[ARC5] Running receivers at low B Voltage

[J Mcvey]

Those were designed to run on 24v plate voltage! No mod required


Sent from my undisclosed location

On Tuesday, September 9, 2025, 11:12 AM, Ken Kinderman <scr274 at gmail.com> wrote:

Add one more to the Low B+ list:
The BC-1206!
On Sun, Sep 7, 2025 at 4:24 PM ac2eu at yahoo.com <ac2eu at yahoo.com> wrote:

 The added benefit of ungrounding the resistor is even less current draw on the batteries since no current will flow to ground through the screen divider. Every bit of current is used to power the tubes!
 
    On Sunday, September 7, 2025 at 01:56:43 PM EDT, Mike Kana <aa9il.radio at gmail.com> wrote:  
 
 Thanks for the tip on the screen resistorI make up a B battery from daisy chained 9v batteries from the dollar store 90v to 180v based on what is laying around. If the audio is low, I connect a 1k to 8 ohm radio shack transformer to a RS pocket amplifier. 73 MikeAA9IL
Warning!  This is transmitted over a non secure medium

On Sep 7, 2025, at 12:40 PM, Ken Kinderman <scr274 at gmail.com> wrote:



Thanks Dennis. I'll look at the sceen voltage. I have plenty of audio. Maybe try an A-B test one of these days

On Sun, Sep 7, 2025 at 11:43 AM Dennis Monticelli <dennis.monticelli at gmail.com> wrote:

Less gain is the biggest thing you will notice.  You can mitigate that by adjusting the screen voltage divider (just short a resistor as I recall).  I have run 60 to 70V satisfactorily (from 9V batteries) and still had enough audio for driving a speaker.
Dennis AE6C
On Sun, Sep 7, 2025 at 8:23 AM Ken Kinderman <scr274 at gmail.com> wrote:

Has anyone had experince with receiver HV lower than the nominal 235 VDC dynamotor output? I like to run everything at or slighly below ratings. Not interested in squeezing out every last watt from the transmitters, etc.
So except for the times I am using the dynamotors, I run the receivers in the test jig and out of the racks at about 175VDC, transmitters at about 540VDC. (By the way, even 175VDC is enough to blow the .05's, so I am on a long term quest to replace all, either with re-stuffed cans or just wiring them in. Otherwise, letting them fail is like playing condenser Whack-a-Mole)
My question is about the receivers... aside from maybe the 12A6, are there any downsides to lower overall plate voltage?
Thanks
Ken W2EWL______________________________________________________________
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