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.
Carl
KM1H
----- Original Message -----
From: "Roger" <sub1@rogerhalstead.com>
To: "Tom W8JI" <w8ji@w8ji.com>; <Amps@contesting.com>
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" <w8ji@w8ji.com>
>> To: <Amps@contesting.com>
>> 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
>>>
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|