Actually... If you're going steam punk, how about getting a BIG A** knife switch and mount it on the wall by the amp to use as a power switch. Now, the actual power would only be a 5 V or 12 V relay control voltage (mounted appropriately on glass isolators). The relay should make a nice and solid KLUNK!! when it switches. If it can make the lights dim, that would be an additional bonus.
Go bold or go home.
Tom
Go bold or go home.
Tom
Jacob's ladders and knife switches... The world's most ominous looking amplifier?
You asked about coil noise leaking into the signal - now that's an easy peasy thing to solve. Make a proper regulated power supply to operate the coils. Just a 7805 or whatever suits your coil voltage is good enough to be forgotten. You'll anyway be operating the relay coils with DC, so making a regulated supply for them is only too easy to realize: rectifier - cap - 78xx - cap, finished. Might also consider using a bleeder resistor (I never ever build PSU's without them).
Oh, and a rule of thumb about relays I heard from a tube veteran who's been doing this stuff decades more than I have. He basically told me, that as a rule of thumb if the relay is rated for small signal telecoms use it is sufficiently good for audio. "Sufficiently good" equaling "just use it and forget it".
You asked about coil noise leaking into the signal - now that's an easy peasy thing to solve. Make a proper regulated power supply to operate the coils. Just a 7805 or whatever suits your coil voltage is good enough to be forgotten. You'll anyway be operating the relay coils with DC, so making a regulated supply for them is only too easy to realize: rectifier - cap - 78xx - cap, finished. Might also consider using a bleeder resistor (I never ever build PSU's without them).
Oh, and a rule of thumb about relays I heard from a tube veteran who's been doing this stuff decades more than I have. He basically told me, that as a rule of thumb if the relay is rated for small signal telecoms use it is sufficiently good for audio. "Sufficiently good" equaling "just use it and forget it".
A walwart might do the job, but they come in all kinds of forms. Many of them are switchmode, which would mean you risk injecting high frequency noise to the signal especially with reed relays. And you'd need an extra outboard supply as suggested by jlangholzj.
Really, a basic linear regulated supply for these is simple as chips. Just get a suitable transformer - after rectification you'd need something like 8 volts for a 7805. Add a cap, a reg and another cap and you're basically done. The whole affair could be done on a vero board with a PCB mounted tranny.
Really, a basic linear regulated supply for these is simple as chips. Just get a suitable transformer - after rectification you'd need something like 8 volts for a 7805. Add a cap, a reg and another cap and you're basically done. The whole affair could be done on a vero board with a PCB mounted tranny.
But remember that you can only use large contactors for power switching. Small signal currents aren't enough to keep the contacts clean. And reed relays are next to silent, the ones I use only make a small "blip" when they operate. Almost sounds like a small beeper. Confused my cat badly when she first heard them going in my preamp.
Then you are back to trying to switch signal through a large contactor or some such. A large thumping contactor could be used to electrically switch some little reed relays, or little reed switches could be hidden under the contactor coil and running current through it activates the reeds without being officially involved with them.
Or if you really want to make it complicated, use something like an Arduino to sniff when the switch state is changed. And command it to use something like a solenoid to ring a traditional bell. And after that activate the ominous Jacob's ladder. And to thunk a contactor a few times. The possibilities are endless.
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