MXR M-206 Time Delay...SAD 4096 Equivalent

[Champagneperfume]

Sup y'all.

I acquired an almost mint condition MXR M-206 Time Delay. Sounds okay, but with certain adjustment to the 3 internal trimpots, it picks up a high pitched hiss...The delay isn't as strong as the clips and videos I've watched.

I'd imagine it's the SAD 4096 BBD chip going bad. Any idea of how to find an appropriate equivalent/replacement?

Upon inspection I found about 3 electrolytic caps that look like they are beginning to bulge. Could that be creating the high pitch hiss?

Anyway, thanks a ton. The pedal is in such good condition physically that it would be a tragedy to not revive the pedal.

 

[blackhatboojum]

I don’t know that MXR circuit at all but, I can tell you that those Reticon BBDs are unobtanium. There are no modern equivalents and if you find a NOS replacement, it’ll cost ya some money. From what your describing, it sounds like the BBD isn’t the issue. Was it making that noise before you started tweaking the trim pots? If you try to squeeze too much delay time out of a BBD, you’ll get a high pitch whine, better known as clock noise.

 

[Champagneperfume]

Ok thank god. I was on a private investigator-like hunt for one last night and now I understand what I've seen discussed about it online.

It wasn't making the noise before I tweaked it. It just seems the wet signal isn't as strong as the audio clips and videos I've seen on youtube etc.

Thank you so much for the heads up!!!

 

[blackhatboojum]

Ok thank god. I was on a private investigator-like hunt for one last night and now I understand what I've seen discussed about it online.

It wasn't making the noise before I tweaked it. It just seems the wet signal isn't as strong as the audio clips and videos I've seen on youtube etc.

Thank you so much for the heads up!!!

You’re welcome. Like I mentioned, I’m not familiar with that particular circuit and my google searches aren’t producing very good results. I was hoping to find a schematic but, came up with nothing. If that pedal is like other reticon based MXR delays, then one of the trimmers you tweaked is like a balance control that cancels out the clock noise. You’re going to need to put it back where it was in order to get rid of that clock noise. In the future, I would avoid just tweaking trim pots without knowledge of the circuit. Especially, with analog delays. Some of them are pretty complicated and the slightest tweak could make the pedal no longer usable. Experience repairing, building, setting up and/or good documentation on analog delays is needed at the very least. A signal generator and an oscilloscope may also be required and sometimes is a must have. You probably won’t ruin the pedal by tweaking trim pots but, it may stop working or sound distorted and messed up.

Now, as far as your output issue, it’s possible that the caps you mentioned might going bad but, without a schematic and what those caps are in the circuit… Well, you’re really not going to be able to know for sure. The easiest thing to do… clean the mix pot with something like deoxit and see if the volume level improves.