Do you leave youe tube gear lit?

Listens2tubes · « **on:** 8 Jul 2009, 01:38 am »

OK the Firewoks for the 4th thread http://www.audiocircle.com/index.php?topic=69481.0 got me thinking. Since rebuilding my amps 15 years ago I often turn the system on in the morning and go about my weekend missions even leaving the house for hours. The tuner will be playing until I/we return or are done with whatever and can sit to listen.

A friend has a Macintosh 240 in his tri-amped system which he leaves on 24/7.

How do you feel about the reliability of your glowing bottle hotties?

JoshK · « **Reply #1 on:** 8 Jul 2009, 01:43 am »

Leaving tube gear is actually good for reliability but wears out the tubes from dissipation. Trade off and most think that the tube wear is worse for a well designed amp that turns on and off gracefully.

I turn mine off as it generates heat even though its only a 10+ watt single ended amp.

zybar · « **Reply #2 on:** 8 Jul 2009, 01:47 am »

NO WAY!!!

My amps contain 38 tubes between the two mono blocks and operate in pure Class A - I can't even fathom how high my electricity bill would be!!

Also, you are using up precious tube life by keeping amps on 24/7 - why would you want to do that?

As for safety...I have seen a tube amp almost catch on fire in an extreme example of what can happen when something gos horribly wrong. Way too dangerous to leave on 24/7 IMHO.

My simple rule in regards to tube amps is that they go on when I want to listen and always go off if I need to go outside or leave the house. This keeps me (and more importantly my family) safe, as well as keeping my costs down (for electricity and tubes) - a winning combination if I ever heard one.

George

zybar · « **Reply #3 on:** 8 Jul 2009, 01:51 am »

Quote from: JoshK on 8 Jul 2009, 01:43 am

Leaving tube gear is actually good for reliability but wears out the tubes from dissipation. Trade off and most think that the tube wear is worse for a well designed amp that turns on and off gracefully.

I turn mine off as it generates heat even though its only a 10+ watt single ended amp.

Josh,

In what way is leaving tube gear on good for reliability? I hear this from time to time, but have never heard why it is so?

I have asked various amp vendors (tube and ss) and the overwhelming majority have said to turn off the gear when not in use vs. leave it on.

I know the Mythbusters proved leaving your lights on wasn't the correct approach and that one was better off (from a cost and longevity perspective) constantly turning their lights on/off rather than leaving them on for long stretches.

George

JoshK · « **Reply #4 on:** 8 Jul 2009, 02:10 am »

Yeah electrical costs and wear on the tubes makes it not a good idea for tube amps. Preamp might be different but depends on the design.

When you switch on/off an amp it creates a sudden in rush of current. Tube rectifiers really do a lot to negate this because they warm up slowly (most) so the tubes have had time to heat their heaters/filaments before getting slammed with high voltage. Also, tube rectifiers usually have a ramp up as rectifier warms up so the high voltage isn't all or nothing.

Solid state diodes(rectifiers) will conduct immediately and if your caps are large and/or there is little inductance/resistance leading the supply filter you will get a heavy current inrush. That can be hard on your caps, your transformers, tubes, etc. There are ways to design (thermistors, delay relay switches, manual delayed switches, choke input supplies, etc) so this is not an issue even with solid state diodes but that costs money, so it isn't always done right.

zybar · « **Reply #5 on:** 8 Jul 2009, 02:15 am »

Quote from: JoshK on 8 Jul 2009, 02:10 am

Yeah electrical costs and wear on the tubes makes it not a good idea for tube amps. Preamp might be different but depends on the design.

When you switch on/off an amp it creates a sudden in rush of current. Tube rectifiers really do a lot to negate this because they warm up slowly (most) so the tubes have had time to heat their heaters/filaments before getting slammed with high voltage. Also, tube rectifiers usually have a ramp up as rectifier warms up so the high voltage isn't all or nothing.

Solid state diodes(rectifiers) will conduct immediately and if your caps are large and/or there is little inductance/resistance leading the supply filter you will get a heavy current inrush. That can be hard on your caps, your transformers, tubes, etc. There are ways to design (thermistors, delay relay switches, manual delayed switches, choke input supplies, etc) so this is not an issue even with solid state diodes but that costs money, so it isn't always done right.

Thanks for the reply Josh.

George

bunnyma357 · « **Reply #6 on:** 8 Jul 2009, 02:21 am »

Quote from: zybar on 8 Jul 2009, 01:51 am

Quote from: JoshK on 8 Jul 2009, 01:43 am
Leaving tube gear is actually good for reliability but wears out the tubes from dissipation. Trade off and most think that the tube wear is worse for a well designed amp that turns on and off gracefully.

I turn mine off as it generates heat even though its only a 10+ watt single ended amp.

Josh,

In what way is leaving tube gear on good for reliability? I hear this from time to time, but have never heard why it is so?

I have asked various amp vendors (tube and ss) and the overwhelming majority have said to turn off the gear when not in use vs. leave it on.

I know the Mythbusters proved leaving your lights on wasn't the correct approach and that one was better off (from a cost and longevity perspective) constantly turning their lights on/off rather than leaving them on for long stretches.

George

Back in the day when tubes were still used in broadcasting it was standard practice to leave all gear powered on to prevent calibration drifting and to avoid failure on power-up, where at least anecdotally most tubes catastrophically fail as opposed to just wearing out over time.

Almost nobody follows this practice anymore, since it is no longer needed with SS and digital gear.

If one is worried about having to wait for tubes to warm up for optimum performance - leaving them on gives more reliable performance.

I turn mine off, since the safety factor and heat generated isn't worth the risk incurred for a very slight and brief performance gain. Also I think if something like a fire did happen, an insurance company would probably try and claim negligence to avoid paying a claim.

Jim C

JoshK · « **Reply #7 on:** 8 Jul 2009, 02:35 am »

That is a little different in broadcasting though. They typically operate in extremely high voltage and there catastrophic failure isn't rare because of the voltage. For consumer gear in the 400-600V B+ range its a lot less of a problem, but still can be a problem in cheap chinese gear or shotty designs.

bunnyma357 · « **Reply #8 on:** 8 Jul 2009, 03:30 am »

Quote from: JoshK on 8 Jul 2009, 02:35 am

That is a little different in broadcasting though. They typically operate in extremely high voltage and there catastrophic failure isn't rare because of the voltage. For consumer gear in the 400-600V B+ range its a lot less of a problem, but still can be a problem in cheap chinese gear or shotty designs.

I should have been more specific, I was speaking more of the philosophy of leaving gear on. I didn't necessarily mean the high voltage transmitter tubes, but generally all of the equipment for production and post-production was often left on 24/7, although it varied depending on the philosophy of the engineer at the facility.

Even with SS gear most of the facilities I've worked at kept power on to everything 24/7 until the late 80's or early 90's when everything started switching over to digital.

I would guess that a lot of audio engineers come from either a broadcasting, or aerospace background, which both tend have a "mission critical" type philosophy, which may be one of the reasons some people still suggest leaving tubes on 24/7 for reliability.

I don't think it makes sense for a consumer, just trying to give an example of where the idea of leaving things on to enhance reliability might come from.

Jim C

JoshK · « **Reply #9 on:** 8 Jul 2009, 03:36 am »

Yeah it was a good point. I should have left it at that. I just thought some might take that to mean that leaving it on was a good thing and justified.

mjosef · « **Reply #10 on:** 8 Jul 2009, 03:38 am »

No way...I have had tubes(output power tubes) run away too many times to risk leaving on when I am out for extended periods of time.
There were times when I would run out for a few minutes, like when doing laundry or a quick run to the grocery(both locations just a couple blocks away), and I would leave the amp powered up and playing. Risky yes, but lately I have begun biasing my amp very conservatively.

All my SS gear is usually powered up 24/7. I think they sound better that way.
I have a lot of carbon credits aa

Ericus Rex · « **Reply #11 on:** 8 Jul 2009, 11:57 am »

Quote from: zybar on 8 Jul 2009, 01:51 am

Quote from: JoshK on 8 Jul 2009, 01:43 am
Leaving tube gear is actually good for reliability but wears out the tubes from dissipation. Trade off and most think that the tube wear is worse for a well designed amp that turns on and off gracefully.

I turn mine off as it generates heat even though its only a 10+ watt single ended amp.

Josh,

In what way is leaving tube gear on good for reliability? I hear this from time to time, but have never heard why it is so?

I have asked various amp vendors (tube and ss) and the overwhelming majority have said to turn off the gear when not in use vs. leave it on.

I know the Mythbusters proved leaving your lights on wasn't the correct approach and that one was better off (from a cost and longevity perspective) constantly turning their lights on/off rather than leaving them on for long stretches.

George

With only one exception, all my equipment failures have occurred at power on/off (not counting tube deaths). The Mythbusters comparison doesn't work so well in this case. When a lightbulb fails at power on you've lost only the bulb. When an amp fails at power on you could have hundreds of dollars in repairs. I used to leave everything on 24/7 but I no longer have the 'listen time' I used to have so everything goes off when I'm done.

Wayner · « **Reply #12 on:** 8 Jul 2009, 12:21 pm »

I see no valid reason to leave them on. I see several reasons to shut them off. The first is just a safety concern. I never leave home with the washer, dryer or coffee pot on either. Fire is such an ugly word. I've seen weird things happen when I've been at home.

The second thought is that it's just a waste of electricity. The third thought is that after about 15 minutes, I think everything is nice and warmed up, maybe even less then that.

Wayner

TheChairGuy · « **Reply #13 on:** 8 Jul 2009, 01:00 pm »

Quote from: bunnyma357 on 8 Jul 2009, 02:21 am

Back in the day when tubes were still used in broadcasting it was standard practice to leave all gear powered on to prevent calibration drifting and to avoid failure on power-up, where at least anecdotally most tubes catastrophically fail as opposed to just wearing out over time.

To that point - I use ancient Dukane (originally PA) amps and there is no on-off switch on them. Which I can only assume they were expected to run all day and every day.

Nonetheless, I shut everything off by unplugging the IEC at my power strip (no on/off on that either) to save electricity (fiscally and morally responsible that way

).

The only thing I continually leave on is my Cambridge Universal DVD player...as I find digital needs an inordinate amount of time to sound right (like, over an hour versus most equipment 1/4 to 1/2 of that time)

John

BobM · « **Reply #14 on:** 8 Jul 2009, 01:30 pm »

My preamp has a stand-by mode and that's what I used to do. Just leave it there where the tubes have a small current running through them. But I soon realized that I was only turning it on on the weekends (busy life). So it was better for me to power it full off during the week and use the stand-by on the weekends when I was really using it.

Bob

bluemike · « **Reply #15 on:** 8 Jul 2009, 02:18 pm »

I'm doing the same Bob with my Mantissa as well

My tubed cdp however is on standby continuously and is never turned off -sounds better that way

BobM · « **Reply #16 on:** 8 Jul 2009, 04:03 pm »

Quote from: bluemike on 8 Jul 2009, 02:18 pm

I'm doing the same Bob with my Mantissa as well

My tubed cdp however is on standby continuously and is never turned off -sounds better that way

Hey - did you see the Mantissa for sale on Audiogon? Someone is sure going to get a rare deal on that.

bluemike · « **Reply #17 on:** 8 Jul 2009, 04:28 pm »

Quote from: BobM on 8 Jul 2009, 04:03 pm

Quote from: bluemike on 8 Jul 2009, 02:18 pm
I'm doing the same Bob with my Mantissa as well

My tubed cdp however is on standby continuously and is never turned off -sounds better that way

Hey - did you see the Mantissa for sale on Audiogon? Someone is sure going to get a rare deal on that.

wow that is a good deal

KCI-JohnP · « **Reply #18 on:** 8 Jul 2009, 04:35 pm »

I have a BAT 51SE and it has the stand by mode. I usually turn it on Friday afternoon when I get home from work and don't turn it off until Sunday evening, wonder if that's ok??

iGrant · « **Reply #19 on:** 9 Jul 2009, 06:58 pm »

I've been told it is not a good idea to leave Class A designs on as the tube is going to burn out faster than if it is actually playing music due to the tube working full out with nothing to work with. Leaving them on reduces the start up stress on the tubes if there isn't pre-heat stage. Since many amps are also biased to have a watt or so in Class A, I wonder if that would follow the above?

I turn my amps on and off as I need them, they are at about 95% within 20 minutes and 99% within an hour.

Cheers,
Ian