Author Topic: Valve etiquette and care  (Read 19176 times)

Offline Winslow

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Re: Valve etiquette and care
« Reply #15 on: July 25, 2013, 09:10:16 AM »
I quote from Line Magnetic 211IA owners manual.

1: Forbidden to operate as unloaded.
2: Forbidden to operate when the output is open or shorted.

I quote from Opera Audio Cyber 800 Mono Block owners manual.

1: Source components and power supplies should be switched on before switching on amplifiers.
2:Always switch the amplifiers off and wait 5 minutes for its power supply capacitors to discharge before connecting or disconnecting any leads.
3: Always use the power switch on the product rather than the mains outlet switch.
4: With the preamplifier volume turned down to zero turn preamplifier on first then turn on power amplifier. This will minimize the chance of damage to the speakers.
5: Note: Never turn on the amplifier unless there are speakers connected to both out put terminals. Operation of the amplifier without a load can damage the output transformers.
6: Note it takes about 1 minute for the EL34 to reach its operating point.

It also gives the same turning on and off sequence in my Audio Research Valve Preamp manual.  These guys know their oats I would presume.

These are all more than decent Amplifiers by a big margin so will obey the guys who made the things.

How many of us have manuals or understand the design of our second hand valve amps these are precautions that are easy to follow why not don't take a chance not worth it.

I have fried a Solid State Mono Block of a very good make by swapping around interconnects amp was off.
Pre was still on with volume up nice pretty blue flash and bang amp cooked nice one.
On having it repaired the tech a well respected fellow said to me never do that turn the volume down always when fiddling around if you are so silly as not to turn it all off first.

Second story fried the power supply on a top class preamp by turning it off and on at the wall and not bothering to turn it off at its power switch.
Well respected Tech the dear departed Gunter Greef asked me what I was doing dold him he just shook his head "don't do that".

As for operating without a load know a fellow who fried his output transformer by switching on with out a load.

So from experience these hints are passed on cant be to careful the stuff is expensive to fix so why take a chance.

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...




You can also try the good fellow Ian (Aka Jim Gore) for power cable 083-4924148.
Not cheap but not silly like prices same as Hi-Phibian's always reasonable prices with excellent service to boot.
No silly things like a rhodium plated ICE plug for R1,500 ea.
 I find the sonic advantages worth it.  Cables do work  :tongue:
The Doof with sensitive speakers is annoying don't know what to do about that have the same problem when turning off some stuff.  Always turn volume down and mute before turning off components and power supplies.  Guess we have to live with it unless we install dedicated individual power lines.

Another annoying thing about sensitive speakers is the volume control either too loud or too soft hard to get it just right.
But as those are the only negatives and they sound so good will live with it.

 
« Last Edit: July 25, 2013, 09:29:01 AM 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 Phase

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Re: Valve etiquette and care
« Reply #16 on: July 25, 2013, 10:49:35 AM »
And the learning curve continues...

Offline charles

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Re: Valve etiquette and care
« Reply #17 on: July 25, 2013, 11:31:30 AM »
"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,"

I will not do it with all valve amplifiers as some have open OTF's and MTF's and when the water seep into the TF then it will be ruined, specially when it has paper insulation. Handle your transformers with utmost care.

There are lots of "ghost stories"around regarding the handling of valve equipment such as "right" procedure to turn it on or off. I do not believe in most of it.

I have fixed and restored probably hundreds of old and new valve amplifiers in my time. True there are the basic principles when working with valve equipment, but if I have to go by some of the extensive do and dont's in this posting it will take me a helluva lot of time to restore/fix a simple valve amplifier.  Or even to listen to a valve amplifier.


Offline King_Julian_S

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Re: Valve etiquette and care
« Reply #18 on: July 25, 2013, 02:04:28 PM »
Tx all
Some major contributions here.
I suppose like most things you take in what u think is relevant.
But again I must say thank you and thank you again for all the selfless info.

Pls keep it coming 👌.

Eish , since my cleaning endeavors with my Alphason , I have vowed to only ever do dry cleaning from here on 😄
Non audiophile music lover...

Offline charles

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Re: Valve etiquette and care
« Reply #19 on: July 25, 2013, 02:07:45 PM »
The bussword is practical and technical experience with valve equipment.

Offline Steerpike

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Re: Valve etiquette and care
« Reply #20 on: July 25, 2013, 02:19:26 PM »
"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,"

I prefer turpentine.
It is less harmful than water if it get into components and remains there. Generally it is safe, but a few plastics can be discoloured by it slightly, so don't use it on injection-moulded-trim panels.

Offline Crankshaft

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Re: Valve etiquette and care
« Reply #21 on: July 25, 2013, 02:41:24 PM »
Not certain if this has already been mentioned or not:

If valve bias is manually adjustable, check at least once a month.

Modern valve don't seem to hold their bias like the originals did.

Offline King_Julian_S

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Re: Valve etiquette and care
« Reply #22 on: July 25, 2013, 04:43:41 PM »
So any tips on setting or checking the Bias ?
Non audiophile music lover...

Offline Winslow

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Re: Valve etiquette and care
« Reply #23 on: July 25, 2013, 05:04:32 PM »
Sorry I am Anal with my stuff it don't come easy I follow to the letter what it says in the book.  Do not like stuff that is fixed modified or fiddled with.  I do not go there have seen too many cock ups and butchers in 45 years at this.   

I only clean with a micro fiber cloth and make covers for my amps to keep them dust free.
Use a spot of Alcohol if absolutely necessary but take care it does remove the silk screening on the valves and can remove paint and logos. Damp Cotton Buds work a treat for the nooks and crannies.
Be careful on painted surfaces with those magic sponges be very gentle they are abrasive they dull the paint
A ever so damp Magic Sponge used gently will remove most dirt.
It is amazing how a small piece of dry magic sponge cleans the pins on the valves and all the contact points.

So any tips on setting or checking the Bias ?

Every amp is different some are Auto Bias and work a treat. My Line Magnetic has a built in meter and switches to select each valve and accessible screws to adjust. Checked when I got it have not touched it and it has not budged on any of the valves in 4 months of daily playing.

You will need a Multi Meter and know what voltage your amp runs the valves and find the point to check that and the adjusting screws. There is a bit of leeway up or down.
The guys reckon it is not necessary to have them all dead on. If they are in spec range don't sweat it.


« Last Edit: July 25, 2013, 05:11:23 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 charles

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Re: Valve etiquette and care
« Reply #24 on: July 25, 2013, 05:18:52 PM »
I agree with Steerpike regarding mineral turpentine. Antique valve equipment restorers also use it as it will not damage the paintwork. Be careful with alcohol (for eg isoprophyl alcohol) as it will eat away certain paints and ducos. 

Offline Phase

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Re: Valve etiquette and care
« Reply #25 on: July 25, 2013, 05:41:50 PM »
What does 32 watts valve power equate to in S/S wattage?

Offline darrylo

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Re: Valve etiquette and care
« Reply #26 on: July 25, 2013, 05:43:39 PM »
What does 32 watts valve power equate to in S/S wattage?

exactly 32 watts. No I'm no kidding but measured power is measured power. If some valve amps are under rated as I suspect some are then they could be more powerful that the sticker says.
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Offline Phase

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Re: Valve etiquette and care
« Reply #27 on: July 25, 2013, 05:50:06 PM »
exactly 32 watts. No I'm no kidding but measured power is measured power. If some valve amps are under rated as I suspect some are then they could be more powerful that the sticker says.
Seriously! Why are they so low powered? I mean a really small S/S amp wouldn't be this side of 50 watts and then go hellish high! My S/S amps where both 250 watts, not that I used it.

Offline darrylo

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Re: Valve etiquette and care
« Reply #28 on: July 25, 2013, 05:57:27 PM »
Seriously! Why are they so low powered? I mean a really small S/S amp wouldn't be this side of 50 watts and then go hellish high! My S/S amps where both 250 watts, not that I used it.

Well its a completely different technology from a lifetime ago.They really didn't need plenty of power with the efficient speakers.

There are modern high power valve amps available these days.
Always Looking for Heathkit, AVO and Leak
"I refuse to prove that my cables will make your system sound better", says the snake oil vendor, "for proof denies faith, and without faith, you will hear nothing."

Offline Phase

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Re: Valve etiquette and care
« Reply #29 on: July 25, 2013, 06:00:31 PM »
Well its a completely different technology from a lifetime ago.They really didn't need plenty of power with the efficient speakers.

There are modern high power valve amps available these days.
High power @ a ridiculously high price.