Valve Brands

[kestrelmusic]

I have been wondering about different brands of valve. I know in the rarefied highest-fi world Mullard and M-O are regarded as being much the best. But are Russian KT66s really any different, electrically or mechanically, from GEC/Osram ones (other than being much newer!)? I've just bought some 'stock' valves - EL42s, ECH81s and the like - and some are Mullard and some other makes including Tungsram and Telam (the latter being, I believe, Polish).
Are the non-Mullards going to be inferior or shorter-lived? Just curious to know!

[paulsherwin]

It's difficult to generalise over time, but Tungsram valves had a good reputation and they made valves for Mullard towards the end of the valve era. Valve remarkers like Pinnacle and Bentley Acoustic sourced valves from all over the place and quality was variable.

A lot of the emphasis on Mullard Blackburn production is just audiophool snobbery, and all the major British, European and American manufacturers (as opposed to remarkers) made valves of comparable quality in the 40s, 50s and 60s.

Modern valve production for guitar amps has seen the introduction of some cost cutting and it's right to view these with suspicion, though that doesn't mean that they're rubbish.

[mark pirate]

Leaving aside the audiphools, there were many good brands of valve apart from Mullard.
Names that come to mind are Brimar, Mazda & Tungsram.
I think it is fair to say that all manufacturers had problems with certain types, but in general valves from Russia seem fine, I have bought quite a few over the years and they seem ok.

Mark

[GrimJosef]

One of the problems that modern manufacturers face is that the economies of scale which applied in the 1940's, 50's and 60's no longer apply today. At the peak of their production the Mullard Blackburn factory was making a million valves a week, and their customer base included purchasers who understood the importance of quality and who had the budget to pay for it. This allowed the manufacturers to push the technology to fairly extreme levels since the payback would be there.

Nowadays the small number of relatively low volume buyers expect those very demanding standards to be maintained at real-terms price levels which are not so different from those of 60 years ago. What this means in practice is a) that there will be a significant failure rate - we can't now afford to put in place the QC processes which allowed the enormous plants to work so consistently and b) that the manufacturers can't afford to trash valves which under-perform. So there is a tendency for every valve to be sold. The top quality ones go to high-end sellers who tend to charge high prices for them. This can be dismissed as audiophoolery but those in the know persistently claim that their intense testing regime and high rejection rate are necessary to keep standards high. The valves which don't make the grade appear at lower prices through a number of more-or-less shady channels. These can lead bargain-hunting buyers to dismiss modern production as shoddy and incompetent.

The fact is that in the end, as with so many things, it just comes down to money.

Cheers,

GJ

[G8HQP Dave]

Some gross generalisations (yet containing nuggets of truth):
- Mullard and other West European valves were regarded as having slightly lower 1/f noise than others, due to higher quality cathode materials
- modern valves don't last as long as NOS ones, due to poorer materials and softer vacuum
- among major UK makers Mullard and GEC were best, Brimar next and Mazda last
- NOS valves from Russia and Eastern Europe are generally fine, and were often officially remarked with Western brands in the latter years of the valve era
- modern valves are a lottery, the best may be nearly as good as NOS, the worst will fail within a few hours use or may be DOA
- modern valves are likely to have higher grid current and higher heater-cathode leakage than NOS - hence the modern popularity of DC heaters

[PJL]

In the case of many audio valves, it is not the hi-fi fraternity but guitar playing enthusiasts who are rating the manufacturers. What they are looking for is distortion behaviour at the limits of operation and usually these limits are well outside the manufacturers recommended operating conditions.

I have not seen any useful stats on modern valves used in hi-fi applications.

[G6Tanuki]

There was a hell of a lot of rebranding of valves from the 1960s onwards, as demand fell it wasn't worth a manufacturer producing a full range of valves so they 'branded-out' to a different manufacturer - often one in Eastern Europe or Brazil or somewhere where the production-lines were still running.

Brands like Zaerix (Z&I Aero Services), Colomor, Pinnacle, Bentley Acoustic Corporation, Haltron - generally came from Eastern Europe and seem generally OK - they were good-enough to be accepted by MoD and given CV-numbers.
Same goes for Edicron, which used to be sourced from what was then Yugoslavia.

I've got a 1960s Brazilian-made Brimar 25L6GT in my collection too.

You also come across "house brand" valves which were made for the big TV rental chains: I've got a couple of "Loyds"-branded EF85s and have seen Granada-branded TV valves too.

These days quite a few old brands have been 'reactivated' for new-manufacture valves: for example "Taylor" was a well-established brand in the USA up until the 1950s; it's now being used on Chinese-made valves largely for sale to the audiophool community.

[G8HQP Dave]

The rebranders varied too. For one or two, if it had the same pinout and the same mu then it was an equivalent and could be relabelled as such!

[Tubeglow]

Going back in time, Here is something from a nostalgia point of view.
Realistic lifetime valves.

Back in 1980 I bought some CVC EL34 and KT66, Chinese I think, and they have worked very well over the years (still going strong). I must admit I thought they would be rubbish. I was wrong.
Some of the Russian valves are very good!

The problem is, does new mean rubbish and old mean good?
I have some Russian 6C33C running well, however I am dubious about Psvane and in the past Shuguang (Gold Dragon).
Some have thin glass envelopes, and a nice blue glow. (Gas or good vacuum it depends where it is)

I think, One of the major issues is with valve rectifiers, these seem to be more critical.

Tubeglow.

[Nickthedentist]

Originally Posted by G6Tanuki

Brands like Zaerix (Z&I Aero Services), Colomor, Pinnacle, Bentley Acoustic Corporation, Haltron - generally came from Eastern Europe and seem generally OK - they were good-enough to be accepted by MoD and given CV-numbers.

Interesting photo of Bentley's premises here. I wonder if the For Sale sign referred to the ground floor shop, in which case it would appear that they folded in the early 1970s. They were founded in 1947.

http://primrosehillhistory.org/wp-co...ey-193x300.jpg

[Bobdger]

Bentley Acoustic Corporation had a warehouse and sales department in the old police station, Littlehampton until the old building was sold in the late 1970s. They then pulled it down and built new flats.

[Nickthedentist]

That's interesting. I can remember seeing that address in ads in the back of Television. So it would appear that they survived longer than I first thought.

[G4XWDJim]

I seem to recall they were in Chalcot Grove somewhere, or is that my dodgy memory.

Jim

[Heatercathodeshort]

Mazda produced without doubt some of the best R.F. and audio output valves but for some inexplicable reason, could not produce a decent post war rectifier.
Another excellent valve manufacturer was Cossor but these are now rather old fashioned types and certainly not trendy with the audio guys.
One of my personal favourites is Brimar. Good quality well made clean valves with an excellent reputation.
Tungsram valves during the 1960's and 70's were manufactured by Mullard and carry the Blackburn factory codes. I think Mullard used the Tungsram brand as an alternative outlet similar to the TV makers did with STELLA, INVICTA etc. Early Tungsram valves were produced in their own factories and were very good quality.
In my opinion GEC/MOV produced the most unreliable valves certainly in the very poor television range. They did produce good audio types such as the KT66 but the PX4 and PX25 suffered from a faulty heater with only 50% of it actually heating. Surprisingly this is often completely missed by the amplifier user or valve purchaser! Their octal triodes and double triodes were very bad and a selection of brand new valves would come up with differing readings when checked on the tester.
I know of several Russian KT66 valves working in Quad 2 units with complete satisfaction. I think it's more a mental thing than a difference in performance.
The British valve manufacturers were all very good including of course the Philips owned but very much British produced Mullard valves and television CRT's. John.

[Cobaltblue]

Originally Posted by Heatercathodeshort

Another excellent valve manufacturer was Cossor but these are now rather old fashioned types and certainly not trendy with the audio guys.

That's unfortunately not quite true.

53KU, 2P, 2XP, 4XP and 6SN7 are all Cossor types which attract a premium.

Cheers

Mike T

[G6Tanuki]

Originally Posted by Heatercathodeshort

Mazda produced without doubt some of the best R.F. and audio output valves but for some inexplicable reason, could not produce a decent post war rectifier.

Yes - the Mazda SP41/SP61 were used in vast numbers during WWII in radar gear and VHF ground-to-air radios. They never seemed to attract the full-on brand-kudos of Mullard/Philips's similar-era EF50 but they were if anything rather more reliable than the Eindhoven/Mitcham product.

Some of Mazda's immediately-post-WWI rectifiers were a disaster: OK, they got misused but a manufacturer should expect an occasional instance of being a bit over-run.

I offer you the U801: http://www.r-type.org/exhib/aay0008.htm

I've actually seen a few instances of these being run with all four sections in parallel with suitable current-control resistors. Treated properly they worked rather better than the mercury-vapour-rectifier equivalents (which had horrible flashover problems) such as the 866A http://www.r-type.org/exhib/aab0018.htm

[m0cemdave]

As is common with fashion and branding in other industries, a lot of this is down to myth, legend, and a buyer's "perception". Consumers are often happy to pay for a feelgood factor even if it makes no sense from a technical or engineering viewpoint.

I've just looked in a bag of 13 x ECC82's in my spares stock. One is branded Cossor (in yellow print), another is only labelled as a CV491, seven are branded MWT (Marconi) with the type number B329, and four are branded Mullard.

I have no doubt that there are some people who would turn their noses up at all but the Mullards.

However, inspection of the factory codes indicates that they were all made in the Blackburn and Mitcham factories of the Mullard (i.e. Philips) company.

I also have various valves carrying Mullard factory codes but branded by general resellers including Z&I, Bentley, Selectron and Edicron.

[Nickthedentist]

Originally Posted by m0cemdave

I also have various valves carrying Mullard factory codes but branded by general resellers including Z&I, Bentley, Selectron and Edicron.

I suppose that these could be "seconds" though.

[Maarten]

Could be, but the consistency of production quality was probably quite high so I don't suppose there's a big difference or even a difference at all, most of the time.

[AC/HL]

They are still identifiable as Mullard production, so it's highly unlikely that a known substandard valve would be allowed out of the factory. Semi-conductor seconds were available, but not valves as far as I recollect.