In yesterday's post I described how our world had just been turned upside down. Two identical measuring devices, IC Op Amps, were sounding remarkably different.
The phono preamplifier we were up against, the Quintessence, was based on an older op amp design called the 709C. This was one of the very first op amps ever produced and it was superseded by a more modern version that everyone else was using called the 741.
The 741 was the accepted standard. The 709C was considered an outdated dog. The 741 was the new darling that everyone flocked to. We wanted to be like everyone else, especially when those "everyone elses" had engineering degrees and were way more knowledgeable than Stan and I (it's hard when you're feeling like an imposter).
What was going on? We were flummoxed. The notion that these little packaged miracles called integrated circuits could be at the core of our quest for better sound was simply wrong (at least all the experts and official engineering folks we had access to were assuring us).
"In the circuit you're building, there cannot be any difference. Yours is at audio frequencies and where the two ICs differ is in the areas of frequency way outside the audio band."
Wait. There was a performance difference? Did we hear that correctly?
This was all new frontier material. We were on our own.Two IC packaged functional blocks, op amps, sounding different when they measure the same?
Wichcraft?
The only logical thing to do was to throw everyone's advice and counsel out the window. Ignore the wagging fingers and tongues and simply try it for ourselves. Easy enough as the two ICs were pin for pin compatible (this turned out to not be completely true as the 709C required some external parts to keep it stable).
The moment we got the new phono stage running with the same ICs Dennis Had was using in the Quintessence our world was turned upside down. Again.
Suddenly, we were within spitting distance of the preamplifier that had plagued and haunted us for months upon months.
We had learned that despite measurements and the wisdom of the engineering world, the amplifying stage itself mattered when it came to sound quality. We were ready to launch the little phono stage onto the market, which we did to great success.
But the story doesn't end here.
