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Synaptic Amps
07-07-2008, 04:24 PM
I'm planning to use a pair of relays for a footswitchable overdrive circuit with front panel LED. The PT I have has a center tapped secondary at 190-0-190 and a 6V filament line. There's no 5V line or bias tap.

I intend to use one DPDT style relay for controling the signal path and a second relay for the LED function.

I'm wondering what the best way is to supply the coil current: tap a line off the HT or add a small dedicated transformer. Would adding the transformer have benefits that justify the added expense?

Is there any reason one type of relay device or arrangement would be favored over another? Higher voltage vs lower voltage coils? Parallel or series connection?
Enzo
07-07-2008, 09:09 PM
Small relays don't draw a lot, so I'd just rectify the 6VAC and make a relay supply from that. I am sure the tubes won't mind having it next door.

You could also use the one relay for the signal path, and just a couple small transistors for the LEDs. Cheaper than a second relay.
Alex/Tubewonder
07-07-2008, 10:11 PM
Small relays don't draw a lot, so I'd just rectify the 6VAC and make a relay supply from that. I am sure the tubes won't mind having it next door.

You could also use the one relay for the signal path, and just a couple small transistors for the LEDs. Cheaper than a second relay.

Someone you all know is rumored to hold a patent (one of many in his collection of patents on trivial circuits) on using rectified filament supply to drive relays in guitar amps ;):D
Enzo
07-07-2008, 11:26 PM
Hasn't he patented filament supplies in general yet? I hear he plans to patent vacuum, so THEN what would we put in our tubes?
Alex/Tubewonder
07-08-2008, 12:44 AM
Hasn't he patented filament supplies in general yet? I hear he plans to patent vacuum, so THEN what would we put in our tubes?

Simple, we patent absence of GAS in tubes :rolleyes::p
Steve Conner
07-08-2008, 11:03 AM
A while ago, I posted a tripler circuit that generates +12V referenced to ground from a 6.3V heater winding centre-tapped to ground, using 4 diodes and 3 capacitors. I used it successfully to power channel switching relays in my Ninja-Deluxe. I can't find the original post, though. Maybe Randall Smith had it deleted :confused: