I just mounted the "guts" of a new Pro Junior in my custom wood PJ cabinet. I bought new tubes from Eurotubes awhile back and was just about to install them but there's a problem.
If you're looking at the back of the amp there are 4 tubes. From left to right:
1: a tall tube
2: a tall tube
3: a short tube
4: a short tube
Eurotubes sent me two JJ EL84's. Those are the tall ones so I know where to put them. There are two small JJ ECC 83 S's and one says (as sticker they put on the cardboard "Balanced Tube for Phase Inverter." Written in pen is "114" then next to it "115." Does this go in slot 3 or 4? I'm not installing it until I get advice because I don't want to ruin the tubes or (worse) amp.
"Nothing...can take the place of persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts."
Dennis
It would not ruin your amp or the tubes if you got the two preamp tubes switched, it just might not sound as good as if you got them correct. You may get a little noise. But it will not hurt anything. Both tubes are still ECC83Ss.
At Eurotubes Bob says the phase inverter is V3. Looking at your amp from the rear, you have the two power tubes on the left, and the two preamp tubes on the right. V3 should be the inner preamp tube right next to the inner power tube.
Send Bob an e-mail, he answers quickly. He will tell you the answer for sure.
If you know something better than Rock and Roll, I'd like to hear it - Jerry Lee Lewis
There are two sections called triodes which are intended to have equal electrical performance characteristics. It's two tubes in one. When you have "Matched Sections" tubes you are getting the assurance that every triode section in every tube will be as closely matched as possible, making it balanced.
However it is possible to get "matched" pre-amp tubes that are not balanced, meaning two tubes may match each other but their own halves are not identical.
joe
