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Glam PT2399 LPF - losing signal

Started by kdmr, October 22, 2016, 04:01:52 PM

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kdmr

I'm building a glam chorus and I'm losing signal at pins 14 and 16. Voltages check out in the LFO and on the 2399 within reasonable variation. I've audio probed the signal path and retain signal to pins 13 and 15 (lpf ins). Checked the caps around the 2399 and everything seems fine. Auditioned about 4 chips and the problem persists for each. Chip removal results in signal retention at the output, albeit very attenuated. Scratching my head on this one. Any ideas?

madbean

It's normal not to hear audio from pin16 ith the PT2399 installed. But, you should hear it on pin15, and obviously pin14. The problem seems to be pin14 which is the delayed output. Pull the PT2399 out and do the following:

Audio probe pin16 with the IC removed to see if you are getting signal.
With the IC still removed, check pin14 for continuity against R9 and C10. Then check to see if pin14 has continuity with any of the adjacent pins (13, 15) and ground (it shouldn't).

Where did you get the PT2399 from that you are using?