From: borowski@hpspkla.spk.hp.com (Don T. Borowski)
Newsgroups: rec.audio.high-end
Subject: Re: Leaving it on
Date: Fri, 2 Oct 1992 23:07:20 GMT
Organization: Hewlett Packard Company, Spokane, Wa.
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu

In rec.audio.high-end, Scott Dorsey <kludge@grissom.larc.nasa.gov> writes:

>> I say, leave everything on all the time.  It's no big deal.
>
>My power amp, while it sounds very good, unfortunately draws 750W while idle,
>and dissipates it as heat.  This makes it difficult to leave operating 
>continuously over the summer months (although it would be pleasant during
>the winter).
>
>I don't bother leaving my other components running continuously, either.
>They generally come up to proper operation within a half hour, while the
>power amp takes a good hour to get up to its best sound quality.  So, I
>just turn them all on together.
>
>I have seen old tube gear bake itself into oblivion, after being left
>in continuous operation for a few years.  On the other hand, the risk
>of filament damage is reduced considerably.  Back to the first hand, how
>many times have you had to replace a tube because the filament has gone
>out; they generally change in sound long before then.

I am something of a collector of old electronics, and have a fair amount
of tube gear, from cheap tube type table radios to old mid-range audiophile
components.  Some is in daily use--a Radio Craftsman tuner (no relation
to the similarly named company now operating) and a Seeburg amplifier.
These have over 30,000 hours of operation on them (I have a running time
meter hooked up), and an extimated 5000 on-off cycles.  The only tubes
that I have seen burn out have been of the small signal variety (as opposed
to power tubes), and most of them had a warning sign.  The warning sign
was a very bright glow from a short segment of filament when first turned
on, which would then subside to match the brightness level of the rest
of the filament when fully warmed up.  Given my experience, I would say
that if you are not going to use a piece of tube equipment for a few
hours, and can stand to wait for the warm-up, go ahead and turn it off.

Solid state equipment is a bit more probematical.  If it is something which
has no "hot spots", it probably is best to leave it on.  The power consumption
must be small (remember, no hot spots), and nothing is running so hot that
the heat itself will comprimise its life.

For things which do run hot, the answer is difficult.  If the equipment is
well designed but still runs hot, the heat level should not be so high
as to shorten the life in any meaningful way (what's the difference to you
if it lasts only 500 years instead of 1000 years).   In this case, the
thermal cycling would be more of a strain then just running hot all the
time by never shutting it off.

On the other hand, for something which is not as well designed and running
hot, such that the life of the components is being affected by the heat,
you would do well to turn it off when not using it for a few hours, as the
hot operation would reduce the life more than the thermal cycle.

Perhaps what you need to do is install some fans, if the equipment doesn't
already have them.  Even a little bit of forced air cooling does a lot of
temperature reduction, so even a slow fan (read quiet) would help a lot.
If you can't stand the fan noise, maybe you can switch them off when doing
your listening, and then switch them back on after you are done.


Donald Borowski    WA6OMI    Hewlett-Packard, Spokane Division
"Angels are able to fly because they take themselves so lightly."
                                       -G.K. Chesterton