A modified and improved Hornby Skewes silicon Zonk 2 that goes for big bucks.
Schematic and a breadboard session(!) is avaiable HERE.
It seems that silicon transistors in the 150-200 hFe range works best in this circuit.
*Update 240203* Reeves Electro got in touch with Gray Bench since two of the pot values was incorrect in the trace. Layout and schematic is updated.
Schematic
Tag it! Used PN2222's at 165 hfe and it sounds massive!
ReplyDeleteNotice some contrasting info from Markus in the comments about the swell and drift values. Haven't tried it yet, but like it the way it is.
ReplyDeleteBuilt it using <100 2n5135. I tried 2n2222a as well but found they were a little gated in this circuit. Thank you Anders!
ReplyDeleteGreat sounding fuzz. Thanks for the layout.
ReplyDeleteWorks nicely, but how much output are we getting out of this? I'd say it's probably only slightly above unity for me, using 2N2222As.
ReplyDeletesame for me .. its really just a FF without the 100k feedback resistor ..the ones that really boost are the mk1 tonebenders ..or like a muff with a lpb1 on the output .. not for sure though
DeleteThose 220k resistors attenuate the output volume, it gets really loud without it?
Deletehandsprings, I would go back over the board to check soldering and/or try different transistors, because mine is massively loud?
DeleteI used a 2n3906 for q1, hfe was 197 and 2n2222A for q2, hfe was 180. Not tried any other transistors yet as happy with this combination. Plenty loud and sounds great.
ReplyDelete2N3906 is PNP, a 2N3904 is the NPN equivalent but if it sounds ok then I guess leave it in
DeleteJust checked my board and I have the 2n3906 orientated the opposite way around to the layout. Guess I had a stray 2n3906 in my 2n3904 bag.
DeleteI've been LOVING this. Just wish there was a bit more output to it. Thoughts on boosting it a bit?
ReplyDeleteLower those 220k resistors on the output?
Deletei havent tried messing with the voltage dividers yet but possibly an lpb1 on the output ..then you can have 4 knob version lol .. not sure if that network at the end is a voltage divider its not connected to the power rail ..the texture pot is
DeleteGreat layout, tried 2n5550, mpsa06 & bc337 all around 150 ish hfe, the Texture pot really makes this shine over the original
ReplyDeleteJust tried Fairchild BC547A 110-220 hfe, sounds great! A huge thanx for your well balanced layouts!!!
ReplyDeleteHello, thank you for this, would anybody be able to draw up a tagboard layout for this? real noob asking here. Thank you all
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ReplyDeleteOften times when this happens, the culprit is a tiny solder bridge or fleck of copper trace bridging on the underside where it shouldn't be. I keep a magnifying glass and exacto knife handy for board inspection no matter how many times I'v built a circuit. If you've used all the right value components and potentiometers and got them all in the right places (this is something I also triple check every time), then I would ask what transistors you used? These primitive fuzz circuits can sometimes be really finicky with transistor choice, which is why I always use sockets. Also, it is not the cheapest tool, but getting a Peak semiconductor tester (if you don't all ready have one) helps out a lot. I follow all this with the caveat that, sometimes, a stripboard build just doesn't work. MANY times, I've started over and had NO problems the second time, even when I wasn't able to diagnose the problem on a nonfunctioning build the first time. I'm, quite obviously, not a scientist. Good luck!
DeleteFixed the mistake, I should have removed the flux better. Thank you.
DeleteCongratulations! Seriously - getting something perfectly right the first time is great and all - but I personally am more proud when I f*ck something up, diagnose it, THEN fix it. Building circuits like this has been the single greatest lesson in patience that I have ever undertaken.
DeleteYou are damn right. I've been doing diy's fx for a while now and every time its struggle. But often I have success.
Deletesome of my diy's
Deletehttps://harlywake.blogspot.com/2024/05/diys-by-my-design.html
Nice work - the old school BMP-style enclosures look really great!
DeleteThanks a lot
Delete470pf is 10 times too big ....... ask me how i know =]
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DeleteBetter off with this one because the Zonk is positive ground?
Deleteper steve daniels and mark hammer the cap can be 47-500pF between base and collector of q1 or q2 to tame some harshness of Si transistors ..it really doesnt even have to be in there ..
DeleteLower values are quite harsh in this particular circuit I found. I actually preferred the “wrong” value that Anders selected here. Season to taste.
DeleteYea, Reeves claims 470pf is 10 times too big, but I think it depends on transistor gain? 220-470pf was more effective than 47pf, but I think 470pf yields the best results, hands down.
Delete*law & order soundtrack* DUN DUN
ReplyDeletei see a suggestion for a cap switch mod, thx!
ReplyDeleteThanks for doing this! I have been looking over this build quite a lot (the point to point build). There are a few things that seem to stand out (and i could very well be wrong!) The schematic calls for 2 x 220k Resistors. I can only ever see one in any variation that markus builds. There is a 220k off the swell pot leading into the 10nf cap. The resistor on the other end appears to be a 1m - which is in the schematic but is this a strange place for it to sit? (i assumed it woud be on the input) The other resistor seems to only appear in some versions. Most seem to be 5 resistor versions but sometimes there is a resistor on the texture pot lug 1 to power. I think this resistor is 820ohm or 10k??? i can also see the 47k, 680 and 3.3k. I also cannot see a diode or 100uf cap in his point to points but i also know they are not essential.
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DeleteThe polarity protection & power supply filtering are an added to every layout here, whether they’re in the schematic or not?
ReplyDeleteHi Brian, i didn't know that - but i also added I knew they were not essential. It was probably an add on comment to my main questions/queries. Markus looks like he dropped using the 100uf in later builds.
DeleteSome think it’s overkill, but really it safeguards the circuit from voltage spikes & noise.
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