Negative feedback, voltage and output impedance

As a general rule, higher amounts of negative feedback will lower the output impedance. If you want a technical explanation of this, your best bet would probably be to head over to the Tube Asylum and ask there. Sean
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Output impedance in tube amp solely depends on output transformer except cases with OTL where the complicated circuitry applied for the output stages to decrease an output impedance.
Negative feedbeck realy doesn't care for tubes or SS and neccessary to increase the freequency bandwidth and decrease harmonic distortions.

Wasn't there a relatively recent review of a tube amp in Stereophile that had user adjustable negative feedback? If i can remember correctly, this not only affected the output impedance but also the bandwidth / linearity of the entire design. Was this the ASL amp??? Sean
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