Plays amazing. A little crackle on the pre amp knob. Nothing a lil De-Oxit wouldn’t fix. All dings, tears and flaws shown. Has a replaced knob on the reverb. You don’t see Dean Markley Signature Series amp too often, though a few graced my bench back in the day. According to my research, these amps were designed by a gentleman named Terry Laul, quite possibly with a small team of others, and were produced between 1983 or ’84 through 1986. They were available in both 60- and 120-watt models. Initial production models had tan vinyl, and later models came in black, though I’m not sure whether that was a design change or simply an option. Another fun fact: Around this same time, a gentleman named BK Butler was also employed at Dean Markley, though I’m not sure he had anything to do with the design of these amps. If that name is familiar, it’s because it adorns all of the real Tube Driver pedals, which were eventually popularized by Eric Johnson. And yes, Clapton, Alex Lifeson, Andy Summers, April Wine, G.E. Smith, and others used these amps. This is a very simple single-channel amp with basic front-panel controls. This means you can dial in a great solo tone, and then use your guitar’s channel selector—err, I mean volume control—when you want a rhythm tone. (Okay, I’m old school, but that’s the way we used to do it.) But while the controls are typical, the circuitry has a rather unique midrange control. Most midrange controls are part of the amp’s passive tone stack, along with the treble and bass controls. But here, midrange is an active circuit utilizing op amps. Its input is taken prior to the tone stack, and its output is fed back into the signal after the tone stack, allowing the desired amount of midrange to be mixed back in. Pretty unique! According to the schematic, the voicing switch you asked about attenuates the output of this midrange circuit in its closed position, giving the amp two different “voices.” I’ve also seen this switch described as a “deep” or “dark” switch, probably based on aural perceptions. The speaker outputs aren’t stereo, which would require two separate output stages. This amp only has one output transformer and one set of output tubes. There are three pairs of jacks: 4-ohm, 8-ohm, and 16-ohm. Each set is wired in parallel, and the impedance associated with each set denotes its total load. For example, two 8-ohm cabinets or one 4-ohm cabinet should be plugged into the 4-ohm jack(s). Likewise, you could connect two 16-ohm or one 8-ohm cab into the 8-ohm jack(s). The funny part is, the amp only needs one 16-ohm jack—in all the years I’ve been servicing amps, I’ve never come across a 32-ohm cabinet! It doesn’t matter whether you use the top or bottom jack of each pair. As far as replacing the filter caps, I believe you should make that decision based not on the amp’s age, but its performance. That said, if the amp has sat unused for years, or you don’t know its history and don’t have the ability to power up the caps slowly using a Variac, replacing the caps might not be a bad idea. It may save you an emergency trip to the repair shop later—after the smoke clears! These amps never really caught on, which keeps prices relatively low. This is great for the buyer, since there may have been as few as 200 or so Signature Series amps made. (There are boutique amps with far greater production numbers!) That alone is enough to make me think you got a great deal, but here’s the icing on the cake: A few years ago Clapton’s full rig from that era went up for charity auction. His two Signature 120 heads—along with a Bradshaw switching system and Marshall cabinets—sold for $4,880.