Warming-Up Amps w/o Inputs or Speakers Attached

Transformers CAN'T, "store" anything, or feed anything back into the amp. Neither SS, not tube amps will suffer, IF THERE IS NO INPUT SIGNAL. I've turned on, and tested amp circuits, voltages, etc., with no speakers/loads attached to the outputs, for decades, with no damage. BUT- ANY input signal(even touching the inputs with your finger), on a SS amp, can be disastrous. The output devices MUST have a load to dump current into, or most will overload/fry. On a tube amp with an output transformer; the x-former acts as the load that the tube, "sees." Less chance for any damage to the tubes, or amp, without speakers attached. If you are worried; you can connect a pair of DUMMY LOAD RESISTORS, such as Mr M suggested, or these(http://www.mouser.com/ProductDetail/Ohmite/C300K10R/?qs=sGAEpiMZZMtbXrIkmrvidP2I4HgSKt85zTh%2fvGSbGfI%3d)across your outputs. Anything smaller(you won't find anything big enough at Rat Shack), and you stand a chance of damaging an amp, should an accidental input occur.

"The output devices MUST have a load to dump current into, or most will overload/fry."

I don't see why. SS amp is basically voltage source that will run with or without load.

FYI for anyone interested

I will not be drawn into some endless debate but Mr Rodman is wrong on most counts. Kijanki is correct. SS voltage sources don't care if they have a load or not.

Transformers do indeed store and release energy. That is why tube manufacturers caution you to always have a load connected. That is why many guitar amps have spike protection across the output tubes in case there is a voltage kickback from the inductance in the transformer.

Radio Shack has 20W 8 ohm resistors which are plenty for the purpose of protecting the output tubes unless you want to drive the amp with an input signal

..

Herman,

Even when driving input 20W should be enough since average music power delivered to speakers is only a few percent of peak power.