Hi Ned,
Yes it?s like the new Marshall reissues, except this is an early original MK1 version late-64 to mid 65.
I bought it used in mid 1970?s ($200/?120), although I really had no idea what model it was until I showed it on 18watt.com where it caused an amazing fuss (not my intention). Fuss due to fact they were only familiar with later MK2 version shown in Doyle?s book, so ?experts? cast doubt on it & sounded like they thought I was trying to con them. I was bit miffed of course because I knew the amp was genuine (cheap as chips in mid-70?s, nobody tried to fake them at that date, & mine was mint with no evidence of even one cap change? still has the original fuse!).
In the end, in order to prove it once & for all, I took it to Marshall in Milton Keynes UK where Jim Marshall himself was kind enough to verify it for me (what a lovely guy) ? in fact he immediately recognized it as one the very first 18?s which he made himself ... there?s a photo of Jim with the amp on 18watt Photo-Gallery (plus lots more photos).
Only obvious differences compared with MK2 version; MK1 has Celestion G12 Alnico?s (same as early AC30 except painted silver instead of blue - whereas MK2 has ceramic Greenbacks), cab has simpler square-cut shape around the control/plexi panel (MK2 is curved/chamfered, and control panel is lowered), and footswitch is totally different. Circuit identical apart from a few value changes (eg 47K tail resistor), plus use of earlier components eg more carbon-comp resistors, RS caps throughout, & older style RS hard-wired tranny.
Still works fine ? just plug in any Les Paul & instant Clapton-Beano ? want any other sound? ehh? sorry ?no can do? (no proper tone controls, no master gain, no reverb) :-? .
Ian.