2. amps-preamps
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Audio Research D400 mk2

Recently when powering up/down one of the 4 big caps under that big board arcs ( light blue)for a few seconds. The amp will power up ok and it stays on and sound great. If I just touch that area I hear a spark. I pull plug to power in/out as the switch seems to make it sound louder. Audio Research does not have caps anymore and say they will need to retrofit and replace that main board to connect to all wires , etc. under it. They say not o use it even though it powers up as normal ( less the spark, arc) for a few seconds or so.

Any thoughts as they say about 2 Grand to replace all for caps and rewire with a different board . Not including shipping.


Where's Leonard  these days as he'd have a FIT.

Thanks George ( It Still sounds Good)



gasjr
gasjr OP
10 posts
 
Yes it's ,fixed. I figured out that when connecting the 2 pairs of speaker cables for my bi-wires speakers one hot lead got loose when moving amp around and was shorting out. it's strange as it would power up and spark but play. at times the left channel (which was shorted) would not play. I tightened all up and no sparks and all is good. this is a Hefty amp and still sounds good after 20 years plus!!
hiendmmoe
198 posts
 
Might be time to have those caps replaced before you run into a serious problem.
20 years is were you start to see them fail. I actual believe D400 mk2 was discontinued in 96 that would make your unit at least 24 years old.

rfish's avatar
rfish
3 posts
 
I was in a car wreck years ago .To make a long story short my capacitor(coil ) that charges up for the high tension spark plug outputs had come loose so it wasn’t connected either .It continued  to work even though it wasn’t connected for about a year and then finally stopped working .When the mechanic saw it he showed me what had happened .Tge spark had jumped the gap to the capacitor and completely eaten away the top of the coil,nothing left .It used50,000 volts since it was for the high tension lead on the car .So no surprise rthat the amp still worked even though the speaker wires were not all connected .
Post removed 
atlvalet
52 posts
 

Responding to this thread because the OP had Audio Research quote him $2,000 for repairs.

The issue is ARC no longer services this unit and "doesn’t" have replacement caps for the Philips units in the amp that tend to go bad. Last time I talked to ARC they said the D400 mkii was "unserviceable." Not sure if anything has changed with new ownership.

The issue is the caps are direct-soldered to the boards, which makes the amp a PITA to work on. The tech at Pyramid Audio did me a solid by feeling sorry for me because the amp I bought on Ebay (with leaking caps) wasn't working, and he didn’t want me to be left with a very expensive paperweight.

Without the receipt I think it cost me $650 or so for the repair. So, Pyramid Audio is a place that can possibly help, but he wasn’t exactly excited about working on one again lol

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