Peavy digital reverb pedal pedal (SRP-16)

[Larry35]

Hi there,

I think a good few people on this forum could help me with this. I just came across a series of those weird looking 1980s Peavey pedals: DDL-3 delay, DEP Stereo Effects Processor and SRP-16 Reverb. The first 2 work perfectly but the Reverb doesn't. When the effect is set to 0 I can hear the guitar normally but increasing the effect level produces digitalish hisses and squeals, a bit like a radio being tuned.

One guy I told this about was pretty pessimistic, his bet being that it could very well be µP-related. Another hypothesis according to him would be that the 5V supply isn't working properly, which might be repairable.
I need to decide whether I should return it or not. If it can be fixed, I'll be glad to do it or send it in but I don't really know what to do just know.

Is there any chance I could find a spare µP if it was the problem?

Thanks a lot for any insight you might provide.

[Enzo]

And what if the uP was available but the problem winds up being the next chip over to the left? And then and then...

The thing to do is diagnose the problem and find out what you DO need, and then find out if it is available. 5v supply? Certainly easy enough to check that.

And you can CALL Peavey service and ask if they are still working on these and what price range is there. Their factory service department does good work at reasonable rates, and if anyone can get the parts, it would be them.

[Larry35]

Hello,

Thanks for your reply. You're right, it's no use looking for a new µP if I'm not sure it can solve the problem. However if it can and a spare one cannot be found I might as well give up now and return the pedal.

I probably should have mentioned I'm currently waiting for a response from Peavey UK (I'm located in Europe) at the moment. I know Peavey US are really good: they responded to my e-mail within a couple of hours. Might not be the same with Peavey Europe though, we'll see.

I want to test the 5V supply but I don't really know how that's done nor where it is located so that's another thing I'm hoping to find out about on this forum.

Thanks

[Enzo]

I understand your outlook, but we can look at every part in it the same way. We need to decide what it needs before planning strategies for replacing everything. I have no reason to suspect the CPU more than anything else. How about the ADC/DAC? The program ROM? RAM? ANy point in the signal path? EVen something simple as a broken control?

Get a schematic for it and post it. My files and my dealer site do not list that model.

[doctor]

I understand your outlook, but we can look at every part in it the same way. We need to decide what it needs before planning strategies for replacing everything. I have no reason to suspect the CPU more than anything else. How about the ADC/DAC? The program ROM? RAM? ANy point in the signal path? EVen something simple as a broken control?

Get a schematic for it and post it. My files and my dealer site do not list that model.

As a rule, specific "digital" hiss means problem with lost significant
bits in the digital part of the device. CPU (microprocessor) always
is responsible only for manage and timing, but never for sound quality.

If the digital part has parallel structure, check an existence of all input
signals at the DAC inputs. If one of signals is absent or looking not intact,
find the source of the problem moving back from DAC to ADC (as a rule
one of latches is the problem).
If all DAC input signals are intact, the DAC itself may be a problem.

If the digital part has serial (1-bit) structure, try to replace the DAC.

Needless to say, that all supply and reference voltages must be checked firstly.

Good luck.

[Larry35]

Hi Enzo,

Thank a lot for your input. I've e-mailed Peavey US for the schematics. I've got a couple of service centres to ring next week too.
I'm saying it might be the processor because the other person I told this about said it *could* be the culprit without by any means being definite about it.
As far as I can tell the guitar signal goes through it normally when the effect is set to zero and it responds to input (the pedal has a three-colour LED that varies according to input level).
I can post pictures if it's of any help or interest.

Cheers

[Larry35]

Hi Doctor,

Thanks. I hope I was clear enough explaining what the pedal sounds like right now:
When it's is disengaged it's perfectly silent.
When it's engaged with the effect ("mix" setting) set to 0, it's perfectly silent.
When I turn the effect knob up, instead of reverb I get noise: the guitar is not audible at all. So it's not even a question of sound quality I'd say, the source signal is not even distorted, it's just not there at all.

Cheers!

[douglasj53]

When I registered for this forum the "random question" I had to answer was "What amplifier is Leo Fender associated with?" I put in Musicman and it returned it as an error!!! Anyway, I hope this helps but the power supply will not be 5 volts; it should be 9-12 volts with a positive tip and an amperage of at least 200ma. Try that and make sure that the tip is positive!!!

Good Luck
Doug

[Bloodbath]

They are talking about an internal voltage regulator. Not the power supply for the pedal.

[douglasj53]

Oops, sorry about that. Guess I should have read more of the thread!