OK To Leave X600.5 On Continuously?

[DarqueKnight]

I am considering the purchase of a Pass Labs X600.5 power amp. The manuals for my X1 and X0.2 preamps state that they are designed to be powered continuously, thus the lack of a power switch.

I am wondering if the X600.5's should be left on continuously. Would the amp be more stressed by the heat generation from leaving it on all the time or by turning it on and off once each day?

I could not find this question addressed in a previous post and the X600.5 manual does not address the topic of leaving the amps on continuously. It does say:

"It is our experience that, barring abuse or the odd failure of a component, the first things to go will be the power supply capacitors, and from experience, they will last 15 to 20 years before needing replacement. Fortunately these components die gracefully; typically with years of warning and are easily replaced. After that, the longevity will depend on the number of operating thermal cycles, but we can attest to having had amplifiers operating in the field in excess of 20 years with no particular mortality except capacitors."

[chinsettawong]

If I were you, I wouldn't leave the amplifier on all the time. Turn it on once you want to listen and turn it off when you are done. If all the Class A amp owners in the world leave their amps on all the time, the world would probably be warmer by a few degrees.

Wachara C.

[MEGA-amp]

This is also stated throughout numerous Nelson Pass manuals:


"The amplifier requires about 1/2 hour of operation to reach normal
operating temperature, and this warm-up time is appropriate for the most
critical listening, but is not otherwise an issue, as the performance
difference between 5 minutes and 60 minutes is very marginal. I do not
personally see a reason to run the amplifier all the time."

[Nelson Pass]

If you are a reviewer, make that 2 hours warmup, as that is the
thermal time constant of the system. 1/2 hour is good enough
for semi-critical listening.

[DarqueKnight]

OK, just so I am perfectly clear regarding the X600.5:

1. The X600.5 should not be left on all the time.

2. Thermal stress from leaving the X600.5 on continuously is more detrimental than switching the amp on and off once or twice per day.

[GRollins]

Actually "thermal cycles" means how many times you turn it on and off again. If you turn it on and leave it on for five years, that still only constitutes one thermal cycle, albeit a rather long one. It's the same as turning light bulbs on and off--it's the turning on that kills them. If you leave them going, they last longer.
When you turn something--anything--on, it experiences a large inrush of current. This is where the problem lies. The inrush is many times larger than the usual operating current and stresses things to their limits. This is why you may notice lights dimming momentarily when turning on amps with large power supplies. They literally suck the power lines dry for a brief instant. Once they're charged up and ready to go, things return to normal. The thing to remember is that that much power entering the circuit all at once causes stress.
The counter argument is simple: If you leave a large power amplifer going all the time, your power bill will be somewhat higher (you could extend this to include broader 'green' issues, but that would lead us farther afield). Other than that, there's no reason not to leave your amp on 24 hours a day.
The same principle applies to preamps. But they only draw a modest amount of power, so that's not a big problem.
Note that this applies to products from every manufacturer, not just Pass Labs.

Grey

P.S.: It may occur to you to ask why a light bulb--which is really a very simple circuit and has no power supply--is subject to the same problem. The answer is that the resistance of the filament changes with temperature. When the filament is cold, the resistance is lower than when it's hot. Thus when you turn on a light bulb, the cold (hence lower resistance) filament draws more power. As the filament heats to normal operating temperature, the resistance increases and it draws less power. But that brief interval when it's cold is the killer. That's why light bulbs nearly always go poof when you turn them on--not after they've been burning for a while.

[Holger Barske]

your power bill will be somewhat higher (you could extend this to include broader 'green' issues, but that would lead us farther afield)

Sry Grey, but wasting 1.1 kW 24/7 can't be a serious suggestion. This has nothing to do with "green" issues, this is ridiculous.

[GRollins]

To me, it would be, but it's not my power bill, it's his, so it's his decision to make. I'm not a sufficient control freak as to tell others how to live their lives as long as it doesn't cause me undue problems.
Besides, if it's winter, the heat averages out with the heating bill. Summer is a different matter, entirely. So turn them on and leave them on for the duration of cold weather and cycle them as needed when it gets hot again. There...problem solved.

Grey

[jacco vermeulen]

Let's face it, each of these after-burners would have some sort of stand-by feature installed if the market dictated it.

Which it apparantly doesn't, so either the regular owner leaves them on continuously or he/she bothers to fire them up a couple of hours in advance.
There's also a third alternative.

[Nelson Pass]

Originally posted by DarqueKnight
OK, just so I am perfectly clear regarding the X600.5:

1. The X600.5 should not be left on all the time.

2. Thermal stress from leaving the X600.5 on continuously is more detrimental than switching the amp on and off once or twice per day.

1. Because you don't want to use any more energy than
you have to. If you're heating the room in the winter, it's not
as big an issue, but if you're air conditioning the room at the
same time, that's right out.

2. It's about the same. My preference is to switch an amp on
before I use it and then shut it off when I'm done for the day.