Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: VMS on January 09, 2018, 04:49:50 pm
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Can the power source for the relays be put on footswitch enclosure and how much relays usually need current?
I was thinking maybe batteries or pedalpower with 12vdc output
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where's the relay gonna be?, if it's in the amp should be fine, if you route signals to a pedal with relay that might get ugly.
this is from doug's relay page;
The relay has a 5 volt coil rated at 40ma
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Like Shooter said, running the power from a board back to the amp isn't ideal. The only relays I've used are the one's Doug sells - I think they draw around 20-30ma each when engaged. It's very easy to tap your 6.3V heater supply to feed a 5V regulated relay supply, and Doug's board is small, or you could build the circuit on a small piece of turret or eyelet board. You only need a bridge, 7805 regulator and large value cap (4700uf or so). The current thru the footswitch will also power an led on/off indicator in most standard footswitch pedals.
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Relays would be in amp. I guess i'm worried that tapping to heater supply induces noise to the circuit.
I also have this london power ERK kit that can be powered from center-tapped plate winding (my plate winding doesn't have center-tap so this is a problem maybe) or it can also be powered with -12VDC source
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There is an abundance of info on relay switching here in ARCHIVES:
http://el34world.com/Forum/index.php?topic=14348.0
Maybe looking over this would be useful in making a decision?
With respect, Tubenit
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Thanks guys.
I think I can use the capacitor coupling method to get the power for the ERK from the HT winding. So i'm going to try that first.