I've build a circuit that takes in an RS-232 signal, and outputs 40ma @ 5vdc (TTL) which I am trying to use to switch on/off 4 amplifiers. I have 4 T1's. One is version 1.2 (no switch) and the others are 1.3 (with switch) I am having trouble getting the load side of my device to work reliably. I tried FETS's first but quickly discovered that all 4 amps have a common ground via the audio input. I then tried relays (the same as the Songle relays that are on the amp.) These work at first but the contacts quickly start sticking. I think the 36vdc is just too much for relays. I have read that the T1's with the switch also have the same issue if you use the switch repeatedly. I'm looking for alternatives. I'd like to avoid putting the relays on the audio output because then I would need twice as many relays, 2 per amp rather than 1 per amp.
1.) Do you think it would be work if I connected the relays to the audio input into the amp? Or would this cause sound issues, popping, etc?
2.) Is there another simple method that I may be missing all together?
I got everything wired up and 3 out of 4 amps work. The 4th fried the SSR. I noticed that when I measure the resistance across the + and - input terminals, initially there is very little resistance, on the order of 1Ω or so, essentially a closed circuit which would facilitate a tremendous inrush current. The resistance increases to infinite (open circuit) over a couple of seconds. The other three amps don't have this issue so I think there is something wrong with that particular T1 amp, althought it still works and sounds good. I'll make another post to see if I can fix the T1.