[TenTec] TL or TH 304's

[Dr. Gerald N. Johnson]

Yes, because the 304T was essentially the guts of four 75T in one 
envelope. The filaments were oversized for the plate to make them very 
good pulse tubes and their original purpose was pulse modulation of 
radars. Being able to run higher peak currents did make them super class 
C amplifiers capable of around 85% efficiency where other tubes did only 
75% or so.

I heard of one pair using a Collins KWS-1 as the cathode driver. Might 
have put out a bit more than FCC regulations allowed.

73, Jerry, K0CQ

On 6/18/2010 11:32 AM, Phil Chambley Sr. wrote:
> As I remember, the 304TH and TL had filaments that could be configured in
> either series or parallel, for 10v/12.5A or 5v/25A respectively.
>
> That filament transformer (prob 10v)might be useable in a good stiff 14v
> supply.
>
> Phil C. Sr.
> k4dpk
> ----- Original Message -----
> From: "Bill Harris"<w7kxb at msn.com>
> To:<tentec at contesting.com>
> Sent: Friday, June 18, 2010 12:21 PM
> Subject: [TenTec] TL or TH 304's
>
>
>>
>> Ray; WA4TT:
>> Sorry to state my long term memory is starting to fade somewhat as well,
>> however, if someone has an old edition of Editors and Engineers handbook
>> handy,(late 40's; early 50's), you will find in the "Audio/Modulation"
>> chapter a modulator using 304 TL or TH's in class A or AB. (memory fault)
>> That will settle which Mu is best.  I'll vote for the TL in RF service and
>> the TH in audio. I believe the TL's required a very "stiff" bias source
>> which may have discouraged many home brewers from using them. Zero bias
>> tubes were making the scene about then. The TL was also finicky above 20
>> meters but was doable.  Those old Eimac triodes were a beautiful sight
>> with their cherry red plates.  Also great for keeping the shack warm.
>> Later
>> Bill-w7kxb
>>
>>> From: Rsoifer at aol.com
>>> Date: Fri, 18 Jun 2010 10:37:20 -0400
>>> To: wa4tt at nlamerica.com; tentec at contesting.com
>>> Subject: Re: [TenTec] Orion AM ALC/304's
>>>
>>> John,
>>>
>>> Well, it was 50 years ago so I can't really be sure of anything!  As
>>> best
>>> I can recall, though, we had THs in the modulator and TLs in the Class C
>>> finals.  The exciter was a Collins 310B and the receiver an A-line, I
>>> believe
>>> a 75A-2.
>>>
>>> 73 Ray W2RS
>>>
>>>
>>> In a message dated 6/18/2010 3:26:42 A.M. GMT Standard Time,
>>> wa4tt at nlamerica.com writes:
>>>
>>>
>>>
>>> ----- Original Message -----
>>> From:<Rsoifer at aol.com>
>>>>
>>>> Yes, indeed.  We actually had  three pairs of P-P 304TLs, one pair
>>>> each
>>>> for
>>>> 80, 40 and  20.  The 2x 304TH modulator was, of course, switched
>>>> between
>>>> them. Those were the days.
>>>
>>> You fellows sure it wasn't  the opposite...... TL's modulating the TH amp
>>> ?
>>> My memory works once in  awhile.....  !!
>>> 73
>>> WA4TT
>>>
>>>
>>>
>>>
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