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Old 2nd August 2011, 01:54 AM   #1
alexg is offline alexg  Philippines
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Default cathode bypass on opt secondary

I came across a schematic of an EL84 SE, the cathode bypass is connected to the 8 ohm tap of the OPT secondary.

Haven't encountered this before, so, why is it connected to the 8 ohm tap of the OPT's secondary?

Thanks.
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Old 2nd August 2011, 02:02 AM   #2
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Hi,

It's called cathode feedback, just like in the attache file.

Basically it reduces distortion greatly, increases damping factor (tighter bass) but needs more input voltage ( just because it's feedback).

I did this on my RH807 and it plays very good.

Rgds,
Eric
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Old 2nd August 2011, 02:04 AM   #3
alexg is offline alexg  Philippines
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Quote:
Originally Posted by e_fortier View Post
Hi,

It's called cathode feedback, just like in the attache file.

Basically it reduces distortion greatly, increases damping factor (tighter bass) but needs more input voltage ( just because it's feedback).

I did this on my RH807 and it plays very good.

Rgds,
Eric
Eric,

Thanks.

BTW, the schematic you posted is the one I was looking at!
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Old 2nd August 2011, 02:08 AM   #4
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Tubelab does this on the Simple SE Simple SE schematic

I tried it on a pentode headphone amp, and was not happy with the sound: ecp.cc
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Old 2nd August 2011, 01:54 PM   #5
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My 1625 amp works this way.
Click the image to open in full size.
A member here gave me a good hint to connect it like in your schematic which doesn't have DC on the speakers (but it is a very small amount, about 10mV). I like the sound.
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