Planar Speaker Asylum: Modifying an Adcom 5802 by Dave

Your Adcom 5802 is a set of modular component sub-assemblies built in Asia of great quality parts (mostly) then shipped to California where it could be quickly assembled and called a USA built amp. Practically everything is soldered on one side only and has a push on fitting on the other, so retrofitting better wire and soldering joints is very simple. Its easy to take apart with allen bits.

Damping Feet made of Sorbothane w/ threaded insert bolt
(sourced from W.M.Berg,) Damps vibrations which improves sound and imporves component life. Also moves amp up off of the floor a bit for better cooling.

Large Transformer Damping Pad made of Polymer
(Sourced from either "Acousti-Sheet" in bulk or Part Connection pre cut) Toroidal transformers vibrate somewhat and depending on the temp the sound gets better or worse. I tried adjusting the nut tension on the hold-down bolt as Adcom recommended but this only moves the vibration point around. I just got a stainless steel spring and a washer to spring-load the tension so that the tension remians constant and the vibration is always damped.

RCA Jacks
These were pretty generic, so I replaced them with Cardas, silver/rhodium jacks w/ the spring loaded center tensioner.

XLR/Singled-ended input selector switch.
This switch is so poor in quality that you can switch the RCA jack off and still about 1/2 the signal gets through, so i removed it from the signal path. If you are using the balanced input, just by pass the RCA side. To bypass it you can either snip (very carefully) the switch lead you don't want to use, or else carefully desolder it from the board. I also replaced the tiny junk wires with Nordost OFC/teflon flatwire. You could also use the Kimber wire or the HGA wire that MikeCH likes.

Binding Posts
Vampire BP Hex sourced directly from Vampire, Welborne Labs, or Parts Connection) I also used the same Nordost flatwire wiring in 12g for the output wiring, and soldered this to the BP Hex Binding Posts. You will have to redrill the holes in the chassis to replace the stock British posts. Be EXTREMLEY careful not to get any metal shavings into your amp. I drilled right into my shop vacume hose end ot keep metal shavings out of the amp. The amp has an ingenious mounting where the ground strap/capacitor holder and chassis brace are all linked together but its tricky to work with.

I found a special heat sink grease (I'll have to look up the name) that moves heat twice as well as normal high quality heat-sink grease. I used this to link the front, back, bottom, and the top to the sides, so the amp has 6-sides of cooling instead of two--its so increadibly easy and effective that I can't believe everyone doesn't do it. I got the basic concept of using all six sides from Bryston; think Adcom's oversite in missing this trick is a major blunder because this amp runs so hot.

Some of the allen head cap screws are not tight fiting into the chassis, so I replaced them with studs and nuts. Cut the stud to the exact lengths you need and sand off the rough edges (do this off of your amp to keep metal particles out of your amp)

I think this mdoified amp is a world better than the orginal. Its quieter, more detailed, damps speakers a little better, and has stronger bass. And since its so much cooler it should last a lot longer. I think these mods are all straight forward and don't require little technical expertise. Be patient, and work slowly. The 5802 is a par excellent design from Nelson Pass, the layout is beautiful, and the basic parts are premium quality. Unfortunately, it has Adcom's normal shortcuts in conncetors, switches, binding posts, hook-up wiring, Chassis, and heatsink size, to keep it within a budget. IMO these modifications are the sonic difference (but not cosmetic)between the Adcom and some products that are 3 times the price.

I think this Adcom is an excellent match to the Maggies.

Dave