Author Topic: Valve etiquette and care  (Read 20811 times)

Offline King_Julian_S

Valve etiquette and care
« on: July 23, 2013, 06:59:30 PM »
Hi all...
As Topic suggests...

I noticed a comment made by Charles on a thread I read earlier...
So I was thinking maybe a good idea is to start this seperate thread.
The idea is for the masters to share some knowledge with novices like myself in terms of simple tips and tricks to enable us to learn how to care for our beloved valve equipment and perhaps not even make silly mistakes that could make one regret the things you wish you knew...Matbe even general Maintenance and care tips if there are.

Tx in advance.

So to start it I will steal Charles's tip as the first one. Cause I know I've done this before and thanks goodness I was lucky that mine survived.

TIP...1

"Always connect speakers to valve amps before powering them up as some of them could go "bang" if you don't."

Non audiophile music lover...

Offline Winslow

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Re: Valve etiquette and care
« Reply #1 on: July 23, 2013, 09:06:42 PM »
Yep. Transformer sees speakers as a load no load puff go transformer happens in a flash.
not all amps are like this but it is a good idea just to be sure.

Turn amp on last turn amp off first.

Don't move or bump when it is hot or on valves delicate when glowing.

Pull valves out at the base

Don't poke around in there if you are not an expert the voltages inside will kill you one time.

Give it at least 30+ seconds before playing give the valves a chance to warm up gives them an easier life and they last longer.  The more modern amps have a slow start feature.

And Myself I run fans on them when not doing critical listening easy enough to turn off if the noise bothers me extends the valves lives in a big way.  Some of them are pricey critters.

I always wear cotton gloves when handling the valves but some say it is not required.
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Audiophiles use your music to listen to their equipment."

Allan Parsons

Offline Hi-Phibian

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Re: Valve etiquette and care
« Reply #2 on: July 23, 2013, 09:24:10 PM »
Don't use your amp as a valve tester for that stash of untested NOS you found on the dump. Confirm all good first.

Unlike solid state amplifiers, adding speakers and putting them in series is not safe.

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Offline darrylo

Re: Valve etiquette and care
« Reply #3 on: July 23, 2013, 09:53:38 PM »
Are you sure you quoted "Charles" correctly ...
 :giggle:
Always Looking for Heathkit, AVO and Leak
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Offline King_Julian_S

Re: Valve etiquette and care
« Reply #4 on: July 23, 2013, 09:58:40 PM »
Shoo tx guys
I can confirm that I have contravened all of the above...

Just a quest ...
My amp switches off at the mains...
There is a switch on the amps self that apparently cuts the inputs off , so I would normally turn volume off , flick those switches and then off the other equipment and then the wall... So , am I switching it off in the wrong sequence then ? Maybe I should put the amps on their own plug and switch off there first ?

I should also stop fiddling with valves when the amp is on , I find I have this habit to switch on , let it heat up long and then decide I have to ensure they are in their holes properly for some reason and tap on them..
I will have to stop doing that... Tx
Non audiophile music lover...

Offline King_Julian_S

Re: Valve etiquette and care
« Reply #5 on: July 23, 2013, 10:00:30 PM »
Are you sure you quoted "Charles" correctly ...
 :giggle:

Maybe not 😄.
But I think mr Wins explained it better in the subsequent post
Non audiophile music lover...

Offline Winslow

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Re: Valve etiquette and care
« Reply #6 on: July 23, 2013, 10:36:16 PM »


I should also stop fiddling with valves when the amp is on , I find I have this habit to switch on , let it heat up long and then decide I have to ensure they are in their holes properly for some reason and tap on them..
I will have to stop doing that... Tx


Remember the old lead lights always having to replace bulbs they did not last long at all.
All the moving around and banging did the filaments in quick. The Filaments are very weak when glowing only reason they don't burn out is because of the vacuum inside same with valves or vacuum tubes


Just a quest ...
My amp switches off at the mains...
There is a switch on the amps self that apparently cuts the inputs off , so I would normally turn volume off , flick those switches and then off the other equipment and then the wall... So , am I switching it off in the wrong sequence then ? Maybe I should put the amps on their own plug and switch off there first ?




I would do that make up a nice box with outlets for the amps alone and put individual switches on each line if you are running Mono Blocks.
Some nice Shielded cable to the amps.

Here is another hint I run shielded power cable on all my equipment and only earth the shield on the source side on everything.

Also my interconnects use balanced two core cable shielded, one core feed one core return shield only earthed on source side. I do not use the shield as return.
The systems are dead quite and I mean silent as death not a rush or a hum to be heard.
The only thing you can hear is a ever so slight rush with the volume turned right up max with your ear glued on the tweeter from the phono input. That is par for the course.
Playing volumes  not a thing.
« Last Edit: July 23, 2013, 10:54:23 PM by Winslow »
"Audiophiles don't use their equipment to listen to your music.
Audiophiles use your music to listen to their equipment."

Allan Parsons

Offline King_Julian_S

Re: Valve etiquette and care
« Reply #7 on: July 24, 2013, 09:25:43 PM »
Tx mr W.
Much appreciated
Non audiophile music lover...

Offline King_Julian_S

Re: Valve etiquette and care
« Reply #8 on: July 24, 2013, 09:30:44 PM »
Mr W
Any ideas on where to source such cables ?
I use a normal kettle type plug , but I also get dead quiet response when volume is all out... And the speakers are very high sensitivity drivers as well.

I do get a very slight " Doooof " sound when I flick those switches I mention above to the on position...


Non audiophile music lover...

Offline Phase

Re: Valve etiquette and care
« Reply #9 on: July 25, 2013, 05:09:36 AM »
Nice thread King_ I'm getting into valves for the 1st time now and as a newbie I knew none of the above...

Offline Phase

Re: Valve etiquette and care
« Reply #10 on: July 25, 2013, 05:14:11 AM »
Please keep the tips coming... and maybe some on the maintenance side...
Thanks in advance  :thinking:

Offline Ampdog

Re: Valve etiquette and care
« Reply #11 on: July 25, 2013, 05:55:51 AM »
All is not that glum.

The heaters in valves are actually quite shock-proof as they are sturdily 'packed' inside a cathode (the glowing tube seen - not talking about the old directly-heated stuff still used in some S.E.T.s). Do remember that WW2 was won with valve equipment ....

The envelopes are normal glass; no need for special gloves. It is well though to keep too many fatty sticky fingerprints off; they 'burn in' and look ugly (power valve glass temperatures can reach 270o).

No decent valve amplifier should go unstable with no load (there is/should-be a built-in load resistor) .... but yes, not all valve ampliifers are that decent. (...and there are at least an equal number of semi-conductor ones also not liking that!). Short the output of some SS amplifiers even for a fraction of a second and they are gone - not so with valve amplifiers.

I am unsure as to why switching on/off should be done in a certain order of things or without signal; not to my experience - enlighten please? (Again, they are actually more rugged in that sense than many SS ones. The 'road-to-fully-on' is actually more quasi-unstable with many transistor amps, what with the high degree of NFB often employed.)

Heat: One might keep in mind that maximum valve dissipation values (EL34: 25W;  6L6GC: 30W;  KT88: 35W etc.) refer to 25oC ambient (as it does for most electronic components). The greater danger is to the components warmed by valves in the vicinity, like electrolytic capacitors. And then keeping the glass clean also assists in cooling. A valve covered in muck cannot radiate as well as a clean one. In fact, a good idea to keep all electronic stuff clean - and also occasionally blow out the dust inside your PC monitor! (being switched off, of course ...) A layer of sticky dust inside a 20 year old valve amplifier begins to provide other paths for the electrons.

How does one clean a really filthy amplifier? You take out the valves, and dunk it into a bath with hot water and some Sunlite liquid or Mr Muscle (not oven cleaner), and scrubb with a brush!! Then wash/rinse all off thoroughly, and let it dry, even more thoroughly!! - before going back to operation. (This is time consuming, also watch out for moisture in unpotted transformers and such - might have to take the covers off or so - blow,  :blah:.)

Valves are sensitive to heater over-voltages. It would seem that some models from the east do not have their transformers correctly aligned. I have measured 6,9V heater voltage instead of the usual 6,3V. If mains tappings do not allow the right adjustment, the only way out is the rather inelegant way of adding low-value resistors in the heater circuits. It might also be done in the primary. Sadly that influences the power supply 'stiffness' slightly - not too important in valve amplifiers. But heater over-voltage (I mean substantially) drastically shortens valve life, particularly power valves.
Audio must be the only branch of engineering where lack of basics' knowledge is considered a superior form of wisdom. (Anon)

Offline Kent Kassler

Re: Valve etiquette and care
« Reply #12 on: July 25, 2013, 06:29:41 AM »
Ampdog....interesting to read re heater voltages.....currently have an amp that shows 5.8 volts for the 6.3volt heaters.....what would be the problems as a result of this?Thank you.
Audiophile Sound Sommelier Extraordinaire....aka Manic Depressive Temporary Void Filler Deluxe.

Offline Hi-Phibian

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Valve etiquette and care
« Reply #13 on: July 25, 2013, 08:52:18 AM »
Mr W
Any ideas on where to source such cables ?
I use a normal kettle type plug , but I also get dead quiet response when volume is all out... And the speakers are very high sensitivity drivers as well.

I do get a very slight " Doooof " sound when I flick those switches I mention above to the on position...

I keep the lowveld audio screened mains cables and recommended gold props and Schurter IECs.
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Offline Hi-Phibian

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Valve etiquette and care
« Reply #14 on: July 25, 2013, 08:55:19 AM »
The reason for the switch on and switch of sequence is to never unnecessarily amplify any switch on thumps from gear further up the chain.

IMO as long as the power amps are switched on last and switched off first the others don't really matter.
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