Optimum warm up time for tubes

[Dave C]

Do you notice a point that the music starts to sound better? I seem to find a 10-15 min. warmup for the best sound to start is in order. If I start listening right away when turned on I can just about set my watch to the fully warmed sound 10-15 min. later.

[SET12]

Do you notice a point that the music starts to sound better? I seem to find a 10-15 min. warmup for the best sound to start is in order. If I start listening right away when turned on I can just about set my watch to the fully warmed sound 10-15 min. later.

I think :scratch2: thats amp design dependent as I'm at about 2 hrs of working amp time to fully bloom.:smoke:

What tubes are you using?

[willyrover]

20-30 minutes for my Eicos.

Don't think it's just the tubes. The transformer temps probably also affect the sound.

[jon_s]

I've found a huge change in bias over the first 10 minutes for my Bogen amp. I'm not sure if it's a transformer thing, or just a property of the tubes and maybe the screen regulation. Within 1-2 minutes, my larger amps are fully settled, in bias and in sound.

Of course, then after 2-3 hours of use, heat starts to catch up and the sound starts going down hill. I usually turn my gear off after the PT reaches "hot" territory.

[audiodyssey]

I have a PAS 3 I leave on all the time, except when I know the system won't be on for a few days. My amps take 20-30 minutes to sound their best. I'm using 70's stock Russian 6B4g tubes in a pair of DIY monoblocks, now being piped thru a pair of Speakerlab K-horns. The thing I find most interesting is that the amps sounded pretty good right after they were built. At thirty hours of use they sounded even better. They are almost a year old now and they recently really underwent another transformation; they probably have seen just about a thousand hours of use and I think they are finally truly broken in. I find leaving the preamp on gives me good sound right away but it's always best at around an hour. I've never noticed any degradation of sound even after 12 hour days of music playing.

[GordonW]

Willyrover and jon_s have it right, IME.

It's not just the tubes, it's EVERYTHING.

Transformers, resistors, even some caps... once things are stabilized at proper working temperature, they definitely work more optimally. Transformers and resistors change in impedance slightly, caps actually change in value a tad... you want these to be at the values that the original designer intended, which will only happen at a proper "steady-state" warmed-up temperature...

It varies, but it's usually safe to say that after one hour on, MOST amps are pretty much stabilized at normal operating temperature and won't change in sound much afterwards...

HOWEVER- any amp that starts to sound WORSE after being on a while, NEEDS SERVICE. That's a sign of something over-loading and over-heating. Not a sustainable situation!

Regards,
Gordon.

[zenith2134]

Agreed, GordonW. Every part needs to reach operating temperature in order to sound as designed. If there are other issues in the amp, warm-up time may be longer.

I feel 15-20 minutes is enough initially, but after a few hours most units take on a new sonic signature and sound more natural.

[Dave C]

On the subject of bias, I noticed a tube was running a bit hot the other night so this morning I got the meter out. I had set the bias voltage to 20V about 2 months ago (Sansui 1000A) This morning my check found bias voltages of 18V on three tubes and 16.5 on the forth. Hot tube explained. I will have to check it more often but why did it change that much? I set everything back to 20V.

[Kegger]

My SYSTEM takes about 45 minutes to "change" to a better sounding system
then when first turned on, by about 2-3 hours it changes just a little more for
the better, as in a touch smoother with a bit more bass authority.

That is my present system, generally I go with about an hour for tube gear to
settle in and sound like what it really sounds like. Just my experience.

[Celt]

My rule of thumb for all gear has been 30 minutes warm up at idle.

[jon_s]

HOWEVER- any amp that starts to sound WORSE after being on a while, NEEDS SERVICE. That's a sign of something over-loading and over-heating. Not a sustainable situation!


I think that any amp getting hotter and hotter to the point of self destruction is definitely a problem. But the sad truth is, many vintage tube amps will get hot enough to degrade the sound due to increased transformer loss and inevitable drifting of carbon comp resistors, even if they won't blow up (Dynaco SCA35, for example). This can add some "warmth" (Ha!) to the sound, but I much prefer the sound of a just-warmed-up "cool" tube amp. Of course, my listening attention span usually degrades substantially after 3 hours anyways. :thmbsp:

[Urizen]

My 6V6 take around 11 sec. to get to speed.

It only gets better from there, as the iron heats up, sounding best after about an hour:music:

[zenith2134]

Sometimes I'll need a cup of coffee (or whatever...) to keep my listening sessions going strong. My digital stuff stays on 24-7 as per the recommendation of an expert in the field.

[SET12]

Sometimes I'll need a cup of coffee (or whatever...) to keep my listening sessions going strong. My digital stuff stays on 24-7 as per the recommendation of an expert in the field.

My Digital is on as well 24/7 as recommended by Digital experts. Unless I'm deep into vinyl.:D

[gogofast]

I'm at about 2 hrs of working amp time to fully bloom.:smoke:


2 hours!?
you must be really patient....my entire listening sessions don't even last that long.:D

[Bruce221]

depends on the geer push-pull tend to warm up faster 20 min good rule of thumb at idle-set-30min to an hour-full bloom of set amps can be as high as 2hours-most sets sound fine at the 1 hour point---these amps need to swet and drip out the sound but well worth it ------only problem must plan on when your going to listen.

[Billfort]

About 30min. of warm up does it for me but it seems to be at it's best after an hour or two.

This tends to coincide with source material for me too - for the warm up period I'll use the tuner or some digital source but when the stuff is all toasty and warm I inevitably turn to vinyl for some real listening.

[onepixel]

The manual for my Cary says 5 minutes. Seems about right.

[ScramMan2]

It's about a hour for me before they really start to get nice and fat sounding ... now that golf season is here it cuts into my listening time at night.

[forum7]

This amp takes 30 minutes to warm up and 1 hour to full resolution.

http://i302.photobucket.com/albums/nn116/forum7/cj11a.jpg

[ablethevoice]

Forum7, that is a stunning looking rig! Absolutely beautiful.

I don't have any tube hi-fi gear, but my Hammarlund HQ145 communications receiver is as stable and good-sounding as it's going to get (which is to say very good sounding and very stable indeed) after a 15 to 20 minute warm-up.

[stuartk]

My rule of thumb for all gear has been 30 minutes warm up at idle.

I've heard gear that seems to be at optimum within a minute or so of being powered-on.

Other gear seems to take longer.

If a piece of equipment isn't warmed up and stable by 30 minutes, it's probably in need of repair or just not designed well in the first place.

So I'd agree that 30 minutes is a good rule of thumb.

[stuartk]

Forum7, that is a stunning looking rig! Absolutely beautiful.

I don't have any tube hi-fi gear, but my Hammarlund HQ145 communications receiver is as stable and good-sounding as it's going to get (which is to say very good sounding and very stable indeed) after a 15 to 20 minute warm-up.

Tube tuners are definitely something that needs warm-up. They always drift a bit until all the oscillators settle down.

BTW, the HQ-145 is very nice. :)

[ablethevoice]

Tube tuners are definitely something that needs warm-up. They always drift a bit until all the oscillators settle down.

BTW, the HQ-145 is very nice. :)

Yeah, I like the old man a lot. It's not the largest and heaviest boatanchor rig I've ever owned. That honor goes to an old "angry5" rig (with original power supply) I had as a teen (c.1976). Like an imbecile, I sold that one, my bottom-end Hallicrafters (model # escapes me ATM) and a DX160A when I got into music. Didn't have time for both and at the time, music was more important. I wish I still had the AN/GRR5 though, but the 145X is an acceptable substitute.


The magnificent AN/GRR5 military communication rig

http://www.roetta.it/ik3hia/surplusm1/grr5/rx_grr5.jpg

http://www.roetta.it/ik3hia/surplusm1/grr5/rx_grr5b.jpg