Clyde McCoy clone issues

Started by harrisxr650, September 04, 2021, 12:30:31 PM

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anotherjim

All pots have grease in them. It's a worry for trying to squirt any solvent-based contact cleaner in there - it thins that grease which should just lube the shaft then it can run all over the carbon track. I do suspect the grease used has changed in recent years. Maybe the old stuff was made of something now frowned upon in these enlightened times?


harrisxr650

Quote from: anotherjim on September 27, 2021, 02:05:06 PM
All pots have grease in them. It's a worry for trying to squirt any solvent-based contact cleaner in there - it thins that grease which should just lube the shaft then it can run all over the carbon track. I do suspect the grease used has changed in recent years. Maybe the old stuff was made of something now frowned upon in these enlightened times?

Problem is that the insides of the pot was a mess. Too much grease plus  the loose shaft and  water.
The was no signs that the pot was used or opened so I assume bad QC?
I believe all the above contributed to the issue. 2nd pot had the loose shaft and water as well. I didn't open it in order to get a refund.
I've already ordered a Joe Gagan pot to put in.

Br

Rob Strand

QuoteI've already ordered a Joe Gagan pot to put in.

See how it goes.  Intermittent behaviours are really tough.   You only really know you solved it if you see the fault.   Changing stuff out you have to play the wait and see game over a long period.
 
The surprising thing is moving that pot wire had a large effect.  Didn't it stop the clipping issue as well as the crackling?   So either that helped but didn't solve the issue, or, you are seeing random behaviour and touching anything in the general area is changing the behaviour (for good or bad).

A common fault with pots is the rivets on the terminals don't have solid connections between terminals and track.  With something like a wah pedal, where there are mechanical vibrations,  the pedal movements could any promote bad contacts to crackle.

Hopefully the new pot works out.

If it doesn't you should try anotherjims  cap on the base of Q2 to ground (say 22pF to 47pF).  Mount the cap close to Q2.   I'd also leave the pot ground wire connected to the ground side of the Q2's emitter resistor.
Send:     . .- .-. - .... / - --- / --. --- .-. -
According to the water analogy of electricity, transistor leakage is caused by holes.

fowl

#63
Some years ago I built a wah with the Whipple inductor, and the CTS-made pot that they often bundle with it on Ebay.  The pot is not sealed, and the one I had got scratchy not long after installation.  I ended up replacing it with a Hot Potz 1 that I got from Small Bear, that solved it.  But later I started noticing problems with other new CTS pots, in my guitar and my amp, getting scratchy after maybe a month of use.  Trial and error found that cleaning all the factory grease out with a general electronics cleaner, then relubricating with Deoxit, then the pots are good to go.  But I haven't tried that on the CTS wah pot, it's still around here in a bag of parts somewhere.

Side note, the current Dunlop rectangular plastic Hot Potz II(?) is actually a very nice wah pot.  It doesn't look so cool, but it has a good taper and should last much longer than carbon track pots.

anotherjim

I also think the grease in some pots can get runny in high temperatures like during a heatwave.
I like the HotPotz. Worth the money. I've found general pots that look the same physically but no 100k in the range.
Open side pots can have dust caps fitted, but I've only seen them for 16mm like Alpha.

harrisxr650

Quote from: Rob Strand on September 27, 2021, 07:04:23 PM
QuoteI've already ordered a Joe Gagan pot to put in.

See how it goes.  Intermittent behaviours are really tough.   You only really know you solved it if you see the fault.   Changing stuff out you have to play the wait and see game over a long period.
 
The surprising thing is moving that pot wire had a large effect.  Didn't it stop the clipping issue as well as the crackling?   So either that helped but didn't solve the issue, or, you are seeing random behaviour and touching anything in the general area is changing the behaviour (for good or bad).

A common fault with pots is the rivets on the terminals don't have solid connections between terminals and track.  With something like a wah pedal, where there are mechanical vibrations,  the pedal movements could any promote bad contacts to crackle.

Hopefully the new pot works out.

If it doesn't you should try anotherjims  cap on the base of Q2 to ground (say 22pF to 47pF).  Mount the cap close to Q2.   I'd also leave the pot ground wire connected to the ground side of the Q2's emitter resistor.

My guess is that by moving the wire from lug one i applied some pressure to the wafer and the made the wiper temporarily to make better contact with the carbon track. but the problem wasnt only the wafer.
I did the following to be sure the pot is bad. used a wooden clothespin to apply some pressure to the wafer. that eliminated the most of the problem, but the pot shaft is loose as well.
Turning the pot with hand didnt bring up the crackling, but when i started, at the same time, to turn and move the shaft a bit off center it started again. New pot had the same loose shaft so i didnt bother to solder it.

Thats why i decided to order a new, better quality, pot.
Every other component is triple checked to be within specs, voltages looks ok, i maintain a wariness about the inductor but after what anotherjim suggested to do it seems to be  ok

The trick with moving the wire eliminate completely the clipping issue,
As soon as i get the new pot i will install it play a couple of days ( or a couple of minutes...depends :D ) and see how it goes.

Thaks again for the info

BR
Harris