[John Byrns]

In article ,
"MarkS" wrote:

"John Byrns" wrote in message
...
In article
,
Bret L wrote:

On Apr 21, 9:41 am, John Byrns wrote:
In article
,
Bret L wrote:



On Apr 20, 9:36 am, John Byrns wrote:
In article ,

flipper wrote:
On Mon, 19 Apr 2010 12:08:26 -0700 (PDT), "Watt? Me worry?"
wrote:

Hi RATs!

I did not say tubes were not purposely designed. I said using
tubes
for audio that were not designed for audio is neither sinful nor
foolish.

Not quite. You said "The reason a tube sounds good is the circuit
it
is in, if it ever sounds good. Not because it was "designed" for
low
(audio) frequency...
.
.
.
It doesn't matter what the tube was designed to do..."

It most certainly does "matter what the tube was designed to do."
A
remote cutoff pentode, for example, is a lousy choice for 'hi-fi'
because it was specifically "designed" for a different purpose
and, as
a result, isn't very linear.

Still anyone who has listened to an AM, FM, or even an FM stereo
broadcast in the early years has listened to audio processed
through
remote cut off tubes, specifically chosen because of their
particular
nonlinearity.

You presumably are talking about the use of these tubes in the
receivers, they were used in the RF sections ahead of the
discriminator and did not affect linearity of the demod signal.

No, these are RF not the audio applications I was referring to.

They were also used in certain broadcast limiters in the audio chain
as gain controllers. This is a most interesting application and the
surviving such units are worth insane sums to working record cutting
facilities, e.g. the Fairchild 670.

Yes, this is what I was talking about, before solid state became the
norm virtually all broadcast limiters and compressors use remote cutoff
tubes as the gain control elements. Western Electric, RCA, Gates, and
others all built such products using remote cutoff tubes.

The photocell type (Teletronix) was more common: although the 670
wasn't hugely rare it was in the minority. The Gates Level Devil used
these but isn't particularly good.

This is an odd blind spot for you Bret, I suggest you check your 40s and
50s era history again, by far the vast majority of broadcast limiters
from that period used remote cutoff tubes as the gain control elements.

My old college radio station was essentially a complete RCA AM station from
the mixer boards to the Tx that was donated by a local AM radio station. I
do believe its limiter used 6SK7's.

Precisely.

--
Regards,

John Byrns

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