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Andre Jute[_2_] Andre Jute[_2_] is offline
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Default Do milspec tubes *necessarily* sound better?

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.

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.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review
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Peter Wieck Peter Wieck is offline
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Default Do milspec tubes *necessarily* sound better?

What massive, incredibly mis-informed crap.

Please note the interpolations:

On Nov 30, 6:31*am, Andre Jute wrote:

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.


Bullsh*t. At least as it applied to Tung-Sol and Sylvania, their
military-destination tubes ran on separate lines with separate
parameters to separate specifications. What actually happened is that
during the times of "Zero-Defect" programs (most of wartime and
immediate post-war production well into the 1960s), tube runs were
'selected out' for not meeting all parameters, not chosen for meeting
them. Consider the implications of that statement - 100% of all tubes
must be tested in order to find those few that meet the mil.spec.
designation. Not quite. RCA had much the same process that they
continued until they ended production, with culls going to the resale
& retail markets - quite an interesting method.

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.


There were no "limited hand-made runs" when it came to general-purpose
tubes from mil.spec. purposes. That sort of thing might be relevant to
radar receiving & transmitting tubes or special-purpose CRTs, but
general-purpose tubes used in everything from field radios to elevator
control systems - no such thing.

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.


And why should that be at issue? Use something else. More-or-less why
there are several flavors of ice-cream.

Andre Jute
18ct ears, lead-contaminated brain.



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.


That would be your opinion, unsupported by the facts. You need to
listen to a couple of Sylvania Mil.Spec. 5751s once or twice, or
RCA's late-run orange-label 7025 a time or two.

In any event, it is well known


Again, only by you as a product of a fevered brain and residual stroke
damage.

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.


Ah, the EL84 - 7-pin miniature.

As to the rest in that pre-war line-up, most of them were developed by
Western Electric for telephonic and theatre-sound (Recording and
Playback) use. Where reliability and long life meant a great deal more
than absolute accuracy. And with telephoney, 300 - 3400 HZ is all one
got. And with theatre reproduction, even 10%+ distortion was entirely
acceptable.

So, with heroic measures TODAY, one can better those figures using
30s-tube designs. WOW, I AM impressed with their accuracy, quality,
and the sound that they might produce. Much as it is possible to put a
lawn-mower engine in a Lamborghini and make it go. Sort-of, with
special gearing, not very fast, don't ask it to go up any substantial
hills. Also impressive from a purely engineering point of view - but
one must ask Why?

Andre, you are reaching that age when the medications no longer are
effective. A minder is the next step. You already have a couple of
acolytes - I am sure either John B, George M. or William W. would be
glad to volunteer - that is assuming that George M. is an actual
person and not a sock-puppet.

Peter Wieck
Melrose Park, PA
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John Byrns John Byrns is offline
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Default Do milspec tubes *necessarily* sound better?

In article ,
Peter Wieck wrote:

What massive, incredibly mis-informed crap.

Please note the interpolations:

On Nov 30, 6:31*am, Andre Jute wrote:

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.


Ah, the EL84 - 7-pin miniature.


Peter's comment about the EL84 is obviously a joke that I am too dense to
understand, can someone please explain?

As to the rest in that pre-war line-up, most of them were developed by
Western Electric for telephonic and theatre-sound (Recording and
Playback) use. Where reliability and long life meant a great deal more
than absolute accuracy. And with telephoney, 300 - 3400 HZ is all one
got. And with theatre reproduction, even 10%+ distortion was entirely
acceptable.


What massive, incredibly mis-informed crap.

You obviously have little understanding of telephoney. Multichannel carrier
systems were in widespread use well before WW2, I suggest you peruse the Bell
System Technical Journal from the 1920s and 1930s to better understand the
implications. It's been many years since I studied these carrier systems so I
have forgotten many of the precise details, but IIRC these systems required flat
response from the tubes to at least 100 kHz, if not 200 kHz, your 3,400 Hz
response would hardly do. Even more importantly, a high degree of linearity was
required from the tubes to prevent intermodulation distortion which causes cross
talk between the multiplicity of voice channels transported by the carrier
systems. Intercity cables would have multiple repeaters, further compounding
the linearity and intermodulation distortion problem.

Bottom line, yes long life was very important in tubes designed for telephoney,
but so was a very high degree of linearity or freedom from distortion, and
frequency response extending to a couple hundred kHz.

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/
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Andre Jute[_2_] Andre Jute[_2_] is offline
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Default Do milspec tubes *necessarily* sound better?

On Nov 30, 3:59*pm, John Byrns wrote:
In article ,
*Peter Wieck wrote:

What massive, incredibly mis-informed crap.


Please note the interpolations:


On Nov 30, 6:31*am, Andre Jute wrote:


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.


Ah, the EL84 - 7-pin miniature.


Did that poor little man Worthless Wiecky really say that? Now you can
see why I have him in my killfile. Even a newbie tube-roller shouldn't
make such a dumb mistake.

Peter's comment about the EL84 is obviously a joke that I am too dense to
understand, can someone please explain?


Ah! You think Worthless has a sense of humour. Methinks that is a
doubtful proposition. The nearest Worthless Wiecky ever came to a
sense of humour was when he was a janitor at a college building, where
his employers used to send him out to walk the cat on a lead, cruel
humour to be sure, but somehow apt to the little man.

As to the rest in that pre-war line-up, most of them were developed by
Western Electric for telephonic and theatre-sound (Recording and
Playback) use. Where reliability and long life meant a great deal more
than absolute accuracy. And with telephoney, 300 - 3400 HZ is all one
got. And with theatre reproduction, even 10%+ distortion was entirely
acceptable.


What massive, incredibly mis-informed crap.


Worthless Wiecky just says the opposite of what I say, whatever I say;
I don't think he cares if no one believes him, if everyone sees
through his pathetic attempts to be a swinging dick.

You obviously have little understanding of telephoney. *Multichannel carrier
systems were in widespread use well before WW2, I suggest you peruse the Bell
System Technical Journal from the 1920s and 1930s to better understand the
implications. *It's been many years since I studied these carrier systems so I
have forgotten many of the precise details, but IIRC these systems required flat
response from the tubes to at least 100 kHz, if not 200 kHz, your 3,400 Hz
response would hardly do. *Even more importantly, a high degree of linearity was
required from the tubes to prevent intermodulation distortion which causes cross
talk between the multiplicity of voice channels transported by the carrier
systems. *Intercity cables would have multiple repeaters, further compounding
the linearity and intermodulation distortion problem.

Bottom line, yes long life was very important in tubes designed for telephoney,
but so was a very high degree of linearity or freedom from distortion, and
frequency response extending to a couple hundred kHz.


And we still get the benefit of their work in the 300B...

--
Regards,

John Byrns

Surf my web pages at, *http://fmamradios.com/


I admire your saintly patience in correcting Worthless Wiecky's
multitudinous errors, but I can't say I aspire to it. Not enough
decades left in my life to turn Worthless into an even half-competent
audiophile.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review
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BretLudwig BretLudwig is offline
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Default Do milspec tubes *necessarily* sound better?

The triodes designed from 1927-1940 were actually some of the simplest
tubes to manufacture. They were often manufactured by small companies with
what today would be considered a hole-in-the wall and could be easily made
in Western countries if there were 1) a stable, non-neurotic market and 2)
relief from the environmental nazis who destroyed First World
manufacturing.

--
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More information at http://www.talkaboutaudio.com/faq.html



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Patrick Turner Patrick Turner is offline
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Default Do milspec tubes *necessarily* sound better?



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
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

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Peter Wieck Peter Wieck is offline
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Default Do milspec tubes *necessarily* sound better?

On Nov 30, 2:57*pm, Andre Jute wrote:

I admire your saintly patience in correcting Worthless Wiecky's
multitudinous errors, but I can't say I aspire to it. Not enough
decades left in my life to turn Worthless into an even half-competent
audiophile.


Couple of things, Fruitless...

a) The 300B (or any of the 300-series tubes in any case) weren't used
in Telephoney. They were used in audio recording and playback
applications for moving pictures - and again, 10%+ distortion in
actual use was neither unexpected nor unacceptable.
b) 300 - 3400hz was the norm for voice lines. And those on either end
of the phone line speaking into their handset got that, and only that,
and until well after WWII, only on a good day in many areas. Coax and
broadband uses of coax were developed in the 20s, and used a great
deal for increasing capacity - but what the user heard was quite
limited.
c) Last I looked (and that is admittedly superficially) the 101-series
of tubes was used primarily for telephoney purposes and for coaxial
broadband applications - where distortion was less a concern than
signal loss. And I don't see you promoting that one in your pantheon
of golden tubes.
d) Actually, as tubes go, very, very few were used for general
telephony purposes anyway. I believe that the only actual electronic
(vs. mechanical) vacuum-tube switch came in quite late, and operated
for only a few years - I also seem to remember it being in the late
50s and happening only very shortly before solid-state took over the
entire process.

John is an excellent historian and makes a good water-carrier for you
- far better than you deserve and he does it to his great detriment.
But do note that he quibbles on one aspect of one of the details, not
the substance. But it is time you promoted him to the striker position
as you have clearly lost it.

I really want to see those hand-made, short-run Mil.Spec. general-
purpose tubes so good for audio purposes. And, comes to it, those that
were pulled from common production "by test". Perhaps in countries
with only limited tube production, or where _everything_ was special-
purpose - and about the only 'country' that fits that model in the
time mentioned (pre-war) would be the Soviet Union... is that what you
meant?

Peter Wieck
Melrose Park, PA
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Arny Krueger Arny Krueger is offline
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Default Do milspec tubes *necessarily* sound better?

"Peter Wieck" wrote in message


a) The 300B (or any of the 300-series tubes in any case)
weren't used in Telephoney.


Actually they were. I've scrapped out enough obsolete telephone equipment to
know that they were used for output stages in drivers for long lines, and
also as voltage regulators in power supplies.

They were used in audio
recording and playback applications for moving pictures -
and again, 10%+ distortion in actual use was neither
unexpected nor unacceptable.


Ever hear of inverse feedback? The good news is that Bell labs did, and
applied it to their equipment.



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Peter Wieck Peter Wieck is offline
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Default Do milspec tubes *necessarily* sound better?

On Dec 1, 8:29*am, "Arny Krueger" wrote:
"Peter Wieck" wrote in message



a) The 300B (or any of the 300-series tubes in any case)
weren't used in Telephoney.


Actually they were. I've scrapped out enough obsolete telephone equipment to
know that they were used for output stages in drivers for long lines, and
also as voltage regulators in power supplies.

They were used in audio
recording and playback applications for moving pictures -
and again, 10%+ distortion in actual use was neither
unexpected nor unacceptable.


Ever hear of inverse feedback? The good news is that Bell labs did, and
applied it to their equipment.


Sure they did - they called it "negative feedback" and I believe they
patented the process initially. And for long-lines they may have used
the 300s for amplification - although all the literature I saw pointed
towards the 101 series for that purpose - and in one case specifically
excluded the 300 as "not suitable for the intended purpose" - and as I
dimly remember based on the high voltages required. Do you have any
specific pointers to the 300 used that way? I have always been curious
as to how *few* tubes were used in telephoney - primarily only used
for long lines and undersea cables as amplifiers and repeaters.

Learn something new every day, I hope.

Peter Wieck
Melrose Park, PA
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Arny Krueger Arny Krueger is offline
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Default Do milspec tubes *necessarily* sound better?

"Peter Wieck" wrote in message

On Dec 1, 8:29 am, "Arny Krueger"
wrote:
"Peter Wieck" wrote in message



a) The 300B (or any of the 300-series tubes in any case)
weren't used in Telephoney.


Actually they were. I've scrapped out enough obsolete
telephone equipment to know that they were used for
output stages in drivers for long lines, and also as
voltage regulators in power supplies.

They were used in audio
recording and playback applications for moving pictures
- and again, 10%+ distortion in actual use was neither
unexpected nor unacceptable.


Ever hear of inverse feedback? The good news is that
Bell labs did, and applied it to their equipment.


Sure they did - they called it "negative feedback" and I
believe they patented the process initially. And for
long-lines they may have used the 300s for amplification
- although all the literature I saw pointed towards the
101 series for that purpose - and in one case
specifically excluded the 300 as "not suitable for the
intended purpose" - and as I dimly remember based on the
high voltages required. Do you have any specific pointers
to the 300 used that way? I have always been curious as
to how *few* tubes were used in telephoney - primarily
only used for long lines and undersea cables as
amplifiers and repeaters.

Learn something new every day, I hope.


Check the archives of schematics of WE electronics of the 30s through 50s
and there should be some devices that are obviously booster amplifiers for
long lines - 600 ohms in, 600 ohms out, lots of guts. I saw the things up
front and personal in the scrap piles and surplus sales of the 50s and 60s,
but didn't take names and numbers.

I also have seen some references to special high-reliability 300Bs used as
booster amplifiers in the early transoceanic cables, say from the 30s. I
did some checking around and could only find specific references to the
cables they laid in the 50s, which used physically smaller pentodes.

The power supplies of the AN/MPQ 34 and AN/MPQ 36 radars I worked on in the
late 60s used 300Bs for series regulators for the B+ supplies all over the
radar (3 total power supplies, about 6 RU each). I think there were 8 300Bs
per unit.




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Peter Wieck Peter Wieck is offline
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Default Do milspec tubes *necessarily* sound better?

On Dec 1, 9:38*am, "Arny Krueger" wrote:

I also have seen some references to special high-reliability 300Bs used as
booster amplifiers in the early transoceanic cables, say from the 30s. *I
did some checking around and could only find specific *references to the
cables they laid in the 50s, which used *physically smaller pentodes.


Interesting. I wonder how they solved the high-voltage problem, or
maybe they didn't and so moved on to different tubes.

The power supplies of the AN/MPQ 34 and AN/MPQ 36 radars I worked on in the
late 60s used 300Bs for series regulators for the B+ supplies all over the
radar (3 total power supplies, about 6 RU each). I think there were 8 300Bs
per unit


Makes sense - wasn't the 34 used on mobile missile systems? That power-
supply would have to be pretty rugged under those conditions.

Peter Wieck
Melrose Park, PA
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John Byrns John Byrns is offline
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Default Do milspec tubes *necessarily* sound better?

In article ,
"Arny Krueger" wrote:

"Peter Wieck" wrote in message


a) The 300B (or any of the 300-series tubes in any case)
weren't used in Telephoney.


Actually they were. I've scrapped out enough obsolete telephone equipment to
know that they were used for output stages in drivers for long lines, and
also as voltage regulators in power supplies.

They were used in audio
recording and playback applications for moving pictures -
and again, 10%+ distortion in actual use was neither
unexpected nor unacceptable.


Ever hear of inverse feedback? The good news is that Bell labs did, and
applied it to their equipment.


Didn't the guy that invented inverse feedback work for Bell, or am I confused?

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/
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Default Do milspec tubes *necessarily* sound better?

In article ,
Peter Wieck wrote:

On Dec 1, 8:29*am, "Arny Krueger" wrote:
"Peter Wieck" wrote in message



a) The 300B (or any of the 300-series tubes in any case)
weren't used in Telephoney.


Actually they were. I've scrapped out enough obsolete telephone equipment to
know that they were used for output stages in drivers for long lines, and
also as voltage regulators in power supplies.

They were used in audio
recording and playback applications for moving pictures -
and again, 10%+ distortion in actual use was neither
unexpected nor unacceptable.


Ever hear of inverse feedback? The good news is that Bell labs did, and
applied it to their equipment.


Sure they did - they called it "negative feedback" and I believe they
patented the process initially. And for long-lines they may have used
the 300s for amplification - although all the literature I saw pointed
towards the 101 series for that purpose - and in one case specifically
excluded the 300 as "not suitable for the intended purpose" - and as I
dimly remember based on the high voltages required. Do you have any
specific pointers to the 300 used that way? I have always been curious
as to how *few* tubes were used in telephoney - primarily only used
for long lines and undersea cables as amplifiers and repeaters.


How few tubes were used in telephoney? I remember when I was in High School I
used to walk past a telephone central office on the way to the Barber Shop. I
think the street level was offices, but when you looked up at the second floor
windows all you could see inside was the orange glow of thousands and thousands
of tubes.

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/
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Arny Krueger Arny Krueger is offline
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Default Do milspec tubes *necessarily* sound better?

"Peter Wieck" wrote in message

On Dec 1, 9:38 am, "Arny Krueger"
wrote:


I also have seen some references to special
high-reliability 300Bs used as booster amplifiers in the
early transoceanic cables, say from the 30s. I did some
checking around and could only find specific references
to the cables they laid in the 50s, which used
physically smaller pentodes.


Interesting. I wonder how they solved the high-voltage
problem, or maybe they didn't and so moved on to
different tubes.


I'm under the impression that the power amps were in series across the B+
power, which was on the order of several kV.

The power supplies of the AN/MPQ 34 and AN/MPQ 36 radars
I worked on in the late 60s used 300Bs for series
regulators for the B+ supplies all over the radar (3
total power supplies, about 6 RU each). I think there
were 8 300Bs per unit


Makes sense - wasn't the 34 used on mobile missile
systems?


Both were Hawk, which was mobile with 30 minute take-down, 30 minute setup.

That power- supply would have to be pretty
rugged under those conditions.


Some shock mounting for especially the 300Bs. Most of the tubes were wire-in
types sitting in metal clips/heat sinks.


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Arny Krueger Arny Krueger is offline
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Default Do milspec tubes *necessarily* sound better?

"John Byrns" wrote in message

In article
, "Arny
Krueger" wrote:

"Peter Wieck" wrote in message


a) The 300B (or any of the 300-series tubes in any case)
weren't used in Telephoney.


Actually they were. I've scrapped out enough obsolete
telephone equipment to know that they were used for
output stages in drivers for long lines, and also as
voltage regulators in power supplies.

They were used in audio
recording and playback applications for moving pictures
- and again, 10%+ distortion in actual use was neither
unexpected nor unacceptable.


Ever hear of inverse feedback? The good news is that
Bell labs did, and applied it to their equipment.


Didn't the guy that invented inverse feedback work for
Bell, or am I confused?


The earliest papers I'm familiar with came out of Bell Labs.




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John Byrns John Byrns is offline
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Default Do milspec tubes *necessarily* sound better?

In article ,
Peter Wieck wrote:

c) Last I looked (and that is admittedly superficially) the 101-series
of tubes was used primarily for telephoney purposes and for coaxial
broadband applications - where distortion was less a concern than
signal loss.


This claim is misleading, distortion was a serious concern "for coaxial
broadband applications". These systems carried hundreds of telephone with a
frequency multiplex scheme, crosstalk between telephone conversations is
considered undesirable, and distortion directly causes crosstalk in these
systems, hence distortion is a major concern. I know that this aspect of
nonlinear "distortion" is difficult for an audiophile to comprehend, but the
crosstalk generated by nonlinear "distortion" in an analog multiplex, such as
was used in "coaxial broadband" systems, is easy for even a tin ear to hear.

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/
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