Hao Rust Driver Schematics

[smank]

Great Markus!

This confirm why the bright position has bad sound...

[wampcat1]

Adding the diode is OK, but soften the tone a bit.

The RD seems to be very sensitive to mods in the BIAS divider. I added the 1uF from Matsumins mod page from VREF to ground, the result was more treble bite and a tighter sound, like switching from a 50W to a 100W. Raising it to 10uF plain foil give more treble and a softer attack, with a 10uF tantal  the tone was kind of steril, all with a battery, with a Carbon the tone was more middy compared to a alkaline. With a 100uF from + to ground the overtones were artificial sounding and the RD was less touch sensitive.

With a good filtered power supply like the VooDoo Lab the tone had a bit more headroom and treble and the RD produce a really tight tone, adding a 100uF didn't alter the tone anymore.

I made the same experience with a TS-9 some time ago. Adding a 100uF to the Bias divider of the TS-9 convert it to the stiffer sounding TS-10 sound and eliminating the 100uF in the TS-10 convert it to TS-9 sound (all with battery supply). With the VooDoo Lab supply the tone was much tighter with more treble and headroom. The 100uF didn't change the tone anymore if it was present or not. In the end I leave the 100uF in and reduced the supply voltage on the chip to 8V in the TS-9 to make it sound like bat powered and w/o the 100uF.

I often use the Bias divider from the Barber pedals for new designs, very good, nearly no difference between supply via the DC jack, carbon- or alkaline battery. Sometimes I put a 10-100n in parallel with the Diode to filter out the added hiss the diode injects.

A lot of Japanese/Chinese TS-clones use a 10k/10k/10uf/10uF Bias divider with the new JRC4558D, with this divider the new chip sounds less harsh producing  a tone like the old chip with the classic divider. ARIA often use a asym. Bias divider in their TS-clones (8,2k/10k) to soften the tone a bit.

I had a similar experience with a net-socket distributer for computer with a varistor spike protection.
All amps and FX connected to the distributor sounded very strange, with thin treble and artificial overtones caused by the varistor in the net-distributor.

JHS

Sounds like 'mojo factor' to me...
What tests did you do to confirm this?