Supa Sustain distortion??

[ranchak]

I just finished the SupaSustain from the GGG site. I used 2n3904 trannys instead of the bc169b, it has a ton of sutain and gain, but it also has a slight distorted sound. I did a search and it seems like this is a common problem with this build. I used a red led from Radio Shack and a photo resistor. I found this at Radio Shack:

http://www.radioshack.com/product/index.jsp?parentPage=family&summary=summary&techSpecs=techSpecs&currentTab=summary&cp=2032058.2032230.2032279&custRatings=custRatings&features=features&accessories=accessories&productId=2049723&support=support&tab=techSpecs

I wasn't sure where my distortion is coming from; either the trannys or the optical end. I think this is worth working through, but I am looking for some guidance.

[sfx1999]

That is a phototransistor, not a photoresistor. They are polar. They are basically variable current diodes.

[ranchak]

Thanks sfx1999, any idea about the distortion?

[sfx1999]

It sounds like a transistor is misbiased.

Did you use the phototransistor you posted, or a CdS cell?