In like new condition this Audio Research D90 Tube Amplifier has had zero cosmetic work done to it. Mechanically it has been thoroughly gone over, refurbished and brought up to spec and is ready for another 40 years of enjoyment. After the work was done we ran the D90 together with an SP6C preamp for a week in our shop where they made our B&W 801's sing. The following work was done on the unit:
* All large filter capacitor cans replaced with long life modern electrolytics (Nippon Chemicon)
* All axial electrolytics tested and verified
* Select out of spec film coupling capacitors replaced with modern equivalents
* Negative bias supply dropping resistor replaced
* All small driver tubes tested on our Amplitrex AT1000 tube tester- Any out of spec tubes have been replaced
* Output tubes replaced with current production Svetlana 6550C matched quads
* Bias and alignment performed to service manual spec
* Both channels tested to rated power
We acquired this unit along with an Audio Research SP6C Tube Preamp w/phono from the original owner which we also have up for sale. From a smoke free, pet free and kid free house, The faceplate, body and cages are in excellent, like new condition. The unit comes in the original Audio research double box with original owners manual and original factory quality assurance certificate.