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Tubes Asylum Questions about tubes and gear that glows. FAQ |
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Tubes Asylum Questions about tubes and gear that glows. FAQ |
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In Reply to: Nothing close to mu=20, plenty of mu=8 posted by andy evans on March 18, 2023 at 03:23:11:
I'll both agree and disagree with Andy on this . . .
Based on his suggestion, I've been using the Hammond 1140-LN-C as a step up in my direct coupled breadboard project that uses all DH tubes and they work great!
Bought the first pair in the US. Best price was from a Chicago dealer and they were just over $100 each shipped. I liked them so much that I ordered 6 more from KGA Enclosures in England, which Andy suggested in a post on DIY Audio. Cost, including shipping, was $45 each and they arrived in two days! THANK YOU ANDY!
But there ARE some DHTs that have mu that's similar and even higher than the 6J5. Whether or not they'll work well as subs, I don't know. Most of them are, however, "battery types" which have reputations for being microphonic. And some of their other characteristics may also be problematic, such as low transconductance. I'm not knowledgeable enough to analyze their suitability for any particular application.
One is the 2J27L, which is a sister tube to the 2P29L. It supposedly has a mu of ~16 in triode vs ~8 for the 2P29L. It's the tube used in the little Nobsound E6 preamp, which is the only mass produced preamp I've seen that uses DH tubes. I breadboarded the 2P29L a while back and started a thread about it on DIY Audio. So for $60 shipped I couldn't resist giving the 2J27L a try and I've been pleasantly surprised. The Chinese tubes that it ships with are sometimes horribly microphonic but using the Russian ones seems to solve the problem. Details in the link below . . .
Some others are the 1H6G / 1B5, which is a single DHT with a pair of diodes. Mu is 20, just like the 6J5. The 1G6G / GT is a dual DHT with a mu of 30. The 4A6G is another dual DHT with a mu of 25. And the 40 is a single DHT with a mu of 30. Unlike the others it has a 5v filament but transconductance is extremely low at 200.
So there are 5 options for you to investigate . . .
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Follow Ups
- RE: Nothing close to mu=20, plenty of mu=8 - FlaCharlie 13:31:49 03/18/23 (2)
- Well, yes, some odd DHTs with higher mu - andy evans 02:53:55 03/19/23 (1)
- RE: Well, yes, some odd DHTs with higher mu - FlaCharlie 06:50:36 03/19/23 (0)
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