[Amps] 572B/T160L tube class C

[Carl]

The Chinesw 572B and 811 (it is NOT a real 811A, not even close) are mostly 
all junk looking for a trash can. They sometimes let a good one sneak thru.

Best bet is to pay the freight for a real NOS Cetron or United Electronics, 
the only USA real manufacturer who private labeled them for others.




----- Original Message ----- 
From: "Jeff Blaine" <KeepWalking188 at ac0c.com>
To: <amps at contesting.com>
Sent: Thursday, August 19, 2021 10:33 PM
Subject: Re: [Amps] 572B/T160L tube class C


> How much service do you expect from a new set of tubes? It's one thing to 
> know "it can do it, if I want" - but then not actually need the 
> capability. It's another thing if you are saying "I want to run a 572b 
> 24/7 at full output."
>
> About 10 years ago I was working on a SB200 which was initially setup to 
> run RTTY. I did quite a lot of profiling of those using the Chinese tubes 
> of the era. Watching very carefully to respect the Pd max of the tubes, I 
> found a typical 25% drop in Po over about 100 hours of testing. The 
> testing was typically 3-15 minutes key down 100% carrier per interval. 
> Plus on-band rag chew, contesting & DX (this was pre FT8).
>
> Carl is about a million times more experienced than I am but I think maybe 
> the Pd spec vs. actual was a bit optimistic for the Chinese tubes I had 
> because this drop off seemed excessive. However my abuse of those tubes, 
> compared to typical ham use, was really bad. Also the SB200 positions the 
> tube horizontally which may be a factor as is the generally poor 
> circulation even with my augmented cooling.
>
> In the end, I abandoned the 572b and went with the GI7T which was an 
> excellent performer by comparison although it required quite a lot of 
> changes to the SB200. Unless there is a specific reason to use the 572b, 
> if I were building a high duty cycle amp in the future, I would probably 
> want to use a metal/ceramic type tube instead of a glass one.
>
> Good luck!
>
> 73/jeff/ac0c
> alpha-charlie-zero-charlie
> www.ac0c.com
>
>
> On 8/19/21 8:50 PM, Carl wrote:
>> That tube was designed for AM BCB service by Taylor but didnt catch on 
>> there or for AM hams as the T-160L in the late 50's.
>>
>> It was later bought by and designated the 572/T-160L for Unitrd 
>> Electronics alone.
>> They couldnt keep up with demand and sold production rights to Cetron who 
>> had a much larger production facility.
>>
>> UE then became the 572A and Cetron the 572B. The step top (shouldered) 
>> glass was Cetron and the round top was UE.
>>
>> At some point the T-160L was dropped for both.
>>
>> You may also find a 572B with the round top and the Cetron name, those 
>> were built by UE as the demand was even too much for Cetron alone at 
>> times....such as the SB-200 and the Clipperton L.
>>
>> I have examples of both (no Taylor T-160L) as well as other versions 
>> including OEM named such as Dentron, Waters, plus Raytheon, GE, and 
>> several others who did not build their own. The top shape ID's the 
>> source.
>>
>> I cant remember ever seeing an actual T-160L spect sheet or the tube.
>>
>> Carl
>> Ham since 1955
>>
>>
>> ----- Original Message ----- From: "Fuqua, William L." <wlfuqu00 at uky.edu>
>> To: <amps at contesting.com>
>> Sent: Thursday, August 19, 2021 8:56 PM
>> Subject: [Amps] 572B/T160L tube class C
>>
>>
>>> I am looking for full power data for the 572B/T160L operating ICAS 
>>> class-c CW and AM.
>>> The only thing I have found thus far is in an ARRL handbook, but it is 
>>> obviously the 811A specs.
>>> Not the full 160W plate dissipation specs.
>>>
>>> 73
>>> Bill wa4lav
>>>
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>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
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