[Heath] HP-23 power supplies - an idea and some questions.

[Kenneth G. Gordon]

On 4 Feb 2018 at 23:40, Bill Cromwell wrote:

> Hi,
> 
> I haven't looked for a while but some of those ratings are DC *input* to 
> the plate.

Yup.

> Later tables from the same sources list the output power.

Again, yup, except that in some cases those specs mention something like "circuit losses 
not included".

> Now 
> I need to look again. All three of the transmitters I have with a pair 
> of 6146 tubes run much closer to 900 volts on the plates and one of them 
> is even slightly over 900 volts. There have been no problems with the 
> higher voltage and I run mine conservatively anyway at lower plate 
> current (offsetting the higher voltage in the power equations). I do try 
> to pay attention to "absolute maximum plate power dissipation".

Me too. To me, that is the single most important parameter when using tube amplifiers.

> But even 
> those can be 'pushed' and I have heard of 1200 volts on 6146s. Yikes.  I 
> do not push the pair(s) much over about 90 watts out and more often 60 
> watts or less.

Good on ya, Bill.

> 
> Ken's proposed empirical test seems worthwhile if he wants the 
> efficiency. I'm not sure that winding would see all of that DC applied 
> but "ratings" and actual limits may be different in your favor.

Yes. As I said, I am NOT concerned about power output: to me (I am probably a bit "anal" 
about this), it just isn't right. Possibly my German ancestry coming to the fore.

> Use the 
> series light bulb trick for testing just to minimize or prevent major 
> smoke damage and shrapnel.

Ha ha! I'm not one bit worried about shrapnel. Nothing to explode in this case. The 
electrolytics (recently replaced anyway) are well within their tolerance, and the 
transformer(s) sure aren't going to explode. Melt down, maybe, if I'm an idiot, but explode? 
No.

> Let us know how that works out.

Will do.

> I have put 
> the buck or boost winding on the primary side where the steam pressure 
> is much less. In your case that raises the heater voltages as far as I 
> know - assuming the transformer has all the winding in just one unit.

It does.

> 
> Put the iron you are testing under an inverted steel washtub in the back 
> yard with the series light bulb outside of the tub. Stake the tub down 
> at the handles. I have taken those measures when other people told me I 
> could 'not do that' but the science suggested I could. I never made any 
> smoke or shrapnel but I still do that for "new ideas" with potential 
> unpleasant results. My next use may be for experiments with rechargeable 
> lithium batteries.

Good on ya, Willie. Carry on. :-)

Ken W7EKB

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