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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
983 posts
 
Viridian - Thanks for the information.

My Yaqin MC-30L is rated for about 50 watts per channel is ultralinear mode. So using a 100 watt load resistor should do the trick, right?

I'll clarify that when using my Mac and iTunes as the source, the source of the Yaqin is really a DAC fed by an Apple Express and the source for the Integra is an Apple TV. iTunes just has the option to send the music to more than one zone. The switch would only swap the speakers leaving both amplifiers with a source signal at all times.
viridian's avatar
viridian
4,184 posts
 
You are more than safe with a 100W resistor. Since you usually, probably, only play music at a few watts you may very well be able to use a resistor of much lower rated wattage.
mceljo OP
983 posts
 
Can you describe the circuit layout you are thinking about?
viridian's avatar
viridian
4,184 posts
 
Your friend is the EE!
mceljo OP
983 posts
 
True. Just gathering as much info as I can. There is always more than one way to do things.
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