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Speaker Switch That Protects Tube Amplifier

A EE friend of mine and I are planning to build a switch box that will allow me to toggle between my Yaqin MC-30L tube amp and my Integra 50.1 receiver to power my speakers.

The current plan is a very basic setup that would require the tube amplifier to be shut down before switching so that it isn't left without a load.

The utopian goal would be to be able to switch between the two amplifiers with a single source feeding both (i.e. the Yaqin has an Apple Express for a source and the Integra has an Apple TV so both could be running from iTunes on my Mac) without risk of damage to the tube amplifier.

I'm assuming that this would be complicated at best and probably isn't worth it, but thought I should as before we purchase parts.
mceljo

Showing 4 responses by imhififan

imhififan's avatar
imhififan
2,220 posts
 
Cool! Just be sure that using make-before-break switch between load on tube amp, and break-before-make switch between tube amp and receiver.
imhififan's avatar
imhififan
2,220 posts
 
Please refer to Is It Safe To Connect Speakers To Two Amps, Almarg and Hifihvn have very good advise on this.
imhififan's avatar
imhififan
2,220 posts
 
"Should I be concerned with the tube amp not being loaded for a instant when the switch is toggled?"
That depends, even though IF the tube amp has some sort of protection circuit built in, I won't risk it. Same thing on the ss amp, even though it has short protection, I wouldn't risk it either.
imhififan's avatar
imhififan
2,220 posts
 
To be able to do live A/B switching, this is an idea:
A Shorting Contact Style 3 Deck 3 Position Rotary Switch,
Deck 1: pole connect to speaker +, position A to AVR + output, position B open, position C to Tube Amp + output
Deck 2: pole connect to speaker -, position A to AVR - output, position B open, position C to Tube Amp - output
Deck 3: pole connect to 8ohm 100w Dummy Load Resistor to Tube Amp - output, position A & B jumpered and connect to Tube Amp + output, position C open
Hope this help
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