All-

This is my go-to for the last several years when I need a B+ supply for a RX or small TX. Powering my BC-474 with it.  Makes a great capacitor charger for a spot welder.  I also built a PP 6BQ5 car audio amp, and powered it with a pair of these:

https://www.amazon.com/Aobao-Converter-45V-390V-Capacitor-Adjustable/dp/B09KRL9132/ref=sr_1_9?crid=3COY7ZW60LRT9&dib=eyJ2IjoiMSJ9.2RzlFZ02G0PaRSmRgHt7B_zoVkkok9_gEnEImwlLtqI8GTtaaejE71ttthwWNnkreW65u4u1kitiPlJM3wqegSkClBaiX3PRRLLkrozZeISSgouoeAw_EZki-zKyl9fvXeHyzNLVbim-jI3vlK4tpOLEj8Ml-WBjssGorEokJQ3BTkFD2kLjqo2yN2j4kWurO_HJDGOpjvyQ6AFD1j6FJJafnqYQQVf-tNTuX_9fMBs.NYGFkN4Snkg--fZovzL4nOM5sNJnvVUI0nTpjumw4fM&dib_tag=se&keywords=90-390V+DC-DC+converter&qid=1750953625&sprefix=90-390v+dc-dc+converter%2Caps%2C154&sr=8-9

Shop it around, can be had for less than $10 in quantities.

regards,

Scott W7SVJ

From: [email protected] <[email protected]> On Behalf Of w1nzr--- via MRCA
Sent: Wednesday, June 25, 2025 3:12 PM
To: B. Smith <[email protected]>; Tim <[email protected]>
Cc: Military Radio Collectors Association <[email protected]>
Subject: Re: [MRCA] bC-474 Power Supply

Seconding Tim's thank you  Breck....yeoman service as we cling to the trailing edge of technology, work on things no one really cares about and take the unimportant seriously...

Cheers, 

Brown  / W1NZR 

On Wednesday, June 25, 2025 at 04:44:54 PM EDT, Tim <[email protected]> wrote:

Thanks for all the work you did to document all this Breck.  I don't have a '474 but your ideas have pretty universal application.

Cheers!

Tim

N6CC

On Wed, Jun 25, 2025 at 12:56 PM B. Smith via MRCA <[email protected]> wrote:

I've revised power supply information on the BC-474.
Revised sections  include info on : Connectors, The FL-10 filter, Use of a GN-45, Dynamotors, Inverters, Battery Bias.
The section on Dynamotors features notes and design info by Al N3FRQ and a Dynamotor list compiled by Robert WA5CAB is also included.  Another solution to the Receiver Bias problem using a small battery is also presented.
K4CHE

http://k4che.com/BC474power/BC474Power.htm

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