Running without a speaker load

[zzmoore]

Re: Running without a speaker load

The vast majority of valve amps, save for some vintage designs have power and standby switches for anything with a tube output section. Now, if you look at any schematic, you'll see that the standby switch 99% of the time interrupts all current in the power supply section. Therefore, no current is going to the tubes EXCEPT for heater current. High voltage is supplied to the output tubes through the output transformer. If no current is through the output transformer with the amp on standby, it is no different than if the amp is off. To the OT, nothing is going down.

When you turn it on, however, all bets are off.

The safe thing is to never turn your amp on without a load connected. Chances are manufacturers tell you not to do it to reduce warrantee claims and just to follow the status quo of the industry. My boss at my day job has a saying, "you get paid the same whether you're fighting or marching" and rather than try and explain the circuitry behind amps to your average guitarist they may just regurgitate the same info out there and keep everyone on the safe side... let dispelling the myths of the intArwebs community be someone else's crusade.

Wow!
A 23 year old had to explain this to all you old dudes......

[Warheart]

Re: Running without a speaker load

I've switched cabs on standby a LOT, and I've never damaged any of my heads.

The Marshall JVM model has a silent recording feature., the line out still works when the head is in standby mode, no load necessary.

Edit:
Actually you can do this on regular amps if they have a line out, you just need to remove the power tubes, and you don't have to have a speaker load since the power section is disabled.