chongmagic
Well-known member
Would these be an equivalent of one another?
1n270 vs 1n34a
- Thread starter chongmagic
- Start date
Chuck D. Bones
Circuit Wizard
Did you mean 1N270?
chongmagic
Well-known member
Yes sorry
chongmagic
Well-known member
Thank you. I was looking through the build docs for a Cornish G2 combo I am working on and it says the 1n34a doesn't work well so I ended up ordering some 1n270s.
Chuck D. Bones
Circuit Wizard
If you believe Bill Finnegan (I do), then Ge diodes can sound different from batch to batch and from one supplier to the next. 1N34A's have a lower Vf, maybe that's why they are not recommended. I don't see a Cornish G2 Combo here. Where did you get the Build Docs?
chongmagic
Well-known member
This is not a PedalPCB board, but a combo drive with Cornish SS-2 and G-2 circuits.
Here are the build docs:
Here are the build docs:
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drive.google.com
Chuck D. Bones
Circuit Wizard
Very interesting... Contrary to what the build docs say, 1N60P diodes are not Schottky, they are Germanium. The clipping diodes in the Big Muff part of the circuit are in a high-impedance feedback loop; if they are leaky (as many Ge & Schottky devices are) they will upset the circuit operation. Given that the various incarnations of the BM use everything from JFET gate junctions to LEDs as the clipping diodes, feel free to experiment. Lower Vf diodes (Ge & Schottky) will produce more compression, however the BM has so much compression you may be hard-pressed to tell the difference.
chongmagic
Well-known member
Yeah I figured I would socket them and see what works best.
1n695 are the recommended diodes for the G2 (imho). Whereas, the 1N34a are great for the SS2. Read the comments for the other mods in the thread over at madbean SS2/G2 thread. There's some good cap/resistor suggestions in the thread.
chongmagic
Well-known member
Are those the values you used? Along with the 100pf cap change?
FWIW one of my favourite mods to do on a Big Muff is either remove entirely or add on a switch the diodes and cap on the third gain stage. (The cap is the one attached to the diodes.) The pedal still sounds much the same but you get less compression and fuzz and more touch sensitivity. It's not for everyone but I really like it. It works especially well on the Skreddy Pig Mine and P19 Muff circuits.
I didn't do the resistor mod but I changed the 3 caps and the diodes. It sounded really good. This was my second Duplex build. The first one used default values and I didn't like it. I used something besides the LM1458 which made the SS-2 sound way too bright. I highly recommend the LM1458 (which is a crappy opamp but works well in this case).
Chuck D. Bones
Circuit Wizard
Speaking of Big Muff circuitry...
The Gerkin (Swollen Pickle) has pots on both diode stages. The The Clip trimmer on the inside and the Crunch pot on the front panel are capable of effectively taking the diodes out of the feedback loop on the 1st and 2nd diode stages, respectively. In a Muff derivative of my own design, I have a 22K resistor in series with the diodes (LEDs) in the 1st diode stage and a 100K pot in series with the diodes (1N4148s) in the 2nd diode stage. That, variable bias on one of the stages, altered tone controls, and a variable clean bleed gives it quite a range of tones.
The Gerkin (Swollen Pickle) has pots on both diode stages. The The Clip trimmer on the inside and the Crunch pot on the front panel are capable of effectively taking the diodes out of the feedback loop on the 1st and 2nd diode stages, respectively. In a Muff derivative of my own design, I have a 22K resistor in series with the diodes (LEDs) in the 1st diode stage and a 100K pot in series with the diodes (1N4148s) in the 2nd diode stage. That, variable bias on one of the stages, altered tone controls, and a variable clean bleed gives it quite a range of tones.
