[Jukebox-list] Re: 6L6 tubes

[James Alexander]

Gentlemen:
With regard to the questions about replacing 6L6 tubes:
Audio output tubes should be reasonably well-matched in conductivity in order to maintain audio performance of an amplifier.  A badly-mismatched set will compromise performance and can put some amp circuitry (resistors, output transformer) at risk.    If you don't have access to a tube checker, the safe thing to do would be to replace the 6L6's as a pair and keep the one good one you have as a spare.
There are at least 6 (possibly more) manufacturers of vacuum tubes, distributed in the U.S., all of which are based overseas countries.                                                                                                                                                                   There is a Chinese-based company (not sure of the name) that offers a large catalog of audio tubes. They resell (and rebrand) them around the world via several marketing distributors under different names.   They tend to have a lot of quality control problems with their product.   Try to avoid any vacuum tubes that say "made in China".    U.S. manufacturer "Groove Tubes" purchases the Chinese tubes but puts them through another stage of testing/quality control before selling them.
Other manufacturers I'm aware of that offer good products are Sovtek and Svetlana (Russian made)   Electro Harmonix (Bosnian made)  Tesla, and Ruby.(Czech made)          An overseas manufacturer has recently begun to sell tubes using the old American brand name Tung Sol and English name Mullard.   I've had no personal experience with the new Tung Sol and Mullard tubes.
Any of the above companies are offering 6L6GC or 5881 tubes (same thing) at a cost range of $15-20 each.  They are offered through electronics parts houses and distributing companies that cater to electronics restoration artists,audiophiles and musicians
In this technician's opinion, there's no longer any value in paying the cost to seek out old American-made stock (i.e. RCA, GE, Tung-Sol, Ken-Rad, Sylvania, etc)   for these audio tubes.     It is necessary occasionally to turn to N.O.S. tubes to find certain tube types that aren't being replicated by the overseas tube builders.
Hope this helps,
Jim Alexander
 
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