Chuck D. Bones
Circuit Wizard
You've read the hype, you've heard the demos, maybe you've even built one. It allegedly makes the "Imminent Amplifier Death" tone. Here's my take on it.
The NG-2 is basically the first half of a Big Muff driving a Tone Bender Mk II with a treble cut at the end. Seems simple enough. Mr. Cornish tuned the gain, bias and EQ of each stage to achieve the desired result. Some users wanted the internal Bias Trim to be on the front panel. I don't know if Cornish built any like that, but the NG-3, the successor to the NG-2, has a somewhat similar architecture with the BIAS knob on the front panel.
I built my breadboard per the Nugget schematic, except I subbed 1SS98 Schottkys for the 1N34A clipping diodes. I picked up some 1SS98's and tested them for leakage. The leakage is quite low, the equivalent of around 1.8MΩ. The compression in the 2nd stage provides a generous helping of sustain. The amount of sustain is controlled by VR1. This makes me think that the names of the SUSTAIN & DRIVE knobs should be swapped.
I tried different Bias Trim settings and I agree, the BIAS pot belongs on the front panel. I reduced R20 to 3.9K so that when BIAS is at 10 (max resistance), the clipping in the last stage is symmetrical. Gating sets in somewhere below noon, depending on the settings of the SUSTAIN and DRIVE knobs.
The tone is quite thick with plenty of bass. Too much bass in my opinion. So I added a 22nF cap in series with C3, and a FAT switch to short out the 22nF cap. Now I can have it both ways.
C10 could be returned to either Vcc or GND. GND is almost always my preference, but either way works.
Like in the NG-3, I changed the TONE network to a BMP-style tone control. The freq response is more-or-less flat with TONE at 4 (11:00).
I changed LEVEL to A100K for a better sweep.
There is a lot of gain (over 100dB), it does some interesting stuff and with the BIAS & TONE mods, produces a wide range of tones. Try it you might like it.
Ref des match the Nugget schematic. R101 is optional.
Knobs: (L-R) LEVEL - TONE - BIAS - FAT - DRIVE - SUSTAIN
The NG-2 is basically the first half of a Big Muff driving a Tone Bender Mk II with a treble cut at the end. Seems simple enough. Mr. Cornish tuned the gain, bias and EQ of each stage to achieve the desired result. Some users wanted the internal Bias Trim to be on the front panel. I don't know if Cornish built any like that, but the NG-3, the successor to the NG-2, has a somewhat similar architecture with the BIAS knob on the front panel.
I built my breadboard per the Nugget schematic, except I subbed 1SS98 Schottkys for the 1N34A clipping diodes. I picked up some 1SS98's and tested them for leakage. The leakage is quite low, the equivalent of around 1.8MΩ. The compression in the 2nd stage provides a generous helping of sustain. The amount of sustain is controlled by VR1. This makes me think that the names of the SUSTAIN & DRIVE knobs should be swapped.
I tried different Bias Trim settings and I agree, the BIAS pot belongs on the front panel. I reduced R20 to 3.9K so that when BIAS is at 10 (max resistance), the clipping in the last stage is symmetrical. Gating sets in somewhere below noon, depending on the settings of the SUSTAIN and DRIVE knobs.
The tone is quite thick with plenty of bass. Too much bass in my opinion. So I added a 22nF cap in series with C3, and a FAT switch to short out the 22nF cap. Now I can have it both ways.
C10 could be returned to either Vcc or GND. GND is almost always my preference, but either way works.
Like in the NG-3, I changed the TONE network to a BMP-style tone control. The freq response is more-or-less flat with TONE at 4 (11:00).
I changed LEVEL to A100K for a better sweep.
There is a lot of gain (over 100dB), it does some interesting stuff and with the BIAS & TONE mods, produces a wide range of tones. Try it you might like it.
Ref des match the Nugget schematic. R101 is optional.
Knobs: (L-R) LEVEL - TONE - BIAS - FAT - DRIVE - SUSTAIN
