Hope someone can help. I recently purchased a pair of rare (50 pairs made) Antony Michaelson mono tube amps (Chronos). There are 2 tubes on the input/driver board. One is a 12AT7 and the other is an unknown GE brand. This tube is slightly taller and has 2 grid plates at the top with no halo. Is there a way to identify this tube with no markings? A third part suggested it is a 12BH7, but how can I be sure? thanks in advance for any info, Rispoli
http://www.diyaudio.com/forums/showthread.php?s=&threadid=37414
http://www.diyaudio.com/forums/showthread.php?s=&threadid=85943
http://www.diyaudio.com/forums/showthread.php?s=&threadid=14116
You might get some info from the above threads.... you could also contact Musical Fidelity
dave
http://www.diyaudio.com/forums/showthread.php?s=&threadid=85943
http://www.diyaudio.com/forums/showthread.php?s=&threadid=14116
You might get some info from the above threads.... you could also contact Musical Fidelity
dave
GE tubes usually have a large etched number... occasionally faint, but pretty durable. 12BH7 or 6CG7 seems most likely, but 6829 and 6414 are tall like that too... pinouts are same as 12BH7, but heater current is different.
Bring one over, and I'll plug it into my tester. I live in Macedon, work in Henrietta... not far from you.
Bring one over, and I'll plug it into my tester. I live in Macedon, work in Henrietta... not far from you.
That tube looks exactly like the 12AZ7N that Angela is selling. You'll find lots of 10 of them for sale on eBay.
If it really is a 12AZ7N, there's a vague reference to it here:
http://db.audioasylum.com/cgi/m.mpl?forum=bottlehead&n=68891
I've found it very difficult to turn up much info on this tube. I can't figure out if it is most like a 12AZ7, a 12AT7, or a 12AV7.
Here's a couple photos of one of the tubes from the lot of 10 I bought. Does your tube look like this? It appears to have a D shaped getter. There are no identification markings of any kind on the tube.
By the way, one of mine has a tiny piece of glass running around loose inside.
If it really is a 12AZ7N, there's a vague reference to it here:
http://db.audioasylum.com/cgi/m.mpl?forum=bottlehead&n=68891
I've found it very difficult to turn up much info on this tube. I can't figure out if it is most like a 12AZ7, a 12AT7, or a 12AV7.
Here's a couple photos of one of the tubes from the lot of 10 I bought. Does your tube look like this? It appears to have a D shaped getter. There are no identification markings of any kind on the tube.
By the way, one of mine has a tiny piece of glass running around loose inside.
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