DIY DS-1 schematic

[MartyMart]

Schematic here in layouts gallery :

http://aronnelson.com/gallery/Martys-layouts-and-photos/BossDS1_edit?full=1


I just completed a marathon 3&1/2 hr DS-1 clone, which I have to say is sounding very
nice indeed !
I Ignored the switching and had to link the tone/volume pots in a different way, tone wiper out
to vol pot lug 3, vol wiper to final transistor and vol lug 1 to ground.
I used a Burr Brown OPA2134 ic and front and back I have MPSA13 darlington transistors, this may
be a little "hot" but seems to cause no problems.
I have not done any of the classic "mods" as yet, other than using a pair of red LED's for diodes.
The tone pot doesn't have any of the originals "shrill" sound on this one and seems more like a
bass boost when turned CCW and bass cut when turned CW, with slight high end lift, a great mistake
My circuit begins at C3= 47n ( Phillip Bryant's schem ) with 2m2 to ground infront and continues "like for like"
from there until the volume pot.
Just before the final MPSA13 from vol pot lug 2 I have a 1M from 4.5v but as yet no cap ... perhaps I need the
47n cap here as a DC blocker, but again, dont have a problem with it, nor any noise/hum at all.
I need two 100kB Linear pots, as both gain/vol require these to avoid "lumpy" and "bunched up" settings.

Was it worth it ?
Well I say yes, it wasn't too difficult and it sounds great, if a little different from the stock unit.
I could do with removing some low end and possibly bias the transistors slightly better, but once I
have those linear pots, I'm sure it will be sounding dandy

MM.

[MartyMart]

As I thought, the final 1uf cap needed reducing, 0.1uf sounds much nicer here, now
all the "woof" has gone and it makes a much better "all rounder" pedal now.
The 22 Ohm from Q1 is making a totally clean tone impossible, with an 820 Ohm the
clean sound is very sweet, but top end of distotion is lost, so I think I'll go with perhaps
a 220-470 ohm here and a slightly larger gain pot, I have a 250KB somewhere .....
I probably shouldn't be using MPSA13's ! may back them off to "Keens second law" and use
2N5088's

Still tweakin'  !

MM.

[Roobin]

Sounds cool! Is that the Tonepad one? I'm thinking of maybe doing one in the summer...

[MartyMart]

No, it's one that I made on stripboard, it's about 2.5cm X 7cm so will fit a 1590BB box.
Could be a bit smaller, but not much !

MM.

[Roobin]

Sorry, I meant the schematic. I've found the Tonepad one and another one for Godikssen (??) -its the service sheets.

Noise wise, how is it? I mean, obviously it will be a bit noisy, becaus eof all the gain, but how does it compare to other pedals?

[MartyMart]

Schematic posted above and here too :

http://aronnelson.com/gallery/Martys-layouts-and-photos/BossDS1_edit?full=1

Please respond if any errors are found.
This was originally Phillip Bryants drawing, if you would rather not have this posted then just let me
know Phillip .

Marty.

[Phorhas]

Well, here only a suggestion -
The input impedance is less than 100Kohm, so you can lower the pull-down resistor to 1M without any problem - this with quite the DS-1 further.

2c...