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JHS - Boss DS-1 mod Synth Drive
Posted: 21 Feb 2014, 15:11
by rousejeremy
Not sure if there's already info out there about this, but I had one come in for repair when a co worker smashed a couple of the switches on his.
C1- .1u
C2- 1uF (NP)
C3- .047u
C5- .1u
C8- 1uF (NP)
C11- .047u
C13- .1u
C14- 1uF (NP)
R35-1.1k metal film
D4-1N4001
D5- 2 5mm red LED's in series, a hole is drilled through the "o" in tone and one LED is held via a holder so it's visible.
There are three SPDT on/on switches mounted on the sides of the enclosure, and they're wired like this.

Re: JHS ds1 synth drive
Posted: 21 Feb 2014, 15:13
by rousejeremy
Oh, and the status LED is a blue superbright.
Re: JHS DS1 Synth Drive
Posted: 03 Jun 2014, 20:12
by AxHxCx
Holy crap, sorry to resurrect an older post but thanks so much for this. For a long time I've wanted a tricked-out DS1 without giving the (alleged) scumbags at JHS a penny.
Re: JHS DS1 Synth Drive
Posted: 04 Jun 2014, 04:24
by astrobass
I don't know if you have to say alleged when it comes to JHS and scumbaggery. Is this pretty similar to the mod in the Wampler book?
Re: JHS DS1 Synth Drive
Posted: 11 Jul 2014, 21:41
by AntKnee
The purple/brown wires are the Synth Fuzz Mod with Octave, from the wampler book. I don't know where the others came from. I assume they are switches to engage the mods to the caps.
Re: JHS DS1 Synth Drive
Posted: 11 Jul 2014, 21:46
by AntKnee
Rather, it appears that it takes the same signal and reintroduces it back into the circuit at different points in the signal path to achieve different tones/feedback.
Re: JHS - Boss DS-1 mod Synth Drive
Posted: 08 Aug 2015, 19:27
by pmkipp
Probably no one is following this now, but just in case: I did this mod very carefully, checked everything over and over. My only difference with what is described is that I only had a 1.2K resistor instead of the 1.1K.
All I get from the purple wire and yellow wire when switched on is loud screaming feedback. I have made sure nothing is in contact (even tried it with the switches just hanging out), no difference. I have even tried wiring in one switch circuit at a time - same two sound just as loud/bad.
When the switches are all turned off the pedal sounds great with the Keeley-like cap changes and upgrades. Any ideas? Would 100 more ohms of resistance cause the problem (somehow I think not).
Any ideas? Thanks in advance.