PCM60 weirdness

[sircletus]

I know, I know, why do I care about PCM60?  Because I still use it as a go-to snare reverb.  Anyway,  the last time I fired it up (last week) I noticed that the left output is significantly quieter than the right, but only in the "room" algorithm.  AND, both outputs' levels change depending on room size selected.  You can see it clearly on the 'scope at the output of the DAC's I-V converter while I change settings.  Attached: room, large, shortest decay time.

What do you think the culprit would be?  ROMs?  Not sure where else to look.

 

[JohnRoberts]

old caps?

JR

 

[sircletus]

old caps?

JR

Hi, John.  Yeah, caps are old.  Only electrolytics in this device are the power supply caps and one in the relay driver.  Could old filter caps really affect the L-R signal levels in digital electronics?  I know almost nothing about digital electronics, btw.  And this is definitely NOT an analog issue, as far as I can tell.

Also, since this is first time poking around in this thing, I noticed it doesn't have an AD converter!  Looks like analog switches for sample-and-hold?

 

[radardoug]

Using a sine wave signal as test stimulus in a reverb program is not a good idea. Try changing the frequency, or better still, use pink noise.

 

[sircletus]

Using a sine wave signal as test stimulus in a reverb program is not a good idea. Try changing the frequency, or better still, use pink noise.

I noticed the issue when using it on snare drum.  Scoping with a sine wave bears out what I was hearing and provides a convenient way to visualize.