speaker selector switch - do I need to turn off amp when using

[philips fx82]

Hi to everyone. I recently bought a 5 position speaker selection switch off the bay. It hooks up to my amp and allows selection of one of 5 sets of speakers. Would I need to turn off the amp (el 84 amp) when changing to a different set of speakers? I know that a tube amp can wreck the output transformer when there is no load hooked up. Would the short time period without a load cause any problems?
my thanks in advance



https://www.ebay.com/itm/vintage-stereo-speaker-selector-and-speaker-wire/282677728896

 

[Hi-FiGuy]

It is only safe to switch speakers on a tube amp when there is NO SIGNAL PASSING. A lot of tube amps have been damaged by hot switching from speaker swaps. Better to do when the tubes are on with no signal.

 

[N8Nagel]

short power cycles are not good for tubes. I concur with advice above, turn preamp volume to min, switch speakers, turn volume back up.

 

[Alan0354]

Only takes micro seconds for arc to punch through the insulation of the OPT. Unless you have a make before break switch, I won't do it.

 

[century tek]

I think that you would be fine as long as you turn the volume down before switching. Most of the old school console and shelf unit EL84, 6V6 etc amps are so bullet proof that even if you accidentally switched between speakers when the volume is up a little, you wouldn't cause any real damage. The feedback circuit would also play a part in it not oscillating.

Some of the more recent expensive or more exotic amps might have a problem with oscillations if the speakers were to be disconnected or switched while turned on.

I can tell you that the Magnavox, Fisher, and Zenith old school amps have no problems with no speakers especially for a short period of time. I used to abuse a Magnavox 9300 series amplifier years ago by switching speakers when powered up and sometime I would hear the sound coming from the output transformers themselves but that thing kept going and going.

I sold it just a few years back still in good working order.

What model of amplifier are we talking about here?

EDIT: If you are leary of doing this with it powered up, just simply turn the volume down as hot switching tube amps isn't really good for them especially if they use tube rectifiers.

 

[philips fx82]

Pilot 240 integrated, pp el84

 

[peterh]

As said, turning down signal to zero is a good advise. Another thing to do is install
a fixed 100 ohm resistor on the amp output, always connected . That will prevent
a "no load" and keep amp safe