Hi,
See if you guys can help out this guy on YouTube figuring out this mystery
Amplifer, rather interesting.
Sam
See if you guys can help out this guy on YouTube figuring out this mystery
Amplifer, rather interesting.
Sam
I think this was something that was possible with the way the signal is generated from a ceramic catridge on a stereo record. I have wondered if that could be emulated with a chip, then if the same trick could be used for a tube 5.1 amplfier with just 3 OPTs.
Simplex stereo
Simplex stereo
This was a fairly common circuit topology in the late 50s and early 60s.
It is a little hard to see at first.
The in-phase signals are output from the amplifier through the common mode transformer, (the one in the schematic with only 4 leads; primary and secondary). The sum of all the signal current of the two output tubes has to go through this common mode transformer. That is the common mode signal. This is L + R.
The other output transformer puts out the difference signal of the two output tubes, L - R.
(The transformer with the many leads).
If you matrix L + R with L - R (Properly) . . . you get:
L + R (- (L - R)) = 2R
and
L + R + (L - R) = 2 L
And that is Stereo.
Try the link at about 31:16.
Unfortunately, all through the video, his hands keep covering different parts of the complete output circuit.
By the way, the 4 lead output transformer has to have an Air Gap, because the DC current is not cancelled.
The many lead output transformer is a push pull, and the DC currents are cancelled by the 2 halves of the primary, just like any push pull output.
Have fun!
It is a little hard to see at first.
The in-phase signals are output from the amplifier through the common mode transformer, (the one in the schematic with only 4 leads; primary and secondary). The sum of all the signal current of the two output tubes has to go through this common mode transformer. That is the common mode signal. This is L + R.
The other output transformer puts out the difference signal of the two output tubes, L - R.
(The transformer with the many leads).
If you matrix L + R with L - R (Properly) . . . you get:
L + R (- (L - R)) = 2R
and
L + R + (L - R) = 2 L
And that is Stereo.
Try the link at about 31:16.
Unfortunately, all through the video, his hands keep covering different parts of the complete output circuit.
By the way, the 4 lead output transformer has to have an Air Gap, because the DC current is not cancelled.
The many lead output transformer is a push pull, and the DC currents are cancelled by the 2 halves of the primary, just like any push pull output.
Have fun!
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