Hi John,
-
Looks plenty straight forward in design and construction,
right out of a W6SAI Radio Handbook....
-
All the parts appear to be common and the construction
very clean.
-
Just my opinion... I would not trust the plate blocking
caps at full input in high duty cycle modes. The loading
cap seems rather large, hopefully most all the sections
are switched out on the higher frequencies.
-
Grid driven layouts... Tetrode Screen circuits were "semi
primitive" in many published circuits. I would trace out
at least the screen grid lead back to the power supply
and see how it is set up. Considerations for protection,
bleeder current and related would be weighed and
opinions vary quite a bit when asking amps folks.
Hard to see, but this amp might be cathode driven,
but I can't tell from here.
-
Didn't seen anything about the power supply.. other
than it was a Heathkit. If the parts and construction
will handle the higher voltage, this type of amplifier
talks very well at +2200 on the anodes.
-
You will need to know if this circuit is grid or cathode
driven... Common operation potentials for both
layouts are given in the SAI and ARRL Handbooks.
It's hard to see what the input coil assembly is
talking to in the pics.
-
I would give the tubes min 3 min warm up, make
sure the potentials are applied in the proper order.
-
The blower is cumbersome, but hopefully large
enough for HF SSB duty cycles. Someone spent
a lot of time building the chassis.
-
cheers
skipp
-
--------- Forwarded message ----------
From: john <johnmb@nc.rr.com>
I'm trying to identify and revive a beautiful HB desktop HF amp (2 x
4CX150s) that I obtained with zero documentation. If you have a moment,
please point your browsers to:
http://www.old-radios.com/amp/amp.html
I would appreciate any pointers to information on this (if it's built
from
published plans) and / or suggestions on carefully bringing it to life,
given a lack
of information.
Whoever built this did a fantastic job. I'd like to give it a good home.
Thanks for the look,
John
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