Adding a clean blend to a DS-1

[kissack101]

Hey,

Firstly, for anyone who saw this: http://www.diystompboxes.com/smfforum/index.php?topic=83637.msg696620#msg696620, my friend (helpfully) decided a DS-1 was better for his 'sound' (bit more aggressive, according to him at least).

So, the idea now is to add a clean blend (this one http://www.aronnelson.com/gallery/main.php/v/BarcodeVeroLayouts/Vero/BlendimumVero.gif.html) to the DS-1.

Hopefully once this is resolved, I'll put all the details up here for all to enjoy ('giving something back to the community' and all that).

So, using this http://www.godiksennet.com/images/sch/DS1PG2.jpg boss DS-1 schem and by trying to translate the SD-1 advice to the DS-1 board, I've hooked the Mixer up as follows (DS-1 first):

R3 (right hand side of) --> Signal input to Mixer
R3 (left hand side of) --> Ground for the Mixer daughter-board
R8 (right hand side of) --> 9v input to Mixer

R18 --> Top end of resistor lifted from board, wire run from hole to lug 1 of Mixer pot, lug 2 of the mixer is than ran back to the R18 resistor and then back into the board.

[R18 is the first resistor the signal from the middle lug of the level pot encounters when it returns from the board, put simply the signal from the level pot now goes Level pot --> lug 1 of blend pot --> outputted from lug 2 of blend pot --> R18 resistor --> original signal path]

The outcome: A signal passes, the distortion and tone controls work, only instead of blending a clean tone the blend pot only seems to cut the level.

I think the problem is that I'm returning the signal from lug 2 of the mixer pot to the wrong place, I'm afraid of mutilating the DS-1 board without a good understanding of what I'm doing however (true-bypass effects I'm fine with, I still can't get my head around how the buffer/soft switching thing in Boss pedals work though?).

If anyone could help me out on this it would be appreciated. Please let me know if my description is unclear, like I said once this is cracked I'll get it written up as a tutorial.

Thanks again,

Adam.

[moosapotamus]

R18 --> Top end of resistor lifted from board, wire run from hole to lug 1 of Mixer pot, lug 2 of the mixer is than ran back to the R18 resistor and then back into the board.

Adam - I would suggest trying this instead...

Lift the end of R18 that attaches to Q7.
Attach the lifted end of R18 to mixer pot lug 3.
Attach mixer pot lug 2 back to the hole that the end of R18 was removed from.
Attach mixer pot lug 1 to the minimal blender output (indicated as BLEND LUG 3 in the strip board layout). I am switching that to lug 1 because that will give the 100% clean signal when the pot is turned all the way down fully to the left (CCW), and the distortion will blend in as you turn the pot up to the right (CW).

Also, try tapping the input signal to the minimal blender from the junction of R5/Q5/C3. That way the minimal blender circuit will be totally bypassed when when you stomp on the DS-1 bypass switch.

Everything between Q5 and Q7 is the distortion part of the circuit. The stuff before Q5 is the input buffer. The stuff after Q7 is the output buffer. Q5/Q7 act as on-off switches for the distortion. Q8 acts as an on-off switch for the bypass signal. Notice that the signal path through Q8 comes from immediately before Q5 to immediately after Q7. When you stomp on the bypass switch, Q5/Q7 get switched off and Q8 simultaneously gets switched on allowing the signal to bypass the distortion part of the circuit and only go through the input and output buffers.

So if you do the wiring like I described, the the minimal blender circuit will be wired in parallel with the distortion part of the circuit. The input and output of the minimal blender will be within the distortion's two bypass switching transistors, allowing the minimal blender and distortion circuits to both be completely bypassed together. For the output, you'll also have the clean (minimal blender) signal going to lug 1 of the mixer pot, the distortion signal going to lug 3 of the mixer pot, and the blended output from lug 2 of the mixer pot will be going to the output buffer (the hole vacated by R18).

~ Charlie

[5thumbs]

Here's a DS-1 clean mix arrangement similar to what the Voodoo Labs Sparkle Drive uses:



The orange wires indicate the mod parts/connections.  If y'all like this idea and want to try it, please reply back here.  I can whip up a strip/vero board layout plus instructions and post it here later on tonight.  If it works out as expected, I'll also add this to the next release of my 'Build Your Own DS-1 Distortion' document.

[WangoFett]

Maybe I am not reading that schematic right, but it looks like when the dual ganged blend pot is all the way 'up' the wiper on the lower gang connects both the output IC2 and the hot terminal of the level control to virtual ground and should silence out.  Is that intended?  Should there not be a resistor going from this wiper to the level control along with the one from the clean buffer?

[5thumbs]

OK, I typed up this huge response and then finally figured out what you were getting at.     Thanks for catching that!

Yes, you are 100% correct.  There should be a 100K resistor between the lower pot and the 13K3 resistor.  I've updated the files.