Distortr on/off/on switch issues

[Plaidesaurus]

Just finished the Distortr build. Everything works well except the 3 way switch. The up position sounds awesome. The mid and lower position make a very low volume fizzy sound. Have checked the position of the switches and they are correctly placed Any thoughts on what the issue may be? Disclaimer: I didn't have an 820n so I put in a 680n. Wouldn't think that would make a difference here but want to come clean on any parts changes.
Attached file is similar to my build.

 

[Robert]

It certainly sounds like the ON/OFF/ON is in the Gain position rather than Subs, that would mess up the bias of the BS170 transistor.


Post a pic of your build.

 

[Plaidesaurus]

Thanks for getting back so quickly. Here we go.

 

[Robert]

Any chance there's a solder blob (or some other form of electrical short) under the toggle switch?

The only component common to more than one switch position is C7, and it's common to all three positions.

 

[Plaidesaurus]

It looks pretty clean to me. Am pretty meticulous with trying to make good solid solder joints and I always use a toothbrush with rubbing alcohol at the end. Could I have fried the switch when soldering?

 

[Robert]

Make absolutely certain the values of C6 and C7 are correct.


This one is a little puzzling because C5, C6, and C7 are the components involved with the Subs switch.

C7 is in circuit in all three positions, C5 and C6 are active in the up and down positions.

The only component in-circuit in the center position is C7, but it's also in-circuit in the down position.


A defective/damaged toggle switch shouldn't cause the issue you're having.


C11 looks a little rough but I'm not sure if the burn goes deep enough to cause an issue.

 

[Plaidesaurus]

So, since I used a 680n (no 820s on hand) would could that be part of the problem? Also, since I'm coming clean, I was out of 56n and used a 47n. Everything else is as it should be.

 

[Plaidesaurus]

Going to do a parts order soon. Will replace C5 and C7 with the exact values then if you think that's part of the problem.

 

[Plaidesaurus]

So, I got the correct values in the mail today and replaced C5 & C7. It works like a champ. Great pedal. Sounds awesome.

As a new builder I don't understand enough about these circuits to know when I can fudge on some of the values and when I can't. Obviously this one required exact values. I just thought I'd go with what was closest.

Thanks for the help. I'm back in business.