I just picked up what appears to be a Trio (Kenwood?) model SM-1
tube-type HF preselector. I can dope it out for the connections to fil
and B+ but can anyone provide type of tubes used? They are both 7-pin
miniature and the fils are pins 3 and 4. Could be 6BA6 or 6BZ6, maybe?
Its a 2-stage device and may be a converter instead of a preselector?
Two sets(decks) of coils and compression trimmers. The vintage is said
to be in the 50's but can't confirm. The size is about like a Heath
VF-1 VFO and typical of early Trio/Kenwood gear. Logo says Trio but
unlike any Trio logo I've seen on their early ham gear. There is a
picture and reference to it being a preselector on a JA's website but no
joy on anything else. Any info would be appreciated. de K3HVG

I have a Trio preselector identified in my inventory
as an SM-1 but the booklet for it seems to have
disappeared from my files. These were offered in
kit form or "factory wired"... mine is factory wired
and in near mint condition. My rf amplifier tubes
are both 6BA6. It says "Signamax" on the tuning
dial. VE7AFN.


"K3HVG" wrote in message
. ..
I just picked up what appears to be a Trio (Kenwood?) model SM-1
tube-type HF preselector. I can dope it out for the connections to fil
and B+ but can anyone provide type of tubes used? They are both 7-pin
miniature and the fils are pins 3 and 4. Could be 6BA6 or 6BZ6, maybe?
Its a 2-stage device and may be a converter instead of a preselector?
Two sets(decks) of coils and compression trimmers. The vintage is said
to be in the 50's but can't confirm. The size is about like a Heath
VF-1 VFO and typical of early Trio/Kenwood gear. Logo says Trio but
unlike any Trio logo I've seen on their early ham gear. There is a
picture and reference to it being a preselector on a JA's website but no
joy on anything else. Any info would be appreciated. de K3HVG

k35454 wrote:
I have a Trio preselector identified in my inventory
as an SM-1 but the booklet for it seems to have
disappeared from my files. These were offered in
kit form or "factory wired"... mine is factory wired
and in near mint condition. My rf amplifier tubes
are both 6BA6. It says "Signamax" on the tuning
dial. VE7AFN.




That is exactly it! It would be nice to have a schematic but that
confirmation is 100% useful. As I said, the thing works. There's no
SM-1 nomenclature on mine, just that funny-looking, I assume early type,
Trio logo and the word Signamax on the dial, as you mentioned. If you
ever find the booklet and can copy the diagram and/or the actual B+
requirement, I'd much appreciate it.

Regards for the Holidays de Jeep/K3HVG

"K3HVG" wrote in message
...
k35454 wrote:
I have a Trio preselector identified in my inventory
as an SM-1 but the booklet for it seems to have
disappeared from my files. These were offered in
kit form or "factory wired"... mine is factory wired
and in near mint condition. My rf amplifier tubes
are both 6BA6. It says "Signamax" on the tuning
dial. VE7AFN.




That is exactly it! It would be nice to have a schematic but that
confirmation is 100% useful. As I said, the thing works. There's no
SM-1 nomenclature on mine, just that funny-looking, I assume early type,
Trio logo and the word Signamax on the dial, as you mentioned. If you
ever find the booklet and can copy the diagram and/or the actual B+
requirement, I'd much appreciate it.

Regards for the Holidays de Jeep/K3HVG

The "factory" versions had some parts fastened to the
chassis by rivets while the home-built ones used machine
screws. Also, the rectifier tube was, I believe, a 6X4 , which
many users replaced with solid-state diodes. VE7AFN.

k35454 wrote:

The "factory" versions had some parts fastened to the
chassis by rivets while the home-built ones used machine
screws. Also, the rectifier tube was, I believe, a 6X4 , which
many users replaced with solid-state diodes. VE7AFN.



Hmmmm.. a wrench has been inserted into the gears! My unit is not
self-powered. It has a power pigtail coming out the rear apron and is
riveted. All else falls into place, though, including the picture posted
on a JA's website. Perhaps there was an SM-2 or something? Too bad
there's no nomenclature on these things. de K3HVG