Pete Cornish - NG-2

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Re: Pete Cornish - NG-2

Postby andy-h-h » 15 Jan 2019, 07:39

Jim-Analog wrote:Greetings,

Good work on the Vero layout Andy! I'm curious what you think of the sound of the circuit as you built it and what (if anything) was your point of reference (a recording, live show, other pedal, etc.)? In general, in what ways do you find the pedal useful? Thanks for any info.

Regards, Jim



Hi Jim

It’s just a really thick sounding fuzz, and you can get a bit more variety out of it in terms of sound compared to a lot of other fuzz pedals that tend to be one trick ponies. It hasn’t changed my life or made me a better player, but I do like this one a lot. I have two that I can’t decide between. One all silicon in the last stage, the other germanium / silicon in the last stage.

The layout could be a few rows shorter, but I like to have a bit of space on a board and I almost never use 150Bs to box.
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Re: Pete Cornish - NG-2

Postby sopapo1 » 16 Jan 2019, 05:04

Hello, first of all, thank you andy for your work on the nugget/ng2, I am very interested in this "build"... I have several questions, why the suggestion of using a ge tranny on the last stage ? and the same question is for de ge diode.
In the cornish page, he says that the "stabilized ge stage is first".... and that its have three stages...

This pedal doesnt have the buffer that have almost all cornish pedal? in his page he doent says anything about if its buffered, while in the p1 page he stated clearly that its double buffer isolated (I/O)....if the original have the buffer in front, i would say that its imperative that this build has to have the buffer to sound proper, like other cornish designs (g2 etc...)
Do you think the tone is similar to this clips of the original?:

https://www.youtube.com/watch?v=aX0FX-PT0Dk

https://www.youtube.com/watch?v=be7zMnCmwOg

Thank you for your time
Best regards
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Re: Pete Cornish - NG-2

Postby palelight » 16 Jan 2019, 09:56

sopapo1 wrote:Hello, first of all, thank you andy for your work on the nugget/ng2, I am very interested in this "build"... I have several questions, why the suggestion of using a ge tranny on the last stage ? and the same question is for de ge diode.
In the cornish page, he says that the "stabilized ge stage is first".... and that its have three stages...

This pedal doesnt have the buffer that have almost all cornish pedal? in his page he doent says anything about if its buffered, while in the p1 page he stated clearly that its double buffer isolated (I/O)....if the original have the buffer in front, i would say that its imperative that this build has to have the buffer to sound proper, like other cornish designs (g2 etc...)
Do you think the tone is similar to this clips of the original?:

https://www.youtube.com/watch?v=aX0FX-PT0Dk

https://www.youtube.com/watch?v=be7zMnCmwOg

Thank you for your time
Best regards


I'll leave the Ge transistor question to andy. The ge diodes (clipping pair) form what Pete calls the "the second stage; a stabilized “Germanium” preamp which overloads smoothly when overdriven" not the first stage. The first stage is lifted from the tone recovery stage of a standard BMP (or the entirety of the LPB-1 if you like), a simple silicon boost circuit. So you have in order, a LPB (q1)going into a Ge version of a BMP style clipping section (q2) into a basic 2-transistor style fuzz (ala a Fuzz-face, q3&4) with a volume/tone recovery at the end of the chain (q5).

Not every Cornish pedal has double buffer's like the G-2. And given the few gut shots floating around of the NG-2 I'd gather (just my opinion, could be totally wrong) it's one buffer. And Mr. Cornish does state that it's buffered on the product page. But you're correct, the input buffer in a circuit like this is important if you want the same blocking distortion or 'sag' effect you hear in the original demos. Having built two of the Nugget boards (which Andy based his layout on), I'd say, yes it can absolutely sound like the vids you posted (and a bit more extreme to be honest). The Cornish buffer layout from tagboardfx works just fine if you end up doing a buffered version.
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Re: Pete Cornish - NG-2

Postby sopapo1 » 16 Jan 2019, 15:46

Thank you very much, palelight, so do you build two with the boards pedalpcb??
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Re: Pete Cornish - NG-2

Postby palelight » 16 Jan 2019, 17:01

sopapo1 wrote:Thank you very much, palelight, so do you build two with the boards pedalpcb??


No problem. And yup, both used PedalPCB boards.
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Re: Pete Cornish - NG-2

Postby andy-h-h » 16 Jan 2019, 23:05

sopapo1 wrote:Hello, first of all, thank you andy for your work on the nugget/ng2, I am very interested in this "build"... I have several questions, why the suggestion of using a ge tranny on the last stage ? and the same question is for de ge diode.
In the cornish page, he says that the "stabilized ge stage is first".... and that its have three stages...

This pedal doesnt have the buffer that have almost all cornish pedal? in his page he doent says anything about if its buffered, while in the p1 page he stated clearly that its double buffer isolated (I/O)....if the original have the buffer in front, i would say that its imperative that this build has to have the buffer to sound proper, like other cornish designs (g2 etc...)
Do you think the tone is similar to this clips of the original?:

https://www.youtube.com/watch?v=aX0FX-PT0Dk

https://www.youtube.com/watch?v=be7zMnCmwOg

Thank you for your time
Best regards


Hello

I tired germanium transistors in the last stage, as it appears to be loosely based on a fuzz face, so why not... The first stage is just a clean boost, the second stage is the same as a clipping stage of a G2 (a modified big muff clipping stage), and then it's followed by the fuzz face type circuit. I tried a germanium transistor in the second stage, and it didn't make a huge difference, where it made a very noticeable difference in the last stage. A G2 doesn't use germanium transistors, just germanium diodes.

I tried a germanium diode to join the second and last stage as I had a dead silicon diode in one build that needed replacing, and I just happened to have a germanium diode sitting in front of me at the time - I tried it and liked it, so it stayed.

I didn't include the buffer here, as there's already a nice vero layout floating around already. Easy enough to build and place in front of this if you want it. Check out the G2 on Guitar FX Layouts as it has the wiring diagram for the buffered bypass, if that's how you want to wire it. The buffer didn't make a massive difference to the sound for me. But I was testing it on a rig with very short leads, and the amp was not opened fully opened up. This may be a factor.

And to answer the most important question - yes it sounds very much like the clips. Very important to play with the bias setting on this pedal with guitar plugged in and amped up to get the sound in a happy place.
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Re: Pete Cornish - NG-2

Postby sopapo1 » 17 Jan 2019, 07:43

Thank you very much Andy, and what about the noise? Its a silent pedal? The layout is critical for low noise??
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Re: Pete Cornish - NG-2

Postby andy-h-h » 17 Jan 2019, 08:27

sopapo1 wrote:Thank you very much Andy, and what about the noise? Its a silent pedal? The layout is critical for low noise??


It's not silent, but I don't find the noise to be a problem, I'd say the noise floor is acceptable, especially considering how much fuzz it produces. All my gear is running off a Furman power filter, so I have a few issues already taken care of before the power even hits the pedal.

I can't really say much about the layout though in terms of contribution to noise, as I've only built this pedal using my layout, so I can't directly compare it to others.
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Re: Pete Cornish - NG-2

Postby palelight » 17 Jan 2019, 22:59

sopapo1 wrote:Thank you very much Andy, and what about the noise? Its a silent pedal? The layout is critical for low noise??


By silent do you mean gated? Cause with the bias set high enough (after 2o'clock on the bias pot), it can be very gated and silent when you're not playing.
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Re: Pete Cornish - NG-2

Postby sopapo1 » 21 Jan 2019, 00:02

Hello Palelight, I was refering more to the usual hiss, yes its true that a fuzz with adjusted to sound gated it will be very silent (between notes :lol: )..my diy mayer octavia is one of my most quiet pedals, more than the usual ts-type ods...
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Re: Pete Cornish - NG-2

Postby palelight » 21 Jan 2019, 00:28

sopapo1 wrote:Hello Palelight, I was refering more to the usual hiss, yes its true that a fuzz with adjusted to sound gated it will be very silent (between notes :lol: )..my diy mayer octavia is one of my most quiet pedals, more than the usual ts-type ods...


Understood. Then like Andy mentioned, it's quiet but not silent. If you were to max both gains and have the bias at noon there's some hiss but nothing overpowering.
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Re: Pete Cornish - NG-2

Postby sopapo1 » 21 Jan 2019, 10:27

Ok, thanks, I was thinking that the most convenient thing to do is to make the bias asjust with a pot, and put it in the outside with de others controls like in the ng3 version...any posible cons to it? More noise?
Its something that I always think, that using a pot instead of a good metal resistor for the critical task of biasing it will add noise, given the nature of the pots...
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Re: Pete Cornish - NG-2

Postby palelight » 21 Jan 2019, 10:51

sopapo1 wrote:Ok, thanks, I was thinking that the most convenient thing to do is to make the bias asjust with a pot, and put it in the outside with de others controls like in the ng3 version...any posible cons to it? More noise?
Its something that I always think, that using a pot instead of a good metal resistor for the critical task of biasing it will add noise, given the nature of the pots...



I noticed no difference with the bias mounted externally. The only issue you might run into, given that it's 50k, is that's very touchy. If you want to "set and forget" then an internal trimmer would be better. But with it mounted externally you get a ton more sounds out of it with no real drawbacks.
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Re: Pete Cornish - NG-2

Postby andy-h-h » 21 Jan 2019, 21:57

sopapo1 wrote:Ok, thanks, I was thinking that the most convenient thing to do is to make the bias asjust with a pot, and put it in the outside with de others controls like in the ng3 version...any posible cons to it? More noise?
Its something that I always think, that using a pot instead of a good metal resistor for the critical task of biasing it will add noise, given the nature of the pots...


I've tried it with an external 50k pot, and it was far to sensitive to be really useful (the internal 50k trimmer is also very sensitive). I'm planning on trying this with a resistor or two to set a range for the pot, and hopefully reduce the sensitivity and get a more workable range. The extremes of the biasing range for my germanium are 8k to 40k. Outside of this it either doesn't work or is completely pointless. Silicon is more forgiving.
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Re: Pete Cornish - NG-2

Postby palelight » 22 Jan 2019, 00:40

andy-h-h wrote:
sopapo1 wrote:Ok, thanks, I was thinking that the most convenient thing to do is to make the bias asjust with a pot, and put it in the outside with de others controls like in the ng3 version...any posible cons to it? More noise?
Its something that I always think, that using a pot instead of a good metal resistor for the critical task of biasing it will add noise, given the nature of the pots...


I've tried it with an external 50k pot, and it was far to sensitive to be really useful (the internal 50k trimmer is also very sensitive). I'm planning on trying this with a resistor or two to set a range for the pot, and hopefully reduce the sensitivity and get a more workable range. The extremes of the biasing range for my germanium are 8k to 40k. Outside of this it either doesn't work or is completely pointless. Silicon is more forgiving.


If you end up using some fixed resistors, please share how you make out (and what values you end up using). I'd like to try it out.
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Re: Pete Cornish - NG-2

Postby andy-h-h » 22 Jan 2019, 13:23

Hey PaleIight,

I've worked it out in my head and have a modified layout ready to try. Will let you know what I end up with after I've tested it properley. Resistors will no doubt vary depending on transistors used in the last stage.
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Re: Pete Cornish - NG-2

Postby sopapo1 » 24 Jan 2019, 16:14

the bias adjust with the trimmer (or pot) is better done entirely by ear? or around a reference voltage....
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Re: Pete Cornish - NG-2

Postby andy-h-h » 24 Jan 2019, 21:50

Hello,

Bias by ear as there are no reference voltages available (at least none that I know of) + personal taste will come into play when doing this. When biasing on the bench with a scope/FFT, I found it easiest to bias with the sustain and drive at lower settings first, and then check again with high gain. When I found something that looked and sounded good at both ends of the spectrum, it also sounded good and gave a wide useable range when I plugged the guitar in.
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Re: Pete Cornish - NG-2

Postby andy-h-h » 26 Jan 2019, 07:44

EXTERNAL BIAS POT

I ended up using a 4.7k resistor with a 25k pot for the external bias. Gave a nice range. Works well on the board I made which is using germanium transistors for Q 4 & 5. Naturally the bias range will be transistor dependant.

So resistor from the junction of Q4 collector and Q5 base, to bias 1. Bias 2 to the power rail.

For this message the author andy-h-h has received thanks:
palelight (27 Jan 2019, 07:26)
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Re: Pete Cornish - NG-2

Postby palelight » 27 Jan 2019, 07:26

andy-h-h wrote:EXTERNAL BIAS POT

I ended up using a 4.7k resistor with a 25k pot for the external bias. Gave a nice range. Works well on the board I made which is using germanium transistors for Q 4 & 5. Naturally the bias range will be transistor dependant.

So resistor from the junction of Q4 collector and Q5 base, to bias 1. Bias 2 to the power rail.


Much appreciated! I'll give it a try.
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