troubleshooting a boss SD-1

[yass]

HI guys,I recently modded my sd-1 from a tone jam ts-808 mod kit with jrc 4558d and some caps and resistors.When I cranck up my my guitar volume,it sounds good up to 3/4 of my guitar volume and at full it sounds very bad.Same problem when it's bypassed...

[Phorhas]

Can shed more light on "sound very bad"?

what exactky do you mean, just not a good tone or is it acting strange?

[yass]

it sounds anormal...  loss of volume and very very distorted only when the guitar volume is full up(at 3/4 guitar volume it's good).when the pedal is off,the problem is the same.

[Dave Z]

OK the SD1 has a buffered bypass stage: since there are 2 transistors (Q5, Q6) in use even when bypassed, I'm guessing you inadvertantly changed one of the resistors around one of these trannies, causing it to get too much signal or even driving it into a gain stage which it should not be.

Grab the SD1 schem, compare to your changes & see if you changes one of the resistors around these two.

[cd]

Not to sound like an a**hole, but if you paid good money for a kit, the company that sold you the kit should provide you with troubleshooting & service.

What parts did you change?  Aside from the parts, standard debugging procedures apply: make sure you didn't solder two pads together, no cold joints/lifted traces, etc.