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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
mceljo OP
1,351 posts
 
I think we have the details worked out on the switch circuit. We'll be using an 8 Ohm 100W Non-Inductive Dummy Load Resistor from Part Express to load the tube amplifier when the speakers are switched to the receiver. I just need to measure the space in the cabinet so that we can get the right sized project box. I think all internal wiring will be 10 AWG to match my speaker cables.
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mceljo OP
1,351 posts
 
I had thought about the possibility of using relays, but I think I prefer the passive route. In any case, the parts are on order. Thanks for the idea.
imhififan's avatar
imhififan
2,141 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.
mceljo OP
1,351 posts
 
The plan is break before make with each channel on a switch. Should I be concerned with the tube amp not being loaded for a instant when the switch is toggled?
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