Can I use an Orange Drop (non-polarized) in place of an electrolytic polarized cap?

[J M Fahey]

(I had the cap wired to a wire lead of about 8", allowing me to move it around).

WHY OH WHY did you connect your cap at the end of 8" leads?
And letting it close to the input jack?
This is not a part *value* problem !!!!
Itīs a *layout* problem!!!!

I was swapping out different capacitor values just to see what would happen, got squealing no matter what I did. Then I wired a capacitor alone without running thru the pot and the squealing went away. But, when I moved the capacitor near where the pot was (I mounted it in the number 2 input spot), I got squealing again. When the cap was away from the input jack, everything was fine. I could actually move the capacitor back and forth near the potentiometer/input jack and it sounded like the world's most annoying metal detector (I had the cap wired to a wire lead of about 8", allowing me to move it around). So, I'm no electrical genius, but the terms "oscillation" and "feedback" come to mind... it does resemble super high pitched feedback. It would seem that the solution is simply to move the potentiometer elsewhere, away from the input jack. I'm guessing the cap is receiving or transmitting a signal that the input cable/guitar signal are picking up?

Yes, yes, yes, YOU are causing that squeal/feedback.
Any discussion on cap *value* is nil, compared to that.
Why didnīt you just tack solder it to the original cap pads?
Which is where it belongs.

This reminds me of a similar discussion, which went on for dozens of answers, where there was a hum problem and everybody offered tons of suggestions about filter caps, transformer orientation, screen resistors, grounding, the works.
After a couple pages of such, the OP said, casually , that the amp hummed a lot "with not guitar attached" ... which only then he expained meant the guitar cable plugged in, no guitar at the other end, the free plug just laying somewhere on the table ... and the volume around 5 or 6.
Talk about chasing goblins!!

[Chuck H]

I know I was asking around the subject on the table. But I didn't see a resolution to this. I don't think it's related.

[hasserl]

which only then he expained meant the guitar cable plugged in, no guitar at the other end, the free plug just laying somewhere on the table ... and the volume around 5 or 6.
Talk about chasing goblins!!

LOL!! Just goes to show you can't assume anything. You always have to start with the basics.

[Jazz P Bass]

Yeah, what a hoot!
Then there was the recent post, round & round & round we go.
The OP had failed to solder the bias cap properly.
Yeah, "I new that"!
It is almost like you have to stoop to conquer

[J M Fahey]

Thatīs what I love about Enzo's no-nonsense, "letīs start with the basics" approach as in:
"Is the amp PLUGGED?"
"DO you have power at that extension outlet?"
And so on.

[Jazz P Bass]

Thatīs what I love about Enzo's no-nonsense, "letīs start with the basics" approach as in:
"Is the amp PLUGGED?"
"DO you have power at that extension outlet?"
And so on.

Which is another way of saying "basic trouble shooting"
Start at the power source.

[Panther35]

So what about that bypass cap your using??? Is it a .68uf or did you use a .068uf??? If it sounds good to you it's all good. But a .068uf will only be bypassing very high treble frequencies. You really only need to cut bass. Did you accidentally install a .068 cap in that circuit?

No, I actually ended up installing a 10uf electrolytic (Sprague) on the advice of Jazz P Bass... the more I read about it, the more I didn't want to do the 0.68uf value cap. And I was incorrect up above when I mentioned a .068uf earlier, the original idea was a 0.68uf... I just didn't type it out right.

[Panther35]

WHY OH WHY did you connect your cap at the end of 8" leads?
And letting it close to the input jack?
This is not a part *value* problem !!!!
Itīs a *layout* problem!!!!

I definitely understand that the 8" wire isn't the proper way to do it, but the way the mod was written out, I had a lead going from the cap spot on the board to the pot anyway... so in swapping out caps, I was just using it temporarily until I could find the solution... which I ultimately did, just in a roundabout way. On that particular amp, removing the circuit board and soldering a cap in the right spot, and then replacing the board to try it out over and over again was just not practical... it's a bit of a pain to take it all apart and reassemble.

This is an abbreviated version of the mod (long version posted above):
1. Unsolder and remove C11 (this is right next to the Master control, a 390pf cap). Obtain a good quality 50k to 100k pot.

2. Obtain a decent quality .01uF cap. Trim the cap’s leads to about ― inch and solder one lead to the middle terminal of your new control. Solder a 3-inch jumper wire to the other lead of the cap. I recommend shrink tubing over this connection. Hold the new control with the shaft towards you and the terminals facing up. The terminal on the right needs a 3-inch jumper wire soldered to it. Solder the other end of this jumper to the right side hole where C11 used to be. Solder the lead attached to the cap to C11’s other hole. The third terminal of your control is not used in this circuit.

You can see where I got the jumper wire from... only mine was 8", not 3".

The guy who posted the instructions on the mod did say he used the Presence control spot in order to not have to drill holes in the chassis... and it just so happened that the Presence control location is far from the input jack or any other interference, but that was unspoken. I also didn't want to drill holes in my chassis, but needed a place to install the pot if I was going to do the mod. I don't use my 2nd input, so at the time, it seemed a logical place for the control... guess it wasn't. So, I won't just leave a cap dangling from a wire, but I need to find a good place for the pot because I do like the mod.

What I did discover (through trial & error... more error than trial) was that the reason he used a .01uf in that spot was to get a very large range in the rotation of the potentiometer... and in that sense it's great. I'll go ahead and do it just like he wrote it out, only now I'll relocate the pot and cap to a proper spot (and hopefully be able to shorten that lead). I like having the presence control where it is, so I'll have to do a bit of thinking about where to put this thing.

[Enzo]

At the risk of going tangent...

Back when I used to train technicians, I'd have all day sessions. The mornings we'd discuss how the system worked and troubleshooting procedures, and we'd go over the printed material I always prepared to hand out for the techs' handbooks. I'd send them to lunch and set up problem units for them to return to. In this case it was pinball machines.

In each case the machine would have numerous problem for them to find, but one thing they ALL would have would be a "dead" condition. They'd have to find the missing main fuse or loose mains wiring or whatever to progress to actual circuit "failures."

In the shop we had power drop boxes. A pair of duplex outlets on a box on the end of an extension cord. We also used those work lights with a clamp on the base, big aluminum reflector around the bulb. Each work station had a drop and the test machine would be plugged into it.

One of my favorite tricks: I'd go into the drop box, and pop loose one of the wires that connected the two outlets together. SO mains went to the first duplex outlet, but never made it to the other. SO half the sockets were dead. I'd set up the machine plugged into the dead side, but the clamp work light plugged into the good side. The machine itself was not dead, just the outlet it was plugged into, but if they assumed the outlet was OK because the light was plugged in and working, I had them.

It never failed on me. They'd see the working light, and ASSUME the outlet was hot, then go crazy taking test readings and looking all over, anything but verifying the darned outlet was hot... or not.

DOn;t assume, KNOW.

[Jazz P Bass]

Thankyou for sharing that, Enzo.
Having observed your posts, there is an underlying thread to them. "hammering home" the basics of troubleshooting, it is a pleasure to read another one.

[mort]

At the risk of going tangent...

Back when I used to train technicians, I'd have all day sessions. The mornings we'd discuss how the system worked and troubleshooting procedures, and we'd go over the printed material I always prepared to hand out for the techs' handbooks. I'd send them to lunch and set up problem units for them to return to. In this case it was pinball machines.

In each case the machine would have numerous problem for them to find, but one thing they ALL would have would be a "dead" condition. They'd have to find the missing main fuse or loose mains wiring or whatever to progress to actual circuit "failures."

In the shop we had power drop boxes. A pair of duplex outlets on a box on the end of an extension cord. We also used those work lights with a clamp on the base, big aluminum reflector around the bulb. Each work station had a drop and the test machine would be plugged into it.

One of my favorite tricks: I'd go into the drop box, and pop loose one of the wires that connected the two outlets together. SO mains went to the first duplex outlet, but never made it to the other. SO half the sockets were dead. I'd set up the machine plugged into the dead side, but the clamp work light plugged into the good side. The machine itself was not dead, just the outlet it was plugged into, but if they assumed the outlet was OK because the light was plugged in and working, I had them.

It never failed on me. They'd see the working light, and ASSUME the outlet was hot, then go crazy taking test readings and looking all over, anything but verifying the darned outlet was hot... or not.

DOn;t assume, KNOW.

I am an A/C tech and I would have saved many sour words had I started with the source every single time.

I do have a strict habit of always using a meter before putting my fingers on any part of a circuit. Once I was working on a rooftop commercial unit that requires 460vac. I turned off the disconnect and checked for power before touching any components. No power. I checked a few things and powered the unit back up. Still had my issue and powered it back down. I reached to pull a lead off and ZAP. The main disconnect(knife switch) had failed right at that particular moment, leaving one leg connected!! NEVER ASSUME ANYTHING AT ANY TIME is the lesson I took away from that experience.