talking of high gm pentodes, i used a russian 6j9(6688) in my EL34 amp in a citation5 topology and results were very nice indeed...
Hi Tony,
Did you modify the phase splitter?
Regards
M. Gregg
How well this driver would work if this circuit was built as is but with PPP..
4 tubes per channel?
Or with UL option..
Paralleled 6L6...THAT is a 6550!!! Actually I already have a 4A filament xfmr for the changeover on my Cit 5 to 6550s. The high-S 6BN11 (about 60-70% higher transconductance than the older 6CG7) is easily able to drive the 50K grid return resistors required for 6550s. As far as UL is concerned check out my 'strategy 100' amp on fleabay. It has the MESA opt's, running 6550s and the 6BN11 front end. There are scope pix
4 tubes per channel?
Or with UL option..
Paralleled 6L6...THAT is a 6550!!! Actually I already have a 4A filament xfmr for the changeover on my Cit 5 to 6550s. The high-S 6BN11 (about 60-70% higher transconductance than the older 6CG7) is easily able to drive the 50K grid return resistors required for 6550s. As far as UL is concerned check out my 'strategy 100' amp on fleabay. It has the MESA opt's, running 6550s and the 6BN11 front end. There are scope pix
Hi Tony,
Did you modify the phase splitter?
Regards
M. Gregg
no, but i used the 6CG7 as LTP splitter instead...
This driver reminds me of this idea: New Phase Splitter
Was something like this the motivation for it? How much gain does it produce? What kind of output swing and how clean is it? Got any numbers?
Was something like this the motivation for it? How much gain does it produce? What kind of output swing and how clean is it? Got any numbers?
^i would like to try that sometime in the future...ihave some 6U8's lying around...
http://www.diyaudio.com/forums/tubes-valves/23099-phase-splitters-constant-current-sources.html
http://www.diyaudio.com/forums/tube...ngly-low-distortion-radford-based-design.html
http://www.audiokarma.org/forums/showthread.php?t=207019
http://www.diyaudio.com/forums/tubes-valves/23099-phase-splitters-constant-current-sources.html
http://www.diyaudio.com/forums/tube...ngly-low-distortion-radford-based-design.html
http://www.audiokarma.org/forums/showthread.php?t=207019
At the end of the article the author says he wishes he had a dual video pentode, well a 6BN11 sounds close to me. I think the dual pentode diff driver in this thread is what he may have been thinking about. I will give it a try. I'm buying test equipment to round out my lab. BTW, off topic, Tony I could/should have hooked up with you, I was in Muntinlupa City for two weeks, I just got back this Saturday. I will be back in 9 months, I hope.
yest, there are lots of tee-vee tubes out there that needs some serious considerations...right now i have a 12AV5 and a 6HF5 pp amps in the works using the 6BH11 tube....
hitachi_nut was at my house the other day, he's from Canada on a visit here, there's another guy from Mandaluyong and he has signified intentions to drop by my house sometime soon...
hitachi_nut was at my house the other day, he's from Canada on a visit here, there's another guy from Mandaluyong and he has signified intentions to drop by my house sometime soon...
Well it is the first time I've seen a person use a pentode diff stage. The link I posted mentioned reasons why someone should do it but I guess most tube amp people would rather stick with what they've seen a 1000 times than something new. I hope in the next few weeks I can breadboard this and test it.
i am one who is not afraid to try out something new....
please look here: http://www.diyaudio.com/forums/tubes-valves/151206-posted-new-p-p-power-amp-design.html
please look here: http://www.diyaudio.com/forums/tubes-valves/151206-posted-new-p-p-power-amp-design.html
3 advantages of running a pentode drive stage:
1) Large voltage swing (tube manual sez use pentodes where a large swing is required)
2) High Gain; allows fewer stages to be used; avoiding instability.
3) High plate resistance allows effective local feedback from output stage
When you run a long tail splitter the 2nd harmonics are suppressed, and...
the pentode characteristics of the drive stage complement the output stage
1) Large voltage swing (tube manual sez use pentodes where a large swing is required)
2) High Gain; allows fewer stages to be used; avoiding instability.
3) High plate resistance allows effective local feedback from output stage
When you run a long tail splitter the 2nd harmonics are suppressed, and...
the pentode characteristics of the drive stage complement the output stage
I like the wide bandwidth of the pentode driver. I am also a fan of fewer stages permitting less phase shift in the feedback loop. Dollar each is nice too. related question, as far as equivalent input noise and distortion at abt 40V rms, would an EF86 or some other pentode be a better choice? Forget about the cost and extra bottle.
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