[Amps] Re: Finals will not neutralize Just how good are

[Will Matney <craxd1@ezwv.com>]

Peter,
Although Svetlana and other foreign manufacturers claim that their tubes are 
direct replacements, under careful comparison, they have some slight 
differences. These include gain and interelectrode capacitance. When it comes 
to actual replacements, sometimes this throws the tank circuits and any other 
tuned circuits off (neutralization circuits). Some even need different bias and 
screen voltages like the 572B by Svetlana. The EL-519 by Svetlana is really a 
6P45 and is not a real 6KG6 or EL509-EL519. Svetlana does have a good tube as 
they were designed around military use where Russia didn't care to spend money 
for the them. I think you'll find that Svetlana will last as long as Eimac with 
about 1/2 the cost or less. You may have to do some tinkering though to match 
everything up.

Chinese tubes used to be terrible when they first come on the scene. If you get ahold of NOS Chinese tubes, you could get a bad one. If you get the newest imports, they are actually quite good. The reason being is the quality was so bad at first, nobody would buy them so they HAD to change them. Their 3-500ZG is as good as Eimac in my opinion now. They are making the 6146B, 6550, and several other audio tubes. I spoke to a manufacturer there about one year ago. I was asking them if they could build the 6LF6 again which they had before. They will do it but there was too large of a minimum order for myself to swallow. The 6LF6 could be used to replace about every 12 pin compactron sweep tube ever made! All those old Yaseu 101-B's with the 6JS6 could cross to them also. I wish that at least one importer that had the capital would get these, they could make a fortune. I have had good experiences with the new 4CX250B's and 3-500ZG's that come out of China also.

Keep in mind that there is still a good stock of U.S. made NOS 6146B's  yet. The price is a little steep but if that's what you want, they're there.

The truth about what caused all of this was due to one company. Richardson Electronics bought the last vacuum tube plant which was G.E., located in Owensboro, Kentucky. They done this without any fan fair in the news. Without any warning, Richardsons stopped all the manufacture of glass tubes and made MPD (formerly G.E.) do microwave, and military tubes strictly. It left everyone holding the bag who was using them. They were the very one who started raising the prices across the board to all these high prices also! Keep in mind that Richardson also owns the majority of Eimac and Amperex as I understand it. Talk about a monopoly that the U.S. Government allows........

Will Matney
US Amplifier

"The subject line says it all. I've read a few posts that cite problems 
with stability and parasetics pronlems with foreign tubes.. I have a FL 2000 that I would like to retube but I'm afraid....... I sure would not want to 'test' these tubes in my beloved TS-820....this my 'Baby' among my 7 boatanchors!Anybody have firsthand experience with these tubes?
What about the Chinese 6146's...I've heard  things not soo good.
I think that I'll go the 6883 route . I don't mind modifying the  
transceiver a bit.....after all I bought it to transmit not to sit in a 'Collection' .   My wife uses her antique furniture in the house ....I use my  boatanchors or they won't stay here. I'm not running a museum. Those electron have to move in my shack!
73's
VE2FAR
Peter"

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