Leaving the amp on 24/7 Is it ok?

[astrostar59]

Hi Guys

I run a KGSShv that take about an hour to warm up and sound 100% performance. Because of that I tend to leave it on all the time unless I am going away for a few days.

My question, is it ok to do that and leave the headphones plugged in, or is it best to power down? The headphones would i guess get a 580v bias but no music signal during this time.

[grawk]

have the local power plant shut off power when you're done, and turn it back on an hour before you're ready to listen again

[skullguise]

Shit, that's just the dumbest idea I've ever heard.  Then you have to reset all the clocks!  (Now, if you had battery backup on the clocks, I'd think it was the best idea everer).

And FWIW, I turn my HV mini off after use.  Doesn't seem to take an hour for me so it seems......

Edited April 7, 2016 by skullguise

[grawk]

I use the clock on my phone

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[spritzer]

25 minutes ago, skullguise said:

Shit, that's just the dumbest idea I've ever heard.  Then you have to reset all the clocks!  (Now, if you had battery backup on the clocks, I'd think it was the best idea everer).

And FWIW, I turn my HV mini off after use.  Doesn't seem to take an hour for me so it seems......

Hello servo!!   

Ohh and running amps 24/7 will drastically cut their lifespan. 

[Wmcmanus]

You should get a pair of JH13 and an iPod.

[swt61]

I like to leave my partner turned on 24/7. Is that the same thing?

[sorenb]

55 minutes ago, swt61 said:

I like to leave my partner turned on 24/7. Is that the same thing?

you might improve your partners life span providing release from time to time ...

[grawk]

Steve kills 3 a month

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[sorenb]

our local Dexter, Steve?

[DefQon]

On the technical side, spritzer is right it drastically cuts down the lifespan of the parts inside. Don't forget capacitors have a limited lifespan and heat does take a toll on resistors over time as well. Once parts start to drift outside of there rated specification hell can break loose on the amplifier.

[mwl168]

5 hours ago, astrostar59 said:

Hi Guys

I run a KGSShv that take about an hour to warm up and sound 100% ...

Perhaps a bit off topic, but all jokes aside, did you build the HV Carbon?

I have both the KGSSHV and Carbon, from my experience, without servo, the KGSSHV does take longer (20 minutes +) for the balance and offset to settle than does the Carbon. Subjectively, the heatsink on my Carbon also reaches stable temperature faster. Both factor are likely related. 

The opto servo on the Carbon pretty much starts working soon as the amp is powered up. I never did engage the servo on my KGSSHV.

Cannot speak to how long it takes for either amp to reach optimal performance from cold start.

Edited April 8, 2016 by mwl168

[Craig Sawyers]

9 hours ago, spritzer said:

Hello servo!!   

Ohh and running amps 24/7 will drastically cut their lifespan. 

I'm with you on that.  I'm very selective what I leave on.  Low power solid state small signal gear:  Preamp (solid state), yes.  Active crossover, yes. DtoA yes.  Power amps and anything with tubes (8-channel power amp, CD transport, T2, BH original), no.  If I'm going to do any serious listening, I power up whatever the heat generators are and have a coffee and sandwich - and everything is on song by then.

But even with a solid state electrostatic amp, I definitely would not leave it switched on - parts are stressed both in temperature and voltage - and I would not want to leave a set of expensive electrostatic phones with bias permanently applied.  Made that mistake with a pair of ML Aerius speakers and the film eventually disconnected itself (later ML's only trigger bias when music was detected, so they knew they had a problem).

[spritzer]

Even if we were to use all film caps in an amp then there are other stresses that go with high voltage.  Film caps are also vulnerable to heat so that is clearly a factor. 

[astrostar59]

Thanks guys, I will from now on start switching off overnight. My reason for leaving gear on was the user manual from Plinius say leave their power amplifier on all the time. Also other manufacturers say the same such as Audio Note. I think the idea is thermal shock and power surge on switch on does more damage than sat there ticking away.

My Plinius is Class A/B as default and pull low current and is barely warm. Obviously this does not apply to amplifiers of DACs using tubes.

[luvdunhill]

astroglide59:

Ever looked at what Audio Note charges for repairs?

[swt61]

22 minutes ago, luvdunhill said:

astroglide59:

Ever looked at what Audio Note charges for repairs?

OK, now you're making him sound like anal lube, just to bait me. not taking that bait.

[Craig Sawyers]

I just love you guys - I'm still laughing five minutes in 

[wink]

6 hours ago, astrostar59 said:

(Snip)

My Plinius is Class A/B as default and pull low current and is barely warm. (Snip)

Must drop out of Class A at about 50 microamps............     Or, perhaps, heatsinking is grossly overdone......    Perhaps, even, it has (ahem) modest power output

Then, again, It could be any combination of the above......   

[spritzer]

Even a 30W Class A amp runs very hot so yeah, very low Class A biasing. 

[Craig Sawyers]

This is the reason that Krell went over to some sort of dynamic biassing scheme, because running flat out class A was just not reliable.  I had a late model KSA100 that demonstrated that perfectly.  Typical Krell battleship construction, with superb engineering, and two fan cooled heatsink chimneys.  Power transistors were rebranded as KrellA and KrellAA.  It blew up three times in my ownership - same symptom each time, power transistors going into second breakdown failure accompanied by lots of smoke.  Lat time it happened was after I had sold it on eBay for quite a lot of money.  The buyer was actually on his way to collect from about 150 miles away - and I thought I'd turn it on so he could listen to it.  Major league failure with plumes of smoke; phoned him in the car, apologised profusely and he went back home.  This time it had taken out the drivers too, and the associated driver load resistors had ignited and burned part way through the board.

Replaced the sand, using generic high power transistors and NOS obsolete drivers.  Dremelled out the char and coated with conformal coating before replacing the load resistors. Worked perfectly, and the guy honoured the sale, paid the money after auditioning and off he went leaving positive feedback.

I've also seen the same generation of KSA50 ignite too.

But it is all down to component stresses - high power class A puts a combination of high voltage and high current through the power devices all the time.  Smoothing caps and power transformers likewise need to be carefully thought about, since they are running flat out all the time too.  But non-linear distortions, including induction distortion are much lower than class B or AB, which is why high end users like it.

[astrostar59]

Good point guys. I am sold, switch of when time for bed! I like the joke about Audio Note repairs Ha Ha. 

Having said that, I had an M3 pre-amplifier by Audio Note that blew after my house got struck by lightning. They replaced the whole amp, no question asked....

Edited April 9, 2016 by astrostar59

[spritzer]

Yeah, Class A is no joke which is why I have so much respect for the companies that do attempt it.  Accuphase and even Denon make Class A integrated amps that seem to sell well enough to warrant regular updates. 

[comzee]

What would be a ballpark MTBF for a KGXXXX amp ? 10,000 hours of powered on operation?

[spritzer]

Depends on the capacitors used and how hot it runs.