| Author | Message | ||
     Michael Kaus |
Just thought I would give you guys a report first hand on the JJ's now that they have been in a while. THey sound great, but they, like a lot of new production seem to have a short life. These tubes have been used in a 210-65 combo amp biased at 15mA cold idle and ran for a year and now are microphonic as hell and will be replaced. They do sound great though and are REAL reasonable-like $29.00 a pair at EUROTUBES, so I guess if you are using them a lot(two jobs a week for a year like I did), it's a good deal. Mike | ||
| Steve Kennedy |
Actually, it isn't the electrical "tube life" that has suffered, it is "tube usability" for this application. The tube's internal construction isn't as robust as the original tubes. Vibration and physical shock have loosened the internal elements of the tube, making them microphonic. This is less of a problem with amps that are never moved, never played loud for long periods, never physically abused or heads that are not placed on top of the cabinet they are driving. It is nice to know you didn't see any electrical failure of the tubes due to the elevated B+ voltage they are run at in the MM amplifiers. The only thing you can do to minimize this sort of problem is to isolate the tubes from as many sources of vibration and physical abuse as you possibly can. | ||
| michael kaus |
I have since boosted the cathode current to 21mA and have used them like this for six months and they show no signs of letting up. They have not gone micro after a year like the first set, so they seem to be holding up well at the higher current They do get rattled physically pretty hard, since they are in a 2-10 and it's really tight in here. They also sound great at 21mA and haven't smoked. | ||
| Steve Kennedy |
That's nice to know...the factory setting of 15mA is a bit on the cold side, but the tubes last forever. At 21mA, perhaps the output tubes might generate some heat and only last 10 years instead of 20! | ||
| Anonymous |
Can I use a matched set of NOS Mullard EL34's in my 212-65? It has the 12AX7 PI tube in it. | ||
| michael murphy |
hello ive just got a music man 210 75,the tube replacment sticker in the amp says 2 el34, but their are 2 6l6s ,how does this amp run with the el34s as compared to the 6l6s,this is a 2 channel unswithcable amp with a master volume on channel 2 and a phase shifter and reverb,can you tell me more about this amp,.t/y | ||
| Anonymous |
Michael, that topic is discussed in this thread. http://www.pacair.com/discus/messages/23/ 63.html?1074130388 | ||
| carl. |
just a quick question, how do i tell the diff between jj el34 and jj el34 L's. Cheers. | ||
| mike kaus |
They SHOULD be marked on the tubes. Other than that, if they're not marked, I really don't know any way. | ||
| carl. |
cool thanks mike, ive spotted some blue bottles ones, they come like that? | ||
| mike kaus |
Yeah! I've thought about ordering some. They come in blue AND red! No difference in the tube, they just look cool. Eurotubes has them at least. | ||
| Jeremy Shaw (jemshaw) Username: jemshaw Registered: 09-2006 |
Hi Im living down under in the land of Oz renovating an old MM 210 with the 12 ax7 and looking for the much discussed JJ EL34L tubes, the ones I have found are jj marked e34L ? are these one and the same? Also any thoughts as to what sort of replacement 12ax7 tube as I gather these should be robust. This site has been a lifesaver (at least for my old amp) cheers | ||
| Mike Kaus (mm210) Username: mm210 Registered: 05-2006 |
Those are the right tubes. The designation is actually E34L. THey should be biased a little on the cool side-around 22-23 ma PER tube. THe 12ax7a Should be a good one. I haven't had any complaints with the JJ ECC83's but this is also a good place for a good old NOS Sylvania or RCA!. |