B&K EX-442 Score

Just grabbed a B&K EX-442 amp off of CL for $100. In good shape, aside from the common power switch light (not illuminating at all), and a couple of scuffs. Hooked it up in place of my custom 40 watt tube amp and am favorably impressed. I know that B&K amps are known to be "tubey" sounding, and my initial impressions are just that. Not at all etched or forward sounding.

One question I have concerns which EX-442 model this is. I see that the early models used Hitachi metal cans, and the newer ones Toshiba. There are some other minor differences in the specs (early models have a bit more dynamic headroom). Does anyone know how to tell one from the other? Will I have to remove the top to figure it out?
Congrats! That is one heck of a score. The later version was the EX442 Sonata which looked much different then the orig EX442. The Sonata went 200 into 8 & 360 into 4 with 75 amps peak to peak I believe. The original Sonata I don't believe was as powerful into 4 ohms but may have had more headroom. Could be that the very early EX442's may have had a push button for the power switch whereas the latter models had the rocker switch for power, just like the ST-140's had...at any rate, this is an awesome amp. I had the Sonata version many years back and a/b'd it against a pr of Paoli M60 tube monos (totally moded dyna MkIII's w/8417 outputs) and you couldn't tell the 2 amps apart - that's how tubey the EX442 Sonata is.

BTW, what is your custom 40 w tube amp like? I'm looking for a more powerful tube amp. thanks
My tube amp was designed by a well regarded guitar amp engineer by the name of John Nau. I've emailed him a few times about how to set the bias and such, and it's clear his design goal was to create a very clean, simple amp circuit, and I think he succeeded. It features 4 EL34 output tubes.

The more I listen to the B&K, the more I think I have been shortchanging my MMGs for many years. I had tried many different SS amps in the past (Adcom, Carver, Marantz, Hafler, NAD, Acurus, Parasound, and more), but all of them, to varying degrees, sounded bright, etched, and very fatiguing. This B&K has been a revelation, and I feel like I'm getting much more out of the MMGs. Much bigger dynamics, more airy highs, but without any harshness.

I'll definitely keep it around for the foreseeable future.