bi-amping with Tube and SS amp

Here's my old discussion for the switch that I'm using.

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Please explain why this would not work?  If you keep the jumper and connect both amps the speaker will sense the signal from either top or bottom binding post. If OP turns off his SS amp, his speaker will only get signal from the amp that is active. 

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I saw a person do this with class D amps. He had the class Ds turned OFF and the the tube gear playing. I heard a high pitched sound and it blew a 20 amp house breaker. The caps in the SS gear charged and BLEW the transformer on the tube gear. Guess whos gear it was?.. MINE...

You have to do what the two gent mentioned above. Dummy loads, I use a 3 position switch. Center is hooked to nothing. I don't trust switches either.. A space between contacts is even better.. 3 position vs 2

Chicken feedin' time

Regards

@ei001h 

I have a SS 5 channel amp, am I able to use just 2 channels out of 5 and not cause any damage to the amp ? 

Since most SS amplifier can stay on without load connected to its output, it is perfectly OK to use just 2 channels out of 5.

If the 5 channel SS amp designed with one transformer to power all 5 channels, use just 2 channels the power supply will provide more power reserve than use all 5 channels.

Please explain why this would not work?  If you keep the jumper and connect both amps the speaker will sense the signal from either top or bottom binding post. If OP turns off his SS amp, his speaker will only get signal from the amp that is active.

 Most (not all) SS amplifier has relay at the output for delay turn-on and protection. If both tube amp and SS amp are connected to the speaker and only the tube amp is on, it will do no harm to both amp because the SS amp output stage is disconnected by its built-in relay.
When the SS amp is on and the tube amp is off, then the SS amp will see the speaker as a load and also the tube amp output transformer secondary winding parallel to it. That will be bad for both amplifiers, there’s possibility fries the tube amp OPT and damage the SS amp or put it into protection mode.
Even though if the tube amp OPT secondary winding strong enough to stand the current from the SS amp, the speaker will definitely sounded weak with no bass because the inductance of the OPT secondary winding drained most bass energy through it.

I have a SS 5 channel amp, am I able to use just 2 channels out of 5 and not cause any damage to the amp ? 

@mceljo is correct. You need a switcher with built-in dummy load to connect both tube amp and HT amp to your speaker.

Amplifier-Receiver-Speakers-Selector-Switcher

The resistor dummy load is to protect the tube amp’s output transformer from damage if accidentally switch the tube amp disconnected from speaker while the tube amp still turn-on.

https://forum.audiogon.com/discussions/amp-switcher-with-tube-amp-protection/post?postid=2198961#2198961

@ei001h I am not an electrical engineer, but I wouldn't connect to amplifier together with speaker cables which is essentially what this would be doing.  I doubt amplifiers have a lot of circuit protection from this type of load.  

Zory is a fireman, nothing he can't handle 

You could use a switch that uses a 12V trigger to switch between the two. 

If I get what you are doing, you'll have both amps connected and one will be on at a time. The problem with that is that the amp that is not on is now a load to the other amp and you will be feeding the amp a lot of current. Probably a good way to start a fire. 

Please explain why this would not work?  If you keep the jumper and connect both amps the speaker will sense the signal from either top or bottom binding post. If OP turns off his SS amp, his speaker will only get signal from the amp that is active. 

in theory this should work. Unless the extra SS amp connection will interfere with the tube amp 

No, and this isn't bi-amping.

Bi-amping is for speakers that have two sets of binding posts AND the jumper is removed so that you are, in effect, driving two separate pairs of speakers with two amplifiers in parallel.

To do this, you need a switch that would essentially be a speaker switch run backwards.  I have my Pathos tube amplifier and my Integra HT receiver both connected to my speakers via a custom switch that I have to manually flip the switch on for each channel.  The switch has a dummy speaker load on the other side to keep tube amplifiers happy and also a resister to keep the tubes safe with a load during the switch flip.