Saturday, 27 April 2013

Catalinbread DLS MKIII

I didn't think it would end up too big, so I thought I'd jump straight in at the deep end and do a modified version with additional 9V/18V switching and the components switching done with individual toggles rather than a single 4PDT switch, which allows you to turn the selections on and off independently.

If you want it exactly like the original, you can omit the charge pump and associated components and take 9V directly to where VSw 3 connects to the board.  Then use a 4PDT toggle instead of two SPDT and one DPDT for switches 1 to 3.

Info about Catalinbread's original:

Introducing the new Dirty Little Secret from Catalinbread. The Dirty Little Secret has earned itself a well-deserved reputation for replicating the sound and feel of a classic era Marshall amplifier, supplying one of the most iconic guitar sounds in music. Able to clean up with a flick of your guitar's volume control, or go from mild crunch to full kerrang with your pick attack, the Dirty Little Secret has seen the inside of arenas and bedrooms alike, providing great overdriven sounds to clean backlines, low-wattage amps, and even direct applications. When the JFETs used as the base for the Dirty Little Secret were discontinued, and as our stock of them began to dwindle we knew we had to find ones still being manufactured. However, rather than simply re-voicing around these new JFETs, we decided to push the envelope and provide an amazingly robust feature-set, from ever evolving listening and circuit skills, and pure power of intention. This isn't just 'a' Marshall in a box, it's the most versatile and dynamic Marshall-style overdrive out there!

What's new in the Dirty Little Secret:

• The DLS now offers two distinct voicings, "Super Lead" and "Super Bass" switchable via an internal slider switch.

• Completely redesigned full three-knob treble-middle-bass tone control complement that reconfigures for each mode setting.

• We've also added an internal presence trimmer that allows you to fine-tune the presence of the pedal precisely to your guitar and amp combination.

• The gain range is much wider and even more responsive to pickup types, playing dynamics and instrument volume knob!

The "Super Lead" mode expands the range of the DLS MkII with more gain available and more control over your tone sculpting with the addition of the midrange control without losing any of the touch-sensitive dynamic qualities that made the MkII so great to play - in fact, those qualities have been enhanced. The gain range now goes from classic plexi all the way to modified JCM800 levels and can get even more raw and open than any previous DLS. This mode was voiced specifically to make humbucker-equipped guitars really rock with clean to scream all from the twist of your guitar's volume knob.

The "Super Bass" mode is a new voicing that gives you the tone and gain structure of a Marshall Super Bass (which is very similar to a JTM45 or JTM50/100). This mode was voiced to really hone in on that elusive in-between "not quite clean, not quite dirty" response that old tube amps were so good at getting. And it was specifically voiced to make fuzz pedals sound great (especially two-transistor based fuzzes like the fuzz face). Plug a Strat into a Fuzz Face into the new DLS in SB mode and you'll see what we mean!








Single voltage only version.  This was requested but it only saved one row, so I don't think I'd omit it for a bit of extra versatility.  But here it is if you just want to power it using a single supply. [smaller version added]




Video of Geiri's build:



136 comments:

  1. Oh hell yes! I'm making this one asap!

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    1. I just got back from work and saw this, very happy this has been done. It's definitely getting built, probably not tonight though so I'll await your vid to make sure it's as awesome as I expect it to be.

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    2. Had a feeling Geri would be on this one!!

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    3. Oh I've been waiting for this one ever since the day PGS posted the first video of it on YouTube. I bet it's gonna land on my pedalboard and stay there.

      I just realised that I'm out of DPDT. I've only got SPDT switches. eBay here I come! .. I might get a few 4PDT as well.

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    4. I've just ordered a bunch of switches since I need them. I also ordered some 4PDTs as footswitches. I don't see why you should bend down to flip a switch to go between Super Bass and Super Lead. Just step on the switch and you've got a different tone! The only thing about that is that you can't put an LED with it. Well, it'll still be worth it!

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    5. What transistors did you use? :)

      cool build!

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  2. I gotta build this one soon! thanks for posting it.

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  3. I own the real deal -- its a great pedal, lots of lovely warmness. I might have to build this and compare side by side.

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  4. I want this pedal but I know I'll hate myself once it comes down to wiring it up.

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  5. Ok, built this up - great work mark!

    Noticed the tone controls were reversed and having compared to the schematic I've come up with the following that seems to match and work great

    Mids 1 to ground, so change from mids3 to mids1 on board connection
    Mids 3 is connected to bass 3&2
    Bass 1 is connected to bass 2&1 marked wire on board
    Treble 1 connected to bass 1
    Treble 3 connected to sw3-2

    Sounds great!

    Mike

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    1. Awesome thanks Mike, I'll make the corrections. I got all the pin numberings off the scheme too!

      One thing I noticed that I put a 22n at Q1 drain instead of 2n2, did you spot that change?

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  6. I got the layout this morning and I have 2n2 there so I think I'm all good from that respect

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    1. Cool. Is the charge pump a worthwhile addition then?

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    2. I'd say so, not much extra space or component count and has a noticeable effect on headroom. Compression, dynamics - all that stuff TGP guys cream themselves about

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  7. ShortScaleMike, wich fets did you put in there? 2n5457?

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  8. and can anyone elaborate on how to put a 4pdt in there?

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    1. Just wire it up exactly as shown but on the 4PDT instead, it doesn't matter which poles you use. Like this:

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

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    2. but this will include the 9v/18v switching, right? if I want to hardwire it in 18v, a 3pdt will do the job?

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    3. You'll still need a separate SPDT for the supply switch

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    4. nevermind, just realized there's 2 spdt and 1 dpdt in there

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    5. Or yes if you just want 18V, take the 9V supply straight to where VSw1 connects and omit the switch and VSw3 wire

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    6. well, dumb questions apart, thank you for the layout! I'll order the switches and 250k pots and do it! I love those Catalinbread pedals, and just don't understand why they aren't very popular here in Brasil... go figure!

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    7. They are to pricey here "meu camarada" Guilherme.

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    8. So basically with the single voltage version, you can still use a 9V adapter OR a 18V adapter? You just can't switch between the two from the pedal? I don't really understand what the switch does

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  9. What would you label the 3 switches as? SW1 is the Rawk switch but what of the other spdt and dpdt?

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    1. I think the other spdt is the 9v/18v, adn the dpdt is super lead/super bass.

      Anyone???

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    2. Switch 1, 2 and 3 all go to make up the Super Lead/Super Bass switch. So you could switch them all together with a 4PDT toggle, or switch the options individually as shown in the layout. As far as a description goes you could label the 3 together as Super Lead one side, and Super Bass the other. Or see how each affects the sound to your ears and label them individually as you see it.

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    3. So the 4pdt will correspond with the other three switches like this, right?

      1 - 1 - 1 - 4
      2 - 2 - 2 - 5
      3 - 3 - 3 - 6
      (sw1) (sw2) (sw3)

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  10. I just completed mine using the latest layout and have been testing it. I tried it with both 2N5457's and J201's. every control works as it should and IMO, the J201's sound better but I think this pedal sounds way too dark (muddy) and bassy (and that's coming from a bass player!). for some reason mine doesn't sound like a Marshall amp. IMO, the distortion is kinda ugly and the low end is very loose. I ordered some MPF4393's for it so maybe that'll get it where it should be.

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  11. also tried it with MPF102's and it sucked. i had really high hopes for the DLS MKIII and it's not Mark's fault at all (since he got the schemo and a working layout correct), but i'm disappointed in this one so far. I really think that it needs the correct trannies (MPF4393's) to sound right.

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    1. Odd. I have an original too and my build sounds like the original to me with J201s from what I can remember (my Catalinbread pedal is at my rehearsal space). I'd be interested in your findings with the hard to find transistors, I can't source them anywhere here in the UK or Europe.

      BTW the original has LOADS of bass, I always run the bass control between off and about 9 o clock.

      In fact in the instructions they recommend you start with all EQ at zero and add as you need it - seems to work for me.

      Did you build post my fixes to the EQ wiring etc?

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    2. I built it according to the latest corrected layout. I realize that the original does have a TON of low end, but I think that it would sound better with more mids and top end than it has right now. IMO, the distortion isn't all that 'pretty' either. I built my own 'marshall in box' about a month ago and to me, it sounds a lot better (and more like a marshall amp) than my DLS MKIII build does right now, so i'm hoping that the MPF4393's improve it.

      BTW, i'm running the bass control anywhere from off to 9 o'clock on mine too. any higher than that and IMO, it's just way too muddy.

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    3. Hello John, strangely i´ve got the same results the you describe with my build of Catalinbread Rah... Muddy, ugly clipping and etc... and the components on mine are all the same in the layout... so i gess that the cause is not a component change.

      BTW I made some mods to open the sound of mine, but the result still sounds very different from the demos on net and i use it as a "slight dirt" booster with almost no gain and level maxed (its very, very nice this way)

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  12. John, where did you source the MPF4393 from? Can't seem to find any on Ebay.

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  13. It maybe worth checking out the Duncan Tonestack Calculator to try to fine tune things to your liking and tame the bass a bit:

    http://i76.photobucket.com/albums/j6/IvIark_2006/DIY/DLSMKIIItonestack.png

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    1. yeah. I use that frequently. I've actually already got mine to sound better with a couple of mods. now i'm working on getting the lead mode to have a bit less gain to begin with, since the super bass mode sounds pretty great right now.

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  14. i got it ALOT better (at least to me it is) now. I replaced the 1K resistor on Q1 with a 50R, replaced the 2n2 with a 220n, and am using 2N5457's for Q1 & Q2 and J201's for rest of them.

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  15. Certainly a lot of Bass, but I just have the Bass turned down Low. I also connected OutPut to Vol 2 which I could not see on the Diagram. I used 2N5457's and am happy with the dark tone. I also guess you are not suppose to switch from 9V to 18V while the pedal is on. I get a weird high pitched sound at the start after doing this. I also decided to add a Presence Knob rather than a Trimmer but now understand why they decided on a trimmer to get the sweet spot. A worthwhile Build. Thanks again Mark. Great Stuff.

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  16. I like mine with a bass so much better on 18V that i'm not even going to install a 9V/18V. i'll just run it at 18V all the time.

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  17. I've not used a charge pump before so I have a few questions. The IC is only needed if I want the charge pump and 18V, correct? I'm having trouble finding this IC at my normal sources (tayda, smallbear) so is there a substitute I could use from those sites to avoid additional shipping from a third source?

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    1. Yes you could use a MAX1044 or LT1054, but you could probably buy 10 x ICL7660S from eBay for less money. If you do opt for the eBay route, make sure you get the ICL7660S and not the ICL7660. The S is important.

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    2. Ok, thanks Mark. Are these 7660s used for any charge pump mentioned in your layouts or are they fairly specific to this build?

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    3. Yes I always use the ICL7660S because they're so cheap and do an excellent job. So anything on here than uses one to either generate 18V from a 9V supply, or as a voltage inverter so you can daisy chain positive ground pedals, can always use that IC.

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  18. I've also been using the LT1054's with excellent results. the only advantage of about the 1054's is that they can take a higher input voltage (up to 15V) than the 7660's max input of 12V.

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    1. Yes I bought a few of the LT1054's too, because they can handle 100mA which I thought may be useful for some things in the future.

      I also snagged 10 x ICL7662 as well which can take a 20V input because I thought it could be useful with some tube based effects like the Boob Tube to cascade a ICL7660 into it and get around 35V in a compact layout.

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  19. I've been modding my DLS MKIII build lately. if you want to remove the mud & wooliness, and actually be able to USE the bass control, instead of rolling it almost all the way off, the easiest way is to just replace the 100n cap (low pass filter) at the output with a 22n. IMO, it really opens the mids and highs up. i'm running five 2N5457's in mine now, and replaced the two 1K resistors that connect the drain to source on Q1 & Q2, and Q3 & Q4 with jumpers to reduce the gain in the circuit (of which it still has more than enough). to me, its distortion sounds ALOT better and more focused without those two 1K resistors.

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    1. Thanks John for that information. I always value and look at the modifications you make in the Pedals you build for improvements. Much Appreciated.

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  20. BTW, I used sockets for all of my mods so I can put it back to the stock schematic once the 2N4393's get here (tomorrow). catalinbread states that they 'revoiced it' around the different transistors so i'll be able see if it doesn't need the mods once I try them in it.

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  21. my MPF4393's just arrived so I put the circuit back to stock and installed the new trannys. they do sound different (a bit brighter) than the J201s and the 2N5457's, but the the pedal went back to being a big mudball with ugly & sloppy sounding distortion, so i'm going to mod it now with the new transistors in it and see what I come up with.

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  22. I couldn't get the low end clipping to sound good with the 4393's so I went back to the 2N5457's. i'm running a 1K resistor on the source of Q4 (instead of the 560R), put a 1K back on the drain to source from Q1 to Q2 and put a 560R on the drain to source of Q3 to Q4. i'm running a 47n instead of the 100n and a 220n instead of the 2n2. I modded the lead setting with a 4.7m resistor in series with a 10n cap to SW1-3 with the other end connected to a lead that enters the circuit board the row just above the green input lead (row 15) that connects to the drain of Q1. so far, the pedal sounds best to me with those mods.

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  23. okay, I finally got mine where I want it. all 2N5457's. two 220R's on the drain to source from Q1 to Q2 and drain to source of Q3 to Q4. 1K replaces the 560R on the source of Q4. 220n in place of the 2n2, 22n in place of the 100n, and modded the lead setting as described above. i'm also mounting presence control externally. IMO, it sounds really good now.

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    1. Thanks for the info John

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    2. Just built mine and I'm getting the bassy wooliness that John mentioned. Sounds more like a wooly mammoth. :) I'm going to try John's mods tomorrow.

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    3. John: with your mods, are you running 2 220Rs (for a total of 440R) on the drain to the source from Q1 to Q2 and drain to source of Q3 to Q4 (again 2 220Rs for total of 440R), or are you only running one 220R for each drain to source connection?

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    4. just one 220R on each drain, plus the other cap mods.

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    5. any chance you drew up your layout john?

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    6. unfortunately I didn't. I just socketed some of the components and modded it after I built it.

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  24. Replacing that 2n2 Cap with 220n certainly makes a very big difference to this pedal. It gets rid of as John described the "mud & wooliness" or to me booming Bass. Does anyone think there could be an error on the schematic used?

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    1. Apologies Mark. I just looked at the single 9V diagram and realised you have to make changes to use the ICL7660SCPA for 18 Volts. You do a Great Job, reason I build your pedals with confidence.

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    2. Was thinking the same thing. But can not quite work out what schematic was used to check it? Would it be possible to post the schematic?

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    3. Personally, I dont have a schematic and I could not find any anywhere on the net. You have to ask Mark? I own a couple Catalinbread original pedals ie. RAH & SFT. This build does seem to have too much Bass and I don't think Catalinbread would sell a pedal with so much Bass. I then thought because I built the 18V version that may be causing it. But maybe not since you can switch to 9V and I guess this circuit must be the same as the 9V version. That is why I was thinking a typo may have been made somewhere on the reproduced Schematic which is easily done.

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    4. http://freestompboxes.org/viewtopic.php?f=7&t=4668&start=320

      You'll need to be a member

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    5. TNKS. Could not find the right schematic in this topic. The other ones where missing the 2n2 cap.

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    6. C4. The schematic further on in that topic only has the SL circuit.

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    7. That's why I used Matt's schematic, the later Eagle scheme didn't include any of the switching requirements.

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    8. Cheers...I understand now. Hope to get the components this afternoon to get started. This is my design:

      https://lh3.googleusercontent.com/-n12Qkug1GU4/UYOSuYumwuI/AAAAAAAAAi0/upRzl6GezDI/s720/ontw_dls.jpg

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    9. @Ad de Bruin: Is it your DLS-clone I saw for sale on 'Marktplaats'? Only €50,-?

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  25. BTW. How important is it to get the right drain voltage with this design? And if so...what would the ideally be?

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    1. I wouldn't worry about that too much, it seems that JFETs in this muamp configuration aren't as sensitive to biasing. We now know of three completely different types that all worked.

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    2. TNKS for the reply Ivlark!. The build will start this weekend

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  26. Just finished boxing up mine. I ended up modding it to my taste, and alos added a footswitch to switch between superbass and superlead:

    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/DLS/DLSMKIII-01.jpg


    gut shot:

    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/DLS/DLSMKIII-02.jpg

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    1. Very nice and neat indeed!. How did you Thought about using a foot switch for switching between SL and SB mode but could not figure it out. Now I think I know!

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    2. I know you've probably been asked this before, but how did you make those stickers? Are they all individual stickers for each knob?

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    3. Hey mate... Lurkers first post...
      Did you change the 680n cap of Sw2-3 on the left of the board. Doesn't look like a 680n in your gut shot. I realise looks can be deceiving, but it looks too small to be a 680n. I'd love to build this thing, with your mods, but want to make sure I've got all the values right. :D

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    4. I don't have it in front of me but IIRC it is a 680n. I often use the tiny multilayered TDK ceramic caps for some of the high value ones (like 470n, 680n and 1u) to save space.

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  27. Hmmm...not working jet. in 9V mode the voltage on the Q4 drain is around 1,9V? Is that correct?

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    1. It's working now!!!
      It was a problem with the fet in Q4. I'm using the 2N5457's now. Will tray out J201's later.

      Question: Is there really that large a volume difference between the lead and bass channel?

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  28. Build is completed. Works fine. I'm using it with a Fender Blues deluxe and made it with the 2n2 cap in C4. (mod for 220n was suggested above). In home conditions it works to my liking. The Bass is very controllable for me (run the amp with the bass around 5). The presence ain't doing that much.

    Plenty of gain for me. In both modes. When using higher gain setting there is a volume de- increase when changing from super lead tot super bass.

    The 9 or 18V option is brilliant and makes all the difference. On 9V the gain kicks in almost immediately. On 18V there is more headroom and, imo, the pedal is responding better on dynamic picking.

    Overall...nice pedal

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  29. In- and outside

    https://lh5.googleusercontent.com/-lqtWUelddC0/UYYcSdm9FxI/AAAAAAAAAjU/mK_GTnLHJDw/s720/DLS3.jpg

    https://lh3.googleusercontent.com/--baCFqWVA4o/UYYcScKTfDI/AAAAAAAAAjQ/RR5NLbQhT5U/s720/DLS1.jpg

    https://lh6.googleusercontent.com/-0d4RvKc1SXo/UYYcR60gbdI/AAAAAAAAAjE/-NaaxAlG95U/s720/DLS2.jpg

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  30. hahaha...the treble works fine in SB mode, but reverse in SL mode ;-)
    Anyone else got the same problem?

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    1. I would double check your wiring of all EQ controls and the switch...

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    2. Yes, will do that in time. It's not a probleme at this time. I'm waiting for some components to arive (cap en resistor mods you did) and will correct the treble at the same time.

      @Mike: Nice result!
      @Ivark: Tanks for the layout indeed!

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    3. The 22n cap from the mid tone was not in the right hole.....problem fixed. Totaly different pedal ;-)

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  31. NIce job, thanks for the pics

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  32. Finished mine. Fixed the 820 (to 1k) and 560 (to 680) resistors after comments on FSB about the traced values. 2n5457s - also included John's two cap mods. Sounds good!

    http://i1178.photobucket.com/albums/x374/MadeByMikePedals/null_zps54d9ef8a.jpg
    http://i1178.photobucket.com/albums/x374/MadeByMikePedals/null_zps10d647ae.jpg
    http://i1178.photobucket.com/albums/x374/MadeByMikePedals/29463dae-8783-425c-8659-1e1dea9f7cac_zpsc5ff654f.jpg

    Nice layout Mark!

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  33. Built this by substituting the values as recommended by John. Now it sounds pretty awesome. I feel John's mods on this one is indispensable. Thanks Mark and thanks John.

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  34. glad to hear that you found the mods useful! ;-).

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  35. Just wondering if I built the single voltage version and wanted to try with 18volt, can I just use 18volts I o the 9volt input or would other mods be required.

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  36. the 4pdt in the original circuit is the super lead and super bass control? and what the dpdt switch does?
    the 6th knob on the video demo are presence control?
    i'm wating for this layout long time thanks a LOT!!!

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  37. I managed to stuff this one into a 125B, I was surprised. It sounds great, but now I see that there are changes since I built it, gonna have to try them. I used LT1054, 7660SCPA had high pitch whine in 9V for some reason, but not with LT1054. Wish I had room to add an external presence control, it is very responsive and makes a huge difference in tone.

    One thing - what exactly does each switch do? I did it with all the separate switches, though now I kind of wish I just did the 4PDT because most of them I don't notice a huge difference besides SW1.

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  38. On mine everything was working fine, but after boxing the Voltage switch has no effect. Its the same level on both settings. I removed the switch and added another but suddenly the voltage switch stopped working. The other switch I am using a 4pdt. What could be causing it? any ideas?

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  39. How difficult is it to put the SB/SL footswitch on a 4pdt switch, and have a bi-color led as an indicator for which mode? Also, I'm a little confused about the 18/9V switch, is it necessary or is it a mod from the original?

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  40. the 9v/18v is not in the original. technically, you'd need a 5PDT if you want led indication with a super bass/superlead footswitch.

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    1. damn, i was hoping to have a do it so it would make it really easy to tell which mode i was in. john, how did you add the 2nd led for the stomp switch on the left. i assume its to switch from super bass to superlead.

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    2. i didn't have the added SB/SL foot switch do all of the switching that the orginal's 4PDT or the three separate ones on Mark's layout do (2 spdt & 1 DPDT). i hard wired the least effective one in my preferred setting (the 270p/470p selector) and wired the others to the footswitch and used the extra pole for the led.

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    3. ahh, was the the wiring for sw3-1 and sw3-3? btw, does having the 9v/18v switch make much of a difference in the sound of the pedal? cause i would think that if a pedal was like an amp, the it would increase headroom, so you'd have to push it more to breakup, or am i missing something?

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    4. I wired the Sw3-3 directly to the treble pot and then wired all of the others to a 4PDT footswitch.
      18V gives it more headroom and less distortion than running it at 9V.

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    5. Well, you could do it with a 4PDT, but you'd also need a DPDT relay to effectively turn the 4PDT into a 5PDT, because I'm almost certain that if such a switch exists(5PDT that is), it is very expensive.

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  41. I am in the process of building this and am a little confused on the switching. This is what I understand:
    VSw - 9v/18v operation, DPDT
    Sw1 - ?, SPDT
    Sw2 - ?, SPDT
    Sw3 - SL/ SB, SPDT
    So what are Sw1 and Sw2 switches toggling between? What do they do? Thanks for any help!

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    1. VSw does indeed switch between 9V and 18V operation. In the original it used a 4PDT toggle for the Super Lead/Super Bass switch. What I did here was split that down individually in the 3 areas that the original toggle altered. This just gives you a bit more versatility allowing you to switch each section independently to get a greater range of sounds. If you wanted it exactly the same as the original though, just use a 4PDT on/on toggle instead of the two SPDT and one DPDT that I used for switches 1 to 3.

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    2. where does the output get wired? Not seeing it labeled on the layout.

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  42. Well, got it all built up, but I have no gain. I mean zero. Voltage switch works and passing sound. I wired up using the 4pdt. I've checked my joints, switch wiring and tranny orientation. All knobs except gain work like I anticipated. The gain knob just seems to boost the volume a little. I'm stumped.

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  43. Hmmm, doing some checking and the only way I am getting any distortion is by removing Q1 and Q2. but then it sounds a little harsh and its still not much gain even when maxed.

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  44. What is doing the left footswitch? And what is doing a small switch in the middle? Please tell me ASAP

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  45. so with the single voltage version I can still use 18v as long as my electrolytic caps are rated + 18V (they're all 25V or 50V) ?

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  46. No luck getting signal for me yet :( I've gotten pretty decent at problem solving and trouble shooting, but this one's got me stumped!! Gonna walk away for a bit as I've been at it for a few hours. Found some mistakes that I'd made, but the fixes didn't help.

    Thanks to all those who put this together. Looking forward to see how my build compares to my MkIII pedal.

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    1. Ok, figured it all out. Pretty much using all of John Kallas' recommendations w/ the 2N5457s. Sounds pretty damn close to my original pedal.

      But I would like to get less gain at the minimum setting and a more useable (less bass) range in the bass knob.

      I tried putting jumpers in place of the 220R resistors at Q1-Q2 and Q3-Q4, but still just a bit too much gain for what I'd like to get.

      Any tips would be great. Thanks again!

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  47. Hey do you know how to get rid off the high pitch when the gain is full? It really annoys me. Please help me.

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    Replies
    1. Keep your cables as short as possible and try shielded cable for your input and output wires. That often sorts out the high pitch squeals.

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  48. I find a 500k pot for the bass to be more tolerable, though I believe the intent of the massive amount of bass is to allow a full stack sound from even a tiny practice amp, which it does in spades.

    For a panel mounted presence, I find a 5K reverse audio taper to have a much more useful sweep and makes it easier to dial in.

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  49. Just a short information for all the builders of that device.

    the 1M 2n2 around Q1 is absolute nonsense. The Resistor (1M) reduces the gain of the muamp with local nfb -> the higher the resistance, the higher the gain of the first muamp stage. the 2n2 has a near infinite resistance at really low frequencies. this makes the combination effectively have full gain at 16Hz, a frequency completely useless for any musical instrument. it should always be substituted with at least 22n. The gain of the input stage can be tailored by using different resistance values and capacitors, but here you want to keep the product of resistance*capacitance always above the 1*22 MOhm*nF.

    cheers,

    Max

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  50. Hi!
    I built mine some day ago now.
    The overall volume is lower than in bypass mode. What to do?

    Best regards
    Dario

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  51. Hello, I have a few questions about this build. First, I cannot hear any difference in sound with the two positions of SW3. I have checked that it is correctly wired and working. What should I expect to hear or is there any consistency check that I could do?. Second, When going from 18V to 9V I can hear a noise descending in frequency for a few seconds. I believe it should be the 7660 lowering its frequency from the moment it is disconnected, should I be hearing this?. Also, the volume pot seems to work in the first part of its lenght very quickly and then it stays more or less at maximum volume for most of the range. I imagine that a logarithmic pot would make things even worse, so with these 3 things together I believe there is something wrong with my build, but I cannot find it if this is the case. Could someone explain to me the precise effect of SW3 so I could at least start here? thanks

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    Replies
    1. Miguel

      Was just reading some comments and saw this. I'll have to open mine up when I get home, but we're probably talking about the same switch. It's a pretty subtle difference. It seems to add a bit more bottom end on one side of the switch. You really don't notice unless you're playing while you switch it, and are playing on the bass strings. Try switching while you're playing the bass strings with some hair on it - if you still don't notice a slight bass shift, then maybe you have an issue.

      I didn't build the switchable voltage version so I can't comment there.

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    2. Thanks, timkercreak, now that you say it, I have tried this and it actually adds some bottom end and changes the eq slightly, thanks for commenting this.

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    3. Cool. Glad that helped. I actually leave that switch engaged most of the time for that little bit of oomph.

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  52. Just built mine and it sounds great. I can understand that some people find the gain ugly and woolly and had doubts about the effect. It is a somewhat strange and in a way 'imperfect' sound but I think that this is intended and to me it has the 'messy' and dark fuzzy qualities of a lot of guitar sounds from the sixties and seventies while still being an overdrive instead of a fuzz.

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    Replies
    1. Zick

      I'm with you. This is still one of my favorites. One of the few that really adds nuts to my Strats. The darkness of the pedal really fattens up the single coils and I seldom crank the gain all the way up.

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  54. Almost finishing mine but I just have a question about adding a led on the 4dpdt switch like John K?
    If I hard wired sw3-3 to treble 3 where is going sw3-1?
    Sorry if it's a noob question :)
    Really impatient to plug this one!

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  57. Hello Rob
    would you give us please the schématic with your transformations.
    I can't find mpf4393.
    Many thanks
    Nad

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  58. Hi guys, just a question: could the voltage change (back and forth from 9v to 18v) damage the transistors in the circuit, in the long run?

    ReplyDelete
  59. Hi guys, just a question: could the voltage change (back and forth from 9v to 18v) damage the transistors in the circuit, in the long run?

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  60. Where the output signal? Vol-2? It's my first project, sorry...

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  61. Replies
    1. If no output connection noted on the board and no Vol 2 connection i presume it will be. Not built this but now i have had a look i might build it. Hope it works.

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