[ARC5] [Milsurplus] Vintage LF/MF Fun with my BC-453B

[Mark K3MSB]

HI Hue

Sorry for the late reply.

I'm blessed to have some friends that keep their eyes out for tuning knobs!

The HP-23 provides 250V B+.  For my full up SCR-274N setup, I use the same
HP-23 but have a 1K 10W resistor in line to drop the voltage to about 190
to 200V.   I'll do that for this setup when I find some time.

The Blue Box under the HP-23 is my 28V supply.   I got it at an estate sale
for $20. It was originally a 12V supply, but it was nicely constructed and
had dual metering.   I replaced the 12V transformer with a 28V transformer
and added a regulator and pass transistor. I think I can source 5A from it,
but in any case it is more than sufficient for any ARC-5 (generically
speaking) receiver.   I have the output filtered, and it's pretty clean.

The box under the headphones is a Timewave DSP-599zx noise filter / audio
processor.  I"ve done what I call "iron man" listening -- no external audio
processing -- and after doing it a few times I find it's much easier on the
ears to be able to adjust the audio bandwidth down to 20 Hz.  By the way,
the little blue box to its left is a Ratzlaff 7 Hz audio filter!    I've
had to use it many times with my SDR or modern receivers.

73 Mark K3MSB






On Wed, Nov 19, 2025 at 4:43 PM Hubert Miller <kargo_cult at msn.com> wrote:

> Nice photo ! i note you have original tuning knobs  not some old TV knob
> crammed on there.
> What is the HP-23 for ?
> What is the unit just under the headphones ?
> -Hue Miller
>
>
>
> Sent from my Galaxy
>
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: https://www.qsl.net/donate.html
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20251121/4bd4bfec/attachment-0001.html>