[HBR] strange thing

[donald haworth]

Ian...Might have been me posting about the 26a6...it is the 26 volt fil -and
plate- version of the 6ba6, as far as I know...no regeneration I can find, I
did have a lot of de-coupling to do on the 26 volt B+ / fil.--I did have an
infinate Z detector-it worked ok, but the precision rectifire LM-318 circuit
is much better-no distortion from very low carrier to 4.5 volts p/p with
modulation at 99%...dont think you can get much better than that....anyway,
I have spent a good deal of time 'watching' the IF strip-stage by stage on
the scope (HP1740a)....so I think I would have seen any oscillation(s) that
didn't belong....the strip was aligned with sweep gear, and with the six
stages, it sounds very much like the IF on the R390 with the bandwidth at
about 4kc.  Always thought the '390 had better audio than the 390a with
machanical filters.....with six tuned circuits-the skirts are very steep and
the bandwidth is right at 4.5kc.....btw, the IF transformers came from
K2GLO...
-thanks for the reply!  I really would like to know what is going on with
this thing....?
Don

On Wed, Oct 19, 2011 at 5:40 PM, Ian Wilson <ianmwilson73 at gmail.com> wrote:

> Perhaps you are getting some regeneration around the
> IF strip.
>
> Is the 26A6 a 26v filament 6BA6 (someone posted about
> it here recently but I have forgotten)?
>
> 73, ian K3IMW
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