Digitech PDS 1550

[dan5150]

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 what I originally thought of the TS808/SD-1 variety, since it is using the  using symetrical soft clipping. However since it is using a 1458 model Op Amp, and thinking this is closer to the DOD 250 variety. Interestingly, there is also a pair of hard clipping diodes right after the op amp as well. Maybe this is a combination of both?

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 closer 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? :-)

[wavley]

I used to have one of those that I bought for like 10 bucks and I really loved it, I got rid of it in a gear purge a couple of years ago along with my rockman distortion and Line  filter pro, I wish I had them all back, I really do.  Sounds like the pds is still cheap, maybe I'll buy one back!