Nakamichi Power amps

they sound like thresholds

Don't know about those, but I have a Nak 620 (circa 1977) and it sounds great and provides about 100w/ch into 8 ohms and 150w into 4 ohms. Interestingly enough, this amp operates in 'pure' class B with low feedback. With feedback removed, the Harmonic and Intermodulation Distortions are still less than .5%, according to tests done back 'when'.
The 600 series of products (pre-amp, tuner cassette decks) never did well in the marketplace, probably too odd. The 630 tuner-pre-amp jhad (has) a superb tuner section and phono.
Much of the reason for going with the 'Pass' circuitry was for marketing reasons, IMHO.
Salut, Bob P.

I have a Nakamichi PA5E and wouldnt trade it for the world. All these amps are superb and bring the brilliance of Nelson Pass's designs to an affordable price. Shame Nakamichi dont do them anymore but thanx for what we have Nak n Nelson.
If you get chance to buy one and want to get into the upper class A market, these are a great way to start. Mine is 20 yrs old, mint and showing no signs of wear except that it takes about half an hour to warm up and get 'sweet' but think this is normal for all stasis amps as they have to get to temperature before running to spec.

GO for the PA-7. That way, you will have suffient power for most speakers you will ever buy, unless you step up to the real high end. They do run hot though so that you know. They really should be placed in a rack. Quality is first rate and if you can find a pristine example, buy it! I wish I hadnt sold my PA-7. Powerful bass, most of the weight is in the power supply. Use an aftermarket power cord designed for some current draw and use some premium speaker cables.

I bought a PA-7 in the early 90's. Reviews rated it higher than the PA-7II. It is an awesome amp, sounds stellar, and yes it puts out some heat. The lights in the house dim when it's turned on. 10 years ago I was running  it in bi-amp mode with a PA-5II. That sounded great, but was a complicated system. I sold off the 5.  Pass circuitry, at a lessor price. The Nak is much prettier, too!  They also hold their value.