advantage of inductive chokes on an amplifier


Hi,

I'm wondering what the benefit of an inductive power supply is that uses chokes before the capacitors? I read in a review of the Aloia that I recently purchased that Ayre, Jeff Rowland and Cello have used this technology on some of their amplifiers to good results? But being a newbie I am trying to figure out exactly why?

Excerpt from Soundstage Wes Phillips:

"That one was the inductive power supply, which sports a honking huge transformer with multiple windings (right and left channels, plus rectification for each channel). Each winding has its own inductive choke, for a total of four -- the chokes are placed before the capacitors, which is the expensive way to do it. Ayre does it this way in the V-1x amplifier (and in the now-discontinued V-3); Jeff Rowland has used this topology in a few of his designs; so has Cello. However, it's not an easy fix and it makes the final product heavy and costly. Musical Fidelity also uses inductive chokes, but the company places them after the capacitors, which allows them to spec smaller chokes"...

"The audio circuit is extremely well executed. It's essentially a fully complementary FET input/bipolar output emitter-follower triple. In other words, the cascoded FET input drives three parallel bipolar devices (emitter-follower driving emitter-follower driving emitter-follower -- and remember, the circuit is complementary, so each channel's parts count needs to be doubled).

The zero-feedback power regulators are also cascoded -- obviously Sig. Aloia likes cascodes. The amp has a DC-sensing protection circuit."

If anyone know what that means in normal language and how that differs from other SS amps please enlighten me.

Thanks
galeriehughie

Showing 2 responses by herman

I disagree with "so my take is that a lot of what you are reading is marketing hype. "

Sorry, I should have been clearer.
Inductors in power supplies are used to store energy just like capacitors, and properly implemented can yield wonderful results. I disagree with Jeff but this topic (power supply design) is waaaaay to complicated to address in a forum like this. Text books are written about power supplies and advanced college level courses dedicated to them. Like anything else, inductors properly implemented are beneficial, but if they aren’t they can be detrimental.