the Smart amp were used in movie theaters
What is the difference between 600 and the 600xl ?
OK, long post warning! I just find it very interesting to learn and share the history of AB International and see just what an amazingly great design these amplifiers really are. Maybe someone will find this on a search and find it interesting or helpful or inspiring so her go nothing, LOL
So the 600 was an older design, the 600A being a newer version and the XL designation lets you know the amplifier will except XLR type inputs.
So here is a little back story on AB International that I have accumulated over the years. Details are pretty fussy but this is what I have pieced together. The original designers name was Bob Bird. He originally worked for ESS and then founded AB Systems in the mid 1970s along with George Anderson. The name was later changed to AB International and all their products were marketed as pro audio equipment. As home theaters become more popular they decided to start Cinepro, mainly to produce a line of high power multi channel amplifiers for the home audio market. Reviewers love there huge clean power output, way more them other multi channel home amps of the time, and the fact that at the time was one of the only amps on the market that could product full power out of all channels at the same time, a true testament to Bob over engineering design philosophy. the bad part, they were ugly and just didn't look their high end part so to speak. Cinepro later ventured into the 2 channel home market with an amp that literally used the same internals as the 600a with a triode transformer. Again, reviewers raved about it sound, comparing it to some of the most legendary amplifiers ( a testament to his amazing designs), but its looks were lacking the high end look. Later Bob contracted with David Goodman (designed some of the Krell amps) if I remember correctly to redesign the "looks" of the Cinepro amp line. this was in the mid 90s and Bob was working hard in improve and expand the Cinepro home line. There used to be huge threads in audio forums of him documenting his progress, even building custom amps for customers. Unfortunately he suddenly passed away in 1999. After his passing a huge legal battle ensued for control of AB International and its parent company's (Cinepro and Verastarr), with none of them being quite the same after.
Most AB international product were made right in the USA, based out of California, but in the 90s they did outsource some of their products to an overseas manufacturing facility but quickly learned the quality wasn't up to their standards. While AB International was a fairly small, little known company, industry giants couldn't help but recognize their performance and robust design. companies like Sony Studios, Industrial Light and Design and even Skywalker Ranch used their products. Other companies like Cerwin-Vega also saw their performance and actually sold pro audio amplifiers using AB International "guts". The interesting thing about the Cerwin-Vega amps was they were mono amps that used the power supply and only one output board from the 1100A which gave it the ability to drive some pretty crazy loads with out a problem. I had actually thought about doing this very same thing for awhile, then ran across one on eBay and bought it. I'm sure other companies might have used AB International "guts" as well, and that just might be the case with the Smart TA-425.
So lets dive into the details of the Smart TA-425. It was marketed by a company called Smart Devices Inc. Notice I didn't say they built it, because they didn't. It was just a recased AB International 600. From the looks of it Smart Devices Inc never designed any of their own amplifiers, just used and/or modified someone else's design. In later years they moved into the home audio market with their 2X150VT which was a modified version of the Hafler DH-200.
I find it extremely interesting that basically the same amplifier, the 600 and its later 600A, where successfully used in commercial theaters, pro audio and in home audio. Being someone who has done pro and home audio, I had used AB international amplifiers in several club setups I did years ago with amazing results. At one club I was offered an AB International amp that was left over as partial payment. I excepted it and hooked it up in my house just for the heck of it. To my surprise it sounded amazing, even more surprising considering it took the place of one of my McIntosh amps. I had to ask how a "pro audio" amp could even sound remotely as good as a McIntosh, but after doing some research I saw I wasn't the only one that was saying how amazing they sounded. that pretty much started my obsession with AB International amps.
