Leave tube amp on all day?

I would consult with Cary on this one. Manufacturers say different things. The manufacturer of my amp, Audionote (uk) says that my amp should stay on all of the time. Other manufacturers say turn on only when in use.

I turn my amp off during the week when not in use, manufacturer's recommendation notwithstanding. I have concerns about the safety of leaving it on unattended for great lengths of time.

The reason recommedations vary has to do with design of amps. The most damaging time for a tube is during power up. The filament is cold. Because it is cold, it has a very low resistance. The initial inrush of current is therefore very high and results in very rapid heating. This is why light bulbs seem to only blow at the instant they are switched on and rarely fail in mid use. But, some amps use circuits that slow the inrush. A tube rectifier, because it takes a little bit of time to warm and start conducting, also slows the inrush to other tubes and affords some protection for startup abuse. Some amps tend to collect heat more than others, so being on all the time abuses other components, such as electrolytic caps (which tend to be dried out by heat), so they should not be left on all the time. For these reasons, there are no blanket answers to what you should do for all tube gear.

As Larryi suggests I would consult with cary and get their recommendation. However, I for one would not leave a tube amp on all day even if it wasn't unattended. If you are listening for short periods of time in the morning and then again in the evening I would turn it off between sessions. I would not even think of leaving it on overnight or over the weekend. The reasons being is tube life, as it will shorten if left on, but more importantly for safety reasons.Tubes can and do short out which could cause a fire especially if left unattended.

Chuck

Chuck a Little over the top, I would saayLeave it on and donrt be so paranoid. Its consumer electronics, not garage gear

I just simply would turn it on and off. Unless you use cheap tubes. That's what will cost you. The rest of the amp even if you shorten it's life should last 10+ years under bad conditions.

If you're going to be using the amp for the majority of the day at various times, leave it on in standby mode. If you aren't going to use it for very long each time and / or have extended periods between use, turn it off and on as needed using your own judgment.

Tubes deteriorate with use, even in standby mode with most designs. Not only that, but some tubed amplifier designs can become hazardous / start on fire when a tube fails. As such, i would not leave tubed amplifiers on and unattended for extended periods of time. Obviously, this is my point of view, so take it for what it is worth.

I say this because most properly designed tubed circuits with reasonably strong tubes stabilize in appr 20 - 30 minutes of use. There is little to no sonic benefit in leaving a tubed power amp fired up 24/7 other than the reduction of in-rush current to the tubes.

Bare in mind that i'm talking about output level tubes here, NOT line level tubes such as found in a preamp, CD player, DAC, etc... The voltage and current levels found here are MUCH lower, hence leaving them fired up is far more benign with less potential for major problems. Sean
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