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Yup, I cleaned it up and played with it (stock) last night just to get a better a "feel" for the tones it produces now.

The "A Channel" (The "Metal" channel) has WAY more gain. Plus it is really fuzzy. I am pretty sure this has mostly to do with all of the clipping diodes.

The "B Channel" is quieter and has a "lo-fi" kinda thing. (Meaning I like my TS clone way better). I am going to try and replicate the clipping diode section in my TS clone and see if that helps.

Someone please remind me, is it more diodes = more gain, or vise-versa?

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Hey, Just to say I  got the download book (how-to-build-effects beginners) and am really glad to have it and this forum too and I cant wait to get started !

      I searched this and got nothin, so here goes ...

   I read that Brian likes the metal film caps for the closer tolerance and I read someplace else that ESD can really be bad for these and other items, MOSFET for one, and also that static builds up pretty easy.

I'm setting up a workstation in a finished basement (not too damp or dry) adjacent to but seperated from a washer-dryer etc. How much do I really need to worry about ESD and if need be; what can I do to safeguard against it in a DIY (cheap, i hope) kinda way ? if it matters, my bench is unfinished Birch ply with PVC for legs on carpet.

Thanks upfront !

470pF vs. 500pF would make hardly any difference. I doubt anyone could hear the difference, no matter how golden their ears are - it's in theory only 30pF apart. That's pretty miniscule. And as mentioned, capacitor tolerances factor in here, too.

Sounds like you're on your way to modding it. Don't expect to hear much of a change with just swapping out the opamps, though. Changing the diodes will be far more effective.

I'd say that would be alright.

I suppose it wouldn't hurt since with the 470pF's 5% tolerance, it could be as high as 494pF, and the 500pF could be as low as 475pF.

The reason I'm asking is the 470pF silver mica cap I bought from mouser is huge, and the leads don't fit into the board.

Jacob

Hey guys,

Will it make much tonal difference if I put a 500pF cap at C5 instead of a 470pF?

You can get the shem here: http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=105&Itemid=26

Jacob

Digitech/DOD PDS 1550 "Programmable Distortion"

I just scored one of these off of eBay for $16. It makes me think that the Digitech/DOD guys were WAY ahead of Vai and Ibanez with the whole "Jemini" thing. :-)

It doesn't sound bad at all, and I know if I spend some more time with it, I can get some great sounds just with tweaking all of the settings.

Digitech was cool enough to send me the schematic. I have it shared out here: http://gg2lpg.bay.livefilestore.com/y1pmXBQj4AJnCZgukohsxwSkjkgKU5kvO502NYuWdwNioqZc537Rb-rcCKI-syFgnqYbDPCaWUKonci8RW-LKlMoRgj_YiSAZ_Y/PDS1550%20schematic%5B1%5D.pdf?download

In reading the schematic, the overdrive looks to be of the TS808/SD-1 variety using symetrical soft clipping through a 1458 model Op Amp. However, there is also a pair of hard clipping diodes right after the op amp as well.

The distortion side reminds me more like the HM-2 with asymetrical soft clippers through a TL062, then a pair of hard clippers and a pair of GE diodes (which I think are used more as a noise filter).

I still don't have my head wrapped around the Parametric EQ and Delay parts of the circut, but I am not sure I want to mess with that stuff anyway.

The great news is that all of the IC's are socketed, so I can really experiement with different Op amps for both distortion sides.

The main thing I need to do is replace the DC jack (it uses the old DOD barrel kind with a standard BOSS style so I can power it with my pedalboard.

If I could make it happen, I would like to get the overdrive side to replicate my TS/SD-1 clone, and the Distortion side to replicate the sound of my keely DS-1.

I think I can get close with some clipping diode removal/replacement and some Op Amp switching.

Anyone have any other suggestions? :-)

http://www.4shared.com/file/100448204/6cd2681d/BOSS_SM.html