Clyde McCoy clone issues

[pqt_bach]

Hi Harris

Changing the 100k Q resistor to a lower value as suggested earlier would make things a bit smoother. Your transistors seem just fine and the build looks good. The burstbuckers are really powerful pickups and could easily drive the way into overdrive as it is not biased to be very clean in general.

Another thing to try is going for 18v power supply which will give more headroom and "presence"

Rock on!
Dan

[harrisxr650]

Here is a short clip with the issue. It might sound like a bad pot but it isnt

Listen to wah noise.mp3 by Harris Hatzianestis on #SoundCloud
https://soundcloud.app.goo.gl/3RwQo

[Rob Strand]

Here is a short clip with the issue. It might sound like a bad pot but it isnt

Listen to wah noise.mp3 by Harris Hatzianestis on #SoundCloud
https://soundcloud.app.goo.gl/3RwQo

To me honest I'm not sure what noise to listen to.  At 10 seconds there seems to be a lot of mechanical noise but I don't know if that is *only* the pedal rocking back and forth.   I can't make out any electrical type noise.

The thing that stood out to me is the wah effect itself seems a bit weak.  Perhaps the sign of a problem. 

For example see this clip about 1 min in with a clean signal,

https://www.youtube.com/watch?v=LpHxOB-VSDM

[harrisxr650]

ok. got some time to fool around today so i though it would be wise to check again, before i start to replace components, for mistakes and all the things mentioned in this topic.

So i checked for: bad or cracked solder joints, short circuits, errors in the values of the components, transistor voltages, voltage leak on pot.
Everything looks perfect.

Though i've noticed something i haven't before,
The tension clutch (dont know if its the correct terminology of the part) was pushing way too much the rack gear against the pinion, too much!
I removed the tension clutch  , opened a bit more the hole with a drill and re adjust.
Now i havent tested on a real amp, will do a bit later. instead i test on my pc with bias fx, could heard the issue there as well before.

The scratching-clipping issue (really i dont know how to describe it, it sounds like both...) is gone.
the pedal sounds as it should be, at least on pc.

Also i another strange thing, i user a wooden pencil to poke components inside, every time i poked the inductor i could hear it from the speakers, is this normal?

I will hold a small basket untill i test it on a real amp and provide any additional info here whether tyhe problem is solved or not.
 
BR

[anotherjim]

The inductor coil can be microphonic. Ideally, it would be wax impregnated just like guitar pickups should be.
It might explain why mechanism noise got into the audio.

[harrisxr650]

The inductor coil can be microphonic. Ideally, it would be wax impregnated just like guitar pickups should be.
It might explain why mechanism noise got into the audio.

ok.. i just checked with a toothpick and the coil around the ferrite is moving. should i consider this a flaw?

Beside pot waxing the coil would it be a big deal if i use a couple super glue drops to stabilize it?

BR

[anotherjim]

I'd do something about that. Superglue is a bit fierce, I would run some clear varnish in or even button polish (old school shellac based stuff).

[harrisxr650]

I'd do something about that. Superglue is a bit fierce, I would run some clear varnish in or even button polish (old school shellac based stuff).

excellent. i will give it a shot later on the day and see how it goes

Thanks

[duck_arse]

I will hold a small basket untill i test it on a real amp .....

pardon my ignorance and possible cultural insensitivity, but why are you holding a basket? is there something in the basket?

[harrisxr650]

I will hold a small basket untill i test it on a real amp .....

pardon my ignorance and possible cultural insensitivity, but why are you holding a basket? is there something in the basket?

It's a a Greek proverb that sais: "When you hear of many cherries, hold a small basket."

It's about not having big expectations for something until you are 100% sure that (in this case) will work 🤣🤣

[Rob Strand]

The scratching-clipping issue (really i dont know how to describe it, it sounds like both...) is gone.
the pedal sounds as it should be, at least on pc.

I don't understand what the cause was mbut it's good news you solved it.

Also i another strange thing, i user a wooden pencil to poke components inside, every time i poked the inductor i could hear it from the speakers, is this normal?

I'm with anotherjim on the wax.    You might not be able to remove the problem entirely.     Look at some of those stack of dimes inductors they are are dipped.   That's pretty severe as well.

[harrisxr650]

The scratching-clipping issue (really i dont know how to describe it, it sounds like both...) is gone.
the pedal sounds as it should be, at least on pc.

I don't understand what the cause was mbut it's good news you solved it.

Also i another strange thing, i user a wooden pencil to poke components inside, every time i poked the inductor i could hear it from the speakers, is this normal?

I'm with anotherjim on the wax.    You might not be able to remove the problem entirely.     Look at some of those stack of dimes inductors they are are dipped.   That's pretty severe as well.

i didnt solve it. I though i did because i was rocking the pedal with my hand, but once i stepped the scratching was there.
I did what anotherjim said but it reduced the problem very very slightly. I think im gonna get a new inductor and see how it goes from there.

One (more) question. if i got it right..since the inductor is not waxed properly and the coil is moving, the inductor pick ups the mechanical noise created from the shaft and the pedal spring when rocking the pedal. Could it be the case?

Thanks

[Rob Strand]

i didnt solve it. I though i did because i was rocking the pedal with my hand, but once i stepped the scratching was there.

Oh man, what a pain.

I did what anotherjim said but it reduced the problem very very slightly. I think im gonna get a new inductor and see how it goes from there.

One (more) question. if i got it right..since the inductor is not waxed properly and the coil is moving, the inductor pick ups the mechanical noise created from the shaft and the pedal spring when rocking the pedal. Could it be the case?

I suspect that's the part of the problem but you could do a test: Remove the inductor but connect it back the PCB via two thin flexible wires about 300mm long.   Twist the wires a locate the inductor outside of the box preferably without the wires mechanically touching the enclosure.  Lay the inductor on something soft like a T-shirt/towel/soft-foam.  See if the problem improves.   You might a bit more mains buzz but don't worry about that.

Techically an unmagnetized ferrite core shouldn't have microphonics.
However,
- the circuit as a small amount of DC current through the coil
- the gain of the amplifier from perspective of the inductor is high
- there's a lot of turns on the inductor
(- it's even possible the coil manufacturer magnetizes to core a bit.  That's speculation  you would would need to check with a compass located close to the core.)

All those add-up to a possibility of microphonics.     In use you can get other microphonics effects because the signal creates a field in the core.

[harrisxr650]

Ok,, recorded a new clip. and i think is a bit clearer now.

https://soundcloud.com/harris-hatzianestis/wah-track-12

From 00.00 - 00.05, is the  effect by passed
from 00.05 - 00.14, effect is on and you can clearly hear the scratching noise
from 00.14 - end, effect is on, with guitar plugged in, guitar volume on 100% and i just rock it without playing.

[duck_arse]

I will hold a small basket untill i test it on a real amp .....

pardon my ignorance and possible cultural insensitivity, but why are you holding a basket? is there something in the basket?

It's a a Greek proverb that sais: "When you hear of many cherries, hold a small basket."

It's about not having big expectations for something until you are 100% sure that (in this case) will work 🤣🤣

somewhat akin to don't count your chickens before they've hatched. those cherries could go on top of a cake ..... :cherries: :cherries: :cherries:

[pacealot]

Would I be way off base to suggest that it sounds a bit like DC noise on the pot? I have had volume pedals with a perfectly good pot going into poorly filtered amps which made exactly that sound, where the scratchiness only appears while there's an audible signal. This sounds more like that to me than microphonics, where you'd expect to still hear the noise at the end when there's no guitar being played...

[harrisxr650]

Would I be way off base to suggest that it sounds a bit like DC noise on the pot? I have had volume pedals with a perfectly good pot going into poorly filtered amps which made exactly that sound, where the scratchiness only appears while there's an audible signal. This sounds more like that to me than microphonics, where you'd expect to still hear the noise at the end when there's no guitar being played...

Yes it sound like DC leak to the pot. 
But I  measure 0 to it, nor to the 220nf caps
Unless it's a small leakage and my dmm cannot measure it?

Assuming it is DC on the pot. Adding a small cap, lets say 220pf, from the pcb output to ground will probably fix this right?

[Rob Strand]

Sounds like a bad pot or DC to me.

Unless it's a small leakage and my dmm cannot measure it?

It's possible the DMM can't see it especially if you have a 1M ohm input impedance DMM.  If the board has an issue you would expect to see something.

Sometimes weird problems have weird causes.  Perhaps the DC isn't coming from the wha but from the circuit you are plugging into.

As a test, not a solution,  you can place a 100nF cap between the PCB Output terminal and the switch.  Just place the added cap between the output terminal on the PCB and the wire.    The cap removes any DC from the output socket feeding back into the circuit to the pot.

Assuming it is DC on the pot. Adding a small cap, lets say 220pf, from the pcb output to ground will probably fix this right?

A cap to ground won't directly affect DC.   If you want to try a cap you need a small cap (47pF) from the base of Q2 to ground (as per anotherjims recent thread).   This high frequency stops oscillation issues which can appear as crackles and hiss - all sorts of bad stuff.  It's a long shot but you can try it.

[harrisxr650]

One thing i forgot,

Yesterday as i was poking the components with the pencil, besides the inductor, i got noise through the amp while poking Q1, Is this normal?

Then, while searching the net, i came across this thread

https://www.diystompboxes.com/smfforum/index.php?topic=121812.0

By the way with what anotherjim proposed to do with the inductor in order to stabilize the coil i dont get any poking sound now.

Also my dmm has an option for mv so i check it again and on lug 3 it starts from 20mv and goes down to 0mv and 0.1mv to lugs 2 & 3 .

0.1mv could be at the error margin i guess

[anotherjim]

If the wah is true bypass, then does your guitar volume pot crackle when it's in bypass? That would indicate a possible DC leakage in whatever you plug in to.