Nakamichi PA-5 serviced and upgraded

 Make yourself a New Year present! Price reduced!!

For sale is a Nakamichi PA-5 power amplifier that I recapped and upgraded. It has been in my system for more than 2 years, playing great and never gave me a problem. Now Selling since I’d like to go different direction just out of curiosity and try a tube power amp.

The PA5 was produced in late 1980s by Nakamichi using STASIS topology under license by Nelson Pass. Same topology was used in highly acclaimed Threshold power amps. 

What was done with this amp:

All electrolytic capacitors were replaced with the new ones, using Nichicon KT/KZ and Elma Silmic II in the signal path;

Two big electrolytes in the power supply were also replaced; 

Several resistors in the signal path were changed to 1% Vishay metal film;

The original Toshiba diode rectifier bridge was upgraded to modern IXYS HEXFRD one;

Trimmers were replaced with multu-turn Bournes;

The amp was modified to extend bass response; improve the protection mute circuit; and DC offset trimmers were installed to mimic the Nakamichi PA-7 as per advice of Nak expert Stephen Sank and others. 

Heat sinks were removed, cleaned, and power transistors re-seated with new thermal grease;

The bias was increased from 40 mV to 60 mV as suggested by Nelson Pass himself;

The PCBs were inspected for cold joints and few suspicious ones were re-soldered;

The fuse was replaced with sliver-coated audiophile grade.

The sound was greatly improved after modification. The "mugginess" at the bottom end is gone; the bass/lower midrange frequencies are now more tight and natural. The soundstage is better now: instrument positions are better defined than they used to be. Tonality or the way how instruments sound is now more natural for guitar, jazz bass and, naturally, drums.

You will especially like how this PA5 sounds if you listen to the bass-heavy music such as rock or new age. 

The power output is now 150 WPC before clipping vs. 100 WPC before. 

Cosmetically, the amp looks used but well maintained and in very good shape for its age. Few small scratches are seen at the front panel and near corners. Letters are intact. No big dings or long scratches. I re-surfaced the top panel and bottom plate and painted them black. I also added new feet from another Nakamichi piece since the old ones were lost. 

Reasonable offers will be considered.