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Re: [Amps] SB-200 DATA

To: "Roger" <>, "Tom W8JI" <>,<>
Subject: Re: [Amps] SB-200 DATA
From: "jeremy-ca" <>
Date: Thu, 19 Jul 2007 17:19:45 -0400
List-post: <>
Ive been providing Chinese tubes in several of the SB-200 and SB-220 6M 
conversions plus other brands plus repairs to HF amps. No reported problems 
in the past 5 years or so. That doesnt mean they will last 30 years either.

The Chinese transmitting tube industry is nowhere near as complex as 
automotive/shop tools. You can count on one hand the factories involved and 
have a finger or so left over. A lot of the bad ones have gone away or 
switched to small audio tubes.


----- Original Message ----- 
From: "Roger" <>
To: "Tom W8JI" <>; <>
Sent: Thursday, July 19, 2007 4:40 PM
Subject: Re: [Amps] SB-200 DATA

>> Im quite aware of the 80's problem. I was reselling Eimacs from CeCo,
>> Richardson and 1 or 2 others before Richardson got it all. I even
>> continued
>> with Richardson for a few more years until I sold off Radio Kit.
>> I also had experience with those black base Russian 811's that Ameritron
>> started with. I got a lot of repair jobs from those. I still have a pair
>> as
>> modulators in my Clegg Zeus where they are running well below ratings.
>> They
>> and the Chinese used receiving tube glass. I havent melted any lately!
>> I would hope that for the past 15 years or so Ameritron is using quality
>> tubes from Eimac that have good life expectancy or is everything now
>> coming
>> from China?
> I recently decided to try a pair of the Chinese 3-500Zs just to see how
> they'd work compaired to the Eimac pair I have in the 2K4. So far they
> *appear* to be working well with the same output as the Eimacs, but only
> time will tell. Like other things, one pair is not enough for much of a
> comparrison let alone data for an anaysis.
> I think I'm going to cheat and take the easy way out and go with the Tokyo
> HL-1.5Kfx, or the HL-2.5Kfx. Unfortunately with either one I have to give 
> up
> something.  The 1.5 runs 1000 PEP out on HF and 650 on 6-meters while the
> 2.5 is the legal limit on HF, but no 6-meters. The 2.5 is just a *tad* 
> more
> price wise too<:-)) Then I still need to comeup with an amp for 6-meters.
>> One would think that ALL manufacturers would band together and push China
>> to
>> produce to original performance specs. The automotive tool industry has
>> done
> The auto industry is a far larger pool than the portion of the electronics
> industry that uses this range of power tubes though.  Time will tell.
> 73
> Roger (K8RI)
>> this, including factory visits, and the quality from many factories is
>> excellent. Ive placed several items on Snap On and MAC Tools trucks and
>> get
>> regular repeat business.
>> Carl
>> KM1H
>> ----- Original Message ----- 
>> From: "Tom W8JI" <>
>> To: <>
>> Sent: Thursday, July 19, 2007 10:08 AM
>> Subject: Re: [Amps] SB-200 DATA
>>>> I buy around 50 a year and many still have original
>>>> 60's-70's date code
>>>> tubes and put out full power. I dont think that you will
>>>> ever see an
>>>> Ameritron or Alpha running that long on original tubes;
>>>> they push them a lot
>>>> harder
>>> That life part is true, but the reason you give is not.
>>> The fact is today we cannot buy tubes that are anywhere near
>>> as good or reliable as those made back in the 60's and 70's.
>>> Around the late 80's it really all started falling apart. In
>>> the mid to late 80's 8877's from Eimac were nearly all bad
>>> brand new (tube failures in MRI equipment nearly put ETO out
>>> of business) and Richardson's swallowed up Cetron and the
>>> rest.
>>> When Ameritron started producing the AL-572B they made a
>>> mass purchase of Svetlana 572B's, and the majority of new
>>> tubes were bad (and old) right off the shelf. The only
>>> alternative, largely due to Richardson's swallowing up all
>>> the manufacturing and pricing 572's out of reach, were
>>> Chinese tubes. The Chinese tubes were tested only at 1500
>>> volts or so and a few hundred watts, and the glass and other
>>> materials were far substandard to the old Cetron's.
>>> I can take 35 year old Cetrons that have been sitting up on
>>> a shelf and the majority high-pot to 8 or 9 kV, but about
>>> 50% of brand new Chinese 572B tubes fail at 5kV or less.
>>> The real truth is no matter how you run most modern tubes,
>>> the life on average won't be anywhere near the life of tubes
>>> before all the people who knew what they were doing retired
>>> or got fired.
>>> The problem doesn't stop at the food supply, anything that
>>> requires extraordinary care (like tubes) isn't as good as it
>>> was. That's the real reason.
>>> 73 Tom
>>> _______________________________________________
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