I agree. I've had so so luck with the Chinese ones. They are nowhere
near the quality of the American made tubes. When America made lots of
tubes; I think we made the best tubes in the world. But, I'm a bit biased :)
73
Stan
KM4HQE
On 8/20/21 6:52 PM, Carl wrote:
> 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@ac0c.com>
> To: <amps@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@uky.edu>
>>> To: <amps@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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>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
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