Hi Guys,
I'm interested in using this schematic but I don't follow how the gain stage/phase splitter is operating. As far as I can tell the gain stage/phase splitter does not have a DC reference on the cathodes only an AC reference. I see a 100 ohm resistor between the cathodes with a 100uF cap from one side of the resistor to ground. Is this a mistake in the drawing or do I not understand what I'm looking at (most likely)? Can anyone explain the operation of this stage? I would appreciate it much.
G
I'm interested in using this schematic but I don't follow how the gain stage/phase splitter is operating. As far as I can tell the gain stage/phase splitter does not have a DC reference on the cathodes only an AC reference. I see a 100 ohm resistor between the cathodes with a 100uF cap from one side of the resistor to ground. Is this a mistake in the drawing or do I not understand what I'm looking at (most likely)? Can anyone explain the operation of this stage? I would appreciate it much.
G
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THE WHOLE PICTURE....
Hi Gavin,
Yes,circuits like this can get a bit confusing....
Thing is you see grounding is taken,with B+ for the preamp to a separate chassis.
So as long as you don't see these two as a pair it won't make much sense.
The amp as shown get its signal straight into the phase splitter and that drives the output stage.
Cheers,😉
Hi Gavin,
Yes,circuits like this can get a bit confusing....
Thing is you see grounding is taken,with B+ for the preamp to a separate chassis.
So as long as you don't see these two as a pair it won't make much sense.
The amp as shown get its signal straight into the phase splitter and that drives the output stage.
Cheers,😉
Gavin,
Yes, there is a dc reference to the cathodes through the 1000ohm feedback resistor and the secondary of the transformer.
cheers
peter
Yes, there is a dc reference to the cathodes through the 1000ohm feedback resistor and the secondary of the transformer.
cheers
peter
No preamp needed. 2V straight in from the CD will definitely get you full power from this amp. Just ignore the arrow extending the B+ to the preamp.
SHORTSIGHTED?
Hi,
When that preamp is not connected B+ is bound to rise at the amp.
You better look at how this combo behaves and write down the voltages.
Cheers,😉
Hi,
When that preamp is not connected B+ is bound to rise at the amp.
You better look at how this combo behaves and write down the voltages.
Cheers,😉
Frank, I doubt the increase will be anything to worry about - in fact, they probably chose the values of PS resistors assuming there would be no additional draw. Anyway, a pre (from that era) is just a bunch of 12AX7's, and draws only a few mA.
FAIR ENOUGH
Howdy,
True,it won't prevent the amp from functioning.
OTH it won't hurt to play it safe either.
The 470K input R can easily be replace with a 500K volpot and you're set.
I must say I quite like the elegant simplicity of that amp.
Cheers,😉
Howdy,
True,it won't prevent the amp from functioning.
OTH it won't hurt to play it safe either.
The 470K input R can easily be replace with a 500K volpot and you're set.
I must say I quite like the elegant simplicity of that amp.
Cheers,😉
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