My experience is that cheap pots crackle a lot more than high quality pots. I only use my SHO clone for boosting vint. Strats/Tele in combination w BF-Fender amps and for every Strat seems to be a certain gain setting where it sounds good. In the near future I'll subs the pot for a rotary switch wit...

The Carl Martin stuff uses f. ex. sym. power supply too. If you build a little IC-booster like this, no I/O coupling caps and RC-networks are needed. With a good IC the result is just pure tone w/o nearly any coloration. The S. Duncan Blues amp has a input booster like this.

JHS

IMHO too much gain from the 1st stage for those GE-trannies, when the gain is maxed they can't stand this pound and the tone is unusable. I would add a trimpot after the 1st stage for limiting the max. gain and would adj. it 'til the sounds starts gargling.

JHS

I only use 32V tantals, but 16V types will work w/o problems too.
Tantals will be damaged/killed if they are mounted in the wrong direction and if voltage will be supplied.
Not a problem with std. electrolytics, they can take some polarity faults w/o being destroyed.

JHS

My fav is a RM with slightly altered BIAS-divider, AC128 trannie for a softer clipping, a smaller emitter R and a different collector voltage (5,5V). Furthermore some switchable I-cap up to 33nF and a switchable GE-diode between E and B. Very dynamic, british distortion. Replaced the 10k pot with a ...

I did the Keeeley trick on a PNP RM-clone some time ago. Wired the I/O-ground to the negative pole and increases the I-cap a bit (only for compensating the added highs). Same sound, better dynamic response and overtones and no problem with other NPN-FX. IMHO sounds better than a RM with neg. ground ...

I never use 1/4W CC, they are a bit noisy and kill tone, 1/2W is good, but IMHO 1W will give the best tone.
The CC in the Landgraff MOD look like Allen Bradley's, a lot B-Makers use Bradley CC and they are not neccessarily noisier than MF.

JHS

Due to the circuit topology the J-Drive sounds like a TS/FD2/OD-1 but has a better tonecontrol, similar to the OVD-1.
IMHO due to the OPA it's a bit more refined sounding but the basic sound is TS/FD-2.
JHS

The drive is called Korg "OVD-1 Overdrive", schem can be found via GOOGLE.

JHS

Similar to a Korg OD, but w/o the I-buffer, IC is a OPA 2134.
Some cap values are slightly different.

JHS

.. should be correct now ...

https://i206.photobucket.com/albums/bb4 ... Collar.gif

JHS

You're right, I'll correct it soon and update the schem. Connection of the RC-network should be at the middle lug of the tonepot.

JHS

Modern high grade CC are better in terms of noise than MF. IMHO soundwise for mmps, fuzzboxes, ODs and distortions the best soundings Rs. If somebody claims they are noisier, he maybe compared it to the cheap crappy CCs from the '60th.

JHS

SCHEM for BC:

https://i206.photobucket.com/albums/bb4 ... Collar.gif

JHS

Yup, but the vintage Rat has only 1M for Biasing the opamp.

IMHO ProCo changes the circuit layout in the mid 80-ties for better low end response and to make it more usable for that Death Metal Anthrax style low string riffing that was quite poular at that time.

JHS

I can mail you a schem of the tube-circuit, if you have any interest.

Tube supply voltage = 230VDC

JHS

Drop the 10k in parallel with the Vol.pot and swap the output cap for a 1uF MF. If that's not enough drop the 1n at the input.

JHS

The basic circuit in the Small Fry, Burnunit, DD, DDSS, DDLG is always the same. Some have Si-harclipping diodes, other Ge-harclipping diodes, some have none hardclipping diodes. Some different part values, that's all. The LTD-circuit is similar, only a different tone control and no hardclipper. All...

The Plusdriver is an early version BOSS OD-1 clone with IC-buffered in-/output + IC-booster (switchable pre/post OD)
It has a LF444 in the OD-circuit (slewrate 1V/us) and VREF is generated via IC (2nd half is used for the boost). W/o the boost it's the Fulltender OD.

JHS

A super clean boost running on 18V is a goos idea, but a lot values have to be adapted to make the booster sound "musical". I did some tests with common boosters running on 18V, all sounded thin, harsch and real stiff. My best sounding booster runs on app. 8V, sounds very good. The headroo...