Buffer #2 Fault

S

sweetjonny

Well-Known Member
Hi Ron.

after a quick search on the forum re. this issue, I really hope I don't have to have the PBC repaired.

So, while putting a rig together, there was suddenly a huge drop in audio signal outputting from PBC (both A and B outs). only tiny audible amount left... finally I cycled through all 3 buffers and discovered that the problem was resolved with turning Buffer #2 off.
this happened completely at random while I just playing the guitar. There was a brief moment of intermittent signal coming in and out some time after this initially happened but Buffer #2 is now definitely not passing signal when active.

I'm pretty sure I checked this with all loops bypassed and result was the same. Using both A and B outputs to separate amps.

I have the PBC set up via bidirectional midi to a GT16 and all midi working correctly.

I previously noted (before the buffer issue) that with all loops bypassed, Mono->Stereo Button pushed IN gives some crazy noise from both A and B outs, Iso B button does nothing to help.... this isn't a ground loop noise but sounds like all kinds of badness.
Leaving it out and sounds fine.

So i wonder if these issues are related? given that Buffer #2 is placed just before loop 7.

My setup is functioning well without that buffer and without needing to press Mono->Stereo Button In... but I really want to get to the bottom of this, if the unit is indeed faulty, then id be concerned about remaining reliability.

This Unit ws bought from Loopers Paradise, Germany and shipped to me here in the UK less than 4 weeks ago.

please advise here Ron.

cheers
 
It definitely sounds like something's wrong with buffer #2. If you can live without that buffer, you can just shut it off. The problem seems confined to that buffer. If it was a more system-wide problem, all buffers would be affected.

This may or may not be involved with the Mono->stereo switch issue. To diagnose further, I would need to know if anything's plugged into Out 5-6 and In 7, and also if you are using any stereo effects.
 
It seemed stable enough just shutting off buffer 2 for the few hours I had with it after this initially happened. not had a chance to try it out since.
But Id definitely need this remedied, how do I go about this repair?

And to answer your questions: Nothing is plugged into either Out 5-6 or In 7, (nor have i tried bridging them) and Yes, I m using stereo effects. Loops 7-10 look like this:

All loops set to Series.
Mono->stereo switch OUT (In position noisy as described)
Mono Output switch OUT

loop 7 - Danelectro cool cat chorus. using ring disconnect cable between loop send (stereo jack) and pedals mono input (mono jack). Insert cable made by myself from pedal outputs to loop return.

Loop 8 - Walrus Audio Vanguard Phaser. TRS cable from loop send to pedal input. insert cable from pedal outs to loop return.

Loop 9 - GFI Specular Tempus. Insert cables to and from pedal.

Loop 10 - Boss DD500. Insert cables to and from pedal.

But as I said, this issue happens when all loops are bypassed.

fyi, loop 6 contains an MXR 10 band EQ pedal. but I'm sure this irrelevant.


I fear this my be a bad PBC unit, wouldn't really want to tour it as is, if i can't rely on something else not going wrong.
 
Please email me at support at rjmmusic dot com - the quickest way to deal with this is for me to send you a replacement circuit board. The Buffer 2 issue is going to require it.

Regarding the noise issue, I would expect this to happen with any PBC. When the switch is in, the mono signal from loop 6 is passed to the left side of the stereo signal, and the right side is left unconnected to anything. I'm surprised that it would come out both sides, but that could happen depending on how the outputs are configured. Making sure the switch is in the Out position sends the loop 6 signal to both the left and right sides of the stereo signal.
 
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