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/