Warming up a tube amp?

[rmp]

Originally Posted by clintj

Once it passes signal, you can play. Generally it takes 15 to 30 seconds for all the tubes to reach full temperature and start flowing current. Letting it sit for several minutes does nothing but waste usable tube life and electricity.

Exactly what the tech that I have work on all my "stuff" told me when I asked him a few years back.

[ghostnote]

I turn on the amp, tune the guitar, and play. Never had an issue doing it that way over many years with many different amps.

[captain_jack]

only 17 responses so far for this topic? must be a slow week for the forum

[DanR]

My amp (TopHat Club Royale) has stand by switch. I typically turn the amp on with the stand by switch on. I will then make sure my guitar is in tune, which might take a minute or so, and then I'll flip the stand by to on.

On my EL-34 loaded Marshall I power up on standby and let it warm up for 3-5 mins. while I fiddle around with pedals, tuning, etc. before playing.

[Dru Edwards]

1 minute when I'm at home, bedroom volumes. When I was gigging/band practice it would be 2-3 minutes but never 10 minutes. Never had a problem.

[Dru Edwards]

Originally Posted by DanR

My amp (TopHat Club Royale) has stand by switch. I typically turn the amp on with the stand by switch on. I will then make sure my guitar is in tune, which might take a minute or so, and then I'll flip the stand by to on.

That's exactly what I do with my Marshall heads.

[Rudy4]

Originally Posted by Dru Edwards

That's exactly what I do with my Marshall heads.

Why involve the stand by switch at all if it's always ON?

[Big Band Guitar]

Back in the late 60's I converted a old jukebox amp to use for a bass amp.

It had a circuit that when turned on 110 volts were applied to the filaments, as soon as there was current in the power amp cathode circuit (relay coil in series) it dropped the filament voltage to normal. It was almost instant on.

So, it really doesn't matter how long the warmup is.

I no longer have a tube anything.

[stokes1971]

The first thing that heats up is the filaments, or heaters,takes seconds to come up to temp, the filaments heat the cathode which takes a few seconds,The screen and plate dont get to optimum temp till the amp starts passing signal and the plate and screen draw current.No need to wait beyond a minute or two but absolutely no harm if you want to wait longer.

[stokes1971]

A more important consideration is when transporting the amp to a gig in extreme cold weather.If you fire up the amp before it gets closer to room temp the amp is so cold you will get condensation as the tubes heat up in the cold chassis.

[Dru Edwards]

Originally Posted by Rudy4

Why involve the stand by switch at all if it's always ON?

lol Rudy!

When I turn on my Marshall the Standby is already set to "Off". After a minute or so, I turn the Standby to "On" and play. I turn the Standby to "Off" a couple of seconds before turning off the amp.

For whatever reason, Marshall's Standby "Off" means the amp is on standby... is it just me or do other people think this is the reverse of intuition?

[Rudy4]

Originally Posted by Dru Edwards

lol Rudy!

When I turn on my Marshall the Standby is already set to "Off". After a minute or so, I turn the Standby to "On" and play. I turn the Standby to "Off" a couple of seconds before turning off the amp.

For whatever reason, Marshall's Standby "Off" means the amp is on standby... is it just me or do other people think this is the reverse of intuition?

I think it simply refers to what the circuit does when the switch is in the "off" position; disabling the high voltage circuit portion of the tube circuit.

A nice explanation of the switch's purpose and (mis)use can be found in the short article "The Great Standby Switch Myth" from the Sweetwater website.

[Rudy4]

Originally Posted by Big Band Guitar

Back in the late 60's I converted a old jukebox amp to use for a bass amp.

It had a circuit that when turned on 110 volts were applied to the filaments, as soon as there was current in the power amp cathode circuit (relay coil in series) it dropped the filament voltage to normal. It was almost instant on.

So, it really doesn't matter how long the warmup is.

I no longer have a tube anything.

I'm assuming "filaments" is referring to the tube heater filaments?

I've never heard of any tube amp that applied more than the low voltage from the transformer (typically 6 volts) to the tube heaters. Tube heaters aren't really anything different than a incandescent light bulb element and even briefly applying much higher voltage than what the filament is designed to use would greatly shorten the life of that critical part of the tube.

In any case, I'm glad that worked for you.

[12GA]

I’ll keep my 1968 Ampeg G-20 on standby for a minute or so but not longer. I’ve owned it since the mid-70’s and it’s never seemed to need a longer warmup.