Without going into this too deep here... I was utterly shocked at the improvement mods made to my old TASCAM Model 5A mixing console. Mixing... err... I use it more for monitoring... although the keyboards and mics go through it to the MicroSound via a APHEX 124A -10 to +4 box.
Yeah I know... your probably saying TEAC??? GEESH!!!!
Well... I was in a decision last year to replace it or improve it. After reading... studying and really tearing into what mods could do, I chose to mod it. I rebuilt the power supply, better caps, all new regulators, external transformer... and better grounding internally... w/12ga stranded throughout.
Then I removed all of the op-amps, installed sockets, and used a mix of 5532's, TLO72's and Burr Brown 2604's. Why three types? Sound. They all have a sound. It's not an EQ difference in sound... it's more how they handle complex waveforms. Tones all passed the same way... but with music, each chip responded differently. My thought was, since they all do have a sound, it doesn't makes good sense to USE ALL OF THE SAME op-amps.
I figured, if I had a lense filter that was very slightly pink, 15 of them would be RED! And so, I thought mixing op-amps was similar. I chose these three chips because I took consensus on the web by designers... about which chips they preferred. The TLO72's were chosen because they had a overall brittle or digital/edgy sound... and were easy on the power supply. The 5532's were popular performers, stable, handle a wide variety of input impedances and sounded warm or tube like and had a low noise footprint. The OP2604's for their high output peak headroom, low noise, and warm low end friendly sound. Together... they sound awesome!
For the short story, I tested each... and ended up putting the 5532's on the inputs, the TLO72's in the middle circuits and the 2604's on all of the outputs. (I did use two 2604's on two inputs for variety). I also replaced all of the signal path caps with Panasonic FC series audio caps. And then replaced all of the audio path resistors with metal film resistors.
The end result? Incredible. It was like a veil dropped. It was a lot of work, but a fraction of the cost of replacing the board, and rewiring the harness and patchbays. Noise dropped significantly, and the sound is (to my ears) very warm, defined and clean.
Yup... I've used Neve consoles, SSL, Euphonix... and Soundcraft... but after this experience... I wonder why most boards use all of the same op-amps??? They clearly HAVE a sound... and if you pass your audio through 30 of the SAME op-amps... you've got a very COLORED end result. I would say my approach appears to blend and balance it all out some. At least, it makes some logical sense. Would I like to own a Neve or similar console? Sure.
But mine has paid for itself over and over again since 1977!!!!!!!
