OPamps still inferior to discrete circuits?

Casouza - Jeff Rowland uses, in great sounding Capri linestage, fully differential high speed op-amps OPA1632.

OPA1632 has:
0.00002% THD
0.00005% IMD
1.3nV/SQRT(Hz) noise
180MHz bandwidth

discrete amp like that is not a trivial task (layout!). Can you imagine the cost?

Chris - This is difficult to answer. Example of Capri shows what is possible. The real question is what you can buy for the difference. It might be better to buy Capri for $3,500 instead of discrete preamp for $10k and spend $7k more on speakers. Benchmark DAC1 praised by many uses $0.50 opamps (NE5532).
I agree with you that it might be better to get discrete circuit if money is no object but even then you might not beat opamps in offset drift to eliminate caps from the signal path.

Problem with opamps is that they are not designed in general for the audio. First opamp really designed for audio was NE5532. It was about 25 years ago and Benchmark claims that it performs better than OPA627. Now National Semi. came with LM4562 but many claim that NE5532 has better midrange.

I was surprised with Rowlands selection of 180MHz amplifier and even more surprised when I checked datasheet - It is an audio amp. It has 180 MHz bandwidth but its full power bandwidth is only 800kHz (Capri swings 7V rms = 20Vp-p). Distortions start to climb-up starting from 10kHz so it was probably necessary to spike-up bandwidth to avoid distortions and any phase shift at 20kHz.

Dgarretson - Jeff Rowland used batteries in his preamps but now he "switched" to switching power supply (SMPS) in Capri. It should be easier to filter out high frequency than 120Hz and also to make stronger supply within same dimensions (and SMPS are load and line regulated) but unfortunately manufacturers use SMPS technology to make it cheap instead of better.

Somebody said that there are two types of fools in this world: One says "it is old and therefore good" while the other says "this is new and therefore better"

Chris - I had a friend who believed that DAC IC should have current output to avoid I/V converter inside and be followed by the tube and discrete transistor circuits to avoid opamp. DAC itself has current sources build using monolithic, opamp like, technology - no escape from that.

I don't have enough experience to judge and my system is very modest, but logic tells me that added distortions add dynamics to the sound (distorted guitar vs clean jazz guitar). Yes, Benchmark sounded lifeless to me at first but it doesn't anymore while it still sounds extremely transparent and clean. I got used to this sound - or learned to listen, if you prefer. I read post where somebody asks how to make sound warmer and less detailed - read "exaggerate even harmonics and add a little distortion" (I advised blanket over speakers).

My small class D amp according to some Audiogon members (with better ears and more experience) has some problems with highs and harmonic structure but I think that for the money it is a great bargain.

Stereophile rated A, couple years ago, amplifier that costs $500k. In my opinion review wasn't necessary because any amplifier with that price tag and company still in business will be rated A. Everything is a matter of money and most of the time people ask for the best bargain and synergy in their systems. Opamps, in my opinion, are very good bargain.

Undertow - Burr-Brown is Texas Instruments now. Perhaps sound changed from "Brown" to "Instrumental"?

Chris - It might "give more harmonic richness/complexity" if you already have rest of the system that you are happy with. I need to spend money on speakers.

Audio always has been neglected an there is only a handful of opamps designed specifically for the audio. Even one mentioned by Undertow (AD843) as great sounding wasn't designed for the audio (no mention of it or any THD data) but rather as fast settling amp to use as buffer for A/D converters or peak capture or sample/hold circuits.


I am afraid that such advances like SACD come to us only because they have absolute copy protection and not for the sound.