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Old 27th January 2013, 11:18 PM   #81
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The GreenValve use the 828 Triode as driver and a battery PSU:
Greenvalve Audio Luddite Maxim GM70 Monoblocks - YouTube
Seems there is a Interstage trafo:
A low voltage GM70 / ??70 amp GREENVALVE AUDIO
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Old 27th January 2013, 11:45 PM   #82
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P.S.: A local hobbist tested various drivers tubes and told to me the 6J9P(E180F) when used as Triode is a better sound than the 6N6P, much more detailed.
He also like the EF184 as Triode.
I wonder why builders like use Pentodes straped as Triodes to Drive?? Maybe hi Transcondutance??
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Old 28th January 2013, 12:17 AM   #83
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Quote:
Originally Posted by FullRangeMan View Post
P.S.:
He also like the EF184 as Triode.
Yes, and I used 6J51P in triode mode driving Gu-50 in last Pyramid prototype.

Quote:
I wonder why builders like use Pentodes straped as Triodes to Drive?? Maybe hi Transcondutance??
In the previous Pyramid I used 6P15P as pentodes, in the same position to drive Gu-50.

I can't tell which is better, both worked equally well. In both cases I used nested fedbacks, including from anodes of Gu-50 to anodes of driver tubes.
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Old 28th January 2013, 10:33 AM   #84
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I forget to ask my friend what type of 6N6P he tested, as there is the ''impulse''(6N6P-i) model, which seems not suited to hi-fi.
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Old 28th January 2013, 10:58 AM   #85
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Quote:
So, how Lampizator do it??
MALPA a owner of this Lampizator GM70 amp informed the sound quality is great:
Lukasz uses the 6N6P as a cathode follower to drive the GM70. Which is a different application. Enzo is looking for a single tube which can do it all. I.e. provide gain and drive. The Lampizator uses the 6N6P essentially just for the "drive".
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Old 28th January 2013, 11:31 AM   #86
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Originally Posted by Bas Horneman View Post
Lukasz uses the 6N6P as a cathode follower to drive the GM70. Which is a different application. Enzo is looking for a single tube which can do it all. I.e. provide gain and drive. The Lampizator uses the 6N6P essentially just for the "drive".
Ops I missing this important detail, Thanks.
In this case seems only a pentode will do this herculean task.
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Old 28th January 2013, 11:36 AM   #87
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And the 6c45pi!

Still not sure i'd use a 6n6p, perhaps a tube with higher gm and mu would deliver lower distortion and lower drive impeadance even before you think about its intrinsic distortion.

Ala wavebourn and 6j51p.

Though perhaps it just sounds good there?


enzo
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Old 28th January 2013, 12:20 PM   #88
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Quote:
Originally Posted by Bas Horneman View Post
Lukasz uses the 6N6P as a cathode follower to drive the GM70. Which is a different application. Enzo is looking for a single tube which can do it all. I.e. provide gain and drive. The Lampizator uses the 6N6P essentially just for the "drive".
Hi again,
I wonder if Cathode Follower is the same circuit named Mu Follower??
Thanks
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Old 28th January 2013, 12:35 PM   #89
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Originally Posted by FullRangeMan View Post
So, how Lampizator do it??
MALPA a owner of this Lampizator GM70 amp informed the sound quality is great:
Lampizator GM70 amp
Wow, the Lampizator guy GLUED the capacitors to the top plate. And he is asking 4000+tax for that mess!
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Old 28th January 2013, 12:39 PM   #90
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The top element of a tube mu follower is a cathode follower ac coupled to a normal triode stage beneath it, but with a load resister and cathode follower bias resistor between them. R load to the bottom tube is ~top tubes mu x load resistor and R out is ~ 1/gm of top tube, same as cathode follower. you could use a dc cathode follower after the gain stage and do without a coupling cap but the gain stage then doesnt have the high load impeadance and thd goes up. i suppose you could have a ss ccs on first tube and dc couple to a cathode follower..?
Or use a gyrator and take the mu output :-)
enzo
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