Solid state warm up time?

My classic Olive Naim amps, from the 1990s, take at least a couple of days to “come on song”. After a week of being on, I’d say I’m fully happy with the sound.

The effect of switching them off is very obvious. The bass starts out as being very undynamic and diffuse. From that point of view, the difference is infinite, as I just don’t enjoy listening at first.

These arguments never get resolved though. Someone always says it’s impossible for this to happen or that it’s due to poor design etc. Or that it’s imagined. I’d say it’s very system dependent though.

 

Any SS amp will make sound within 30 seconds. Whether it is worth listening to immediately is a completely different story though. As a general rule of thumb, it often seems like the higher-end an amp is, the longer it takes to get to that point where it has fully stabilized.

This is actually true for much of the very highest precision electronics. I've run across some very high precision test equipment over the years which actually contains miniature ovens to keep the temperatures of certain very sensitive devices as constant as is humanly possible.

Until you have tried matching JFETs, you just can't imagine how temperature sensitive some SS devices are. Believe it or not, simply picking-up a JFET with your fingers for 2 seconds can be enough to make its characteristics measurably drift!

 

I'd say a few seconds, probably not needed, but just to be sure.
But it really depends on what you have - it's a real thing to consider when using a vintage amp.
Vintage amps often rely on bias currents and resistors that change when they get warm because of their inefficiency.
This doesn't apply to modern class AB and D amps which stay cool or become lukewarm while idle, at most.

Edit: don't forget that "ear adjustment" is also an important part of it all.
If you listen to something it can become either worse if you start to notice artifacts or better if you start to like the color of the sound.
It's something that can be mistaken for "equipment warmup".

 

I've noticed the biggest difference/improvement in warm up with the equipment I own is with the Bluesound streamers. Even though you can't turn them off, they sound better after playing a couple full album's. Whether you stream or access your library through these unit's the difference is unmistakeable. Most notable in smoothness.

 

I leave my DAC on 24/7, I can’t remember what it sounds like cold at this point But I don’t think it’s a huge difference. My VTL phonostage sounds terrible when it’s cold. 20 minutes makes a big difference and an hour is best. That’s the one I’ll forget to let warm up before using and is annoying.

Anything that isn’t class A or using tubes, I’ll leave on. Sitting idle doesn’t draw hardly any power and I think the benefits to Continuous power to the component is worth it. I run my equipment a lot everyday, turning it on and off a few times a day feels like it’s more stress on the component and waisted time waiting for a warm up.

 

Same here. But that first second can be hell.

 

Agreed.
I also think the thermal issues of a component going from cold to hot continually outweigh the small increase in one's power bill.
As well I leave my DAC's on continually but often wonder if they need to be playing music for a while before coming on song. Nothing I've noticed.

 

My Luxman definitely sounds better after a half hour or so.. I don't typically think about listening with any serious thought until I'm at least half way through an album.

 

One of my amps is a First Watt F5. I believe Nelson Pass sets the bias with the amp warmed up about 1 hour.

 

From my Lavardin IT manual : ‘best performance will be reached after ten minutes’.

 

It may not only be temperature that affects the performance of a transistor, but simply the amount “work” it gets. After all transistors work on a quantum technology principle and electrons are subject to a memory effect, meaning electrons do not alway immediately fully adjust to transients of the music signal.

Lavardin is actually the only one that claims to be able to minimize the memory effect of transistors. Their technology is patented and the unit in the amp is sealed into plastic. May be that accounts for the fast run up to reach full performance?

 

Most all techs make final bias adjustments after 15 - 30 minutes of warm-up time. This time is usually specified in the service manuals, written by the factory engineers. Time to stabilize varies by the design of the amp.
-Bill

 

First, I did not ever think that warmup was important is SS. Quite a while ago I read Steve's comments on the topic and tried several warmup periods and methods (with music and without).

For my ears and listening experience, I can say the system sounds more to my liking after some warmup. It seems to me that the most change occurs in the first 20-30 minutes after turn on. It is not possible for me to fairly compare beyond that as my acoustical memory decreases after time and comparing at turn on to 1 hour after seems not a big difference from after say 30 minutes.

The quantification is not important to me. What is important is that I prefer the sound after some warmup to none at all. Thanks Steve for "teaching an old dog new tricks".

I did some research I felt relevant to my system and here is some of what I found:

Schiit the maker of my DAC recommends never turning it off. Bryston has told me in phone conversations that they recommend warmup and directed me to a FAQ quoted below.

In the end this is a personal decision for us all. I say try it, ask others in your house to participate if you can (my wife said "Day and Night" easy to hear it). Some may not have systems able to resolve this change.

The speakers are very important but we tried it with some smaller and older ones and the change was clear. It is such an easy thing for each of us the checkout, why comment before you do? Gather data before making an opinion.

From a Bryston FAQ:

"Perhaps the most definitive answer for solid state electronics warm-up times comes from the test equipment industry. In the Tektronix 422 oscilloscope user manual it specifies a 15 minute warm-up period prior to taking any critical measurements. This implies that a sophisticated solid state test instrument is fully functional after 15 minutes. It also implies that even solid state electronics are not 100% fully functional without some period of warm-up. Our testing seemed to prove this.

Amplifier output continued to rise from start-up to approximately 15 minutes into operation. Bandwidth, however, remained consistent, and did not improve. The evidence suggests that solid state electronics do in fact require some initial period of warm-up to reach full operational capabilities. It also, however, indicates that extended warm-up periods beyond 15 minutes provide no additional improvement in performance."

Cheers and happy listening...I always try to remember this "hobby" is about the music not the hardware.

 

'70s Sansui here. I turn off the amp every evening. I experimented a little bit.

Warm up takes up to two hours. Then, strangely, the loudness option seems to boost less when activated. The difference with flat settings is much smaller.

After the warm up, the amp has more punch and dynamics.

Might be the age though.

Now I think of it: after sleeping, I can't jump out of bed like I used to, either.

And that amp is like 5 years older than me!

 

I did check this out and posted in detail the change in sound and no one gave a crap. And how do you know anyone making claims either way didn't check this out? You're having to take someone's word in a forum. Not enough research to prove one way or the other. It could be opinion as you claim or it could be a fact.

Most here indicate they hear a change and the rest just say they let their system warm up for some time before playing music and don't bother to describe in detail what they hear after warm up. Not very helpful or interesting to read.

 

Mine never gets hot or warm no matter how long I play music at comfortable volume so I can hear it walking from bedroom to living room in a 700 sqft. apartment. Thanks for the helpful response.

 

That’s funny, I’ve left my Sansui 9090 turned on simply because I’m afraid it won’t turn back on. They do get fussy in their old age.

 

Sound like it’s time to get yourself some fresh caps, deoxit spray and do some basic recapping maintenance.

 

I feel guilty when I leave electrical devices on when I'm sleeping or when I'm away. I'm brought up that way and it's difficult to let go. Almost a trauma of my youth.

Almost.

 

The device itself doesn't get hot. It's more like a fuzzy, cozy warmth.

 

Old but powerful equipment that didn’t had proper maintenance can become a fire hazard if you’re having some bad luck and leave it on for extended periods of time.

 

It does have original caps but it sounds nice so I’m keeping it original until it doesn’t. I have taken it in for a left channel that would cut out intermittently when I would first turn it on. Leaving it on seemed to eliminate the issue but I don’t use it enough for that to be a reasonable solution.

 

From my experience, you are much more likely to get smoke when you turn something on rather than from leaving it on. Class A or certainly Tubes would be a different situation, way too hot to leave on.

 

Depends on the PSU, some have relays that switch on the rest of the amp a second after it’s turned on, so that the power-up spike/inrush current doesn’t enter the rest of the device.
Some amps only have those protection relays at the amp outputs, so that the speakers don’t make that “pop” sound when it’s turned on.

 

Many modern amps too.