Looking for High Quality Selector to switch two amps to one pair speakers

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#3
Be sure to use a break-before-make switch, or the amplifier outputs will be shorted together and destruct.
No reason to use either switch or relay, both would work. Get an adequate current rating for the contacts.
 
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#6
Amplifier selector with dummy load

Attached is a schematic of amplifier selector with dummy load for safely switching tube or solid state amplifiers. The selector is a Grayhill 44A45-02-03S three position shorting style rotary switch, one per channel. Center position is for "speaker off" to prevent both amplifier outputs shorted together.
The reason of using shorting style (make-before-break) rotary switch is to ensure both amplifiers will be connected to a load at all times, either to the speaker or a resistor dummy load.


44A45-02-2-03S Grayhill | Mouser
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#7
Thank you very much for Input guys and specially @chrisng which solution I Intend to use

Chris,

can I remove dummy load part from schematic If I do not use tube amplifier
that way I will have one Grayhill 44A45-02-03S selector per loudspeaker / channel
 
#8
schemeit-project(9).png
If you do not want to use dummy load for your switching circuit, a Grayhill 44A45-02-2-03S actually can switch two amps with one pair of speakers, please refer to the attached schematic. In this case, a shorting style 3 position rotary switch can be use but is not necessary, you can also use ON-OFF-ON toggle switch to get higher power handling capacity with lower cost.

https://www.mouser.com/Electromecha...0z2qmZ1z0z2qcZ1z0x8fvZ1z0x8gwZ1z0x8h3Z1y8pmra

If center OFF position is not necessary then a ON-ON toggle switch like the link provided by Galu should work as well, just be sure to use a break-before-make switch as rayma mentioned.

However, Not all solid state amplifier can be ON without load (like those without a Zobel network at output). Best to check with user manual for safe switching.


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#9
Chris,

Great post, once again thank you
I forgot to say that one of the amps will always be power off and switching will be before power on
Idea Is to select between F5 amp and Home theater receiver
using just one high quality switch Grayhill 44A45-02-2-03S Is welcomed

best regards
 
#10
chrisng said:
Amplifier selector with dummy load

Attached is a schematic of amplifier selector with dummy load for safely switching tube or solid state amplifiers. The selector is a Grayhill 44A45-02-03S three position shorting style rotary switch, one per channel. Center position is for "speaker off" to prevent both amplifier outputs shorted together.
The reason of using shorting style (make-before-break) rotary switch is to ensure both amplifiers will be connected to a load at all times, either to the speaker or a resistor dummy load.
Click to expand...

@chrisng

I know this is an old thread, but this design is pretty darn clever!

I started looking into adding a class D SS amp that would share the same speakers with a SE tube amp that always need a load to be happy.

So, I need a switch, with all the right properties.

It should break before make, switch all 4 wires independently, swing a dummy load left or right so that said load is always present regardless of what amp has dominion over the speakers at any given time.

This purely mechanical solution is attractive, but what else is out there?

I imagine toggle switches and relays, etc.

?
 
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