|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
97.95.43.235
In Reply to: RE: 813 triode connection posted by vinnie2 on April 20, 2017 at 10:01:23
Vinnie
The 813 is a great tube but I use them in one of my AM modulators. I never thought of wiring them triode with 845s and GM70s out there in abundance.
Check out this AM modulator/RF deck. A pair of 813s have to be making 250w to 300w of audio drive a 500 watt RF deck to full power.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Follow Ups:
"A pair of 813s have to be making 250w to 300w of audio drive a 500 watt RF deck to full power."
That's true, but I'm pretty sure the circuit you posted isn't capable of that. The screens need positive bias for the tubes to produce full output.
--------------------------
Buy Chinese. Bury freedom.
I was wondering about that as well but we are limiting the bandwidth to 3khz and the bottom end is probably no more than 120hz which you would have to limit at the input.It looks like he took a standard tube output transformer and is driving G1 with it but I'm curious what impedance he used.You could put regulated DC on the screens but I'm not sure you would need to.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Edits: 04/22/17
Mikey
This amp started out as an 845 amp, but at an inmates's suggestion I tried the 813 and found I liked the sound of it better.
Edits: 04/21/17
...a "special" class B2 triode strapping. RCA shows same setup for 807s in TT5...good for 120W.
I did notice that as that's the way I did my stand alone 813 modulator.
Look at the Altec 260A amp. Notice the grid chokes in parallel with the 180k resistors.Notice the GNFB that feeds each tube of the same channel.I'm curios as to what the bandwidth is of what is probably an interstage trafo that is probably acting as a gain stage? I almost bought a pair of these but they were too heavy to move.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
I'd have more concern about the response of a 16Kohm OPT with insulation good for 1.8KV+. Wasn't the 260 pretty much a PA booster amp?
That schematic is missing a ground point between the two 10k pots at the final's grid choke.
The input trans is a K-241-D, and yes there is significant step-up in voltage.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: