General Asylum: REVIEW: nOrh Multiamp Amplifier (SS) by TKP

I still remember five years ago when I first entered the world of high-end audio. I was looking for a two-channel amplifier that would be small, lightweight and sounds great. I wanted to be able to move the amplifier without breaking my back. I wanted it to run cool (so it will not heat up my house after a few hours of play), and I wanted it be to be priced reasonably (I work for a living and support a family of five). After trying approximately a dozen of amplifiers (Adcom, Parasound, Sunfire, Proceed, etc.), I settled for a Plinius SA100 MK III.

The Plinius SA100 MK III sounds great. I believe it is one of the best amplifiers in the world for the money. The Plinius, however, has some serious drawbacks in my book. First, it runs very hot in class A mode. Unfortunately it sounds best in class A so I always ended up using it in class A mode. Second, it weight 70 lbs. (not too heavy but not too light either, and I am getting old). Third, it is big, and it is hard for me to find a rack that provides proper ventilation. Fourth, it consumes a lot of power in class A mode (1000 watts at all time). It could heat up a small room in no time. I live in Houston, TX where the summer lasts 9 months. Even with all these caveats, I still love the Plinius because it provides the best sound for the money, and not to mention its beautiful look and build.

I got the nOrh Multiamp about two weeks ago. The nOrh Multiamp is the creation of Werner Hartinger of Audioform. It comes as close to fulfilling my dream amplifier as any I have previously auditioned. First of all, it is small (11" width, 16" deep, and 6" tall). It is lightweight (around 35 lbs.). It runs cool and consumes very little when idle (5Watts in idle, and maximum power consumption of 270Watts). Obviously, all of this would mean nothing if the sound is bad. I am here to tell you that it approaches the sound quality of the Plinius for 1/5 of the price.

I chose to compare the nOrh Multiamp in passive amping mode (the nOrh Multiamp. has a built in active crossover) with a Proceed HPA2 (MSRP $ 3250.00) and the Plinius SA100 MK III (MSRP $ 4500.00. After extended listening between the three amps. I got the following results:

a) High frequency

The nOrh Multiamp. beats the Proceed HPA2 by a good margin, and edges out the Plinius SA100 by a little bit.

b) Mid-Range

Both the nOrh Multiamp and the Plinius SA100 MK III beat the Proceed HPA2 by a wide margin (no surprise here). However, the nOrh Multiamp tied the Plinius SA100 in this category. The nOrh Multiamp sounded lean, clear, and detailed where as the Plinius SA100 sounded lush, clear with little bit less detail. I could live with either one, and it would be up to the listener to decide which one is better.

As for me, I could live with both. The reason is that there are times I like to listen to music where the female vocal breathes life and lust into the music. Sarah McLachlan's "Surfacing" CD is a good example of this. The Plinius managed to convey the lust in her voice more so than the nOrh Multiamp. On the other hand, there are times I like to listen to human voice in a more realistic manner. The Eagles "Hell Freezes Over" is a good example. The Plinius does not sound as realistic as the nOrh Multiamp for this type of music. It is very close however. We are talking about splitting hairs here.

If I absolutely have to pick one over the other, I would choose the Plinius because I am a sucker for the lust in female vocals.

c) Bass

The nOrh Multiamp. put out good bass, but it cannot compete with either the Proceed HPA2 or the Plinius SA100 MK III. Out of the bunch, The Plinius puts out the best bass, and has the best control over the woofer. It has a lot of guts. I think Peter Thompson designed the Plinius SA100 to be both a racecar and a dump truck where as the nOrh Multiamp. is primarily built for speed. As a result, the nOrh Multiamp beats out the Plinius in speed but falls short in power.

d) Sound Stage

This parameter is very important in music reproduction because this is where a good amplifier will embrace the listener with music. A mediocre amplifier will play the music away from the listener. The nOrh Multiamp sound stage is wider than both the Plinius and the Proceed HPA2, but not as deep as the Plinius. The Multiamp managed to edge out the Plinius in width (I did not think this was possible), and beat the Proceed HPA2 by a good margin. I would rank the Plinius to be the best in this category since it has both width and depth. The nOrh Multiamp. second since it edges out the Plinius in width but falls short in depth The Proceed HPA2 placed last since it falls short in both categories.

e) Imaging

All three amplifiers produced excellent images and were very close in performance. I rank the Plinius is in first place. The nOrh Multiamp is second and the Proceed HPA2 is last.

f) Musicality

This is the criteria that I use to separate an excellent amplifier from a good one. What do I mean by musical? There are amplifiers that produce the entire audio band, but sound cold and un-involving. The Proceed HPA2 is a good example of this. The HPA2 puts out good detail, image, and power. However, it sounds cold and un-involving to my ear. It does not bring the music to me, but instead, it is as if I am looking at the music from a distance. After about an hour of listening to the HPA2 I grew tired and did not want to listen to music any more. There are amplifiers that embrace the listener with the music and breath life into the sound. The Plinius is such an amp. There is another amplifier that equals Plinius when it comes to musicality. That amplifier is the 300Watts LLANO Trinity. The nOrh Multiamp came close to the Plinius when it comes to being musical. I can live with the nOrh Multiamp on a long-term basis and not miss the Plinius.

If money is not taken into consideration, then I would pick the Plinius first, the nOrh Multiamp. second, and the Proceed HPA2 last. That is right, I would pick the nOrh Multiamp over the Proceed HPA2 even though the Proceed HPA2 is listed at $ 3250.00 versus the nOrh Multiamp sells for $900.00.

If money is being considered, then there is no contest. The nOrh Multiamp gives me 95% performance of the Plinius SA100 MK III at 1/5 the cost.

Some people look at the weight of an amplifier to be an indication of good sound. This is true to certain extent because heavier amplifiers usually have larger transformers. However, some manufacturers figured out that some consumers use the weight of the amplifier to be a criteria for buying amplifiers so they put more weight in the chassis and charge the end user more money. Let's compare nOrh Multiamp and the Proceed HPA2 as examples:

The nOrh Multiamp weights 35lbs. However, I guess less than 5 lbs. is chassis weight while the rest is in the circuitry (30 lbs. for two channels or 15 lbs. per channel). The Multiamp employs a pair of R-core transformers are better than toroidals of the same weights. The only caveat is that R-Core transformer is more expensive. I have not seen an R-Core transformer in any amplifier I have auditioned including the Plinius. You can go the nOrh website to see the internal construction of nOrh Multiamp (www.norh.com) to appreciate the work to ensure the signal paths are as short as possible. Most of the cost is put into the circuitry not the chassis. The chassis, however, is solidly built.

The Proceed HPA2 weights a whopping 100 lbs. shipped. However 60 lbs. is in the chassis and shipping material. How do I know that? Well the HPA2 is a dual mono design, and it is upgradable to the HPA3. The HPA3 weights 120 lbs. Shipped. It has one more channel than the HPA2. I subtracted the weight of the HPA2 from the weight of the HPA3 to get the weight per channel for the HPA amplifier from Proceed. In this case the number came out to be 20 lbs. The heat sink of the HPA2 is a lot larger than the heat sink of the nOrh Multiamp. If we take the heat sink out of the circuitry than the weight per channel of the HPA2 is very close to the weight per channel of the nOrh Multiamp, which is 15 lbs.

This means nOrh put the money where it counts and gives the customers value for their hard-earned money. It is refreshing for me to discover a company such as nOrh where they care more about providing good value to consumer more than getting rich quick.

As I mentioned early in the review that the comparison was done with the nOrh Multiamp in Stereo mode (using the speakers passive crossovers). The nOrh Multiamp has an integrated 24db/octave Linkwitz-Riley active crossover. This means I would need two nOrh Multiamps to use it in active biamping mode.

Many audio enthusiasts are not aware of biamping. Most of the ones that are aware of biamping become confused between active and passive biamping. I am not going to explain the differences because it will make this review too long to read. You can contact me if you want to know the differences.

If I have the money, then my choice of amplification would consist of a pair of Plinius SA100/SA250 and an active crossover such as the Bryston 10B (MSRP $ 1500.00). The cost for this configuration would be $ 10,500.00 for a pair of Plinius SA100 MK III/Bryston 10B or $ 18,500.00 for a pair of Plinius SA250 MK IV/Bryston 10B. Even with 25% discount from dealer (most dealers won't discount this much) we are taking almost $ 8,000.00 and $ 14,000.00 respectively.

I am not made of money therefore I would choose the path that I believe most of us would, a pair of nOrh Multiamps with a price of $ 1,700.00 per pair. I believe this choice of amplification would give me at least 95% of the sound of the Plinius SA100/Bryston combination or might be even better. The reason why I say it could be better is because the built-in active crossover of the nOrh Multiamp is a 24db/octave Linkwitz-Riley where as the Bryston 10B is only 18db/Octave. You can get a 24db/Octave at a fixed frequency from Bryston at additional cost.

If you look at cost wise, a fixed frequency 24db/octave Linkwitz-Riley active crossover from Bryston would cost as much as a pair of nOrh Multiamps and you get a pair of world class amplifiers for free from nOrh.

I will evaluate the performance of the nOrh Multiamp in active biamping mode in a few months, and put a follow up review on the performance.

Associate Equipment:

Custom built tube preamp.
Rega Planet CD Player
Proceed HPA2 2-channel amp.
Plinius SA100 MK III 2-channel amp.
nOrh 7.0 speakers
nOrh 4.0 speakers
A pair of nOrh subwoofers
Monitor Audio 705 PMC
nOrh Silver Interconnects
nOrh Silver Speaker Cable
Power Wedge 116 MK II
Audiodyne Power Cords

REVIEW: nOrh Multiamp Amplifier (SS) Review by TKP at Audio Asylum