Hi, today i do a mistake! I power on my ampeg svt-vr and also switched on the standby while no cab was connected to the head. I totally forgot it...and i use it for a couple of minutes. I have no cab to test the amp so i would like to now if someone can help me with diagnostics: At the time of the mistake it do nothing like smoke, smell, flares etc...all seems to be ok. The amp seem to run fine (stanby on)...all tubes power on... The led of BIAS and BALANCING are light fine as ever.. It's there any test that i can do without a cab to now if i broken something?.... I'm so afraid....thank you so much! Gabriel.
I think you got lucky. If you burned the transformer you probably would have smelled it. No way to know without plugging in a cab.
I have to ask though, how did you play for a few minutes without noticing the distinct lack of sound?
A studio we recorded in a couple years ago did this to mine, and it seemed fine for about a couple weeks. After that I had some pre-amp tube failures, but I'm pretty sure it was from long term wear more than just the one accident. Got it all sorted now, though, and it's good as new.
Most tube amps use an output jack with an internal switch that shorts the transformer secondaries (not in SS amps) that is designed to protect the amp in the event someone does what you did. No smoke is a good thing but you won't know till you hook a speaker to it. Tube amps are at risk when run open circuit and solid state amps (without output transformers) are at risk when run shorted. Thus the shorting switch is standard on most quality tube amps and they are NOT used on (most) SS amps.
Unfortunatly i was using the head in te control room while i tought it was connected to a cab in the other studio room...so i notice the problem when unmuting the mic line...previously i was only hear the preamp balanced output... I hope no damage was done to the head...as soon as i can i'll connect a cab... Thank you so much!! Gab.
As explained above..... You picked the "best case scenario". It could have been much worse if you were plugged into a cab and the cable was pulled from the speaker end. If the amps sounds/plays fine, then you are OK. Best