Emitter bypass capacitor question

Hello, I've read many threads on this site, and finally have something to post!
A question, actually.
I'm testing a design with two transistors and both emitters are going to ground via resistors.
What I'm wanting to do is apply a SPDT switch between ground, and the negative side of each bypass cap in order to give me a way to engage a "boost" type effect when desired.
Alone, they work perfectly. The problem is, when attempting to apply ground to both caps i get this awful howl out of the amp, almost like feedback.
I don't see how that's so since adding the cap is supposed to be removing feedback, correct?

My question is, how can I make both caps switch to ground, and eliminate the howl?

It's removing NEGATIVE feedback - the increased gain might easily make it oscillate, you need to post your circuit and a picture of your layout.

Maybe there is a microphone at the input and when the gain is increased it hears a speaker at the output and produces acoustical feedback howling?

I'm so sorry guys, I was in the middle of a residence move and just now got up and running.
I'll post the schematic and see if that makes more sense.

Thanks again for taking a look.

Ok, the first image is showing part of the circuit with an individual switch on each cap.
Individually, theres no howl. I can ground either one, or both, and it works as designed.

Image 1:
Removed

The second image shows where I have a single switch going to ground, and when switched on, it sends ground to each leg of both caps.
This introduces the howl in the audio output.
Now, just to clarify things, when I've put both caps to ground without the switch, no howl.
Why is it when I have both caps on a single switch does it introduce the "feedback" howl?

Image 2:
Removed

In response to: audioguru...

It's a guitar effect, with or without the guitar attached produces the same "feedback" howl.
But thanks for pointing that out, that was the very first thing I thought of.. "maybe it's feeding back
through the pickup????".. Nah, either way, attached, detached, volume up, down, doesn't matter.

crey said:

Ok, the first image is showing part of the circuit with an individual switch on each cap.
Individually, theres no howl. I can ground either one, or both, and it works as designed.

Image 1:
**broken link removed**


The second image shows where I have a single switch going to ground, and when switched on, it sends ground to each leg of both caps.
This introduces the howl in the audio output.
Now, just to clarify things, when I've put both caps to ground without the switch, no howl.
Why is it when I have both caps on a single switch does it introduce the "feedback" howl?

Image 2:
**broken link removed**

Click to expand...

Looks like if you tie both caps together to connect to the switch,
it creates a feedback loop causing the howl.

Thanks for the reply!!
I thought that as well, but if it were to create the howl that way, then why wouldnt it howl anyway if both are already
tied to grown when the circuit is activated?
The howl doesn't start UNTIL I pop the switch to ground.
Being tied together at the switch without ground applied has no effect.

As already mentioned, you can't use a single switch - you're introducing positive feedback making it oscillate.

Use a double-pole switch instead.

I suggest you're probably confused about which way the switch is to make it oscillate?, or you've used very poor construction techniques, causing it to oscillate regardless.

Ok, thanks for your time.

There are no schematics attached in this thread.