MINe 109 wrote:

In article ,
Paul Dormer wrote:

For the uninitiated, the Gaincard is a simplistic amplifier produced
by 47 Laboratory, which at it's heart uses apparently mundane National
Semiconductor's IC opamps.

It's actually an entire amplifier chip. No di#screte are needed.


The DIY fraternaty reverse engineered the
Gaincard and now *hundreds* of people worldwide are building Gaincard
clones or modifications thereof, referred to as Gainclones.

I have now read a few reviews of these amps and, for the most part, it
seems reviewers have *transandental* experiences with them.

Comments..?

Since they built them themselves I supect the usual 'I did it so it sounds
great' effect.



This reminds me of a review of the Linn Majik integrated amp, in which
Linn made a virtue of the IC amp therein, IIRC, it was easier to design
around as it didn't need the expensive component matching of a discrete
amp.

Is there a circuit-designing statistical advantage to ICs?

Nope. In fact the limitations of the devices that can be produced using IC
fabrication techniques normally means that an IC design has to make
comnpromises compared to a fully discrete design.

Not many ppl are tutored in discrete circuit design anymore however, it's a
vanishing 'art' - sorry science.

The device used in the Gainclone is this I understand.

"The LM3875 is a high-performance audio power amplifier capable of
delivering
56W of continuous average power to an 8 load with 0.1% THD+N from 20Hz to
20kHz"

http://www.national.com/pf/LM/LM3875.html

The output stage isn't even the complementary type !

Some modern IC amplifiers are *ok* - but I've never seen one that truly
shined. You can do so much more with discrete circuit design.


Graham