What Make Valve?

MadHat

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Please don't laugh at the question, but does the Make of the valve have an influence on the quality of the sound and if so for what Make should one strive to go for?
 

ScottulusMaximus

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Depends on the type of valve, date of manufacture and how it's used...

Or some will say it's all random and you just need to try and hope..

Some others will say it's all nonsense and tube rolling is a waste of time.

If you say what exactly you're trying to achieve there are very knowledgeable people on here to point in the right direction, the people who know what they're talking about will refrain from giving such a broad answer to such a broad question.
 

stereosane

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From the little Ive tried, besides make I find NOS tubes to sound more musical and 3D sounding than the new made tubes which sounded a bit sterile to me, buts that's just on the few ive tried in my Exclame.
 

Ampdog

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Madhat,

To use Scottulus's post as an example:

ScottulusMaximus said:
Depends on the type of valve, date of manufacture and how it's used...

Correct, but see below,

Or some will say it's all random and you just need to try and hope.

Yes, in a sense - but see below!

Some others will say it's all nonsense and tube rolling is a waste of time.

No.

Point being that, particularly with recent manufacture, spread in valve characteristics (same number) is often unacceptable. If you have the patience, look for experience by Ufudu and also myself months ago. Such can lie +/- 20%, and + 20% - 30% is not impossible!

In addition, manufacturers also ad another letter to the type and off you go! A 12AX7 should be a 12AX7 - if you think yours is better, give it a different number!  Or at least publish your specs.

The same number valve (bogey or book specs) will give the same result irrespective of make.  I am not going to irritate those believing they hear a difference between makes but valves (all active components for that matter) pass electrons according to particular natural laws. They do not know about bass, mids and highs or frequency per se, only start behaving differently when internal capacitances etc. start getting into the mix and so forth. With valves, how they 'behave' lies 95% with the circuit anyway.

I recall an incident published many years ago of 'tube rolling' by an honest guitarist. He listed the varying experiences of a group, but took the extra trouble to have the test examples measured. Some were drawing more than X2 the current of others (same type)!

I cannot differentiate between brands per limited experience. The older types: Yes, they generally seem to have closer tolerances. Long ago when I worked for the CSIR, we frowned on valves exceeding a +/- 10% spread. Presently I have mostly found EH to be acceptable, but not to the exclusion of other brands.

That in a nutshell (perhaps a coconut one).   
 

handsome

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Different brands do sound different but trying to quantify that difference is extremely hard. As Ampdog pointed out variances are rather large so the same brand but a different batch or even part of a batch can sound different.

The older 'original' valves have much cachet in the fraternity - and matching prices - but even they are not  reliable. Unfortunately when the valve era came to an end western valve production moved to the east, and whilst the facilities in the east often had the original manufacturing equipment they didn't always have access to the exact same materials. Unfortunately many of these valves were branded Mullard, Ampex, Phillips, RCA etc as the original manufacturers bought and resold them as replacements. So many NOS valves actually aren't despite being marked as such. Date codes here can be a help.

So yes valves can and do sound different but trying to quantify them is not so easy. However i have noted that if one is prepared to spend a really ridiculous amount of money on a valve AND tell your wife/significant other/friends how much you paid then it will definitely sound better than whatever brand you had in there before........
 

MadHat

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handsome said:
Different brands do sound different but trying to quantify that difference is extremely hard. As Ampdog pointed out variances are rather large so the same brand but a different batch or even part of a batch can sound different.

The older 'original' valves have much cachet in the fraternity - and matching prices - but even they are not  reliable. Unfortunately when the valve era came to an end western valve production moved to the east, and whilst the facilities in the east often had the original manufacturing equipment they didn't always have access to the exact same materials. Unfortunately many of these valves were branded Mullard, Ampex, Phillips, RCA etc as the original manufacturers bought and resold them as replacements. So many NOS valves actually aren't despite being marked as such. Date codes here can be a help.

So yes valves can and do sound different but trying to quantify them is not so easy. However i have noted that if one is prepared to spend a really ridiculous amount of money on a valve AND tell your wife/significant other/friends how much you paid then it will definitely sound better than whatever brand you had in there before........

Love it!

Surely there are companies such as Octave still building new  Valve Amplifiers, and for obvious reasons they will source good sounding valves to sell the product?
 

Ampdog

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On the other hand, MadHat ......

I am going to try to state this cautiously. Amplifier designs should be such that there will be no difference using valves within an acceptable spread - certainly no audible differences.  When designing (in the past) instrumentation amplifiers the demands were quite more stringent. But users could mostly not be expected to test replacements first.  Still we managed (auto balance, negative feedback and such, not going to expand now).

That is why I am, respectfully, mostly sceptical when large audible differences in 'sound-of-valves' are claimed.  (Strange how mysteriously, particularly these days such are claimed. Decades ago when principles of amplifier operation were more generally known, such claims were less frequent .....
 

Ampdog

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AH!

This is an almost definitive report. As good reports are sometimes indicated, : "Mr Lafferty and Dr Gillespie should be listened to."

If F_D is reading here, I would suggest making this report (including the comments afterwards) a sticky. There are so many tests necessary to define a valve - and then the next batch comes out different! Note that the writers stress that the test batch was limited. As I pointed out before ....  Still, this is one of a very few investigations which highlights important aspects.

I know Mr Lafferty less well, but Dr Gillespie contributes on several forums as a respected authority on valve operation. The man did a lot on valve use even if it is a bygone facility.

Thanks for that reference, Fredeb!
 

fredeb

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Ampdog said:
AH!

This is an almost definitive report. As good reports are sometimes indicated, : "Mr Lafferty and Dr Gillespie should be listened to."

If F_D is reading here, I would suggest making this report (including the comments afterwards) a sticky. There are so many tests necessary to define a valve - and then the next batch comes out different! Note that the writers stress that the test batch was limited. As I pointed out before ....  Still, this is one of a very few investigations which highlights important aspects.

I know Mr Lafferty less well, but Dr Gillespie contributes on several forums as a respected authority on valve operation. The man did a lot on valve use even if it is a bygone facility.

Thanks for that reference, Fredeb!

A pleasure Ampdog ! I have noticed that with same brand matched pairs , that reading can differ immensely ( from one pair to the next pair - from same supplier ) . Which makes me wonder about valves testing better than 100% ( people state 120/130/140% on Fleabay ) . Is the valve not out of spec then ? ( if tested as , say , 130 % )
 

Family_Dog

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>> If F_D is reading here, I would suggest making this report (including the comments afterwards) a sticky.

It be done, Sire!  :)


-F_D
 

Triton

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Hi All

Has anyone heard or own the EAT cool valves 6922/Ecc88 ? They are uber expensive (R2500 a piece) and wondering if they are worth it or something better out there for the price..

Thanks
 

Ampdog

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Revisiting previous comments:

The EAT 'cool' valves: ........

Again (as always?  :( ) I am sceptical.  Nothing I could find shows a definite advantage for audio.
  [My favorite phrase, but to be fair it must be acknowledged that 'better' performance under certain extremes often (mostly?) translates to nil for audio. E.g. some shock tests; unless you are going to use your amplifier in an army tank barreling over rocks and through ditches those are irrelevant under home conditions.]

Thus to pay that much more for practically mainly somewhat improved heat radiation; sorry, count me out. Not to re-start another point of contention, but similar hype reigned regarding cryogenic treatment some time ago; died a quiet and welcome death since.

In electronics, to make a rather sweeping statement: The pattern is always roughly the same: A grand term suddenly pops up or is regurgitated, its often imaginary advantages are lauded by the manufacturers (how else), and a small group tags along nodding their heads up and down, confirmation by the wife-in-the-kitchen, the gardener, the family dog (apology to F_D!) .......  To stop there.

Not that improvements cannot still be made particularly with new materials, but somewhat sterner proof is needed than "I tied a knot in my speaker cable and it sounded better."

Explanatory:
The working of normal valve testers need also be considered. To my knowledge they mostly use 'pulsed' voltages as in half-wave rectified ones. The steady reading on a meter is then really an integrated "average" of a half wave sweep. Because valves are non-linear this will give different Gm readings than datasheet stats, which are mostly taken at steady-state values of the listed voltage or current (pulsed in case of high values to accomodate dissipation limitations).  That does not imply that a valve tester is useless; given parameter values are often adapted to give realistic results of the valve's condition. But that data cannot be used for design purposes.

Coming closer to Mr Lafferty's and Dr Gillespie's tests: The reading of distortion at high levels is valuable, but a mid-value measurement is also required. Small differences in valve characteristics will cause overload to occur at different points, thus seemingly significant differences could be measured at maximum output, one valve being just shy of overload while the next one is just in it.  As Dr Gillespie mentioned, the sample was too small for measured differences to be tacked onto the brand itself (see the differences found between EH valves under different conditions).

Complex?  Not really, if one just understands what exactly is being measured and what not.
 

Triton

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Hi Ampdog

The fact that they advertise the valves  - ( The tube withstands accelerations of 2,5 g at 50Hz for lengthy periods and momentary shocks of 500g for short periods.) I would like to know what the sound pressure would be at 50hz to produce 2.5g of shock. Snake oil?
Ok so being the sucker and skeptic that i am i bought 2 of the EAT cool valves Diamond 6922. Once i got them it did not start off so well. One of the valves had thinner pins than the other and seemed like a softer copper. This caused hissing and popping and thrown the amp into protection mode.. Mailed EAT direct and asked about this as they have such high standards as advertised. They just came back with asking for a proof of purchase and from which country. 3 mails later (not hearing back from them) i contacted the dealer and asked for a replacement. That's 2 weeks ago, the dealer still waiting to hear from the EAT team about the replacement. You would think to dish out 5k for 2 valves the service would be better...
In the mean time i also bought 2 Telefunken 6922 NOS tubes at about a 1/4 of the price of the EAT valves..
Going to be interesting to put them up against each other...that is if i get a replacement EAT valve.

 

Schalk

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Do not go blaming the monos if clicking/popping/hissing and protection frights damage those panels...  :nono:

Also had another customer who bought from the same supplier (Down in the Cape area I think !) 5 of those. One also had thinner pins and the gold also chafed off of the pins in places like they had been used before? Your photo seems to confirm this "used" state. The differing pin thicknesses would suggest they do NOT in fact make their own tubes like they promote in their sales blurb, but pick from the crop available and then "do their magic wand thing" .

 

Ampdog

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Triton said:
The tube withstands accelerations of 2,5 g at 50Hz for lengthy periods and momentary shocks of 500g for short periods.) I would like to know what the sound pressure would be at 50hz to produce 2.5g of shock. Snake oil?

Not necessarily snake oil.  But this spec is often misunderstood; it has nothing to do with sound waves 'impinging' on valves. It refers to rough handling, in equipment such as heavy machinery or military equipment (I was not joking before re army tanks!).  It was relevant in the days of mainly valve equipment; these days one can hardly imagine such applications not to be served by solid state devices. In that sense I intimated that such specs are of little relevance in audio; specs regarding mechanical stresses referred to the above applications. Specs regarding valve life and operating conditions for 'special valves' will also apply to audio and are of value mainly for use in bands, guitar applications and the like, i.e. daily use and perhaps manhandling in transport from A to B.

Relevant to valve specs Philips states for their valve tests:

"Shock:  The tube is subjected 5 times in each of 4 positions to an acceleration of 500g supplied by an NRL shock machine with the hammer lifted over an angle of 30?.

"Vibration:  The tube is subjected during 32 hours in each of 3 positions to a vibration frequency of 50 Hz with an acceleration of 2,5g."

(Note: NRL = National Research Laboratory;  g = gravitation force: 9,8062 dynes)

Triton,

Firstly, respectfully,  not suggesting that anybody buying these valves was a fool! All of us get mislead despite careful research into claims. Sadly, that is what keeps certain brands/devices selling.

Now that you are where you are, pity it can perhaps not be possible to 'slide' off the surrounding metal tube to investigate what actual brand of valve is underneath. (You may void any guarantee still in existance.) As Schalk said, one of the many things to be checked if one can is the so-called gold plating or other marks on pins. Even in proper products gold plating does not mean a lot. This can be 'scored' or damaged during the first couple of pluggings in and out.

You have my sympathy, and I hope you can make life difficult for the relevant sales people/manufacturer. You have paid dearly (well, hopefully you can get back some of your money); I hope the rest of us learns from your misfortune.

Regarding valve pins: Jeepers! I vaguely recall a similar experience with octal valve base pins but certainly once only. Can you perhaps check the two diameters with a suitable tool and warn us? (Normal miniature valve pins I have as 1,0 mm. I could not find the tolerance on this at this time.)

Apology that this went somewhat OT. But information like this is mandatory to the valve community.
What a world ....


P.S. later:  I will mention this experience on the large audio forums where I am a member.  The "audio heavies" on there can make life difficult for manufacturers when necessary. 
 

Triton

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Hi Schalk

Haha i would never dream of blaming the monos, ive blown up a few speakers and every time been amateur mistakes..i just got a massive skrik when the protection kicked in and felt like jumping on those valves!!

Ampdog

Not a problem, getting the correct information is what's needed..
I tried to slide off the metal part but pretty sure it's glued on there, was sure im going to crack the glass if i pushed it any harder.
Would have liked to put a vernier on those pins to see what the difference is, just out of country at the moment. Im sure they would not have been replaced by the time im back so will have a look then.
The supplier actually told me he can crimp my valve sockets so the valve would sit snugly? Yeah good luck with that. That's beyond the point that i have 2 different valves!

Will see what happens in the next week or so before i start sending them mails naming and shaming them.
 

ScottulusMaximus

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Oh deary me, R5k for 2 random valves with a bit of aluminium stuck over them...

I must say it's a smart business(read: scam), shoddy execution if they couldn't match pins though. All they needed to do was buy JJ's and no-one would've noticed.
 

charles

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Some correction please:

6922 is not the same as ECC88


6922 direct equivalent is E88CC
and
6DJ8 direct equivalent is ECC88
Source: Telefunken Taschenbuch 1963 Rohren und Halbleiter

I may be possible to use an ECC88 in place of an E88CC under certain instances.


 
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