I would like to convert the 0B2 and 0A2 voltage regulators
to solid state in two Hallicarfters HQ-170 and HQ-180.

I guess zeners are part of the answer. Does anyone have
any ideas for this?

Rich W3FYD

Hmmm ... ???

Hallicrafters or Hammurlund??

Rich Evans wrote:
I would like to convert the 0B2 and 0A2 voltage regulators
to solid state in two Hallicarfters HQ-170 and HQ-180.

I guess zeners are part of the answer. Does anyone have
any ideas for this?

Rich W3FYD

Hmmm....indeed!

Hammarlund for now - HQ-170 and 180, then an SX-28 and an SX-101.
I hope it's a long winter! Thanks...a least you read the group.
Do you have any ideas for the tubes?

Rich W3FYD EPA

Rich Evans wrote:
Hmmm....indeed!

Hammarlund for now - HQ-170 and 180, then an SX-28 and an SX-101.
I hope it's a long winter! Thanks...a least you read the group.
Do you have any ideas for the tubes?

Do you have a specific reason for making this conversion? OA2's, and
OB2's are very reliable, and certainly have withstood the test of time.

If you are intent on doing this, string up some 1W zeners until you get
the desired voltage. The OA2, and OB2 are good for a maximum dissipation
of 4.5W, so distribute your zeners evenly until you have at least that
much dissipation. (5, 30V, 1W zeners would make an OA2)

-Chuck

I do not want to discourage you from changing things - but the regulator
tubes are quite reliable and are also a visual indicator of high voltage.
They will have exactly the same heat and power usage as zener diodes, so
there is no advantage to use them.

Except, of course, if you need the socket for a product detector.

They sell higher voltage zener diodes, although you will need to be able to
dissipate the power dissipated by the regulator tube. You can series
zeners to get the correct voltage.

Colin K7FM

Why modify old beauties for the sake of tubes which are readily
available? The power saving will be negligible if any, and the
beauty of the glowing tube contributes to the beauty of the classics.

Irv VE6BP

Rich Evans wrote:

I would like to convert the 0B2 and 0A2 voltage regulators
to solid state in two Hallicarfters HQ-170 and HQ-180.

I guess zeners are part of the answer. Does anyone have
any ideas for this?

Rich W3FYD

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Irv Finkleman,
Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP
Calgary, Alberta, Canada

COLIN LAMB wrote:
I do not want to discourage you from changing things - but the regulator
tubes are quite reliable and are also a visual indicator of high voltage.
They will have exactly the same heat and power usage as zener diodes, so
there is no advantage to use them.

I will say that the regulator tubes in a lot of equipment is problematic
because they are noise sources that spew RF trash all over the place. In
the Hammarlund sets they are well-shielded and decoupled at the base, but
it still would be interesting to compare receiver noise floor with and without
a zener string.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."