What does feedback control on Cary 805 do?


I cannot find info on this anywhere. The manual says you can adjust the feedback from 0 to 10.

I can see that just by looking at the damn knob. But what the heck does it do or is it supposed to do? That, the manual doesn’t say.

Does anyone know what the feedback knob is used for?

Thanks.
Previewaudiodwebe
The use of negative feedbacks has several advantages. It stabilizes the gain of the amplifier, decreases output impedance, increases input impedance, increases bandwidth, and reduces distortions.

Set it where you like it, Carver does it, I did it, others did it...

CD, LP, RtR, all sound a bit different... Tinker...and enjoy..

Happy new year... 

Regards


audiodwebe
The manual says you can adjust the feedback from 0 to 10.
Yeah,  I can see that just by looking at the damn knob.


When I used to do them on my 805 SE’s monoblocks
0 was the min feedback and 10 was the max feedback (maybe Cary did the same)

When you a/b different settings you have to re-adjust the volume as it will be different.

As more feedback (10) gives you
1 Less gain (lower level)
2: Better distortion figures
3: Better damping factor (tighter bass makes up for average output transformers)
4: Not as stable into difficult loads (could ring or worse oscillate)

Less feedback (0) gives you:
1: More gain (higher level)
2: Worse distortion figures (usually second harmonic the "nicer sounding" one)
3: Less damping factor (fatter/thicker/heavier bass)
4: More stable.

This was the circuit diagram of my 805 mono’s I used to build around 40kg each, no feedback at all on this one, my output transformers were good enough in the bass to use without it, and a bit more complex than the Cary. https://ibb.co/PjLktwr

Cheers George
Thanks, guys.

So if I'm understanding:  It's used to better match the amps to any given speaker?

Am I tracking?
True, if you have a purposely over damped speaker design (the only one that comes to mind is old Linn Isobarics they even were recomended to be placed against the back wall) then less feedback will stop the bass being too tight/dry.

Cheers George