Re: Marshall Experts: 50w Mark 2 Lead?
You should get it if you can. 77 was the from the era of the low plate voltage 50's. The 50 watt models ran about 390-400 volts to the plates, so they had a warmer, creamier, softer response. However, if the filter caps are spent it may sound overly soft and flabby, and a lot of people just quit using them over time.
In such cases the amp can be restored to like new performance fairly easy, and you may be able to pick up the head rather cheap.
A 77 cab for a 50 watt head will probably have "black back" G12M25 speakers. Regardlees of the color of the speaker magnet they are most likely either 25watt or maybe 30 watt G12's (assuming it has the original speakers) eqivilant to early 70's "Greenbacks". If the (original) speakers and cab are in good shape, then the cab is worth a lot of money, perhaps twice that of the head. I know of a single 78 checker grill 4x12 cab with the 25 watt speakers that is priced at IIRC $1200. You can't replace the quality of the wood from that period, and reissue greenbacks don't sound as good as the original run of 25 watt speakers.
Just a guess but, the head and cab together could probably bring $1600+ on the open market if it's in good shape and has 25 watt or 30 watt Celestions.
These are great amps with serviced tubes and filter caps. They don't really come alive untill you get em nice and loud, despite the MV, but the tone is wonderful once you get em loud.
The four input (non master) JMP 50's are just about as good as the early metal panel amps sonically imo, if your lucky enough for it to be one of these.
There was an amp head called the "artist" from the 70's that was designed for cleans, and although it has reverb, it doesn't have a good reputation among Marshall fans.