|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
71.29.35.241
In Reply to: RE: 813 triode connection posted by Tre' on April 20, 2017 at 11:10:20
Opps. You are right, the signal comes in at G2. Ok, looks like everything is as it should be. Thanks Tre. I will plus up my schem.
Follow Ups:
The signal comes in at G1, the control grid (pin 4)
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Actually, on mine the signal comes into G2 (pin 3) and then goes to to the plate through the connection of pin 3 to the plate knob via the 200 ohm resistor. As I said earlier, G1 (pin 4) goes to ground through via a 30k resistor. All four 813's are wired this way and the amp seemed to be working fine in bread board mode. This is what I have on the schem, I will have tso check in the morning and see how it is actually wired on the bread board.
"the signal comes into G2 (pin 3) and then goes to to the plate through the connection of pin 3 to the plate knob via the 200 ohm resistor."
So the input signal is connected to the screen, which is in turn connected to the anode through a 200 ohm resistor? Are you sure that's how it's wired? Don't see how there could possibly be any gain in that configuration.
--------------------------
Buy Chinese. Bury freedom.
See reply to Tre's post below. Mislabeled schem.
Is this your design?
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Sort of. It all started with Willie's 26/26/45 SE amp (which I built and still have) and then I decided to try the same idea with the 845, but try to use sukumos idea of an 845 driving an 845 and ended up using the 813 instead. I also wanted a low voltage amp as I don't like playing with high voltages. The design is not a formal one, trial and error mostly. If you look at Mikey's last post above, my 813's are connected the same as the one on the upper right in his schem except for pin 3 beginning also connected to the plate via a 200 ohm resistor.
Edits: 04/21/17 04/23/17
"If you look at Mikey's last post above, my 813's are connected the same as the one on the upper right..."
That input connection is correct.
The signal is applied to G1 (pin 4), not G2 (pin 3).
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Checked the breadboard and it is wired correctly. I think I must have redrawn the schem at one time to clean it up and labeled it incorrectly. I am going to go back before I do anymore building work and redraw the schem based on the breadboard and post it. Hopefully you guys can tell me if you see anything else that looks incorrect. Thanks for the help!
Edits: 04/21/17
Dang! I was looking at the wrong number. It's labeled kind of funny. Now I will have to go take a really close look at how I actually have it wired up and see what I have for sure.
Edits: 04/21/17
"G3 is the screen grid and connects to ground (or the cathode) when you use the tube as a triode."
I'm sure Tre' meant to say that G3 is the suppressor grid.
--------------------------
Buy Chinese. Bury freedom.
"I'm sure Tre' meant to say that G3 is the suppressor grid."
Yes, I did.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
The so-called g3 in this sort of tube is actually a beam concentrating set of plates. Beam tetrode is the correct term, as the electron concentration has the same sort of effect as hanging a third grid at ground potential, known as the suppressor grid in between the screen grid( g2 ) and the anode.
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: