Vision Music

[CU24]

Hi all,

I just want to say hello. I'm from Germany and I'm glad to find this nice place. I love e-guitars, good tube amplifiers and Jazz, Blues and Rock music. I also have much fun by repairing old tube amps and tube radios. My greatest wish at the moment is to own also a good jazz guitar some day .

kind regards
Arno

[MRDMV]

CU24 - Arno,

How do you locate replacements for old tubes? Thanks.

[CU24]

Hi MRDMV,

do you mean replacements tubes for old radio's or for tube amps ?

regards
Arno

[MRDMV]

Arno,

Old tube amps. I know where a good one is but my friend can't find a replacement tube. One of the tubes does not light up we unplugged it and cleaned the pins but I guess it's blown out. A few of the others glow. We live in California. A guy at a "fle market" who had a bin of old tubes said tubes from the early 1960s are hard to find.

[CU24]

Hi HDRMV,

nowadays, actually it should not be so a big problem to find the right replacement tube, because the tubes usually used in tube amps also of the early sixties are still available, at least in most cases. For example, preamp tubes like 12AX7,12AU7 or 12AT7 and 6L6, 6V6, 5881, 6CA7/EL 34 or 6BQ5/EL 84 powertubes for the powerstage, also perhaps a rectifier tube like the 5AR4/GZ34, EZ80/81 etc. But of course that depends on the specific brand / type of tube amp. Perhaps the tube amp of your friend is no common model and fairly rare, with some odd ball tubes used in it.
Could you tell me the brand of the amp and the type and specific name of tube , ( preamp-,poweramp-, rectifier tube) your friend is searching for.


Arno

[MRDMV]

CU24,

I'll see him after Easter. We'll pull the tube and see if we can find any numbers and I'll get you the make of the amp. More later.

[MRDMV]

Arno,

Thanks for the help. We found the name of the amp it's Traynor. We think it was manufactured in Canada. Four of the tubes say 5881 and three tubes say 12AX7A and there's a tube laying on its side on the bottom of the case (I think it's a spare) that says 6550. The one that we think is burnt out is 5881. It dusty back there should we get a vacuum cleaner and clean it out?

[CU24]

Hi MRDMV,

OK, i's a Traynor, not bad but it would good to know the exact name / type. I don't believe, that the one 6550, you found on the bottom of the amp, is a spare tube. It's also a beam power pentode, but with very different technical specs in comparison to the 5881. Don't use this tube, at least as long as you don't know the exact type of traynor amp.
If one 5881 is defect, as you say, you need at least one matched pair for replacement. If all 5881 are worn out, the better deal is to substitute all four tubes ( matched quartett or two duetts ). It's more expensive of course, but you will get the better sound ! Very important is not to forget biasing the amp. If you are not familiar with such technical stuff, you or your friend should do this by a good amp tech. It's no big deal, but as already said, it's very important for the right function and to get the best possible sound out of the amp. A wrong bias, for example way to hot, would end at least in very short tube life, bad sound and more worse perhaps kill the amp. to take the old dust away from the amp inside with a vacuum cleaner is a good idea. But please be careful. Tube amps work with very high voltages inside .
The big filter caps could storage the high voltage over days, although the amp is switched off. Always make sure, that the amp is not connected to the wall outlet, while working inside of the amp.

regards
Arno

[MRDMV]

Arno,

There's a chain store here in Sacramento called Guitar City and we took your counsel and asked a technician to install four matched 5881 tubes, clean the amp, and we requested to have the amp biased like you suggested. We can't beat the price since the amp was free. It had been laying around for years. We think someone moved and never came back for it back in the 70's. Your help is indeed generous. Take care friend.