OffsetGuitars.com

Quick!  I need to know everything there is to know about a 1984 Fender Concert Amp!  OK, go!

..I found this link:
http://www.birddogbobby.com/geardetail.asp?id=BA005

When Paul Rivera was at Fender in the 80's he designed this series of amps for them to more or less compete with Boogie, who was taking a big bite out of the market. This was Fender's first channel switching design and incorporates one channel of classic "Fender Clean" and one channel with 2 gain controls and a master volume. The unique thing about this amps design is that both channels have their own set of tone controls and they both have reverb. Try finding that nowdays for under 1500.00. This is a 60 watt amp with one 12 inch speaker, and a tube driven effects loop. I love these amps and own and use one, and I think they are one of the best kept secrets of the Fender history.

...there is also a ton of info from various sources on harmony central's review pages...and ampwares site too:
http://www.ampwares.com/ffg/concert_II.html

I'm being offered to trade my Marshall TSL60 half-stack for one of these.  I payed about $1400 for my Marshall, and have used it extensively for the last 3 years.  I figure I can get about $700-$900 trade-in for it at any local guitar shop.  Whaddaya think?  Good deal?

Which speaker layout does the potential trade amp have? I think these were made as 1x12", 2x10" and even 4x10".

Of course if you love the amp, go for it. But purely speaking of economics, I'm not sure that you're going to come out the winner on this trade. It might be worth selling your Marshall (although you use it often, right? No Fender is going to do that sound) and just buying a Concert separately. There was a Concert from 1983 that just sold a few weeks back on eBay for under $600:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0131774180

And there's a head on eBay right now:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0151663906