Andre Jute wrote:
Patrick Turner wrote:
And its a moot point if the milspec NOS tubes drawn from military stores
will always sound best.
No reason why milspec tubes or other "special quality" tubes should
sound better. It is true that some were especially designed to be
superior to standard tubes on some parameter, and that the parameter
(higher voltage, higher current, low noise, lower microphonics) may or
may not give better sound if exploited. But many of the improved
parameters were useless for audio applications. Furthermore, the
majority of military or otherwise special tubes were not redesigned on
some parameter, but simply taken off the line and selected for that
parameter, in most cases regardless of other parameters which might
be, and usually are, more relevant to audio tubes. Even if the special
tube was redesigned and manufactured to enhance some audio-sensitive
parameter, you may not want it because it was a limited, handmade run,
and the slightly less audionically-desirable tube from the mass
production will be much more reliable. Finally, among the tubes that
suck in audio amps, I might single out the longlife ones, which were
designed for incredible MTBF but generally (I don't know of any
exceptions) sound like **** because you can't run them high enough and
hot enough to get really low noise.
Andre Jute
18ct ears
And perhaps an even mooter one if you argue that war promoted
development of more musically accurate tubes.
I didn't argue that. I think the 9-pin tubes were, with a very few
exceptions, a disaster for audio. The 12AX7 is and has always been
crap; it's a guitar tube, pure and simple.
Well, the AX7 is loved for its sound though, even if it is crap.
It wsn't always just a guitar amp tube, but saw use in 1,001 modestly
priced hi-fi systems. And unfortunately, many modestly priced hi-fi
components sold in the 50s to the present have been designed by
dickheads or bean counters with no regard for linearity and noise beyond
compliance with the the most lenient specs. Even the Mullard 520 used a
single 12AX7 as the LTP tube driver for EL34. Crap design, not crap
tubes.
12AX7 also was used in early opamps and for many scientic amps where
linearity was wanted. It *is* a very linear triode.
I have drifted away from using it because I have found medium µ triodes
to sound more dynamic and accurate. But every tube has its knockers and
praisers. The Williamson line up with 2 x 6SN7 as the input driver is
"better" than the Mullard crap.
It is possible to get great sound from a 12AX7. I used one in a
µ-follower in my 10 tube preamp for years with a Shure V15 cart.
Bloomin splendid I thought.
Quad went even crapier by using EF86 toys for the input/driver for the
Quad-II.
And just one lousy EF86 for the phono amp, like many others. Crap has
always been around....
In any event, it is well known that the most accurate tubes existed
well before the war: 845, 211, 212E, 300A and B, 6L6 which spawned the
KT66 and KT88 that you still like, and, as a byblow of patent
circumvention, the development of the wonderful EL34 and its little
sister the EL84.
There is no doubt that very linear and great sound triodes were around
well before 1935, and that we didn't need to develop anything at all
after that.
Hey, we have humans in this world. They develop things the world doesn't
need. They develop the most appalling things the world hates, like the A
bomb, and not content with that they moved onto the H bomb. Some
inventors apologised for their terribilities.
Do a list of things that should never have been invented. Its a
loooooong list.
You could write a book about it.
I've thought one easy book could be titled, 'Fifty reasons why I never
got laid last night'
Nobody over 50 would buy it; they hate facing up to realities.
Anyway, when they took out the NFB from a triode by putting a screen
into it, they doubled the class A1 power. And the power supply B+ could
be 70% lower. The linearity was horrid, output resistance way too high,
but there was an enormous heap of gain if you wanted it.
Like many primary developments, there had to be a secondary tweaking
development to counter defects one always gets with primary
developments.
So in went a supressor grid.
Along with the huge pentode gain came ideas of using NFB.
The folks in America were surprised to be beaten in the land of feature
inventions, so they countered with beam forming plates. Its not a bad
idea it turned out, and better than having a screen plus supressor grid
IMHO. Ansd as soon as people marvelled at the invention of pentodes and
beam tetrodes, some marvelled how these sounded when connected as
triodes! Nobody bothered to make a 300B with octal socket and indirectly
heated cathode. It still has not been done but should be done!!!!. And
it'd be successful. I reckoned it be called a 300BPT.
Just plug in a 300BPT with slimline glass envelope to the same socket
that takes a KT88.
I mentioned it to the guys at the Ei factory in Yugo some years back but
they said they were already working on it and it was to be a 400B. Sure.
and their emails were those of drunken management.
But the insertion of objects into empty bottles didn't stop with
pentodes. It went on orgiastically with the invention of frequency
converter
tubes like the 6BE6, and 6AN7, and in FM decoding tubes like the 6BN6,
et all.
Many of these still litter the Planet, and not enough inventive audio
nutters have used them for Queer Signals you can create for electronic
music that sounds better than the digital crap.
Heard a fully tubed Hammond organ in fine repair recently? Magnificent
compared to later crap with all solid state.
The tubes tend to make people believe in a god, and SS leads them to the
devil.
Patrick Turner.
Andre Jute
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