[ARC5] Receiver Power Supply

[Kenneth G. Gordon]

On 29 Apr 2015 at 17:11, Mike Hanz wrote:

> It seems pretty clear that the "optimum" B+ is a variable, Ken.  Between 
> your assessment and Leslie Smith's ~60 volt suggestion, it would seem 
> that  a variable supply might be a good thing.  For the one or two 
> people on the planet who might be interested, I have been fiddling with 
> an idea that provides at least a modicum of flexibility, and combines it 
> with a way to use your old dynamotor hulks.  It is still a work in 
> progress, but such as it is at the moment is at 
> http://aafradio.org/garajmahal/virtual_armature.html

VERY interesting, Mike!

> Buttoning up the dynamotor end bells reduces the RF noise to about what 
> you get with a standard dynamotor, but some adjustment of the original 
> mica capacitors on the armature ends should reduce that even further.
> 
> 73,
> Mike  KC4TOS

That is very, very interesting, Mike.

Hmmm....

Now I have some very serious thinking to do about all this.

My first instinct, of course, is simply to 1) replace the bad components 
(capacitors) in some non-obvious way, coupled with 2) reducing plate voltage 
to all of the tubes (which is unnecessarily high in my opinion), and 3) 
adjusting screen voltages closer to where the tube manuals say they should 
be for best operation of the tubes at that lower voltage.

In my case, I no longer have any museum quality receivers, having been 
"saddled" in fact with nothing but real junkers, many of which I can restore to 
operation, but most certainly not to anything even remotely close to original 
condition.

In fact, I am actually quite glad that I no longer have museum-quality 
receivers, since it relieves me of the burden of dealing properly with them.

However, your device gives me several other intriguing ideas.

The only thing missing from your device is that lovely dynamotor whine. 
Maybe you could incorporate some sort of audio stage and small speaker to 
emulate that! ;-) (Just kidding.)

Ken W7EKB