Sound City Schematics: What Was Lost Is Found

Discussion in 'Amps and Cabs [BG]' started by Wasnex, Nov 20, 2022.

  1. Wasnex


    Dec 25, 2011
    After multiple failed attempts, I found the old Sound City website in the Wayback Machine.

    Here is the link to the Main page:
    Sound City Site (

    Here is the page with the schematics:
    Sound City Schematics (

    The pages may time out quickly/frequently, but I was able to refresh/open and save the L/B200 Mk3 schematics I have been looking for.
    Last edited: Nov 20, 2022
  2. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    I hadn't seen this before, there's some fascinating stuff here for me especially, because my very first job working in the pro audio industry was as a west coast service shop for DMI-Kelsey, as well as my first touring console was a Kelsey +3 (two of them actually). What I didn't know was that the first console was actually built in England and then shipped here for sale. I've never actually seen one of these but later consoles were built here in the states (New Jersey).

    I followed DMI through the purchase of Crest Audio, a couple of Kelsey's early power amps (used in the PowerMix) were designed by Crest. Once Crest moved into developing the next generation of consoles (much advanced from what Kelsey offered), Kelsey was shut down. Myself, along with an old touring friend ended up buying much of what was left of Kelsey and I continued to service these consoles (as well as all of the newer Crest consoles) until it stopped making sense. An $8k console back in the 1970's ($44k in today's dollars!) can be purchased for about $1k and it will work better too.

    Things were a lot different back then, there were a lot of small companies making niche products and it was fun. People were generally more respectful too, as business was done face to face or over the phone. Pricks were not tolerated, if you wanted premium products you had to be nice or your wait time would be forever (for years products like this were always in short supply). I worked directly with Jon Lee who in addition to running the entire operation was also a designer/engineer and a first class guy. There was another guy there, Craig Hannaberry (sp?) who I also worked with, but I'm pretty sure he passed about 15 years ago.

    So for those wondering how I got started, these are the first of many older folks who passed their knowledge onto us young guys. There wasn't much in the way of books on audio electronics, nor internet resources.

    Here's from the link:

    But to continue, Peter Salton (deceased) was the head of the then-new Sound City line of products, and in 1968 John Lee joined the company and would eventually become president of Dallas Arbiter and, eventually, would run Dallas Music Industries (DMI). John stayed with DMI well into the 1980s, when DMI eventually closed up shop.

    Meanwhile, John (Jean-Pierre) Prideaux was designing some innovative power amps, among them the first low-profile rack-mounted professional power amps that fit into half the rack space of the competition. Mr. Prideaux then launched Crest Audio.

    A few years later, John Lee of DMI, which was producing Kelsey Audio Mixers, purchased Crest Audio from John Prideaux, who went to work for DMI overseeing the Crest Audio line of power amps. Mr. Prideaux left DMI a few years later, but his Crest Audio went on to produce a line of audio mixers (based on Kelsey audio mixers, one of DMI's last products) and they continue to produce excellent audio products to this day.
    31HZ, Patrice B, Redbrangus and 8 others like this.
  3. Geri O

    Geri O Endorsing Artist, Mike Lull Guitars and Basses Gold Supporting Member

    Sep 6, 2013
    Florence, MS
    Don’t know who designed the Crest Pro 9200 power amp, but we were able to buy 28 or 32,(can’t believe this, but I’m trying to count currents amps in racks and I’m not certain of that count) 9200s from a Peavey demo rig to replace a bunch of heavy, constantly-failing Crown MA 5000VZ used for sub duty. I was quite dubious of this move, but we were sent 4 to try on a small gig and we were quite impressed. So we were quite impressed with a 24-box SB1000 driven by the 9200s. According to numbers, the slew rate wasn’t quite as good as the Lab Gruppen FP6400s driving the main line array rig, but by then, my high-mileage ears couldn’t really tell a difference. Besides, the 9200s were primarily for sub duty as well as old KF850 and other generic duties.

    Rock along to today and we have been watching the Lab Gruppens die one by one from a “fatal and unserviceable power supply failure” as described by Lab Gruppen service. (Gee, they’ve been in constant use since 1999, can’t imagine why that’s happening!….:roflmao::roflmao:). (And we/they are replacing the dead Labs with a Linear Research 4-channel amplifier that is most impressive on its own merit). But the 9200s are carrying on quite nicely, only 5 units have needed service since we bought them and we’ve no idea of the life they led before we bought them. In most of those cases, I drove the problem amp to Meridian 90 minutes away, handed it to the service desk, then had a 2-hour lunch with my good friend, the national parts manager of Peavey Electronics, then not very long afterwards, pickup up our repaired amp and drove home. I continue to be really impressed with those amps. Quite dated by now, but still earning their keep quite nicely.
    We own a Crest LM 40x20 monitor desk that hasn’t seen the light of day in well over 10 years and mannnnnnnyyyyy moons ago, I guest-mixed on a Crest V12 console twice and absolutely loved it.

    Well, that’s my Crest experience. And it was/is a great experience
    31HZ, Patrice B, Wasnex and 3 others like this.