Hoffman Amplifiers Tube Amplifier Forum

Other Stuff => Solid State => Topic started by: tubesornothing on June 14, 2009, 06:35:02 pm

Title: channel switch with relays and LEDs
Post by: tubesornothing on June 14, 2009, 06:35:02 pm

Hey all, I am building another amp that has footswitch channel plus footswitch boost.  This time I am going to try using relays.  I am keen on have LEDs for the front panel as well as the footswitch.  I found a Marshall two button footswitch that work well for this.

The problem I am having is: how can I have two different LED lights for the channels (like red for dirty and green for clean) for the front panel?  I dont care about the footswitch, just the front panel.

Here is my schematic, thanks.

ToN

Title: Re: channel switch with relays and LEDs
Post by: Heinz on June 15, 2009, 03:22:51 pm

Two simple solutions come to my mind:

• you use a relay that has more switches than needed for your circuit and use one of these to switch the LEDs
• you use a transistor for switching the LED that indicates footswitch 'off'. The other LED works the 'traditional' way.

Title: Re: channel switch with relays and LEDs
Post by: G._Hoffman on June 15, 2009, 03:45:39 pm

There was a simpler way to do it in the Kevin O'Connor's first TUT book, though for the life of my I can't remember it at the moment. 


Gabriel

Title: Re: channel switch with relays and LEDs
Post by: tubesornothing on June 15, 2009, 03:56:39 pm

Heinz thanks for the info.  I like the second idea, as it keeps "not so clean" power out of the switch mechanism.

Title: Re: channel switch with relays and LEDs
Post by: PRR on June 16, 2009, 06:59:12 pm

If relay current is much greater than LED current, just do this: