Nakamichi PA-1 five channel amplifier review
By: Mark Donnigan, courtesy Audiocore (markadonnigan@earthlink.net)

Overview
The PA-1 is a 100-watt by five-channel power amplifier sold in the US by Nakamichi and was in production from approximately 1996 to 1999. In this review I?ll attempt to give a basic overview of the strengths and weaknesses along with my conclusions based on extensive listening. Without giving it all way before you read on, this amplifier is an excellent contender for anyone looking for high performance on a budget. Whether you?re building a dedicated home theatre or already have one and are looking to upgrade to separates; this amplifier will please most listeners in applications from two channel to discreet multi-channel.

Performance Specifications
Rated power is 100 watts per channel with all five channels driven at 0.1% THD 10Hz to 30kHz at 8 ohms. Dynamic power is measured to be 140 watts with all channels driven. Suffice it to say, this amplifier has sufficient headroom to drive even the most demanding speaker loads. Output current capability is 15 amps continuous and 30 amps peak per channel with all channels driven. The power supply contains a 910-watt R-core transformer and houses 60,000uF of capacitance. Weighing in at 49 pounds, this amplifier definitely leans toward the high current conventional side of modern amplifier design. Original MSRP was approximately $1799 with current pre-owned street prices in the range of $700-850 based on condition and other intangible factors.

Strengths and Weaknesses
Being a positive guy, I?ll cover strengths first. The first thing I noticed after much listening and analysis is that this amplifier has headroom to burn. Volume was never for lack of want, and the amplifier always matched the level demands I made of it. As I mentioned in the above performance section, this amplifier incorporates a high current design giving much emphasis to storage in the power supply and the ability to deliver up to 30 amps for each of the five channels. Bottom line, if you like volume or have speakers that are difficult to drive, the PA-1 should suit your needs for all applications except possibly the largest of rooms.

Of course one of the trade offs typically found in an amplifier of this design is thermal efficiency. Consequently I was pleasantly surprised to note that even after prolonged listening sessions or heavy use that it never over heated.

Nakamichi incorporates what they call Harmonic Time Alignment into the design of the PA-1. Unfortunately I was unable to obtain detailed technical documentation on what it really means. Therefore I can only assume this circuit contributes to the ultra wide frequency response of 10Hz to 130kHz that Nakamichi reports, and based on listening tests I would also surmise that it contributes in some way to the forward and open sound quality I heard.

Another positive for this amplifier is the chassis and front panel build quality with the front panel being nicely milled and finished. However, I must comment that the RCA connectors are not as robust. Due to their close spacing, it was difficult to connect high quality cables, and in addition the connectors themselves seemed to be prone to mechanical failure from excess stress placed on the connector when a large cable was used and not properly supported.

This amplifier may have guts, but if you are powering a pair of speakers that are a little bright or bass shy, you will probably be disappointed with a perceived lack of bass or roundness to the sound. Additionally, the system will possibly sound overly bright and forward. Consequently pairing the PA-1 to a pair of neutral or ?fat? sounding speakers will be the key to getting the best spectral balance or blend from this amplifier and your speaker system.

Listening Observations
Obviously sound quality is very subjective, so rather than go into great detail about how I THOUGHT it sounded, I?ll briefly discuss my listening system and the basic conclusions I arrived at. My reference system at the time of this review consisted of a Sony TA-E9000ES processor/pre-amp and Alesis Monitor 2 studio monitors for Left, Center and Right, along with Alesis Monitor 1?s for the Rear Surrounds. The Alesis Monitor 1 and 2 are a conventional 2 and 3 way speaker design respectively. Their primary application is for recording studios and as such they work best in the near field. If you are asking why I choose those speakers, it?s because I also own a personal recording studio and desired as much coherence as possible between my studio monitoring system (Monitor 2?s) and my home theatre.

One quick note on the program material used; my listening tastes range from modern rock to jazz and movies run the gamut of major Hollywood motion pictures. (I am very fond particularly of female vocals in both jazz and rock contexts.) Needless to say with my recording background, anything I listen to whether it be a CD or DVD Movie, must be well recorded. Consequently the conclusions I?ve arrived at are not based on popping in a few disparate tracks over the course of a single evening or weekend, but instead of listening for possibly over a hundred hours and as many different pieces of software.

I?ve already mentioned that this amplifier plays loud; therefore if you are driving a decent pair of speakers and not expecting them to work outside their natural mechanical limits (i.e. Pounding bass from a 6 1/2? woofer at 110dB), then you will find volume and headroom to spare. As to the lack of bass or accentuated high frequency response, this is a characteristic of the PA-1. Consequently if you like a fuller more round sound, the PA-1 may not be the best choice for you. Especially if the speakers you?re driving are on the bright or lively side of things. But then again this is all subjective, so possibly what I perceived as a bright or even harsh sonic quality at times is exactly the sound you prefer. It?s worth noting that Nakamichi is a Japanese company and generally speaking Japanese amplifiers exhibit these sonic characteristics. (Obviously as in any generalization, that?s not always the case, but it?s probably true in more cases than not.) In my opinion, that is one of the things that makes audio so much fun. There is no right or wrong and thank God that?s the case, because if it were there would only be one system to listen to and after a while we wouldn?t even know if it still sounded good since no alternative point of reference would exist.

More Information
I sincerely hope you found this review helpful. As an audio consultant and system designer specializing in residential and commercial/professional system designs. I feel I possess a unique perspective in putting together systems that tends to be practical and real world focused. I?m like a lot of my clients in that I am always looking to improve my system and achieve better sound or results, but don?t always have the budget to go ?all the way?. Consequently I welcome any inquiries you may have for my services, I can enter a project at any level and am very comfortable putting together a reasonably priced home theatre or Hi-Fi package, all the way up to the design, project management and tuning of large scale dedicated theatre?s or church/auditorium sound system?s. And of course I also make it a point to always have a selection of inventory available to sell that represents high value and sonic integrity.

Mark Donnigan
Audiocore -- Seattle, WA
Tel: 425-583-0022 ? Email: mdonnigan@hotmail.com

Similar Products Used:

Acurus, Creek, AudioControl, Alesis, Stewart

I drove to Phoenix and got a chance to listen to this model along with the ATI AT1505 (see review). I also reviewed the Sherbourn 5/1500 today (see review) and the Sherbourn can't hold up to either the ATI or the Nakamichi. The set up was as follows
Setup
ARCAM Alpha 7 CD
Rotel pre amp
Audioquest ruby interconnects
B&W 603 speakers.

I started out listening to some Jewel "Adrian" and the sound was just wonderful. Full of life, great depth and lot of air in the vocals. I then went on to listen to some Rush "Xandu" and the intro was right on. All the detail was there, the windchimes rang, and the chirping birds a had lots of depth. I wish I could have auditioned this amp longer, but the store was getting ready to close. Knowing that I wouldn't be buying today and decided not to keep them there. The main thing I notice about this amp compared to the ATI and Sherbourn, was that the base seemed to be a lot tighter and quicker then the others. I also noticed that all though it had a good sound stage it seemed that the amp was more detailed than deep.

If given my personal choice between this and the ATI, my first instinct is with the ATI. Better warranty and build quality seemed superior. However, I think I would need to give these two a listen again before I can say for sure which one I prefer. Both sounded very nice.

Coherent imaging (more on that later),can handle almost any speaker load,drives Accustats with aplomb (much,much better than the Haflers could) utterly reliable. Rich,warm bass.

Midrange/high focus and detail not quite as good as some others in its price class. Not really good on the bass slam issue.(Matter of taste of course).

When I first took the PA-5 home I thought it airy and very nice..until I played Judy Collins and other high-pitched singers. They sounded truly bad,like early solid-state recievers. I put the amp on the test bench and found that it easily met all its specs. So what was wrong? Well,when I put square waves into the amp (a way of testing the transient and phase behavior of an amplifier)they did not come out the way they went in...this is never a good thing. Upon analysis I found that the feed-back loop was not configured to properly address the low midrange/upper bass. Attempting to find out what was up I called Nakamichi. Everyone I spoke to refused to talk to me about it...until I got to one brave tech who told me he knew what I was talking about but would be fired if he said anything!
Well,it turned out the solution was to examine a REAL Stasis amp and incorporate the componant feedback values into the PA-5. What a difference! The amp was warmer with better dynamics and the voices were now coherent. It seems that Nakamichi set the feedback values to make the amp look good on paper at the sacrifice of its real world
performance! At any rate the total cost of parts was $5.00
so I would not hesitate to buy this amp on the used market.
Now to the sound...The PA-5 has a warm softly detailed quality,never bright, and is very gentle on the ears. It produces a COHERENT soundstage. Coherence here means that all parts of a voice (for instance) are located in the same part of the image,that there is no tendency for various parts of an instrument to wander around the sound stage. This is a rare quality in a solid-state amplifier of this vintage. The bass is warm but lacking in slam compared to the Bryston,SAE, and the Dreadnaught (the Dreadnaught can push a speaker right out of its basket!). The midrange/highs are warm but lacking in detail and focus compared to the Sonographe and the Bryston (both newer designs),and the Fet-Valves midrange is much more lush and natural sounding, but the PA-5 holds its character into more difficult loads than the Sonographe and Fet-Valve can.The PA-5 has a very forgiving sound, almost never going harsh or hard.The PA-5 is also very easy for a preamp to drive due to its high imput impedance...I have even let the CD player drive it directly with no bass loss. Even into the Accustat speaker the amp still sounds warm and forgiving. This is one of the best amps for electrostats that I have found of that vintage (it easily out-performed the largest Hafler on the 'Stats. The over-all sound can best be described as coming from behind a velvet curtain...very much like the more expensive Threshold Stasis amps (but without Thresholds power,nearly holographic imaging, and detail),it is a good approximation of the Threshold at not nearly the price. The best statement that anyone can make is that,tho I can find flaws in its performance,I can,and have, listened to the PA-5 for hours without fatigue.

Similar Products Used:

Bryston 3BST,Van Alstine Fet-Valve 300i,Sonographe 250A,Yamaha M-80,Conrad-Dunlap Dreadnaught(A massive powerhouse),SAE.