Why does my amplifier/stereo sound better when it's been on for a while?

It's a little B+O Beomaster 3500; I run the sound from my computer into it. I'm not expecting it to produce 'hi-fi' Woppit quality sound, but it's a decent little set up for my bedroom/office (B+W speakers).

After it's been on for a while, it seems noticably louder, and the sound seems clearer and has more 'depth' (I can hear 'more' of the music).

Is this a purely imagined effect, or does having it on for a while have any effect on how efficient the system is at reproducing the sound? Is it something electrical? I don't understand stuff like electronics much.

No its not imagined. Mr Woppit will no doubt come along and put us both straight – but NAIMees leave their electronics on all the time.

Any of the analogue components may warm up slightly affecting their characteristics (gains, responses etc) which may help. Or you may have a poor connection somewhere and the expanding joints (with the warmth) may make a marginally better connection. This is why lots of very sensitive electronics like instrumentation electronics require a warm-up period before use, they use vaguely similar componentry.

Yes it's weird; it's 'louder' without being louder, if that makes sense. The sound becomes more 'open', clearer. I can hear more of the instruments etc. It takes an hour or two to be really noticeable, and I can't compare it withh when it's just been turned on, of course, but there does seem to be an improvement.

My Denon amp in the front room doesn't seem to have this characteristic. Strangely, in spite of being more powerful (30W rather than the 20W of the B+O), the B+O somehow has a more 'enjoyable' sound. Better quality?

bad talkemada – NAUGHTY talkemada

What on Earth have I done now? ❓ 😯

You are thinking about hifi.. it's all nonsense, you know – in your imagination. I am sure TJ will be along soon to set you straight.

I think it's usual, my Marantz has always benefited from a warm-up.

I tell you what, it's sounding bloody lovely now. Seems like the longer it's on, the better it gets. It's not any high end component, but it certainly does the job. I paid a mate £200 for it a few years ago.

I'd love the same sort of sound quality, but in a slightly more powerful form. 40-50w or so, nothing too mental.

The Denon is better than the Sherwood it replaced, but just seems somehow 'lacking' in ultimate sound quality, compared to the B+O. And no, I'm not going to go and buy a B+O amp; they cost a bloody fortune! 😯

The B+W speakers were given to me by a friend, who didn't like the aesthetics of them (too big, black and bulky 😯 ). They are lovely speakers, really nice sound.

I know this is leading to me wanting a new amp for the front room…. 🙄

It's the molecules in the wire moving faster as the wires warm up allowing the music to travel along them more easily.

Is this true, Czechoslovakia? I'm not saying you're talking crap, but there's a lot of bollocks surrounding 'hi-fi'.

I can understand that heat increases conductivity, and the amp does get quite warm, so it does make a bit of sense I suppose. Will it reach an 'optimum' temperature?

BTW this is a genuine search for understanding and enlightenment, not an attempt to provoke silliness.

As Coffeeking states, there are many electronic reasons. To give one specific example, the bias of the amp should have stabilised, giving you less crossover distortion. It's also reasonable to assume that in an hour or so of listening you will have relaxed, perhaps partaken of a little alcohol 😉 and be more inclined to enjoy the music.

The 30W/20W thing is irrelevant really, as you won't be using that much power and the measurements quoted are often spurious. The 30W amp could be producing 1% distortion at that power and 0.5% at 20W, Whereas the B&O could be capable of 0.005% at 20W.

What are you listening to?

so it does make a bit of sense I suppose

sorry, no it doesn't – it's an amplifier, not a conductor, and heat increases resistance in most metals anyway 🙂 It does increase the conductivity in semiconductors, but that's usually a bad thing, encouraging catastrophic failure from thermal runaway. Any sensible amplifier will be designed to prevent thermal effects.

I was advised not to turn my amp off, so I never have. It's been on for about 3 years now, minus the couple of times we've been on holiday. Dunno what this achieves thoigh, apart from moving my carbon footprint up a couple of shoe sizes.

Any sensible amplifier will be designed to prevent thermal effects.

You'd like to think, but as stated, I've nearly 30Ks worth of instrumentation in my lab that has all it's specs specified after a warmup period… of course we're talking so little I doubt you'd hear it, but for an audio amp of a few moons ago, not quite so unrealistic.

It's also reasonable to assume that in an hour or so of listening you will have relaxed, perhaps partaken of a little alcohol

This is possibly possible… 😀

I haven't ruled out a perceived change due to my state of mind. I certainly think mood can have an affect on how music is enjoyed. But I have noticed this phenomenon whilst sober, so was wondering…

The difference is definitely noticeable with the higher quality recordings, such as some of my classical CD rips, and more recent stuff. I listen to bloody anything, literally, so I've got a lot of range of types of sounds.

The Denon is a 'budget' type amp, and IMO not as good sounding as the B+O. I'd like to upgrade it, but finances won't allow that for the forseeable.

I'm intrigued that this 'warming up' phenomenon is far more noticeable in a 1980s bit of kit, than in a reasonably contemporary component.

I knew a lad who was into hifi and he'd never turn off his amp.

Shocked my environmental sensitivities at the time but I'm over that now.

When in a mood for listening, ny audiolab 8000 is never off for days on end, or the lp12 that feeds it.

Sounds a little thinner, more brittle when cold.

I'm intrigued that this 'warming up' phenomenon is far more noticeable in a 1980s bit of kit, than in a reasonably contemporary component.

Some components don't age well, capacitors in particular.

There are only four possibilities:

– You are imagining it.
– You amplifier is very very badly designed. While B&0 is generally overpriced it is almost always good kit.
– The quiescent current is out of adjustment. Quite likely.
– It's broken.

Quiescent current effects crossover distortion massively. It's level has to be balanced carefully so as to be correct to keep cross over distortion to a minimum but low enough to not allow the transistors to hit run away overheating. The effect of it sounding better can be traced back to too low quiescent current, as when the amplifier warms up, the transistors naturally draw more current from the circuitry. While this effect is minimal, in a badly out of adjustment/designed amplier, the effect is audible.

A correctly designed and in service amplifier should not change it's output distortion irrelevant of temperature unless overheating.

Most people running older amplifiers would notice a dramatic difference if they got it serviced and resetup.

+1 for RP. I would venture that the effect is caused by the power supply becoming more stable in it's output. At what time of day do you use the amp most, btw?

sorry, no it doesn't – it's an amplifier, not a conductor, and heat increases resistance in most metals anyway

Yeah, sorry, I said I didn't know electronics stuff! Heat increases electrical resistance, yes?

So why does it sound better after an hour or so? I concede my observations aren't very scientific, but there is a difference.

Don't take the piss just because I don't know stuff. It's not nice. 🙁

it's more likely to be the speakers warming up than anything going on in the amp, they do change a little after some use as the mechanics of the materials what bend come in to play. Your hearing is also far more likely to change over the course of an hour than anything electrickery.

and listen to what solomanda says, he's the :FACT: man

Hi Sally [WAVES], thought you were dead or something

At the end of the 80s I shared a house with a chap who was rather keen on his hifi. Once term started he never turned off his amp, tuner, cd player and turntable. The only thing that remains in my memory from all of this was that his room was the warmest in the whole house. Fortunately his trust fund allowed him to pay an appreciably greater proportion of the electricity bill.
Apparently he bought a vineyard in France, not sure if he plays music to the vines….

and listen to what solomanda says, he's the :FACT: man

Seeing as this is what my father does for a living and has in the past been many of the top brands recommended repairer for classic equipment, pretty much is :fact:*

*No doubt I'll have misunderstood some points but most amps sounding better after a service = fact

[wave] Yes, still alive. Have you still got any mtb's?

What are you listening to?

Mozart: Fantasia in D Minor k.397, followed by Beethoven: Moonlight Sonata.

Which I think is quite an essential mix.

yes, 3 mountain bike rides last week, and only 2 road ones

off to wales for some sick mtb stylee radness this weekend as well. trying to get my arse back into gear.

no big bike any more though

Erm, 'scuse me, fellers, d'you mind?

Tcha. Being helpful on MY thread, then hijacking it for personal chit-chat? Tut tut… 🙄

Before I had my own amp I borrowed a Marantz amp from the 80's, it was lovely, but the signature changed dramatically once it had warmed up. It used to hum a lot more when it was cold too. I've got a Rotel 1062 now, and I can't say I notice any difference if it's been on all day or I've just turned it on.

I was advised not to turn my amp off, so I never have

because it'll wear out sooner and you'll have to buy another 🙁

So it could all be purely psychosomatic? Oh well.

Can't handle Nurse With Wound at this time of night. Give over.

Ah, nice bit of Bach…

Kim Wilde on in a bit!

GJP – Member

No its not imagined. Mr Woppit will no doubt come along and put us both straight – but NAIMees leave their electronics on all the time.

Yes.

Most people running older amplifiers would notice a dramatic difference if they got it serviced and resetup.

Hmm, how old? Seems like my setup isn't quite as nice as it once was but that could just be me getting used to it…

On the original topic – seems like engineers could design it to work best when it's up to temp, and hence be worse when it's cold – like a car.

All electronic components change their properties with temperature.
Amplifiers are particularly prone to 'warm up' effects because they dissipate a lot of power and thus heat.

Of course most decent amps are designed to minimise excessive variations in performance with temperature, but they are also designed to work best at an stable operating temperature that is generally above room temp and only reached after a while.

molgrips – bipolar capacitors degrade measurably within 10 years or so.
variable resistors used to set bias currents are also prone to degrading.

you'll probably find that it also sounds better later in the evening when peoples washing machines, showers, electric cars and fridges have stopped clicking on and off and the mains current becomes more stable/cleaner.

yeah, or you've had a few beers….

How much is a service, and does it help with even lower-end hifi stuff? I'm talking Cambridge Audio here.

because it'll wear out sooner and you'll have to buy another

except most electronics fail at switch on.

except most electronics fail at switch on.

Only because that's often the point of max inrush current in several locations, and things like capacitors that have dried out over their warm on-time fail then. It doesnt extend the life of them leaving them on, it just prevents the mechanism that triggers death.