Four Hour Tube Amp Warm-Up

Which Prima Luna?

The dialogue HP premium sitting in the rack sounds pretty good by the time the preamp is warmed up… (90 seconds.)

It could also be that the dross and flotsam of/from the stress of the day take 4 hours to be washed away…?

The old VTLs also sounded good pretty quickly.

But maybe there is somethng like capacitors forming that is happening?

When I had my Viva, it was 45 minutes. You could set your watch by it. 4 hours seems long, but who knows.  Ask Kevin from Upscale.  He’s pretty familiar with that brand so I hear. 

Solid state monos here: on and idle about 6-9 pm , listening about 10 am or so, that is my laser beam zone, where the sound just lasers my ears with clarity and envelopes me with perfection. 
same with pre and spinner, on and morning listening, there is a huge difference from initial “on” and the 12-20 hours at idle to warm.

the odyssey strato amps take about 5-7days……yup days, but worth the wait.

clariy, bass, crunchy Mustaine mids! 

No !   I have had Rogue Audio amplifiers (Cronus magnum integrated, stereo 100 power amp). 

Each of them starting sounding great by the end of a record- e.g. 40 minutes or so.  

Definitely an improvement after side 1, maybe an hour max.  

Yes, with my past four amplifiers, all Class A or Class A/B, here is what I’ve noticed. This includes Tube and Solid State amps with big iron transformers though:

45-60m: sounds pretty good, and initially I’d think its warm enough.

120m no major changes but still sounding good. Close to the same as 60m.

240m (4hrs), with the big transformers now fully heat saturated, 3-dimensional sound kicks in, with sounds coming from the sides and slightly to rear of me too.

• My local 50+ year audio tech and builder colleague tells me "its the transformers getting to be fully heat saturated is when things can begin to sound magical" on some of the better amps w quality transformers.
• My local dealer fires up his amps at least 4+ hours prior to letting any customers in the door for listening sessions.

Longtime PL user.

5 minutes warm up, and it's ready for overdrive the next 4 hours.

I don't have 4 hours to wait for anything to perform "better."

I'd get my hearing tested and avoid reading audio forums.

Don't forget, speakers need warm up too. All my tube amps were good after 45 min.

Happy Holidays!

Pretty much in agreement with the above, this with many tube, both push pull and SET over many years. I notice as the amps age magic time can lessen to around two hour mark, also depends how hard I run them, running them hard further lessens time. I do always give at least hour lower volume prior to kicking things up. I also use boutique caps over much of my system, the physically huge caps I run in speaker crossovers need the hard running time.

By far the most incredible listening session happened two days ago after the PL's had been accidentally left on for 7 hours. Technically, the Sophia EL 34 power tubes may not be "fully" broken in yet, but they have about a 100 hours on them of playing time.

I can agree that full transformer saturation may explain a lot. The solid state cd transport and DAC are of course kept on all the time. The Primaluna pre and power tube amps are not in the interest of tube life. If they didn't sound so good I would probably go back to a full solid state system.

Dozens of tube components later, the only ones I ever had concerns about a warm-up time longer than (say) 15 minutes were the hybrid electrostatic amps with lots of high-voltage transistor CCS on their outputs.

Never really experienced that with any pure tube components. They should sound really good very quickly. Unlike transistors, tubes need heat to operate at all, and they have filaments for that very purpose - which efficiently heat up so the tube operates at spec very quickly. Transistors are however affected by heat, and can take a relatively long time to reach their final stable operating temp - because heat sinking is used to pull heat out to keep them at a safe operating temp under maximum load conditions. There’s no such heat tug-of-war with tubes, so they get stable quick.

The only aspect of tube amps that has a slowly heat-accumulating element would be the transformers, and maybe silicon rectifiers and voltage regulators in the PSU. Though only large transformers should take hours to fully warm up. I don’t know if that significantly affects their performance - maybe. That could be the "4 hour warm-up" in your case.

My experience mirrors Tablejockey 

I always enjoyed the process of hearing things open up- I'd say 45 minutes is sufficient for the Lamm ML2 SETs and a couple or three sides of LP for the cartridge to really come into its own (after initial settle in which could vary depending on cartridge). My small vintage system running old Quad IIs with period glass (GEC KT 66s!) and restored Quad 57s is pretty much the same on warm up time. And you can clearly hear when these systems just bloom- everything opens up. 

I've been using various tube amps and preamps since the early '70s and can't say my experience decades ago is much different using then current ARC tube gear, but my sonic memory isn't that good. 

Same here my Qualiton X200 is ready to go in 15 min.

My experience mirrors Tablejockey 

Agree with @tablejockey when it comes to tube gear, DAC's and digital components.   I do feel like solid state amps benefit from a 1 hour warm up period to sound optimal. 

@bolong "The solid state cd transport and DAC are of course kept on all the time."

I can see why you would do this if the equipment has a auto standby mode that kicks in (my Hegel H590 did but my H30 does not) but otherwise I fail to see the sense.  I'm not aware any any manufacturer that suggests leaving equipment powered up 24/7?  I would think you are only shortening the eventual life span of things doing this?  Just asking.  

My David Berning designed Linear Tube Audio ZOTL40 takes about 10 minutes to get there.

Funny you should bring this up. While the system sounds great after 20 minutes, I too have noticed that things get sublime after about 4 hours. All analog and tubes here.

I have never had a tube integrated amp and I’ve never had a tube preamp take more than 15-20 minutes and an amp take more than an hour to reach the “Sweet Spot “.

10-15 minutes is great, but after an hour or two I'm often finishing my 2nd hazy IPA and it sounds wonderful! 😂

Op, +1 although my amp was more like 3 hours. Or should I say at least 3 hours 

I agree with lancelock. On the LTA design. What a benefit. Think about it over the lifetime of YOUR time. LTA deservingly should be considered with appreciation that often isn’t spoken about. For the Ultralinear, I can listen at the ten minute mark and get full value at about 30. Maybe due to the transformerless design,without noise, or product weight, ez access and inexpensive tube replacement, and the fact that the tubes last far beyond the norm so can remain on and don’t need to wait for any warmup.  What’s wrong with this other than one needs consideration for moderately efficient transducers for this design to ultimately not be a great choice?  

My ARC amp/pre need about 30 minutes or it sounds a little thin to me. Every hour after that just gets better and better.

I don’t know how people wait that long. It might warm up a lot faster if you just start using it from the get go rather than leaving it idle. I may watch some tv or better yet blast some cooking music that I can hear from the kitchen. Then, when I’m ready, I’ll switch to triode mode, make my selection, and let the music wash over me. 

My carver black magic take less than 5 minutes to get the bias meter up & stable at 100. It's playing nonstop for the next 6 hours, every single day. Sound starts great & stays there. 

My Mal Valve 2 and VAC 300.1 have a good sound after 45 minutes. After 4 hours , they sounds amazing !

It took my solid state equipment 4 hours to sound its best.

My current Primaluna Evo sounds great in less than an hour.

It could be equipment that's in front of the Primaluna that needs more time.

But certainly my sense is that tube gear hits its sweet spot sooner than solid state.

My tube amps seem to warm up pretty quickly...10 to 20 minutes maybe? My Pass XA-25 takes about 45 minutes although it sounds damn good immediately upon start-up.

PL Dialogue HP Integrated here. Sublime within 15 minutes of power-up. 4 hours? Sounds like your confirmation bias needs adjustment!

4 hours -- wow. So, tube life is, in effect, one quarter of their expected life for good listening? That will sound like an argument for solid state to many.

I agree with @designsfx for ARC stuff.  A half hour definitely benefits it, but I live in SO FL where it is warm most of the time--NOT THIS WEEK!

As far as hours and hours, I don't really notice much difference after a couple of albums.

Cheers!

My Elekit 300B sounds better than most of the other integrated amps on earth after 20 minutes.  But after 4 hours they’re magic.

Had a pair of Gryphon SS Class A monoblocks that peaked at 12 hours even though I kept them in standby all the time.

Go figure.

That seems rather long---that wouldn't cut it for me since I rarely listen to my music for 4 hours straight. I don't have tubes but my Sugden A21 sounds pretty sweet after about 15-20 mins.

Maybe it’s your tubes. My tube amps, both vintage McIntosh, get with it pretty quick, like less than 20 min.

My CJ Premier 1B takes about 20 minutes.

@hilde45 wow -- 4 hours -- wow. So, tube life is, in effect, one quarter of their expected life for good listening? That will sound like an argument for solid state to many.

And if you like your tube amp(s) more, keeping spare tubes around is an option. With extended long term use, and not a common situation, one of my former/older SS amps expired too. Kept a spare SS amp around for back-up parts.

Simple point-to-point tube amp design won for me - - no extinct circuit boards or extinct SS output transistors to keep spares for any more.

I've never experienced such a long warmup time with tube gear (usually fine in 20-30 minutes with "maybe" a slight improvement over the next 30 minutes).

Of course the speakers, turntable bearing/cartridge, CD deck, tape deck et cetera were also warming up @ the same time.

This said (since the 70's) I've never owned PP amps with large output tubes (just PP 6L6/EL84/EL34, and single ended EL84/2A3/300B amps).

DeKay

~20 min for me as well

I have 3 tube integrated amps between 2 systems - Line Magnetic 518IA, (845 tubes), Finale Audio Mk2 7189A (7189A/EL84M tubes, and an Audio Audio Spirit 2 (KT88) none take 4 hours to warm up; each sounds good after initial 15 minutes of warm up, and very good within the hour. If it took 4 hours 1st I’d look for new tubes andif that didn’t work then I’d be looking for new amps

I’m becoming more open to the idea that sound quality could improve up to 4 hours, which seems to be around the amount of time for the big transformers & their potting to fully warm up. However, it is very difficult to separate any such sonic differences from psychoacoustic explanations (without 2 of the same amp), and I still posit that if an doesn’t sound good within 10 minutes of power up, something might be wrong or "off" with it.

4 hours -- wow. So, tube life is, in effect, one quarter of their expected life for good listening? That will sound like an argument for solid state to many.

@hilde45  As per above, I would never wait 4 hours to start enjoying the amp. And as for solid-state, there’s another thread floating where a very well regarded SS amp blew and took out the unlucky owner’s JBL speakers. I think tube amps are a lot more reliable than many audiophiles give credit to, and SS are not the infallible devices either, perhaps with even more potential for downstream damage (direct coupling!). A lot can go wrong with transistors; they’re mechanically robust but don’t take electrical trauma well - the reverse of tubes!!

I'll try to be more precise in my warm up time for this post. Much of the warm up time has to do with amp, tube and parts replacement. New tube components, or new tubes or parts in well burned in tube equipment never bloom in initial phases or hours of burn in. Over time, at somewhere between 50 and 100 hours blooming will often take more warm up time, this may be as much as 4 hours, as burn in progresses warm up time decreases until a consistent warm up time of aprox 1 hour at full burn in.

My 300b monoblocks are undergoing this  repeated progression at this very moment, recently replaced all coupling caps with Duelund Cast, getting up into 60 hour range and blooming is coming in starting around 3 hours and progressing from there. Between changing out tube components, parts and tubes for nearly thirty years now this is entirely common occurrence.

@mulveling "However, it is very difficult to separate any such sonic differences from psychoacoustic explanations"

This is the Achilles' heel for many discussions. Obviously, the OP knows his own mind best, and we have to stipulate to what he's hearing. That said, 4 hours is a very long time, certainly an outlier in terms of what others report and what the equipment should be able to do. (Imagine a car that took a full 60 seconds to reach 60 mph --- that would obviously indicate a problem or bad design.)

As for your comment about the fallibility of SS -- good point. Tangentially, I'll confess that my Pass XA25 takes about as long as my KT88 tube amp to sound decent, and it sounds great after it's been on a long, long time. 

bigtwin wrote: "I'm not aware any any manufacturer that suggests leaving equipment powered up 24/7?  I would think you are only shortening the eventual life span of things doing this?  Just asking."

When I bought my Pass Labs XP17 phonostage I called Pass and asked if it would be OK to leave it on 24/7.  I was told that it was designed to be left on all the time and that is why the only off/on switch is located on the back of the component. 

From the Pass XA25 owner manual...

Leave it on or turn it off: The product is designed to be left on all the time. The exception to this might be a case where the unit will not be used for an extended time - in that case it can be turn off. The main power switch is located next to the AC power cord. (THIS REFERS TO THE REAR MAIN POWER SWITCH)

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

You are now ready to play music. Turn the level at the source or preamp to a low level. Press the power switch on the front panel of the XA25, the blue LED above the power switch will light. Turn the volume up to your preferred listening level. Sit back and enjoy! The XA25 takes approximately an hour to fully warm up and sounds better as it does. Pushing the power button on the front panel of the XA25 a second time turns it off and extinguishes the blue LED. (THIS REFERS TO THE FRONT PANEL POWER ON PUSH BUTTON)

@bigtwin Heed Audio, Simaudio, Pass Labs, SPL, AVA, just to name a few. 

bigtwin wrote: "I'm not aware any any manufacturer that suggests leaving equipment powered up 24/7?  I would think you are only shortening the eventual life span of things doing this?  Just asking."

@jerryg123 Thanks.  I stand corrected.  My manufacturers, Hegel, Esoteric, Triode Audio Japan, PrimaLuna, all recomend turning equipment off when not in use.  Oh well, whatever works for you is all that counts.  Merry Christmas.  

@bigtwin I cannot think of a single Tube Amplifier manufacturer that would say leave it powered on. Nor a Hybrid tube SS manufacturer.  

It’s difficult to really know for sure because I’ve not listened to the same music at 30 minutes, 1 hour, 2 hours etc. It’s also difficult to remember & accurately compare w/ that time lapse in between. I don’t think our sonic memory is that good over time, even relatively short amounts. 
 

“Warm up” time could also be be within in our brains & it takes me time to relax, unwind & really get into the music & really enjoy it.

That all said, I have noticed w my Rogers EFH 200 Mark II ( 2- KT 150’s per side & a seriously large power transformer) that the sound definitely sounds more full body & fleshed out after about 1 hour. Beyond that , I can’t say much. 

My 300B SET amplifier also sounds it best after 3-4 warm-up hours. After 1.5-2 hours it sounds not bad but not as magical smooth and clear as after 3-4 hours. 

When I had transistor amplifier Plinius 8200 integrated it was always on. Without couple of days warm-up the sound was hard to listen to.

I am really sorry to hear your system requires such an extended warmup. For tube equipment this is simply rediculous. I have owned a PrimaLuna integrated amp for over 10 years in my home office. I may have never discovered it’s sweet spot. I seldom have spent more that two or three hours in my office.

My main system is contemporary Audio Research Reference gear and my headphone system is Woo 300b… and neither have much of a warm up gain. In the past the Reference 5 series premps had a strange ~ 12 minute requirement to have signal passing through it until reaching optimal sound quality… it could be on for hours… but still had to have a signal going through it. This went away with the 6 series preamps. I don’t hear a noticeable improvement after the first couple minutes.

In decades prior, my equipment had a noticable improvement after 15 minutes or twenty… nothing like four hours.