General Asylum: REVIEW: nOrh Audio Control Amplifier (ACA) Preamplifier (SS) by Tyson

First, before we get to the actual review, I would like to give a little background first. Up until about 2 years ago, I had a mid-fi to upper mid-fi system. At that time in my life it was all I could afford. Then we moved to Denver, I got into telecommunications and information systems & started making enough money that I could for the first time really afford to indulge my audio passion. So I started on the "upgrad path" that so many of us seem to spend all of our time/money on. Speakers were my first upgrade - after many auditions of speakers in my price range (upper limit of $3.5k), I stumbled across nOrh on the internet. They were certainly different than anything else I had auditioned & looked particularly well engineered. They were in my price range & I decided to give them a shot. I was very happy/impressed with their sound and their overall level of finish. When nOrh came out with their subs, I decided to give them a shot too, as I really wanted a "full range" speaker. Again, I was very happy with them when I got them. Well, having had good luck with them thus far, I decided to take a very big chance & order their multiamp (I knew their speakers were top quality, but electronics are a whole 'nother ballgame - just because you are very good at one does not mean you will necesarily be good at the other). Yet again, the multiamp was quite a good performer, and I was very happy with the sound of my system (which was now using an Acurus ACD-11 CD player, a modified MSB Link DAC, and the pre outs on a Bryston B-60). Then nOrh announced that they would be coming out with a pre-amp. The same person that had done such a wonderful job on the Subwoofer amp and the multiamp would be desiging the ACA (preamp) - the designer is Werner Hartinger, who I think is a truly gifted engineer. So, while the design is still being refined, I place my order. It takes about 6 months from when I placed my order to get a completed product to my door. I didn't really mind the wait because I was using the Bryston as a pre & it does a nice job, IMO.

So, the ACA showed up a several days ago, and like all of the nOrh equipment, it was extremely well packed - lots of foam packing and lots of packing peanuts. My first impression of the unit when I opened the box is that it is much smaller than I anticipated. About 12 inches wide, but only about 7 inches front to back. It is about 7 inches tall, a 2 layer design, with the power supply housed in the bottom layer, and the signal/control circuitry housed in the upper "deck". This is very smart design as it keeps the toriodal transformers well away from the audio circuitry.

One of my worries when I ordered the unit had to do with the DACT CT-2 volume control. I was afraid that the stepped attenuator would have too much attenuation between "steps", making it hard to get just the "right" volume, and also I was worried that the physical mechanism itself would be stiff & the knob would be difficult to turn. But, neither concern was founded - the attenuation is about 1 or 1.5 db at the most, and the mechanism itself is buttery smooth. Even the input selector switch is pretty smooth. And I love those solid stainless steel knobs.

Enough with the physical descriptions, how does it sound? It is very very good. The first thing that you notice is a whole slew of extra detail - especially in the mids and highs - on orchestral recordings you really can "hear" the hall quite clearly. In fact, on on recording I have of the Brahms Violin Concerto and the Schuman Violin concerto, they are recorded with the same soloist, same orchestra and in the same hall. Between the 2 recordings, you can "hear" he difference in the microphone placements on each recording. Now that is resolving power! The next thing you notice about the sound is the incredible dynamics - without a doubt, in this area the ACA just kills every other unit I have ever heard. You start listening to a piece at what you think is a moderate level, then a crescendo comes along & blows you out of your chair. The macrodynamics are sometimes downright scary. The microdynamics are excellent also - dynamic shading, slight differences in the force of playing are rendered very clearly. It really makes you appreciate all of the small things a virtuoso does to make a performance truly unique.

The next thing you notice is the absolute iron fisted control that the ACA has on bass (I'm sure the multiamp plays a part here too). Not only is the bass powerful and "tight", but most important, dynamic shadings and changes in tone are easily heard. This lends to the illusion that you are listening to real instruments instead of an amalgam of woofers, tweeters, and boxes of electronics. If you listen to much rock or rap or trip hop, you will appreciate that the bass is very forceful and driving.

Another area where the ACA excels is hard to elucidate. nOrh calls it "speed". I am not sure what to call it myself, but I will attempt to describe it. It is how quickly notes start and stop, combined with how voices, intruments, etc, all sound quite distinct from one another, even when they are all playing at the same time. In large orchestral music, the sound does not bleed together & homogenize when the everything is playing at once. you still hear basses distinct from cellos distinct from violins distinct from the various brass instruments distinct from the other wind instruments. This is especially exciting when one or 2 instrument groups are playing a slightly different line than the main body & you can really hear the nuances that a composer puts in to a piece. On piano, it lends the sound a crystaline type clarity and you really hear the resonace of the board when the pianist plays forte, especially on the left hand. It reminds me of what a famous pianist said of his own playing - "Others may play the notes better, but I play the silences between the notes better", or something to that effect. The ACA gets the notes AND the silences spot on.

The final area that I feel the ACA really excels is in tonal presentation. This will be controversial, because others will not agree with me on this, I am quite sure. Let me explain - ever since I started listening to high end audio, there was always a ubiquitous coloration that always has bothered me & to a greater or lesser extent, every piece of gear I heard had this particular coloration. It is a certain "bloomy" quality lent especially to vocals, male and female. If you have ever met a singer in real life & talked to them, they sound similar, but not exactly the same as their recordings. There is a certain "larger than life" quality to their vocals, a bigness that somtimes makes them seem not quite like real people. Sort of like the difference you hear when you break in to song outdoors or in a resteraunt as opposed to singing in the shower. Well, with the ACA (combined with the multiamp), this is the first time that particlar coloration is absent. Johnny Cash no longer sounds like an almost mythic figure, he sounds like a real man who has travelled a rough road. And unlike many SS preamps, the ACA has no hash or grunge or haze. It sounds clean and smooth. And unlike many tube preamps, it does not sweeten the signal one bit. When the music has sharp edges, the ACA reproduces that edge with all of its abrasiveness intact. I like this better than tube pre's because tubed units, while sounding "nice" on most recordings, tend to homogenize the musical presentation, making (for example) Horowitz sound not much different Byron Janis. Of course, many people want to have their music smoothed out a bit & maybe sweetened a bit, to make for a "pleasant" listening experience. That is certainly their right & no-one can argue personal preferences. As for me, as long as the equipment itself is smooth (ie lacking in grunge, grit, hash, etc) I want to have my music without artificial sweetening because that tends to cover up real differences in musical presentation. If the music is sweet sounding, I want it to sound sweet. If it is sharp or rough (Shostakovich for example) I want it to sound rough and sharp. A romanticised presentation of Shostakovich would destroy the musical message. Likewise, a rough or harsh presentation of Holly Cole or Jewel or Patricia Barber would ruin their message or "feel". The ACA is as close to a chameleon as I have come across in this respect.

A couple of other features that I personally will not use, but that others might find usefull are the video passthrough and the head phone jack. I tried out the headphone jack & it sounds very good, but I have my Sennheiser HD-600's set up for my main usage in another room. Also the video pass through is not something I can comment on since I have a seperate HT system in another room. Bur for people wanting to integrate a high quality music system with an HT setup, I am sure it will be very useful.

Well, that is my review, but remember that you have to take this review in the context of my current system. The multiamp in particular is a sonic match with the ACA. With another amp the particular strengths of the ACA might not be as apparent. Also, with speakers that are less resolving than the nOrh 7.0/sub combo, many of the small details would be covered.

REVIEW: nOrh Audio Control Amplifier (ACA) Preamplifier (SS) Review by Tyson at Audio Asylum