Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Coastie99 on September 10, 2010, 08:23:42 pm
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I can't see where else this might best fit, so here goes.
I have some old 6L6G's that are of little use to me, and somebody has expressed an interest in them. I could not, in good faith, sell them if they're of poor quality.
They are a Philips ( USA ), Transvision, Ken-Rad, and RCA.
Now, the RCA I know about, but the others are largely unknown to me. Am I right in my assumption that these are "other manufacturers" re-branded valves ? And, of good quality ?
I should add that they have all been tested, and all test "as new" although they are not necessarily NOS.
Thank you,
Gary.
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Well, RCA's seem to command the highest price on the used market, and thus would seem to be the most desired.
I have always had great luck with Sylvania tubes. The garage of doom yielded a considerable pile of NOS JAN Sylvania 6L6GA which I plan to match in the matcher I am building and will theoretically finish one of these days. Also a pair of RCA 6L6G and a pile of metal 6L6s. Those can go into power supplies as pass elements. There are 2 or 4 of them in parallel and they can be weakish, emission wise, with no worries. Long as they aren't gassy and don't short out!
Ken-Rad = GE, unless you are talking very, very old.
Never heard of Transvision.
I am not that sure what you are worried about. If they test as new, or very good, state that they test very good, and that's that. Hey, you can buy brand new Russian 6L6GCs for $5 each and have them turn out doggy.
There is NOTHING wrong with rebranded tubes. ALL manufacturers rebranded some types, yes, even the mighty RCA.
Perhaps the larger concern is that 6L6G are theoretically not capable of taking the highest of high voltages in an amp designed for a 6L6GC or GB. Dissipation wise, they are nearly as good, but IIRC their ratings are 100 volts lower than GC's.
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Thank you Eleventeen.
I know that there's not necessarily anything wrong with re-branded valves, just curious to know what these are likely to be.
Your comment re. power handling is appreciated, thank you.
Gary.
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Hello,
I have some old 6L6GA that I just love. And they sure look cool with the big coke bottle shape.
Specs sheet reads 360V max plate voltage, and 19W max plate dissipation, so they're quite different from the newer 6L6GC. They work GREAT in tweed amps though.
Put them in an old Tweed Pro and see for yourself.
Best!
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Usually on old tubes and most items other than resistors and caps there is an EIA date code.
It can tell you the manufacturer and the date made.
its 6 or 7 digits. the first 2 or 3 tell you who. the next number gives the last digit of the year 1951,1961 and 1971 all just have a 1.
the next 2 digits are the week of the year manufactured.
good info here http://www.webervst.com/codes.html
click the link to "Codes for Manufactures of Other Products" to view RCA's Mfr code of 274
My Ken Rad 6V6's were RCA made
Ray
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Never heard of Transvision.
Transvision was an early TV manufacturer. Thay resold OEM'ed tubes.
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Usually on old tubes and most items other than resistors and caps there is an EIA date code.
It can tell you the manufacturer and the date made.
its 6 or 7 digits. the first 2 or 3 tell you who. the next number gives the last digit of the year 1951,1961 and 1971 all just have a 1.
the next 2 digits are the week of the year manufactured.
good info here http://www.webervst.com/codes.html
click the link to "Codes for Manufactures of Other Products" to view RCA's Mfr code of 274
Thank you Ray. A very interesting reference page.
Gary.
My Ken Rad 6V6's were RCA made
Ray
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Usually on old tubes and most items other than resistors and caps there is an EIA date code.
The full EIA source code database is available thru the ECA web site: http://www.ecaus.org/engineering/sourcecodes.cfm