Curious, wonder why there was not a little (or a lot) more fanfare before they arrived on the market. Until I saw this post it had not registered that there might be a new manufacturer making 300Bs. (Maybe it is just another obscure branch of Shuguang, who knows...)
It is difficult to tell as I have not even seen recent Shuguang production, but from the lousy pictures on eBay there appear to be slight differences in plate structure. From what I can tell the Gui Guang appear well put together, but so did the Valve Arts 300Bs that failed very rapidly in my products about 9 yrs ago. (A lot will have changed in that time hopefully, but I have no recent experience)
Just some idle speculation on my part, I've been using JJ for quite a while now and not paying much attention to anything other than WE, KR and TJ..
It is difficult to tell as I have not even seen recent Shuguang production, but from the lousy pictures on eBay there appear to be slight differences in plate structure. From what I can tell the Gui Guang appear well put together, but so did the Valve Arts 300Bs that failed very rapidly in my products about 9 yrs ago. (A lot will have changed in that time hopefully, but I have no recent experience)
Just some idle speculation on my part, I've been using JJ for quite a while now and not paying much attention to anything other than WE, KR and TJ..
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hello Kevin,
I bet you're using the old sort of JJ300B too?
I love these, based on experience of 1998 manufacturing. Mine must have done thousands of hours - over ten years at my main listening station. Current driven filaments doesn't hurt lifetime! I looked at the getters recently and detected some 'early balding' signs. Uh-oh.
Have you heard any of the newer JJ productions? folks on here complained they were worse-built & worse-sounding a while ago.
Did KR ever fix their filament breakage problems, or is TJ the only item to compare to the old JJ?
I bet you're using the old sort of JJ300B too?
I love these, based on experience of 1998 manufacturing. Mine must have done thousands of hours - over ten years at my main listening station. Current driven filaments doesn't hurt lifetime! I looked at the getters recently and detected some 'early balding' signs. Uh-oh.
Have you heard any of the newer JJ productions? folks on here complained they were worse-built & worse-sounding a while ago.
Did KR ever fix their filament breakage problems, or is TJ the only item to compare to the old JJ?
Hi Rod,
I purchased my JJ 300B in 2001 sometime, but they may have been earlier production - I'm not really sure, but they do sound good and have been quite reliable.
Hi all...
I see big price differences between sellers on Ebay for this tube. Anywhere from $102 per pair to over $300 for a pair. Are these for different types or are they all the same basic tube, but with different bases?
Thanks, Daniel
I bought an amp in Guangzhou China recently while on a business trip with NGG (New Gui Guang) 300B's. They look to be assembled well, but as many have said... who knows.
I'll let you know how they work out. Recent Google searches are pulling up stupid money for these tubes. That doesn't mean they are good though.
About 10 years ago I bought some Sovtek 300B's and went through two pair in only a few months. the first pair, both filaments opened for now apparent reason. I checked my DC filament voltage and it was steady at 5VDC.
The online store I bought them from warrantied the tubes for me, and sent me a new pair. Before inserting the new pair of Sovtek 300B's, I doubled check the circuit, etc. All was ok. The new 300B's lasted about a month and the filaments opened up again.
I did not bother calling the online retailer again and through them in the garbage. I should have saved them just for bookshelf relics.
I modified the amp for 2A3's and have never had a problem. I don't think there was a problem with my filament circuit, but it was a strange incident with those Sovtek 300B's.
I'll let you know how they work out. Recent Google searches are pulling up stupid money for these tubes. That doesn't mean they are good though.
About 10 years ago I bought some Sovtek 300B's and went through two pair in only a few months. the first pair, both filaments opened for now apparent reason. I checked my DC filament voltage and it was steady at 5VDC.
The online store I bought them from warrantied the tubes for me, and sent me a new pair. Before inserting the new pair of Sovtek 300B's, I doubled check the circuit, etc. All was ok. The new 300B's lasted about a month and the filaments opened up again.
I did not bother calling the online retailer again and through them in the garbage. I should have saved them just for bookshelf relics.
I modified the amp for 2A3's and have never had a problem. I don't think there was a problem with my filament circuit, but it was a strange incident with those Sovtek 300B's.
The filament on the old sovtek 300B is much thinner than, say the JJ300B. It lights up quicker when heated with constant current.
Filament breakage is a real problem with much of the recent production DHTs, I hear that the Svetlana is worse than the Sovtek, and just about all factories have had problems with this. I think it is by far the biggest failure mode of 300Bs.
I just measured the cold-filament resistance of a 1998 Sovtek 300B and found 0.7 Ohms. With a high current secondary winding [ac heat], or large capacitors [dc heat] you get a 7A peak at switch-ON! This is not kind to the DHTs. Even high quality types will risk some mechanical distortion of the filament, and shorter life.
This is a quantified problem in the transmitter tube world, check out page 2 of
http://www.burle.com/cgi/byteserver.pl/pdf/voa.pdf
The solution is straightforward enough: use current-driven heating. A properly-implemented current heater starts the filament at normal operating current - no shocks or peaks - and it warms up very gently.
If that is not enough, You also get a remarkable improvement in the sound quality! we've been discussing current-heating at the 'New DHT Heater' thread for a while:
http://www.diyaudio.com/forums/tubes-valves/38248-new-dht-heater-5.html#post2336382
Current drive modules for DHT filaments are available from Tentlabs, or you can obtain my regulators in kit form - please PM for details.
Filament breakage is a real problem with much of the recent production DHTs, I hear that the Svetlana is worse than the Sovtek, and just about all factories have had problems with this. I think it is by far the biggest failure mode of 300Bs.
I just measured the cold-filament resistance of a 1998 Sovtek 300B and found 0.7 Ohms. With a high current secondary winding [ac heat], or large capacitors [dc heat] you get a 7A peak at switch-ON! This is not kind to the DHTs. Even high quality types will risk some mechanical distortion of the filament, and shorter life.
This is a quantified problem in the transmitter tube world, check out page 2 of
http://www.burle.com/cgi/byteserver.pl/pdf/voa.pdf
The solution is straightforward enough: use current-driven heating. A properly-implemented current heater starts the filament at normal operating current - no shocks or peaks - and it warms up very gently.
If that is not enough, You also get a remarkable improvement in the sound quality! we've been discussing current-heating at the 'New DHT Heater' thread for a while:
http://www.diyaudio.com/forums/tubes-valves/38248-new-dht-heater-5.html#post2336382
Current drive modules for DHT filaments are available from Tentlabs, or you can obtain my regulators in kit form - please PM for details.
Friends
I see some Guiguang 300B tubes in ebay.
The look of this tube is fine.
Anyone have experience com this tube ? Sound fine ?
FWIW I'm a "recent convert" to the black carbonized (or whatever it is) plate and gold pins one, I presume that's the one you mean. I luv 'em. Good value for money IMO. Though really needs something like Rod's CCS DC reg heater supply to get the best out of them IMHO. So far mine come from citiysystems88 on eBay (Hong Kong).
FWIW I'm a "recent convert" to the black carbonized (or whatever it is) plate and gold pins one, I presume that's the one you mean. I luv 'em. Good value for money IMO. Though really needs something like Rod's CCS DC reg heater supply to get the best out of them IMHO. So far mine come from citiysystems88 on eBay (Hong Kong).
What kind of 300Bs did you have before you bought the treasures? I've been thinking about getting some but need to hear more results for others that are using them. How wide is the soundstage by comparison to your other tubes?
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