So I had a bit of free time tonight, and decided i’d finally take a look inside a Leak 2200 poweramp that I picked up from an auction last year.
I started out by adding a new plug. Being the lovable, forgetful clutz that I am… I left my multimeter at Leicester, so I can’t really check for faults/shorts (DOH!). And airing on the paranoid end of caution I opened the box up to see if there were any nasty surprises of loose AC wires, I was right to do so: As it turns out, this amplifier is designed to power a stack, including an AM/FM Tuner and various disk/cassette decks (which I don’t possess), some careless miscreant had left a 200v AC line dangling out of the socket in the back!
I then proceeded to try and remove some of the accumulative dust that has gathered inside this piece of 70’s hi-fi wizardry. The circuit is completely discrete (no ICs), and from my first impressions, none of the capacitors look bloated or have leaked any nasty acids on the PCB. The design is very logically laid out and nicely labelled, meaning that sections can be checked off if they pass muster.
The unit powers up with an assuring ‘clunk’, it didn’t blow up either… so for that I am grateful! A couple of the bulbs are out, but I kind of expected that, plus I have some salvagable ones from the 2300 tuner that I bought it with. It was too late in the evening to pass any audio through, so I just loaded one of my trusty B&W DM110 bookshelf monitors and let it idle. Without proper testing equipment, or the schematic on hand to check, I can’t say that it is 100% working, but I am confident that it shouldn’t be overly difficult to repair.
I’ve seen these amps go for £100-200 on eBay and such, so restoring it and selling it on for a profit is feasible. However, I would love to bring this amp kicking and screaming into the 21st century. The inputs are a 5-pin design that I haven’t seen before, presumably it’s +/- L, +/- R and ground for each input which is actually kinda neat (one plug per input, compared to lots of terminal connections)
I would like to strip it back, and take away some of the excess baggage to economise the real-estate on any new panelling that I design for it, however.. it is very logically laid out and I am pretty fond of the retro appeal this box has (the little VU’s look killer). I think that I will probably end up replacing the majority of components with finer % tolerances, and probably replace the input and output sockets with terminal points so that it can be more easily used in the system i’m planning to build.
This will be an ongoing project, as I will have to do it in my spare time (if there is such a thing) and given that it’s not really a priority it probably wont get done any time soon. I will however, post updates when I do start to do things :) I hope this thing works out in the end! Any thoughts/comments/suggestions, please feel free to pipe up.