Aragon 4004 mk2 (D’Agostino) vs Nakamichi PA-5 (Nelson Pass)

The Aragon’s were and are really good amps but they’re not the most neutral or refined amps.

^^^ this captures my recollection of the aragon 4004/8008 amps, brute force minimal subtlety sophistication of sound character

Heard both in the same system but it was a long, long time ago. The Aragon has more power so it definitely grips a speaker with more a authority but it sounds like a big amp and I felt it couldn’t disappear. The Aragon definitely has more bass but it can be a little overwhelming. Between the Nak and Aragon, the Aragon is more forward sounding and maybe a little hard on the edges. 
The Nak is easy to throw some bypass caps over the two large electrolytic caps and then the PA5 really opens up pull ahead of the Aragon, by a pretty good margin. The Nak is more neutral and has a better balance. The PA5 with some simple mods is far from bright or harsh. Before the mods it is a little on the soft side and maybe a little closed in... maybe not extended on the top stock.
Worked part time at a store that had both the Aragon and McCormack amps in the day, and the McCormacks were hands down the better amps. At the time Aragon was spending a lot of money on advertising and was the inside cover of Stereophile for years so they were popular and the store sold their share. The Aragon’s were and are really good amps but they’re not the most neutral or refined amps. At first I found them fun to listen to as they have great slam but might be too much with some speakers and room.

In summary I’d take a Nak PA5, especially with a simple mod, over an Aragon 4004 MKI or II. If you can find a McCormack DNA Deluxe or SMC upgraded amp you’ll be even better off.