ST120 with no speakers connected???

I have a Tubes4HiFi ST120 Tube amplifier I built a couple years ago. I have a number sets of speakers that I like to audition from time to time. It is my understanding that you are not to disconnect speakers from a tube amplifier while it is running or for some time after you have disconnected power or damage will result?

Can I build a switch box of some type that would put 8ohm resistors on the outputs with the amplifier still on, while I switched speaker leads from one set of speakers to the other.

If "yes".....What type of switch or circuit would I build for such a device?



Thanks

Rbertalotto wrote:I have a Tubes4HiFi ST120 Tube amplifier I built a couple years ago. I have a number sets of speakers that I like to audition from time to time. It is my understanding that you are not to disconnect speakers from a tube amplifier while it is running or for some time after you have disconnected power or damage will result?

Can I build a switch box of some type that would put 8ohm resistors on the outputs with the amplifier still on, while I switched speaker leads from one set of speakers to the other.

If "yes".....What type of switch or circuit would I build for such a device?



Thanks

Any switch box that connects the next speaker BEFORE disconnecting the present .
"Make before break" as they call it.
NEVER LEAVE OUTPUT OF A TUBE AMP DISCONNECTED !!!

I was told that p[utting a 100 ohm resistor across the speaker output terminals would not degrade the sound and would protect the output transformers....??

Rbertalotto wrote:I was told that p[utting a 100 ohm resistor across the speaker output terminals would not degrade the sound and would protect the output transformers....??

Yes, this can be seen as an insurance. But i would still never leave the output open. Shorting
however is no problem for a tubeamp.

Thanks! I just ordered two 10w / 100 ohm / 5% wire wound aluminum case resistors.....