Hi.... I recently got a really clean 1978 JMP 2104. The guy I bought it from changed all the tubes, and gave me the preamp tubes that were in it. Ones a newer JJ ECC803S, but the other 2 are identical and have no logo. I’m thinking they may be original... can anyone advise? I know the pictures are a bit blurry so I made a short video.
That’s what I thought. I’ve got two of them... one has a 56 on the foil tag. I’m not sure if they’re any good...
The number at the getter is apparently what identifies it as a Hungary made tube. You can also find them with the Haltron branding, and I have one that has the number missing although same construction. Only way to really know if they're good is by testing them. My experience is that is 90% of cases the old "vintage" preamp tubes measure as good as new. As long as they are not microphonic, or give hum or noise, you can be sure they'll outperform current production tubes. It's one of my guilty pleasures, buying cheap 60s-70s tube amps and pull out the tubes, exchange for JJ and sell them on.
Well, this JMP needs bias caps replaced at least, so when I go to the tech I’ll have him test these. Saw the boxes of the new tubes he put into the back of the amp when I bought it but had no idea they had tubes in them. He replaced the two tungsram and the JJ ecc803s with standard JJ ecc83. I’ve already pulled two of them out... put a tung sol 12ax7 in v1 and the ecc803s in v3.
Put them back in and see what you like best. I would say put them in V1 and V2, and see which tube you like best in the PI
I have tube testers and i can assure anyone that irregardless of how the tube's test results come out the sound can not be determined by the numbers. The only way to know is to use it in circuit. So my advice to those who may be considering throwing big bucks at old tubes would be to approach this very cautiously.
I'm not sure why you're saying this, as the OP is just wanting to know what the tubes that were already in his amp were. He wasn't buying old tubes. Al
Yup.........I had an old dark at the base high milage I61 mullard in V1 of my 2210 a few years back........Bought a strong testing clear glass pretty I61 as a spare on ebay....and it sounded like poo. I buy cheap used on ebay and if I like um.........then I buy spares from KCA Brent Jessee or a couple ebayers I have come to trust.