nakamichi pa5 or 7


Can anybody help with the dimensions of these amplifiers?
I am strongly advised to buy one of the mk2-versions if I can find one, but size matters a bit.
What kind of problems should I expect with a 20 years old amp - I am a little worried about the heat.
Thanks!
Ole Felsby, Denmark
felsby
Well... regarding the last posting, that's not entirely true. There are some differences between for example the Nak PA 7 and the similarly specced Threshold S/300. Both use the STASIS-design made by Nelson Pass, but due to a different lay-out and different components, for example the power-transistors, there is a difference in sound. To my ears, the Threshold sounds better, but the Nak is a great sounding amp.

As for the capacitors: a very rough comparison is that they act as batteries, only faster responding. They separate the electronics from slight changes in the incoming elektricity by storing energy, releasing this energy as the music/volume demands more power form the amp. When caps get older, they lose the ability to store and release energy. I had my Threshold revised a couple of months ago. The technician measured all components, and they were still on, or even over spec. Changing the big capacitors will cost around 250 dollars. So it's up to you to decide if you think the amp is worth it. Also, caps tend to get older quicker when the amp gets hotter, so caps in a Class A amp wil lose their capacity quicker.
PER TONE PUBLICATIONS - Introduced in 1988, the PA-7 retailed for $1,595, a bargain compared to the Threshold S-350e that cost twice as much and sported a rated power output of only 150 watts per channel. Nakamichi’s scale of manufacturing made it easy to grab one of Pass’ best designs at a very reasonable price. Today, clean PA-7s can be found on the used market for $600-$700. According to Pass, the original PA-7 (not the PA-7 series II) is “the one you want.” (continued) If you troll the Internet in search of a unit, insist on seeing pictures and deduct heavily for cosmetic dam- age. Replacements are unavailable and greatly diminish the resale price should you decide to resell at a future date. Run away screaming from an amplifier that has been “modified.”
Last year i took in on trade a system containing 5 pa5 amps.

I tested and sold them all fairly quickly. One of them came back with an intermittent channel issue wich ended up being a cold solder joint possibly opened in the shipping process. I fixed it and have been using it to drive a pair of BW nautilus 804 quite happily. It runs slightly warm to the touch but shows no signs of stress. Im very hapy with it.

Its a series one and does in fact have heatsinks so im a bit confused regarding and earlier post. Ive seen some that have handles and thought that was the identifier btween series one and two.
Handles are available for the first series but some don't have them when they show up on fleabay. The larger heatsinked version two has prominent handles.