FV-1 gets noisy when I turn on the reverb pot! plaese help me

[sajy_ho]

Hi guys, I've built an FV-1 based pedal using Slacker's 'Bablefish'.
I loaded up Spinsemi GA demo programs into it and there is not any noise present when the pots are at zero, but when I turn them up, specially when I turn on the reverb pot, it gets some cracking noise.
Here is the schematic and pcb layout, everything is the same as Bablefish except C6 that is 1u instead of 10u in original scheme:
https://db.tt/015nK6aO
And here is a sound sample, at the first all pots are at zero, then I turn on delay pot and it's almost clean except a clock noise present at large delay times, then I turn on the reverb pot and the annoying noise begins:
https://db.tt/28ulXcju
Please help me through this, it's so important to me.
Thanks
Sajad

[Digital Larry]

I'd start with a basic bypass patch, e.g.

RDAX ADCL, 1.0
WRAX DACL, 0.0
RDAX ADCR, 1.0
WRAX DACR, 0.0

I believe that noise is sometimes due to the main oscillator not running cleanly.  For sure you should contact Frank over at Experimental Noize/Spin Forum.

[slacker]

Yeah, like Larry says that noise could be the crystal not running properly, try making the 15p cap bigger. I think Mick (Ice-9) mentioned having to use 47p for some crystals. If that's not it double check the soldeting on the FV-1 bad connections on some of the pins can make it noisy.

[octfrank]

Sounds like a damaged chip to me.

[sajy_ho]

Thank you all guys
The bypass works properly, the noise starts when I turn the reverb mix up. I'm gonna use larger cap for the crystal and also double check all the soldering and see if that's my problem.
Thanks
Sajad

[sajy_ho]

I checked everything and also raised the value of crystal bypass cap but still the same issue. I think Octfrank is right, I might damaged the internal ram while soldering.
Now I have to order another chip...
Anyway thank you all for answering.
Sajad

[Ice-9]

The larger cap for the crystal was to help with some xtals not starting properly, some builds with the 15p crystal will cause a squealing screetching noise for a bout a second at start up, the 47p cap solves this issue.
I also think Sams problem sounds more like a damaged FV-1. Try reflowing the FV-1 solder connections again just in case of a dry joint.

I had an problem like this some time ago as well and eventually removed the chip and found two pads had a solder bridge on them but this couldn't be spotted as the bridge was at the back of the pins, worth metering out the pins on a continuity tester just in case.

One last thing, if you need to remove the Fv-1 I posted a video the other day to show a very easy cheap way to remove SMD stuff and in fact it was an FV-1 I used to make the vid. It's in the LOUNGE-OT section of the forum.

[sajy_ho]

The larger cap for the crystal was to help with some xtals not starting properly, some builds with the 15p crystal will cause a squealing screetching noise for a bout a second at start up, the 47p cap solves this issue.
I also think Sams problem sounds more like a damaged FV-1. Try reflowing the FV-1 solder connections again just in case of a dry joint.

I had an problem like this some time ago as well and eventually removed the chip and found two pads had a solder bridge on them but this couldn't be spotted as the bridge was at the back of the pins, worth metering out the pins on a continuity tester just in case.

One last thing, if you need to remove the Fv-1 I posted a video the other day to show a very easy cheap way to remove SMD stuff and in fact it was an FV-1 I used to make the vid. It's in the LOUNGE-OT section of the forum.

Thank you Mick for answering, I cheched all the pins and there was'nt any shorts,cold joints,..
I also found this thread over Spinsemi forum that is exactly like my problem:http://www.spinsemi.com/forum/viewtopic.php?t=85&sid=9a12745e2b24679e5b14992b976a28c7
So I think I should buy another chip.
Also your method is killer, thanks for sharing.

[Ice-9]

Yeah it does sound like the chip, but I thought it worthwhile to mention the under chip bridges anyway.

Glad you liked the chip removal vid, I will be uploading a chip soldering vid as well with a couple of methods but it looks like you already familiar with smd soldering anyway.

[sajy_ho]

Yeah it does sound like the chip, but I thought it worthwhile to mention the under chip bridges anyway.

Glad you liked the chip removal vid, I will be uploading a chip soldering vid as well with a couple of methods but it looks like you already familiar with smd soldering anyway.

Thanks man, I've been waiting for this one. Maybe after seeng that I won't fry the chip again