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Transient Attack and Amp Design

I have observed with my new McCormack DNA-1 Deluxe (CJ Rev. 1 upgrade) that the transients are significantly better than my previous amps. Everything from classical, rock, and jazz has, for lack of a better term, better rythm and transients. (Granted, I have only owned mid-fi amps like Marrantz, Rotel, and Sunfire.)

I was wondering if the McCormack amp design explains the reason. It has eight caps on each output board instead of just one large cap for each channel. Maybe that means there is just more storage capacity? In any event, the amp is a heck of a lot more responsive than what I have heard in the past.

Is the multi-cap board topology more conducive to better transients or is this benefit dependent on the skill of the amp designer regardless of board layout?
jragsda
almarg's avatar
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almarg
9,670 posts
 
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
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shadorne
7,477 posts
 
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).
saki70
907 posts
 
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 .
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