I have this old Microsoft Gamevoice thing, which I only use for switching between my headset and speakers. Since the switch (mechanic) is getting old it's beginning to have bad connections, and makes noice. Can you help me making one out of a flip-flop kind'a construction, to avoid noice? Looks like you are one of the best, at electronics in this forum, so I am hoping you can help.
Basically took the de-bounced flip-flop schem from cpemma's site, added the 4066, which switches the audio signals. It's setup so that each audio channel gets two switches, one for each source. One pair of switches has the Q output, while the other pair has Q', so the two pairs will never be active at the same time (provided something doesn't go catastrophically wrong). One thing I just realized is that maybe the signal hanging off the C inputs of IC2C and D might want to be tied directly to Q' instead of hanging off of R3. Other than that, should be sound.
4066 would be OK for an active speaker input switch, but it's got quite a significant switch resistance that could reduce low-impedance headphone volume overmuchly. A DPDT switch, slide or toggle, would be a simple solution. Toggle might last longer and be quietest. If you want a push-button change, you could use the flip-flop to switch a small DPDT relay, the small telecommunications types are very reliable. Though again you can use a latching push-button to switch the relay on & off. KISS.
QFT... if you have a collection of junk electronics like i do, any old (70-80's) sterio will have many of these switchs. your not going to the moon ( ) so use a switch, lol
I agree with the "keep-it-simple" idea. If you want to use a relay, I would get a small one similar to what was in alot of modems. Most of these were what is known as "bifurcated contact". They have two contacts per connection, made of a split leaf spring. These are self cleaning by their wiping action, very reliable and very quiet. Several companies like Hasco even make miniature latching types, and reed relays also. You can get them in up to quad DPDT. I have used them in datacom circuits where they were switched tens of thousands of times and never had a failure.
I wouldn't take power from USB, USB's finnicky when it comes to power. (No pun intended ) I'd buy some DC plugs and make external 12v/5v from a molex. That way you can pwrovide power for furture external mods too
... but 1 mistake and you've fried more than a cheap wallwart. A molex will just melt all the wiring and carry on regardless (well, mine did )
