[Hallicrafters] Re: HT33B and output

[Roger (K8RI)]

Mark Shaum wrote:
>> From: Glen Zook <gzook at yahoo.com>
>> Subject: Re: [Hallicrafters] Hallicrafters HT-33A
>
> On my 33A, the best of my three used PL-172's would manage about 900 
> to 1000 peak watts output, measured on 40 meters as I recall.  I 
> picked up a NOS 8295A and that output jumped up to 1200 watts.  If you 
> want to maximize the potential of the amp you will

Both of the HT-33Bs I've owned would put out well beyond 2000 watts PEP 
(with my voice characteristics it was about 2200) with a 1KW DC input 
measured the old way with a plate current meter using a 1/4 second time 
constant for measuring the input and that was with the PL-172s.
It drops rapidly using a bit of compression, but the one I have 
currently will still hit 1500 watts PEP.  The straight 33 with the 
4CX-300s was only good for about  800 to 1200.   These power levels were 
without doing any modifications to either amp.
> need to add some positive suppressor grid voltage.  I kludged in a 
> bypass capacitor ring and with 75 volts on the suppressor grid output 
> went easily over 1500 watts with no other changes. The tube manuals 
> will indicate the recommended suppressor grid voltage.  I returned 
> mine to ground as I didn't want to overstress anything else in this 
> fine hernia generator of an amp.  And you better have a stiff 120V 
> supply, with the added output I was popping the internal 22 amp 
> breaker on CW tests.
>
I had about a 15' run of #10 so there was very little voltage drop.
If I come across another, I may replace the plate transformer with one 
using a dual 110/220 volt primary.

Roger (K8RI)
> Mark K9TR
> ______________________________________________________________
>