Transient Attack and Amp Design

There are innumerable design variables that could relate to the good transient response you have noted. And we wouldn't have adequate visibility into most of them without at least having schematics and other detailed design documentation on the amps being compared.

If you haven't seen it, you'll be interested in this review of the DNA-1 that appeared in Stereophile in 1992. Robert Harley had observations about its transient response that were very similar to yours:

http://www.stereophile.com/solidpoweramps/520/

Regards,
-- Al

Transients require large amounts of near instantaneous current without the voltage in the power supply dropping. Essentially the bigger a power reservoir you have the better an amplifier can cope with transients. It matters less how the power is stored (a capacitor bank or a couple of large capacitors compared to the total amount of stored energy). In theory, the lower the internal impedance from the power supply to the output transistors and teh lower the output impedance of the amplifier the less voltage drop will occur when drawing large amounts of current and hence a better transient response (less compression).

It helps to have a speaker with higher impedance. Speakers with dips of quite low impedance will be the cause of most observed problems (rather than the amp).

Shadorne ;
You stated ...
Speakers with dips of quite low impedance will be the cause of most observed problems (rather than the amp).

Can you supply a definition/value of this impedance dip ?

Thank you .

Saki70, the difference between 8 and 4 ohms can be all that it takes; nearly every amplifier made will sound faster (as well as less bright, more natural) on a speaker of higher impedance.