[HBR] Power Supplies used in HBR 14 and HBR 16

[WA5VGO]

Don,

I haven't actually measured the total current of the HBR 16, but I'd be 
quite surprised of it was anywhere near that value (157 mA). Most 
communications receivers with a single class A output tube draw about half 
that amount.

73,
Darrell, WA5VGO


At 07:01 PM 12/18/2007 -0800, you wrote:
>I hope everone has a pleasant 2007 holiday season.
>
>A death in the family this year kept me off the workbench. However, I am
>ready to tackle another project.
>
>I have a question concerning the HBR power supplies and how the choke
>and transformer requirements were determined. I believe I generally know
>the answer but would appreciate a clear reason for doing what I have
>done in the past....overkill.
>
>My question: The sum of the plate and gride currents for the tubes used
>in the HBR 16 exceeds the currents listed in the tubes specs. The tube
>specs show the sum of the typical plate currents alone to be approx
>157ma. The HBR 16 only uses 150 ma choke(s). The transformer requirement
>in the HBR 16 is for 120ma.
>
>How do you scientifically choose the ratings for the transformer and
>choke assuming the recommended plate voltage is used?
>
>After the fact I can measure but what rule of thumb would help up front?
>
>
>There was a mention of HBR receivers in January 2008 QST.
>
>Don K5UOS
>