Tuesday 1 April 2014

Cornish G2

I was surprised I hadn't already posted this one since we've had the schematic for a while.  Iconic and much admired builder to the stars, popular on TGP and everywhere that guitarists want the size of their gear budgets to be known by all.  It sounds pretty good to me.  This includes the famous Cornish Buffer at the input as per the original, but omits the bypass buffer for the usual true bypass switching.   If you do want to make it buffered bypass then you could use the standalone buffer layout as a bypass daughterboard.

For those who do want the bypass done in the same way as Cornish, the input socket connects directly to the input of the bypass buffer.  The output of the bypass buffer then goes to G2 input and daisy chains to the 3PDT stomp switch, lugs 1 and 4.  The output from Volume 2 of the G2 will go to 3PDT lugs 3 and 6, and the output socket connects to 3PDT lugs 2 and 5. 

The third pole of the 3PDT is used for LED switching.

You could do this with a DPDT stomp just making single connections, but Pete did this using two separate poles to add some redundancy in should one of the contacts fail.

Info from Pete about his original bomb proof effect:

The PETE CORNISH G-2™ has been hailed as the most original sounding distortion unit available to guitarists in the Rock Arena. It features a four stage overdriven discrete transistor Class A circuit with additional Germanium components that generate much warmer sounding harmonics than anything else on the market. Within the huge tone generated by this unit, the original guitar sound and dynamics are present creating a much more musical effect than any other distortion pedal.

The G-2™ gives a higher level of overdrive for that classic cranked up Marshall sound found on most British rock records of the 70s (Led Zeppelin, Free, Bad Company etc.). The G-2™ with its warm Germanium qualities and higher gain starts at around the rhythmic crunch stage of the SS-3™ and continues through in controllable degrees to a rounded but dynamic lead.

The input to this unique device is our universally acclaimed High Impedance, Unity Gain, Class A, Buffer Preamp with it's superior RFI rejecting capability (to eliminate Radio Station interference) and Low Impedance output, allowing the use of extended cable runs from the G-2™ in bypass mode. The fixed High Impedance load presented to the Guitar allows the pickups to operate at their optimum, even when several effects units are connected after the G-2™. The Unity Gain Buffer also prevents "Ghost Distortion" being audible in Bypass Mode. This effect unit gets the most benefit from being fed into a clean, full frequency response amplifier and I recommend that when you receive your pedal you connect it up without anything else in line, just Guitar/Pedal/Amp, and discover the way the controls interact, both with themselves and the guitar/amp controls. Then adding the rest of your effects, you may find that you need to make slight adjustments to these as they are now being fed with a constant signal when the G-2™ is in Bypass Mode.





[updated 15th July 2014]




And the wiring diagram for buffered bypass with all the peripheral wiring removed to simplify it.  You can see the first two poles are linked meaning that if a contact on one of the poles fails, then the switching will still work, and so it's adding redundancy.  But you really don't need to do that if you prefer not to, you can just use a DPDT and use a single pole instead of the linked pair.




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99 comments:

  1. Tried to hold myself back, but dould stand it any longer...

    Soooo... It's a Big Muff with a buffer....
    +m

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    1. I drew up my own vero and built one of these a while ago, and IMO, it smokes a big muff.

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    2. John, I think you mentioned on talkbass that this is one of your fav bass fuzzes. I built the Musket and love it and am interested to try this one... does it need any mods for bass?

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    3. well, its one of my favorite 'muff type' fuzzes for bass. on mine I replaced the two of the 47ns with 150n's (the one connected to lug 2 of the sustain pot, and and the one connected to the Emitter of Q1. I also reduced the 10n on Q1 to a 1n for a bit more to end since I thought it sounded a little dark.

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    4. Musket, Pharaoh, Iron Bell, Fire Red Fuzz and probably 100 more circuits all smoke BMP. But all of them share the same circuit footprint, with more or less component value changes.
      +m

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    5. Yes John I thought that 10n at Q1 looked too large as well. Probably one worth socketing.

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    6. I agree with miro. the fire red fuzz is an awesome BMP type fuzz.

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    7. The FRF is on my short list to build but I've slowed on the fuzzes since I finished the Musket.

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  2. This reminded me that I've got a G2 build sitting in a drawer based on the Dirk Hendricks schematic.

    I tried a few of the usal Ge diode suspects (1n34a, 1n270, 1n60) but they all resulted in a very very light amount of distortion compared to 1n914s. I had meant to try some Ge in series to change the forward voltage but never got round to it.

    Any suggestions for good diode options?

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    1. Funny you mention....I put a few G2's together from another popular layouts site and found the same thing. 1N34, 1N60 and OA91's all produced much less saturation than the demo vids.

      Tried the plain jane 914s and it sprang to life! Ended up settling on a combination of 914s, BAT41s and BAT46s. I found using the BATs in the last gain stage helped tame the raspiness of the 914s in the first stage. Very pleased with the result and sounds pretty close to the original.

      And as John and Mark mentioned, I also lowered the 10n to 2n2 at Q1 as it was too dark even for a tele bridge pickup. Also makes the tone pot a little more useful.

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    2. The problem with replacing the diodes with silicon, is that you're basically just left with every Big Muff that has come before and after it (well most of them). If I was going to mod it, I'd probably be more inclined to keep the germaniums and push it a little harder from the first stage. The 680R at the emitter is much larger than you usually get in this circuit, 15K and 680R gives a gain of around 22 compared to (for instance) 15K and 100R in the Triangle giving around 150. I'd put a 1K trimmer in there, drop it down and see where that got me.

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    3. Hi Ciaran, I had some BAT41s which I was thinking of using in conjuction wit a GE pair so may give them a try.

      I agree with Mark though that putting silicon diodes in seems to remove the main thing that makes a G2 distinctive - this is why my build has sat in a drawer for ages!

      I'm sure I remember reading somewhere in the monster long freestompbox topic that voltages were key with the Ge which is why I was thinking of trying some Ges in series.

      Like a fool I didn't bookmark the page and so will need to search through the posts again!

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    4. Mysteriously deleted comment... Anyway, what I said was to try it and see what you think. I've recently rehoused mine in a horrifically painted box so I may dig it out and try Marks trimmer suggestion while its still fresh in my mind. I'll report back.

      Good luck

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    5. I'll be interested to hear how that works out Ciaran.

      I found the diode info from freestompboxes.org and had remembered it the wrong way: Dirk measured the original unknown Ges as having a Vf of 220mV which is typically lower than modern Ge diodes.

      If anyone's got a good sounding G2 build then I'd be grateful for info on what diodes they used.

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    6. Right I found my old build in the back of the drawer, not much clipping with all Ge diodes. Took out the first pair and replaced with two BAT41s and it now sounds pretty close to the youtube sound clips.

      What is interesting is that I haven't got any of the bassy/dark issues that some people experience. My amp is pretty dark sounding too and so I do have to reduce the bass on some pedals to compensate.

      I didn't use this layout for my build, I used a DIY muff PCB with various daughterboards to recreate the Dirk Hendricks schematic. As well as the effects buffer I also included the bypass buffer which is split either side of the main effect circuit - not sure if that would eliminate the bassy issue?

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  3. Every time I think I'm going to take a little break from building....

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  4. in both stages with germanium diodes the pedal is a real crap, bassy and moody ,the only way to make it sound a bit acceptable is first stage silicon second stage germanium or schottky diodes

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    1. i disagree completely. i'm using germs in both satges in mine and it sounds awesome.

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    2. What diodes have you used, John?

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    3. I used 1N34A's. I built mine about a year ago but used a different vero layout.
      mine is a smaller vero at 21x16, but it does have a lot of stand-up resistors.

      http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/Cornish/CornishG2VERIFIED.png

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    4. Hey John, I was just looking at your layout for the G2 and I was just wondering if the resistor by the +9V hole is a 1N4001. I can't make it out. What is if for?

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    5. it's not a resistor, it's a 1N4001 diode used for polarity protection (which is a common feature in a lot of pedals)

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    6. Ooops, my mistake. I actually meant to type diode. That is what I get for doing this at all hours of the night. Sometimes it is the only time I can get a few solid hours without child interruptions. Thank-you

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  5. for everyone it is personal taste , but with germaniums in both stages is miles away from David Gilmour's tones , can not be compared to the real one , with 1n34A in both stages is gainless

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  6. I build this vero today, but with minor luck. It only sounds when the tone and gain controls are at max, strange. Although when it sounds its quite nice. Anyone built this vero? I will have a look at my vero for problems.

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  7. Okay, now it works. :-D Change the Gain pot to A50K and put a 100K resistor from Bias to ground at the last gain stage.
    For the record I used germanium diodes, 1n270 and 1N277. Sounds very nice but a little dark.
    Cheers!
    /Mr Andersson

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    1. Oh that's so annoying, the schematic I did it from didn't have that bias resistor and I thought it looked peculiar but just left it, and it showed a 470K log. I just checked Madbean's Darkside documents and it's there and the pot is 47K. Grrrrr.

      Anyway thanks for the heads up, I've updated the layout. I had to move a couple of things around to accommodate it, but if anyone is in the middle of building it, just solder a 100K resistor from the 390K resistor lead to ground (or push the lead of the 100K in the same hole if it will fit). Doing that and swapping the pot to 47K should get it right for you.

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  8. I have built both the buffer as well as the G2. I love the way that they both sound. I am a total newbee and was wondering if anyone has a picture of both together on the switch. I would love to make it exact with the buffer and the G2 together. I really appreciate the help.

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    1. I'll do a little diagram of it and post it in the main topic, but it won't be until tomorrow now

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    2. Thank you so much!!!! You are AWESOME!!!!! I am so stoked. I will test it and let you know how it works. I really appreciate it.

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    3. Good morning , I just finished G2 ( clone ) and I found that it work really really bad . It tone is dark and muddy. Transparent ???? Like a muddy water , the tone control is trash !!! When i turn down the ton pot the tone is worst ever. Have you a suggest for me ? The layout and connessions are correct of course . Thanks in advance

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    4. Without transistor pin voltages we have nothing to go on, but if it sounds bad then that suggests there is a problem with the build either in terms of layout and/or connections, or faulty components. The voltages will give a better clue.

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    5. Good morning Ivlark , I will send to you the pin voltage of All five transistors. Anyway I controlled all connections by magnifier lens and the layout is correct. Many thanks in advance for your kindly attention and eventually help.

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    6. Good afternoon Ivlark , I changed D3-D4 with BAT41 and I ow of cap value from 10n to 1n. . Now the sound is bit better but when i turn down ( half ) the gain pot the tone still muddy too .I measured voltages pin transistors. The first near vol.3 and ton.2 wires are : E= 1,17V. B=1,76V. C=4,64V , down the second near gain1 wire are: E=0,19V.B=0,76V. C=4,62V , down the third in half the board are : E=5,33V . B=5,86V. C=8,94V , up the fourth near D1-D2 are :E=0,013V. B=0,77V .C=4,65V, up the last near D3-D4 are : E=0,032V. B=0,614V. C=3,77V. Power supply is 9,45V.Can you give me suggest for to avoid the muddy tone when I turn down Gain control ? I am in the same condition of "INFO"

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    7. EXCUSE ME . Many thanks for all

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    8. Good afternoon Ivlark , I changed D3-D4 with BAT41 and I ow of cap value from 10n to 1n. . Now the sound is bit better but when i turn down ( half ) the gain pot the tone still muddy too .I measured voltages pin transistors. The first near vol.3 and ton.2 wires are : E= 1,17V. B=1,76V. C=4,64V , down the second near gain1 wire are: E=0,19V.B=0,76V. C=4,62V , down the third in half the board are : E=5,33V . B=5,86V. C=8,94V , up the fourth near D1-D2 are :E=0,013V. B=0,77V .C=4,65V, up the last near D3-D4 are : E=0,032V. B=0,614V. C=3,77V. Power supply is 9,45V.Can you give me suggest for to avoid the muddy tone when I turn down Gain control ? I am in the same condition of "INFO"

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    9. Your voltages look ok to me, so maybe it is working as intended but just doesn't match well with your gear. So I'd look at altering it to try to reduce the bass content and the first thing I would try is replacing the lowest 47n cap near the input with a lower value. Try 22n or 10n and that should reduce the bass content entering the circuit.

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    10. Thanks again Ivlark for your quickly answer . I think the same thing about to low cap near input but I wait your answer about correct voltages or not . I assembled a Cornish buffer also but nothing change. Anyway I think that a Jan Ray or Zendrive sound are many many better , its only my opinion of course. Have a nice weekend.

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    11. Ok Ivlark . I substituted both 47n caps on gain 2 wire and near input wire with 10n.It now sound many times better although when turn down the gain pot the tone is muddy trend. I use simple instruments : a 89' E.C. strat and 73' L.P.Custom , Deluxe Reverb , Blues J. and 62' VOX AC30 amplifier. I seem that it's are not a particular gear.Anyway I remain on my opinion about tone trasparency, Jan Ray and Zendrive are in another planet. Thanks again for your help.

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  9. Hi all! Today finally had some time to try this circuit. Well, in my opinion, this circuit is not correctly traced.

    As per Dirk's schematics, it just sounds like pure shit: not fuzz, not distortion, nor overdrive, just a muddy cleanish and ugly sound.

    All suggested mods, try to get rid of the greasy lows, and to swap the germanium transistor with silicon ones in order to increase gain, but no one, using sheer germanium diodes has got good results, or similar to the original. Ok, Johnk with his layout, did get it working, but he's the only one, including all the people at FSB, and some other diy sites. Everybody, including Madbean people, has changed, at least partly, germanium with silicon, caps values, pot values and so on.

    I agree with Mark, with the 680r from emitter to ground at the first stage, added to the double clippin stage with germaniums in 2 and 3 position, there's no way to get enough volume and gain.

    Besides Dirk:
    -Was mistaken with the gain pot value.
    -Did not remeber if he checked the vf of the trannies. Finally did tell that he checked them, and that they were about 0.220v vf........ shit, this is extremely too low fv, the output would be heavyly affected.

    Well, I have even 0,19v vf germaniums, I've tried them in the coircuit and the sound is low and plain (muddy) clean, no trace of overdrive unles you hit the strings with a hammer.

    Have tried too with germaiun in one stage and silicon on the other, and changing order. With Ge in stage 2 and Si in stage 3, there's nice sound, but low gain and volume. With Si on stage 3 and Ge in 4: cleanish sound and no gain. Best results habe been obtained with 1N4001 on all positions, creamy sound and noce volume and gain, but tends to be muffesque

    Tomorrow i'll follow Mark's advise and put a 1k pot instead of the 680r and see what I get.

    J.

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  10. Well, after many mods to the circuit, it "reminds" of the original. So, I'd say again: this effect is not correctly traced. It works, that's ok, but as per schematics, it sounds shit, and after heavy moddin' it reminds of the original.

    Checking the schematic, there's no way that with 640r resistors from emitter to ground and 15k from +9 to collector, (q1 and q2 of the muff like part) you can push hard enough two clippin' germamium diode pairs and get enough output and gain. If the diodes are, besides, as recommend of ~0,2vf, then there's absolutely no fucling way to get the circuit even at unity level.

    I've swapped the 680r resistors with 100r ones. The first diode pair is 1N4001, and the second pair, germanium, with 0,19vf each.

    If you try the modded effect on a solid state amp, sounds like shit, no matter what settings you use with the amp knobs.

    On the other hand, using it in a valve amp, and setting it low on bass, and high on treble, the sound reminds a lot to the demo videos you can see on the net, but no way 1:1.

    I'd say: don't waste time with this build, is worthless any effort. Let's hope someone does a good reverse of this pedal, because this schematic is no way correct.

    J.

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    1. IMO, that's really strange cuz mine sounds awesome.
      i'll post a soundclip of it tomorrow.

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    2. Well, take in mind that you layout is modified too, specially in the input buffer, 10n instead 220n in the input cap, and 1n instead of 10n between base and emitter.

      This means to get rid of a lot of bass, one of the most extended claims of builders. As I told before, tweaking values, and using this effect on a valve amp, can get good and similar results to the original, but if you have to change values, diode types and so on, the only thing for sure is that the effect is not correctly traced.

      Thin for example of the Klon Centaur, no one knows which diodes are used in the real thing, but from germanium, to silicon, with schottky, or even zener diodes, will sound ok. This trace is extremely bassy and dull, with low gain if you build it by the schematics, and if you use, besides, 0,2v fv germanium diodes, as Dirk seemed to remember, then the result is pure shit. I've tried it with 4 germaniums (1n34) that I have marked as defective (0.65v vf) and sounds ok.

      I firmly believe that Dirk made some error(s) in the trace values. Is not sure even if he checked the diodes, as he didn't even remember if he checked them, just said "germanium", as they were gooped, while a 1N4007 gooped (for example) is hard to tell from a do-7 germanium.

      No doubt your unit sounds great, but is a modfied board too.

      J.

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    3. As you say mate, in the original the bypass buffer was always in circuit, so I wonder what affect that will have if added. Do you have a standalone Cornish Buffer that you could plonk in front of it to see if it alters anything? The values used in the standalone Cornish Buffer here are exactly as per the bypass in the G2.

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    4. Nope, but I have the vero cut for it :P, so this afternoon will build it as is a five minutes job, and we'll see if it affects the overall tone.

      J.

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    5. Oh, fuckin shit, Mark anf Kitrae gave me the final hint!

      First and most important: the input buffer is mandatory. Has a 100nf input cap, so cuts lots of bass, that are uncut with the initial onboard 220nf. It has too a 1nf cap between base and emitter, the change that John does in the main board. Well, we have now some bass cut that we didn't have before.

      As I didn't trust Dirk's trace, I've been searching schematics, traces, and all that I could use to compare and finally Kitrae, seemed to confirm Mark's suspictions: in the firs stage of the circuit, after the two buffers, a 15k collector + 680r emmiter to ground, was difficult to push the following clippin stages, if done with germanium pairs, so, in Kitrae's schematic, you can see a 18k collector resistor, and a 100r emitter to ground resistor PLUS an input cap of 47nf.

      So, after a first buffer, a high bass cut, and a more gainy first stage + 2xAA143 in the first pair + 2x1N34 as the second clippin' pair + a valve amp what do we get?

      A fuckin' working effect, verbatim to the demos, and hard to believe that is based in the Big Muff schematics :)

      This one's been a real bitch, but finally here are the results. Thanls Mark, Kitrae and everyone that can be interested :)

      J.

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    6. Nice one. I'll change the input buffer values to match the bypass buffer and make that change to the first stage. Good work buddy

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    7. Thanks mate :) Finally, I've used AA143x4, as the sound gets meven rounder . Sadly, they were my last ones :(, have to tell to my local store man than he has to check again his old lockers, to see if he finds more or similar. These are by far the better germanium diodes I've ever tried. Constant 0,35v vf, and not a faulty one in the whole batch I purchased a year and a half ago.

      It's funny, how now this effect can get even too bright when gain and tone are fully rolled up.

      J.

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    8. Guys wich one is the real deal? Top pic or bot pic?

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  12. Hi,
    If you build it with the buffer do you use the 18K/100R or 15K/680R combination?
    Does the buffer improve the sound of the pedal?
    Thanks

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    1. I'd use the 18K/100R no matter whether I was using a bypass buffer or not. The 15K/680R combination doesn't give enough gain from the stage IMO.

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  13. I just made the pedal using the updated layout, and it barely distorts and gets to unity volume. I triple checked everything, and used the Cornish input buffer. Is the modified layout verified yet?

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  14. I really appreciate your help. I have wired the buffer and the G2 together as per the diagram. I have encluded a link to dropbox which have the pictures of wiring. My issue is that the light will not light up though the switch does engage the pedal. I have switched with a brand new 3pdt and checked the LED to make sure that it is not reversed. If I connect to a DC adpter using aligator clips and the current red positive and black negative the light works fine. At this point, it seems like a wiring issue. I have 2 other pedals in line as you can see the wiring and they light up fine. I like the way that this is wired because it always leaves the buffer engaged for the chain whether the pedal is on or not. Please assist me to figure out the light. Thanks again.

    Dennis
    Pictures of wiring are as follows:
    https://www.dropbox.com/sh/jkfml2m8pzhtytz/AADXXniOxQ_aOO2P9eLnZuIVa?lst

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  15. I just looked at the picture and compared it to the diagram. I might have the posts on the switch reversed. It looks like the diagram shows the negative away from the post. I will try it when I get home. That would explain why the light will not work. I will try it and post the results. I do agree as per the previous posts that it sound a lot better with the buffer. I really like the pedal. Thank you again for all that you do. I love this forum.

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    1. I figured it out. I looked at your diagram and then looked at my wiring. I realized that it will not work without power. I then wired the 2nd post to my power and it worked. Your wiring diagram was awesome, I just read it wrong. Thank you again.

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  17. Hi there, thanks for the layout, does anyone know if I could use a BC550 instead of the BC549 for the buffer transistor, straight drop in? Thanks!

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  19. Built this using BC549c, 1N34As in D1 an D2 and 1N270s in D3 and D4 and its awesome. Socketed all the important bits so i could mess about. This will keep me happy until next weekend.

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  20. I truly love this pedal. I have created a newer version. I have found that I like the tone with the 1N270 Diodes the best. Here is a picture of the board that I just built. I hope it helps someone.

    http://s1383.photobucket.com/user/denfox1/media/Cornish%20G2_zpsqibz0w5g.jpg.html?sort=3&o=1

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  21. Hello everyone! I'm going to build this pedal soon. All I have is bc549b. I know that the difference between b and c is the c has higher gain. My q's is if the gain is not enough is what resistors may I change to get more gain? Or will it even matter that much just find the highest gain b' s I have? Thnx much for any input!!!!!!!

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  22. Cool thnx john! I'm going to use your layout.

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  25. I am finding that this G2 seems very dark compared to my friends actual cornish SS3/G2 combo pedal. I socketized the diodes so I can test other diodes and have tried BAT41's, 914's and even 1n270's on stage 2 with 914's on stage 1. Does anyone know the actual diodes that Cornish uses or have any suggestions. Here are pictures of my build. I did a SS2/G2 with buffer on the input. I really appreciate any help.

    Here is my build
    http://s1383.photobucket.com/user/denfox1/media/20150910_053411_zpscselcnhe.jpg.html?o=0

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  26. I decided on the 914's in stage 1 and the bat41's in stage 2 and it sounds awesome!!!

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  28. Would adding the input buffer help boost the overall volume level? And what's the point of the D5 on the ground?
    Thanks!

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  29. Can anyone help me? I'm a newbie and I cannot go on. Please, Can you send me complete wiring of G2 with Buffer? Thanks a lot.

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    1. hi' I'm a newbie myself. I think you are better build the standalone buffer layout (IvIark has posted its link above) and then include it as a dougther board. go to offboard section of the site and use the switchable boost wiring diagram.good luck

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    2. Thank you ashkan.
      I thought that someone could show me, with a drawing, the complete wiring.
      Thank you all anyway

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  30. Hi
    I bought the kit BitsBox. My realization has unfortunately too little distortion.
    Please, someone has found a solution to the problem?
    Thank's

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  31. hello i have build my hown G2 with your shematic but when i'd try there is any sound through the pedal :( i dont know why please anybody have an idea?

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  32. Hey guys, I solved the darkness issue last night. Going by the BigMuffPage FSB/ Madbean schematic trace, replace C10 (1n) with a 100pF and the circuit comes to life! It sounds spot-on the demos with germanium diodes in the .33fV range (measured by Atlas).

    Here's the schematic: http://www.bigmuffpage.com/images/schematics/Big_Muff_Overdrive_G2_Schematic.jpg

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  34. Hello,

    First, I apologize for my English.


    I have built this version:

    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/Cornish/CornishG2VERIFIED.png

    With 1N capacitor left low as indicated by JhonK.

    I have NOT built Buffer added because I already have a buffer pedal on my pedalboard before the pedal chain.

    I have left the resistors of 680R and 15K. I hear it right now.

    What result will I get if I change to 100R and 18K ???? I see that this topic is being talked about here, but I do not know what this change is for.


    Diodes:

    I have used in the first ethane 2 germanium 1N270 (I have not found difference with 1N34A !!!!!!)

    And in the second one silicon 1N914

    The possibility of putting the 4 diodes 914s I did not like,
    With the 4 diodes 914s I have sounded too fuzzy, undefined and like horses with no control.

    ... for those sounds I already have other pedals.
    With this combination of 1n270 and 914's the sound is balanced and not very salvage.

    That if, this pedal is not a fuzz with long sustain, is "sustain normal" quite controlled.

    Some photos of the final project:

    http://s1033.photobucket.com/user/josepqr/media/IMG_0307_zps8uwbvmbk.jpg.html

    http://s1033.photobucket.com/user/josepqr/media/IMG_0302_zpslsdxmt1e.jpg.html?sort=3&o=7

    http://s1033.photobucket.com/user/josepqr/media/IMG_0300_zpsdn2affim.jpg.html?sort=3&o=0

    http://s1033.photobucket.com/user/josepqr/media/IMG_0301_zpstsjzr7x2.jpg.html?sort=3&o=1

    http://s1033.photobucket.com/user/josepqr/media/IMG_0304_zpsh5e8v2dc.jpg.html?sort=3&o=4

    http://s1033.photobucket.com/user/josepqr/media/IMG_0303_zpswje46nie.jpg.html?sort=3&o=3

    http://s1033.photobucket.com/user/josepqr/media/IMG_0305_zps89t4fl6n.jpg.html?sort=3&o=5

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  35. Can anyone help please, why is there no circuit output marked on the diagram?

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  36. it clearly says volume 2 to output

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  37. Hello folks, can I wire up the buffer in series and box the effect normal wiring with good affect? Thnx!

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  38. Just finished mine, it's great! (Buffered version)
    Thanks guys!

    https://hgecontraptions.blogspot.ro/2018/01/cornish-g-2-clone.html

    ReplyDelete
  39. I also build this Version
    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/Cornish/CornishG2VERIFIED.png
    with 1n34 diodes, but why is the G2 so quiet compared to a big muff?

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  40. it has a lower output volume because germanium diodes have a lower forward voltage than standard silicon 1N4148 diodes.

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  41. I have build this using 1N60 diodes with forward voltage of 0.38V. Although I have used 100/18K resistor combination instead of original 680/15K the volume is too low, tone is muddy and almost no breaking. Based on comments so far I expected this combination to at least produce decent volume. Should I experiment with different diodes or something is wrong with my layout?

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    Replies
    1. Something is wrong with your layout. It should work perfectly.

      Delete
  42. Just to clarify my build is as per schematics here that are different to original Dirk tracing which is:
    no buffer - input capacitor of 220n is replaced with 100n
    10n capacitor between base and emitter on Q1 is replaced with 1n
    680R emitter resistor on Q2 is replaced with 100R
    15K collector resistor on Q2 is replaced with 18K
    Here is some readings:
    transistor voltages
    Q1 (E=2.23V, B=7.7V, C=8.2V)
    Q2 (E=0.025V, B=2.7V, C=3.2V)
    Q3 (E=0.2V, B=3.1V, C=3.7V)
    Q4 (E=0.025V, B=3.2V, C=3.7V)
    Q5 (E<0.001V, B=3.8V, C=4.4V)
    battery is showing 9.2V

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  43. Hi everyone. I tried this build last night and i'm running into a real weird problem. I've troubleshot just about everything but basically, I get a bypass signal but no sound when the pedal is on.

    While the pedal is on but isn't making any sound, I can still hear the controls doing stuff to the hiss that my amp is making (volume control works, tone does a sweep, the sustian control adds more noise when brought in). but still no fuzz.

    I tried probing the problem tonight and starting from the input, I was able to get a clean sound (not fuzzy) as far as the row that the 1st transistors collector is on where I dont get any sound and i cant get sound further on the circuit from there. I assumed the 100u electro cap that is on that same row could be the problem so I replaced that but still have no fuzz or any sound at all. My build uses the buffer circuit and I know thats not the problem. I also have mine built exactly to the diagram noting the very slight change in placement of one of the 39K resistors that differ between the diagrams with the buffer in play and without.

    In saying all that, does anyone have any idea where I go from here in probing the circuit and figuring out what component is at fault? I've checked my wiring, cuts, polarity, placement, and jumpers and transistor pinout and im just about clueless. thanks for any help in advance.

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  44. This comment has been removed by the author.

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  45. Finished my second one. For those who are wondering, this particular one as stated above, being with the Germanium diodes , DOES have a much lower volume, so unity is about 2 O clock on gain + volume. It is normal! The first one built was identical. I've built this one buffered also

    Thanks again guys!

    https://hgecontraptions.blogspot.com/2019/04/pete-cornish-g2-hge-contraptions-clone.html

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  46. Hello and good luck everyone. I need your help dear pedal builders. I soldered the G-2, but there is no sound. At the maximum values ​​of the gain and volume potentiometers, the sound appears (in the form of a crackle, similar to a dirty fuzz) for 0.5 - 1 sec and disappears. I checked the board for errors - everything is correct. I checked the signal flow with an audio probe and found out the following. There is a signal at the base of the transistor of the last stage. But there is no signal on the collector. I tried to short-circuit a capacitor (22 mF) connected to the emitter of this transistor and through a resistor to ground, the sound appears. I replaced this capacitor, but the problem persists. Can you please tell me what could be the problem and what does this capacitor do? I use BC549C in my circuit. Maybe someone has any ideas, I would be very grateful for any help or advice.

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  47. Would it be possible to jave a tagboard version?

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