Carey -
The "B" style started with Version 4, around s/n 27000. Rather than the
main tuning knob with insert, which can be changed any time, the 'real'
"B" version had the little lucite illuminated fiducial behind the main
tuning knob skirt. Starting with Version 7, around s/n 30500, a single
transistor audio preamp stage (Q5) was added just before the 6AQ5 AF
Output stage to increase the audio output.
So.... IF you have a "real" "B", but the s/n is earlier than 30500,
then yes, you will have less audio output than a "late B" or C model.
If your B s/n is above 30500, then you might have a gassy 6AQ5, bad
cathode resistor R92, bad cathode bypass cap C135, leaky coupling cap
C212, bad Emitter bypass cap C214, or ...
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line & TR-4/C Service Supplement CDs
<www.k4oah.com>
Carey Lockhart wrote:
is there anyone who has noticed a difference in af output between the
tr-4c and the tr-4 with the knob that has the insert. i guess that is
the tr-4b maybe. anyway there is a very noticeable difference between
my two rigs.
Carey Lockhart, KC5GTT
[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
www.kc5gtt.com
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