Bruce Swedien's Harrison Console

[klett]

Hi... I was cruising through and spotted the thread about Bruce Swedien's Harrison Console in the guest archives. Someone asked about what mods were done.

Bruce's desk has had a few mods but none really too drastic. The console has had the power supplies upgraded to some beefy Acopian custom units. It's been recapped. There have been some careful chip upgrades and a few of the more critical transformers have been changed out for better ones. We also shortened up some signal paths by ditching insert points that Bruce never uses so we don't have to deal with a couple buffer amplifiers, a bunch of wire, connectors and normalizing contacts on patch points that are never used.

As far as IC's go, this may surprise to many who "know" the IC game... there are still some 4741 amplifiers here and there. Dave Harrison was a tremendous applications engineer. He obviously had ears and knew how to communicate in musical terms so he could dial his consoles in to match the users better than most. He needed a quad opamp that had some ability to drive a load (and remember when he designed the 3232 console - late '70's). He chose quad 741 amplifiers... and you may say yeeech! but he knew how to design around the flaws and maximize the performance of even a lowly 741, i.e. by dropping the console's internal operating level to get around the slew rate limitations and so on.

We did some listening tests and selected specific IC's for each circuit block. I think we ended up using four different parts. If there was no audible improvement we tended not to mess with it. There is some talk of further upgrade to the console's mix buses but the thing sounds so good now there is no particular pressure to jump straight into doing it.

The rest of it is straight maintenance. Bruce uses the VCA automation so those are still present and they have to be trimmed up to minimize distortion. There are contacts and connectors to be cleaned. There are a lot of things that are universal to old consoles.

Bruce quoted me in his book where I said something like 'don't go off and buy something because the specs are better or because all the industry rags are touting it...'. I wasn't telling him anything he didn't know but it seems that a lot of people don't get this. I know too many techs who read a bunch of numbers off their AP or whatever and they say... 'oh yes this things sounds better than that thing' and they didn't even listen - they looked at some numbers with their eyes and made some decision about how their ears would perceive things. Different is not always better and really good numbers don't tell you much about musicality.

So... chips and mods. National has just released a new opamp, that has good numbers... like .00003% THD+N, 2.7nV/SqrtHz noise density, ±20V/µs slew rate... and so on. Is it going to sound good if I drop that chip in to some socket formerly occupied by a 5534? even if I take care to trim up the compensation and so on? Not necessarily. Numbers are good to quantify and back up or explain what you are hearing but numbers do not define the listening experience. I often see gear all modded up with video amplifiers or whatever whose owners are telling me it sounded better... maybe a little noisier but better BEFORE the mods were done. I sometimes undo mods to make gear sound better.

anyway... Bruce's console mods... nothing drastic... all done carefully and step by step with time to evaluate each step using some of the best test equipment we have for evaluating how things sound... those are called ears... and I haul my AP down there and measure after we decide what sounds better what just to see if it tells us anything about why.

[by-tor]

WOW awesome! Thanks!