Amplifier chips

[Mr Peabody]

Probably around the time of going into the 80's I remember the big thing, buzz word, if you will was discrete circuitry. It was better than IC's, integrated circuits, in audio gear. Receivers at the time like Harman Kardon at the time cost a premium because they were discrete opposed to the many competitors who used IC's.

It seems now with the push to Class D we are being told IC's, chips, are good. Or at least on par with those built with discrete circuitry.

I wondered about this and watched a tutorial of sorts on Class D. Probably just enough to be dangerous, LOL The guy literally made a Class D amp on a circuit board with a chip, power supply and the appropriate caps to do the low and high filtering. Some of these Class D amps today have some hefty price tags.

I bring this up with a genuine curiosity if chips are better now than those used back when in amps or is it apples and oranges? If IC's were not as good as discrete circuits then wouldn't the same still hold true today? Could the circuit being a chip be a handicap to Class D ever really being able to compete with a equal A/B amp?

I realize the IC's used back when were not used for Class D.

 

[Randy Myers]

I managed an audio store back then. The "chip" amplifiers were designed to simply be lower priced. In general, companies such as Sony, etc., used chips to make it cheaper. Companies like Yamaha made a lot better amplifier using discrete circuits. It was easy to show and easy to hear the difference. I sold a lot of Yamaha, Harmon Kardon, Nakamichi, etc., because of this.

 

[puroagave]

Nelson Pass has said in numerous interviews, discrete through hole parts like transistors are becoming obsolete in industries that drive the parts business. ICs and surface mount parts have taken over for numerous reasons, except sound quality. the audio business isnt large enough to influence the production of discrete parts. Bottom line the reason is economic.

 

[Mike]

I can tell you this: my receivers from the 1970’s (Pioneer SX1250 and Marantz 2270) use discrete components of individual transistors. The older receivers also used larger components that you could easily see. Modern receivers use integrated circuits and very small parts they call surface mount components. Also there could be differences in the amount of negative feedback used.

I will tell you that my older receivers still sound amazing and I wouldn’t want to put up against a similar priced receiver today. It would get smoked in all areas I bet.

Any my vintage JBL’s…oh yeah.

 

[Bones13]

While there are decent “chip” amps, many are limited in power due to cooling concerns. The real culprit of change has been the surface mount technology that is miniaturizing electronics over time. Through-hole components are becoming limited over time.

The DIY hobbiest, and certain manufacturers, will spend time measuring the discrete components to be sure of the values as they use the parts, but also to “match” them within the circuits, and to try and balance the R/L channels.

Surface mount technology is being used more and more. Boulder, and MSB, both use this a lot. I also know that the Gallium transistor, used in my Class D amps, are discrete components, not a “chip amp”

I have done transistor matching, and resistor value measurements on surface mount components. My ability to use them is rather limited though, and I have only used them sparingly. It’s a different set of tools, and my eyes are not the best anymore.

 

[Randy Myers]

Things have definitely changed a lot. Back in the day the differences where more clear cut. With tech changes, etc., the differences are not so clear any more.