Warming

cronker · #1 11-03-2012, 01:02 PM

Hey
My Ashdown is a lovely, loud amp.
I tend to let it "warm up" before I play, because of the tube pre.
Is this necessary?

Mr. Foxen · #2 11-03-2012, 01:07 PM

Tube won't pass signal until it is warm, so you'll have to let it warm up for the 20-40 seconds that takes before it sounds right.

RickenBoogie · #3 11-03-2012, 01:08 PM

+1, it'll only work after the tubes have had a short warm up period, but if it makes sound, it's good to go.

B-string · #4 11-03-2012, 01:20 PM

Small preamp tubes warm up to operating temp quickly. Less than one minute.

Pilgrim · #5 11-03-2012, 02:33 PM

In other words, once you can hear through it, you can use it.

B-string · #6 11-03-2012, 02:34 PM

Quote:

Originally Posted by Pilgrim

In other words, once you can hear through it, you can use it.

That about sums it up.

jlepre · #7 11-03-2012, 02:59 PM

I have a related question. I have an STM-900 with 3 pre-amp tubes. Is it better to keep amp running between sets, or would it not make a difference if I power it down.

UrsaMinor · #8 11-03-2012, 03:59 PM

Correct me if I am wrong, but wouldn't the pre-amp tubes be of no huge deal. I would think that power tubes would need to stay warmer, as they tend to sound better the more they're cooking. Like I said, this may not be the case.

**mjac28** · #9 11-03-2012, 04:13 PM

Quote:

Originally Posted by jlepre

I have a related question. I have an STM-900 with 3 pre-amp tubes. Is it better to keep amp running between sets, or would it not make a difference if I power it down.

It won't make a difference if it were all tube I think it might. I had a SVT Classic and was told to keep it on rather than keep powering it up and down nice amp by the way.

jlepre · #10 11-03-2012, 04:27 PM

I was also thinking about what would be best for extending tube life.

**DethByDoom** · #11 11-03-2012, 04:46 PM

The analogy I was given is tube amps are like Diesel engines. They don't have to have an extended warm up but they run better when they do.

+1 on preamp tubes warming quick. Power tubes do sound noticeably better warmed up well. And they take a bit more time.

I was told, however, that its rough on the tubes to move tube heads that are on or still very warm.

I've had the same power tubes in my head for like 6 yrs. At gigs I put it on standby for a min then turn power on and finish setup. I like warm power tubes for gigs. I try to put it in and out of standby as little as possible. I put it in standby the most at practice. If its gonna be on for more than 30-45min w/o use I'll put it in standby. If its gonna be a long gig ill put a fan on it. I baby it.

Also the harder you push the tube the less life you get. If you run the power section real hard (3 o'clock or more) its gonna affect tube longevity.

Mykk · #12 11-03-2012, 06:13 PM

I have an amp that uses 12ax7 pre-tubes and MOSFET power section. After several hours of playing I can hear my amp's tone change for the better, it begins to sound thicker and fuller.

After changing my pre-amp tubes (I don't think it had ever been done) it sounds great right out of the gate. My point being, if the sound does change after a long warm up period it's time to try new preamp tubes.

**DethByDoom** · #13 11-03-2012, 07:16 PM

Quote:

Originally Posted by Mykk

I have an amp that uses 12ax7 pre-tubes and MOSFET power section. After several hours of playing I can hear my amp's tone change for the better, it begins to sound thicker and fuller.

After changing my pre-amp tubes (I don't think it had ever been done) it sounds great right out of the gate. My point being, if the sound does change after a long warm up period it's time to try new preamp tubes.

I've generally used the "tap test" for preamp tubes. Lightly tap them while amps on. If they're microphonic I replace them. Ive found that they start sounding lifeless and get microphonic at about the same time. If you get good tubes it can get pricey to try to replace them often i.e. telefunken or tung-sol.

Growly Lytes · #14 11-03-2012, 08:32 PM

Quote:

Originally Posted by B-string

Small preamp tubes warm up to operating temp quickly. Less than one minute.

What about a solid state power amp class H, do you let it warm up a little before blasting away ?

**DethByDoom** · #15 11-03-2012, 09:03 PM

Does it even have a standby mode? Shouldn't need to… is it an SVT 3? They kind of do that on their own.

cronker · #16 11-03-2012, 09:20 PM

Thanks for the replies. Interesting stuff.
I find my amp sounds "warmer" and more tonally pleasing if I let it warm up for about 10 minutes before playing.
It sounds really nice when it's been pumped for about 30 minutes.
I tend to drive it a little hard every now and then, just to "clean out the cobwebs". Works for me

iiipopes · #17 11-03-2012, 09:32 PM

Quote:

Originally Posted by cronker

Thanks for the replies. Interesting stuff.
I find my amp sounds "warmer" and more tonally pleasing if I let it warm up for about 10 minutes before playing.
It sounds really nice when it's been pumped for about 30 minutes.
I tend to drive it a little hard every now and then, just to "clean out the cobwebs". Works for me

Warm-up and overall heat affect more than just the tubes. All components shift values anywhere from a not hardly noticable amount to really noticable depending on their construction and condition (age - especially paper filter capacitors). This sounds like the capacitors are shifting in value from the heat. It's alright - they all do that. But a few years from now, when it stops sounding fine after 30 minutes, and starts feeling hot all over after a gig in spite of tube changes, then the filter capacitors and maybe some other components will be needing changing as well as tubes.

B-string · #18 11-03-2012, 10:08 PM

Quote:

Originally Posted by Growly Lytes

What about a solid state power amp class H, do you let it warm up a little before blasting away ?

SS needs no warmup. My 800RB gets no warm up at all, the Fusion 550 gets powered on and off while in mute and generally in less than a minute I am tuning in mute mode and ready to play (three tube preamp).

Growly Lytes · #19 11-03-2012, 10:19 PM

Quote:

Originally Posted by B-string

SS needs no warmup. My 800RB gets no warm up at all

iiipopes · #20 11-04-2012, 06:42 AM

Modern well-designed solid state amps have a built in buffer that delays full power on until any risk of voltage spikes (you know - the infamous "thump" in a speaker when an amp is turned on) have been buffered. My Carvin MB12 is like that. It does the equivalent of a mini-diagnostic every time I turn it on, and a few seconds later, I'm good to go.