any one here built the 805 SE ?

That tube is a positive grid, high Mu (50) tube. You have to drive it with a 7 watt amplifier as to use it as a single ended audio frequency output it is used in A2. An OPT of 6K to 10K with 1000 v on the plate will work.

Several schematics on the net, but the driver circuits are a lot harder to implement than they look.

805

RE: OPT Impedance is the least of your concerns, posted on September 24, 2016 at 23:16:24
lovetube Dealer Posts: 3008 Location: Melbourne Australia Joined: June 8, 2003	thanks

A2 Drive, posted on September 26, 2016 at 11:19:34
gusser Audiophile Posts: 3649 Location: So. California Joined: September 6, 2006	Take a look at the "Power Drive" circuit over on the Tubelab site. This guy has done a lot with power RF tubes for audio.

RE: A2 Drive, posted on September 27, 2016 at 10:21:03
Triode_Kingdom Audiophile Posts: 10048 Location: Central Texas Joined: September 24, 2006	Any amplifier with both tubes and FETs in the signal path is a hybrid. A2 can be also accomplished with tubes alone for those who prefer a purer sound.

Sure, but a lot more difficult with tubes (nt), posted on September 27, 2016 at 11:07:39
gusser Audiophile Posts: 3649 Location: So. California Joined: September 6, 2006	z

If the FET is set up as a follower, posted on October 2, 2016 at 13:54:39
Michael Samra Dealer Posts: 36118 Location: saginaw michigan Joined: January 30, 2005	I haven't found them have a negative influence on sonics so much.Technically Mosfets are nothing more than a heaterless pentode. "For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken

RE: If the FET is set up as a follower, posted on October 10, 2016 at 08:38:35
PakProtector Audiophile Posts: 12365 Joined: May 14, 2002	on that response Mike, I must refer you to your very own signature quote...LOL Douglas 1. there is no screen in a FET to keep the gate-drain capacitance out of Miller 2. Pentodes do not vary their grid capacitance based on the cathode-anode voltage. that'll do for now...:) Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

SET Asylum

any one here built the 805 SE ?

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