beginning to think the pedal might just have low output.

      Any more ideas on what it could be are most defintely welcome haha

      Delete
    4. Unknown8 March 2015 at 21:06

      I've checked the orientation of the trim pot and it's correct.

      I've gone through and checked the position of every component and I really cannot see anything out of place, same for the cuts and the links, I've been very thorough and I honestly can't see anything wrong.

      I've tried switching round the wires on the lugs of the pots, and it literally changes nothing, the pedal sounds exactly the same and works in exactly the same way no matter which way round the wires to lugs 1 and 3 of the treble and bass pots are wired.

      Also, I tried switching round the orientation of the transistor, and again nothing at all changes, still sounds and operates the exact same way.

      Please can someone help? I haven't struggled like this with a pedal for a very long time, and I need to try and get this done tonight as a friend needs it for tomorrow morning.

      I would be massively grateful for any help.

      Thank you

      Delete
    5. Amereservant16 March 2015 at 11:15

      It appears the issue is with the 1M Ohm resistor having been moved to pin 3 of the LM308, whereas it was below it in the previous layout. This seems to be the only revision too and I do not see why it was made. I can verify the previous version, https://www.dropbox.com/s/7k5aoupkqxznrqk/Idiotbox-Blowerbox.png?dl=0 DOES work, so try it and see if that fixes your problem.

      Delete
    6. mirosol17 March 2015 at 18:35

      ? Isn't the image in your dropbox the same as in the post? In the tracing process there was some confusion whether the VREF via 1M was straight to pin 3 or to the input cap's opamp side. Either way, this doesn't affect the operation. In both cases the reference voltage will get to non-inverting input.
      ++m

      Delete
    7. IvIark17 March 2015 at 22:59

      Yes mate, I swapped it back after reading the post on FSB. I had the old version saved so thought I would just do it.

      Delete
    8. 903 Effects15 October 2018 at 23:49

      having the same issue, except it only works without the transistor. Whenever i plug the transistor in, the signal cuts out.

      Delete
  16. johnk8 March 2015 at 22:46

    if you've reversed the transistor and the lugs to the pots and it's the same, then obviously you have an error (or possibly more) somewhere. you might take some voltage readings and post them. or take some clear pics of the top and bottom of the board and post them.

    asking what's wrong with your circuit is kinda like saying 'my car doesn't run right, what's wrong with it?' ;-)

    ReplyDelete
    Replies
    1. Unknown8 March 2015 at 23:00

      Thank you for the reply. I know it's stupid of me to like, as that haha I totally know what you mean, I'm just kinda desperate for help as my friend really needs this for tomorrow and I promised I'd sort it out.

      I don't have my Multimeter with me, which is another reason this is being so difficult, I have no way of testing the board that way. I'll upload some pics now, hopefully they'll be clear enough for some help.

      Thanks again for your reply I can't express how much I appreciate it.

      Delete
    2. Unknown8 March 2015 at 23:07

      http://postimg.org/image/qb3y0fqk1/

      http://postimg.org/image/mlpfc27wp/

      http://postimg.org/image/tnncy9bih/

      http://postimg.org/image/a4irowcqx/

      Delete
    3. johnk9 March 2015 at 00:30

      first, I would 'knife' between all of the rows to make sure that nothing is shorting out.

      Delete
    4. Unknown9 March 2015 at 11:28

      I've just finished knifing between all of the rows, made sure there's definitely no shorts, but it hasn't changed :/ ..

      any other ideas? :/

      Delete
  17. Unknown10 March 2015 at 16:59

    Okay I got my multimeter back today.. So I took some voltages..

    The transistor:
    D - 8
    S - 0
    G - 0

    IC:
    R L
    4 6
    8 0
    3 5
    0 0

    All of the lugs of the pots read 0 apart from gain, which reads 4,3,4

    Any ideas based on these? :/

    ReplyDelete
  18. Unknown12 March 2015 at 13:28

    Sorry to keep spamming with questions, but I am really struggling with this pedal, I've made no progress as of yet to solving my problem, despite having spent the past 3 days trying to get it to work properly.

    Any help would really be massively appreciated.

    ReplyDelete
    Replies
    1. dexxyy12 March 2015 at 16:22

      It looks to me that the 1.5k resistor that goes to the source of q1 is going to the gate instead.

      Delete
    2. Unknown12 March 2015 at 17:27

      Ah man, you're right! I don't know how I've missed that!! :/ Thank you so much for you reply, I can't believe I missed that, I've been over it at least 6 times..
      I've just corrected that, but it hasn't changed anything, the output seems slightly higher, but the treble and bass controls still aren't doing anything.. :/

      Can anyone spot anything else I've missed? I'm gonna go over it again and keep going over it until I figure this out, any help will still be massively appreciated!!

      Thanks again!!

      Delete
  19. Unknown13 March 2015 at 08:58

    I've just found that the pedal still functions in the same way even without the transistor completely removed.. :/

    Why can't I see where I've gone wrong!?

    ReplyDelete
    Replies
    1. Unknown13 March 2015 at 09:36

      With*

      Delete
    2. Unknown18 March 2015 at 06:24

      Start again from scratch, lol. When this happens I just begin again and try not to get frustrated.

      Delete
  20. Unknown19 April 2015 at 06:36

    Quick couple of questions. Firstly, would it be ok to use an OP07 instead of the LM308? I would like to avoid paying $5 for a 308. Secondly, can I sub a 1n4001 (or similar diode) for the 1n5817? It is just a polarity protection diode right? Or am I missing something?
    Thanks for the help! You guys are excellent!

    ReplyDelete
    Replies
    1. ξεναγός νεκρόπολης19 April 2015 at 11:54

      yes in both. 1n5817 is for polarity protection.

      https://www.youtube.com/watch?v=WsJ9tE6j1jc

      $5 for an lm308???!!!
      the first thing i found on ebay was this!

      http://www.ebay.co.uk/itm/New-10pcs-LM308N-OP-AMP-IC-for-guitar-effect-pedal-/220812768199?pt=LH_DefaultDomain_3&hash=item33697773c7

      Delete
    2. Unknown19 April 2015 at 16:48

      Thanks man. I am never 100% on substitutions.

      That's a good deal for the 308s. I am hesitant about buying from china though. I have heard that there a lot of poor counterfeit chips coming out of there.

      Delete
  21. anon13 September 2015 at 15:25

    Hi!
    sorry for stupid question, but whats mean "rev log"? what characteristic: A, B or C?

    ReplyDelete
  22. gavinmacneil1 December 2015 at 15:32

    Think I found the solution to the lost tone controls (I have the problem & I haven't fixed it yet.)
    The 10uF electro that goes to the gate from the long jumper I have it plugged into the Gain 1 strip. I've got 2 built this way... Gotta verify, but I'm sure it doesn't look right.

    ReplyDelete
  23. Unknown29 February 2016 at 19:21

    Seriously, this thing just fucking rules, one of the most badass dirt pedals I know, it certainly gets boxed.

    ReplyDelete
  24. Unknown6 March 2016 at 23:37

    This does sound good, but I am having issues with the output being too quiet. It's barely at unity gain with vol/gain maxed. Anyone have suggestions?

    ReplyDelete
  25. johnk7 March 2016 at 00:53

    it should be a lot louder than that. you MUST have an error in your build.

    ReplyDelete
    Replies
    1. Unknown13 March 2016 at 00:36

      Any suggestion in where to look for that? I followed the vero layout precisely. I'm not exactly sure if my ears were playing tricks on me or not, but I do seem to remember a tonal difference from testing the vero through a breadboard vs. after boxing it. Think there could be something happening there?

      Delete
  26. Unknown15 March 2016 at 17:10

    This comment has been removed by the author.

    ReplyDelete
    Replies
    1. Beaker15 March 2016 at 17:28

      This comment has been removed by the author.

      Delete
  27. Beaker15 March 2016 at 17:26

    This comment has been removed by the author.

    ReplyDelete
  28. Paul18 March 2016 at 17:57

    Hi! First comment on this blog :) I built one of these for my bassist, and it works!! Thank you! I have a question about modifying this circuit: it sounds great on (regular) guitar and I'd really like to build another one for myself, but the tone sweep of the treble knob is very abrasive and ice-picky on guitar, and have to pretty much dial it out completely. Is there a simple mod I could do to bring the treble pot into range that is more useable for guitar? Also, are there other IC's and transistors I could try swapping in and out as an experiment? Thanks in advance for any advice!!

    ReplyDelete
    Replies
    1. NHTMF27 April 2016 at 10:20

      Hey mate, I'm far from an expert on these things but to my eyes (and the little I know about tone control) and someone can correct me if I am wrong...

      You could change the Capacitors (caps) on the same row as your Treble 1 and 3 connections, the caps you are looking for are 15nf and 150nf. I would socket them and increase the value for each or the very least increase the 15nf, to my knowledge the higher the capacitor value, the more low end "Bass" frequency is aloud to "pass"

      Sockets are great and you can use them to easily swap in and out components to experiment with sounds, usually I socket my Diodes and Transistors.
      A few transistors you could try are, 2n5457 or MPS102 or 2n5484, just be sure to google the Pinout to make sure you put them in the right way.

      Delete
    2. Paul15 May 2016 at 20:16

      Thanks so much for this! Will give your suggestions a try :)

      Delete
  29. Scott2 May 2016 at 00:06

    Hey - I'm pretty green to building these, so forgive me if this is an obvious thing.

    Can anyone tell me which direction the IC is supposed to go? What kind of damage would I do tossing it in backwards?

    ReplyDelete
    Replies
    1. Zach2 May 2016 at 00:27

      if you look closely at the layout you'll see there's a little halfmoon on the IC pointing upwards. the halfmoon represents the top of the IC. in some instances you can blow an IC putting it in backwards and firing it up.

      Delete
    2. Scott2 May 2016 at 00:59

      Ahh, thank you so much. I had printed the image off and that little bump wasn't showing up on my paper. Thank you Zach!

      Delete
  30. Scott2 May 2016 at 00:52

    This comment has been removed by the author.

    ReplyDelete
  31. radioburning13 May 2016 at 23:06

    Can someone tell me if I'm doing something wrong here? No matter what I do, I can't even get a clean signal through the footswitch, on or off. I've followed the "standard pedal wiring diagram" from madbean. All I can seem to get is a a loud buzz.

    http://s61.photobucket.com/user/Rusty_Cavender/media/AC7A5A00-C52D-4F65-ACB9-D6464FD645CA_zps1f58r1xz.jpg.html?sort=3&o=2

    http://s61.photobucket.com/user/Rusty_Cavender/media/030CB7D0-C0A9-470F-85DB-A47134F28408_zpsmjc5eu2p.jpg.html?sort=3&o=0

    ReplyDelete
    Replies
    1. NHTMF14 May 2016 at 00:19

      Try soldering a a ground wire from the ring (the empty lug)of the jack on the left to the same lug on the jack to the right, or wherever your ground wires are connected.

      Delete
  32. fuzzbeerpizza27 September 2016 at 16:46

    First time i made this it worked. But i made a second for a friend that has low output.

    Here are the voltages:

    Transistor (MMBFJ201):
    D: 1V
    S: 0.8V
    G: 0V

    IC (LM308):
    Pin1: 8,5V
    Pin2: 4,35V
    Pin3: 3,85V
    Pin4: 0V
    Pin5: 2,5 mV
    Pin6: 4,34V
    Pin7: 8,62V
    Pin8: 8,56V

    Anybody able to help me out?

    ReplyDelete
  33. wizombie8725 November 2016 at 05:47

    Verified took 3 attempts but I showed it who runs the show

    ReplyDelete
  34. Anonymous17 January 2017 at 18:40

    I built this box once successfully, but my second version is having the "tone controls don't work issue". I've spent hours checking the component values and layout, and soldering, i've run an olfa over all the spaces between the traces. I've compared it against the working one i made. No love. Does anyone have any guidance on how to troubleshoot? I'm about to unsolder it from the pots and start really ripping it to pieces.

    ReplyDelete
  35. DerPr15 February 2017 at 04:25

    Hi! Build one and it sounds realy good but on lower gain settings (about 1/4) and with volume full on it sound quieter then uneffected bass. Is it some mistake or them all work that way? first i were thinking that its some problem with 201, but i tried different ones (and even 5457) - all the same. Tweaking bias is not solve problem too. Has anyone any ideas?

    ReplyDelete
  36. Unknown16 April 2017 at 21:34

    Mine weirdly didn't work until I attached the 9v+ to the very top rail. The polarity protection diode side of that 47k would not work. It seemed that 47k resistor was just sapping all the power from the circuit.

    ReplyDelete
  37. shaggy4517 February 2018 at 21:44

    I had problems with eq not working also. i had volume 1 and bass 2 up a row higher than they should have been. hope this helps. I also added a buff n blend and i can say its absolutely not needed.

    Pic:
    http://www.nconspicuous.com/uploads/bb.jpg

    ReplyDelete
  38. Mulekicker27 October 2018 at 23:01

    Just built it and it's great. Used a dpdt for standard, none, and asymmetrical silicon clipping (my favorite). Killer take on the Rat.

    ReplyDelete
    Replies
    1. spectreman14 November 2019 at 20:22

      "Just built it and it's great. Used a dpdt for standard, none, and asymmetrical silicon clipping (my favorite). Killer take on the Rat."

      Hey Mulekicker,

      If I wanted a spdt switch for just standard and asymmetrical clipping, can you explain how I would wire that up? Thank you!

      Delete
  39. Traktop22 July 2019 at 22:14

    What voltages should I expect from j201?

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  40. Traktop12 November 2019 at 19:59

    I finally used a smd 2n5457, just because the voltage readings gave me better range with the 20k trimmer.
    I´ve been checking around on some rat threads and all of them got the drain reading almost 9v.
    The thing is that I only get similar readings with the trimmer at 0, being that setting the lowest in volume level.
    Maximum volume level was achieved with the drain at 4v.
    Lower voltage settings made it sound ugly and blurry.
    I´m about set it by ear, but I´d like to make it work as it should.

    ReplyDelete
    Replies
    1. mirosol13 November 2019 at 05:35

      Hi Traktop.
      Please do note that Blowerbox has the JFET wired as an amplifier, not as a buffer, like it is with a standard rat. I think the main reason for that is the tone stack, which acts as an active tone control with an amplifier (or gain stage) after it.

      The stock Rat has that transistor that JFET as a buffer and thus, the drain voltage should be around the supply voltage. Here however, the sweet spot may vary with the individual JFET. Due to how these operate, you should fine tune it by ear. The suggested voltage should be somewhere around half of supply. So basically that means it will perform like it should with 3,5-5,5V on drain - depending on the FET.
      +m

      Delete
  41. Traktop13 November 2019 at 17:36

    That makes sense then.
    Love this thing indeed.
    And thanks for the quick response!!

    ReplyDelete
  42. Alamondm12 November 2020 at 19:37

    Is there any pots I can use in place of the c100k? Could I use A or B 100k

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  43. Aethium11 September 2021 at 17:30

    After some rookie mistakes (had a 1M resistor connected wrong and wasn't sending the input anywhere and not grasping what double link means) it came out great. Can't get enough of how huge this thing is. Planning on grabbing a real one soon, atarimatt seems like a great guy. Fun circuit and a great board, thanks mirosol!

    ReplyDelete
  44. j-pee23 April 2023 at 05:51

    This comment has been removed by the author.

    ReplyDelete