tube matching is the source of a lot of controversy

you can match tubes on transconductance, plate current, or several other
factors

there are even well respected experts who feel that the best sound comes
from tube pairs that are somewhat un-matched (R.G. Keen, for example)

JJ/Tesla tubes are a best buy, but I would also say that SED "winged C"
sound as good or better, and are just as good of a buy, perhaps even a
better choice.

I recommend you test the tubes you already have on a calibrated
transconductance tube tester i.e. Hickok, TV-7D/U, etc.

the ones already in there may be better made and better sounding than
anything you can buy new, if they are not worn out

don't worry if they are not "matched", or of different manufacture, as long
as they are similar in their transconductance characteristics and condition,
they will be great

tube "matching" is way overrated

tube biasing is what you want to worry about!
now that IS important!

PS - examine the tubes carefully, the best tubes typically have welded
(soldered) plates, and opposed to stapled plates
if you can determine the original country of origin, that is another good
indicator
my order of preference - britain, germany, russia, czech republic,
yugoslavia (avoid usa and chinese EL34)


"Jim Stewart" wrote in message
...
This weekend I rescued a beautiful old Dynaco
Stereo 70 amplifier from the dumpster at the
recycling center. It's in good shape, but the
output EL34's are of all different manufacture.

I'd like to get 2 sets of matching pairs for
replacement. I take a look on ebay and there's
a zillion people selling matched pair EL34's.

How do I know that they are truly matched?
There's never any statements about how they are
matched. For all I know, "matched" means the
same manufacturer.

On one website I looked at, the writer suggested
matched Tesla EL34's for good performance at a
reasonable cost. Any opinions on this? Where
can I get two pairs?