What does a STANDBY switch do?

[Jones]

On a tube amp, what does a standby switch do, in simple terms a caveman can understand?

I hear people talking about these standby switches, and I have a Fender Princeton Reverb tube amp, but it doesn't have a standby switch. Just wondering what it's supposed to do. Thanks,

Jones.

[avwalker]

Tubes have basically two voltages they operate with. A high current, low voltage "filament" line and a low current, high voltage "mains" line. The filaments have to be heated up for a little while before the main voltage hits. When you turn on the power, the filaments start heating up, when you turn off the standby, the high voltage hits the plates.

[avwalker]

......additionally......your princeton reverb doesn't require a standby switch. The princeton uses a tube rectifier which limits the high voltage slam on the power tubes while it warms ups.

[Bryan T]

......additionally......your princeton reverb doesn't require a standby switch. The princeton uses a tube rectifier which limits the high voltage slam on the power tubes while it warms ups.

I had one installed on my Princeton Reverb for times when the amp is going to be on for a period of time, but not in use. I use the standby on stage and in the studio pretty regularly.

Bryan

[Mike T]

Standby keeps the filaments warm without B+ (high voltage DC). A GZ-34 (5AR4) rectifier has a slower warmup time that 5Y3 or 5U4 because of an indirectly heated cathode. That is the best alternative to a standby switch. I believe a 5V4 has an indirectly heated cathode also, but it has a lower B+ than a 5AR4. 5AR4 has the highest B+ and least sag out of all of these.

[John Phillips]

......additionally......your princeton reverb doesn't require a standby switch. The princeton uses a tube rectifier which limits the high voltage slam on the power tubes while it warms ups.
Warm-up is only one issue. It also allows you to stop the tubes wearing if you're not going to use the amp for a while, without subjecting them (and them amp) to extra cooling and heating cycles, which aren't good for them either.

Basically, a standby switch helps prolong tube life. An amp doesn't need one, but it's better to have one than not.

Most of the amps not fitted with standby switches were made like that for cost reasons.

[sector9]

It keeps your amp warm and ready to go. So easy a caveman can do it.

[Exothermia]

In caveman terms, turn it on for 30 seconds or so before turning your amp on. And if you want to leave the stage for 5 minutes put it back on standby while you're gone. In layman's terms it warms up your amp and makes your tubes last longer.

In scientific terms there is a lot more going on. But who cares.

[Jones]

OK, thanks everyone.

[Jones]

......additionally......your princeton reverb doesn't require a standby switch. The princeton uses a tube rectifier which limits the high voltage slam on the power tubes while it warms ups.

Interesting!

Does anyone know or have an opinion on whether my Pignose G40V amp (40W, three 12AX7 preamp tubes and two 6L6 power tubes) should have a standby switch?

I like the idea of leaving electronics on to avoid heating/cooling cycles and capacitor/power supply surges (my Power Mac stays on 24/7/365 minus thunderstorms), and I like having the amplifier ready to play for five minutes anytime I want (I work at home), but not if it's going to wear my tubes out faster.

Is installing a S/B switch a complex or expensive proposition?

Thanks again for all the great replies. This board is a HUGE resource for dummies like me.

Jones.