this is the salvaged posts from the search cache, a printout from last week, and my memory
squeal/whine type noise when pedal switched off
brokenstrings
Posted: Tue Mar 03, 2009 11:54 pm
Hi. I finished building my Mouse a few days ago. I plugged it in, switched it on, and all is good. Sounds fantastic. However, when I switch it off (in bypass mode), if the distortion is dialed above around 2/3rds, I get a squealing/whining tone that is around 500Hz at that point (from what the spectrum analyser s/w on my computer tells me), and increases in frequency up to around 10Khz when distortion is set at full. Below this point there is no noise, just pure guitar signal. I've also noticed that the volume and tone controls affect this (squeal) tone! Of course, if I remove the battery, the guitar signal passes through with no squealing tone added.
Measuring the current flow between input and output sockets showed around 0.5mA. But I didn't see any current flowing between In and Out on the PCB.
Does anyone have any ideas what might be causing this, or what further tests I can do to isolate the fault? I was wondering if it could be a faulty switch, or, more likely, my soldering of the switch.
Unfortunately, I don't have Any decent resolution photos to most (my phone camera is not good enough for this purpose).
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duhvoodooman
Posted: Wed Mar 04, 2009 8:13 am
That's interesting! Sounds to me like it must be DC current leaking through the effect, but how it's getting out of the pedal when bypassed isn't clear to me. I'll consult those more learned than I (a long list!)
Couple of questions:
Have you tried a fresh battery, to see if it makes any difference? Does it do the same thing if you disconnect the battery and power the effect with a 9V AC adapter? Does it make any difference if your guitar is connected to the pedal chain or not? Have you you tried moving the effect to a different position in your pedal chain to see if that makes any difference?
BTW, one thing you might want to check is that big 100 uf electrolytic coupling cap at the upper left of the PCB. Make sure its installed with the correct polarity orientation and that the solder connections are good. AAMOF, probably a good idea to to check all six electrolytics....
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byoc
Posted: Wed Mar 04, 2009 2:32 pm
Disconnect the in and out wires from the PCB. Then see if it behaves the same.
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brokenstrings
Posted: Wed Mar 04, 2009 7:02 pm
Hi guys. Thanks for the suggestions. (due to the time zone differences between Australia and US, I just had time to try a few things late last night) OK, I tried replacing battery - no change. Haven't tried AC adapter yet, will try tonight. Also tested to see if the problem occurs before switching the pedal on first time - it does.
I've tried with both single coil and humbucker equipped guitars, and also with short leads (from reading posts about active squealing noise), neither of which makes any difference.
Lastly I tried moving the pedal in the pedal chain (just tried with Mighty Mouse and a modded Ibanez TS-9 Tube Screamer) - which had interesting results:
guitar -> MM -> amp - problem is there
guitar -> MM -> TS-9 -> amp - problem is there
guitar -> TS-9 -> MM -> amp NO problem, whether TS-9 is on or off!!!
Why would this be?
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duhvoodooman
Posted: Wed Mar 04, 2009 8:10 pm
What's different is that the TS-9 has a high impedance (~500 Kohm) input buffer, and when you put the TS-9 on the front of the chain, your Mouse (unbuffered, like many vintage effects) is behind that buffer. Apparently, that's enough to keep the squeal at bay. Still shouldn't be happening, though, so check out your wiring thoroughly and examine your soldering for evidence of bad joints, solder bridges, etc.
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brokenstrings
Posted: Thu Mar 05, 2009 4:48 am
Hi again As suggested, I checked what happens when an AC adapter is used - same problem as with battery. Also as suggested, I disconnected in and out wires from PCB. When switched on, nothing but noise and some electrical interference. When switched off, still get the squealing tone but louder/clearer...
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duhvoodooman
Posted: Thu Mar 05, 2009 9:54 am
Without some clear, close-up photos, this becomes very difficult to help troubleshoot. Strongly suggest that you borrow a decent digital camera from a friend and post some images here. In general terms, I'd be looking for shorts/solder bridges that might be connecting the signal path to the power .. [track along the edge of the PCB]
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byoc
Posted: Thu Mar 05, 2009 11:38 am
If you've disconnected the in and out wires and you're still getting noise. And the noise is affected by pushing the switch and turning the knobs, then you've seriously screwed up the wiring.
We cannot help you any more without pics.
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brokenstrings
Posted: Sun Mar 08, 2009 8:01 am
here are some photos of the PCB, jacks, pots and switches.
Note that I rewired the footswitch to what is seen in the photos - previously I had it wired so that the flat sides of the lugs were aligned horizontally, but I noticed that there was what appears to be a "7" next to one of the lugs [ and rewired the reoriented footswitch with this in the upper RHS so the "7" matches the 7 in the switch diagram ]
http://picasaweb.google.com.au/lh/photo ... directlinkhttp://picasaweb.google.com.au/lh/photo ... directlinkhttp://picasaweb.google.com.au/lh/photo ... directlinkhttp://picasaweb.google.com.au/lh/photo ... directlink---
Stephen
Posted: Sun Mar 08, 2009 8:31 am
Well for one thing you have the stomp switch wired all wrong. This is how it should look.
http://pic20.picturetrail.com/VOL83/511 ... 836704.jpg Notice the difference?
http://lh3.ggpht.com/_u8oY6BAW0lc/SbPFx ... s_pots_s...
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