NAD C160 Preamp. Audio Heaven Part 1.
Dec 18, 2001 (Updated Feb 20, 2002)
Review by mnehr
Rated a Very Helpful Review
Over the past six months I have been slowly re-building my sound systems both in my cars and in my home. Instead of attempting to find the best value (i.e. cheapest) equipment, as I have done in the past, I am building my home theater with components that I plan on keeping the rest of my life (still with in a reasonable budget.). It is a general rule that with any stereo system, the quality of your system is only as good as the weakest link. In a series of reviews on the building of this system, I will build the ‘chain’ link by link, in the most logical progression of components, as an average consumer would buy them. Normally, the start of ones audio-visual chain would be the receiver, however, I am actually starting with the power for the system.
Recommend this product?
The main power amplification for my system starts with a NAD C160 pre-amp, one Bryston 3BST, two NAD C320 amplifiers and an Audire Monarch Mono block 1200 amplifier, (not found on Epinions.) For this review I will discuss the start of this chain, the NAD C160 pre-amp.
What is a pre-amp?
Think of a pre-amp like a switching station at a railway station, you have many different tracks coming in and going out. At the switching station is decided what trains go out on what tracks. A pre-amp works in basically the same fashion. In most high-end sound systems, you have your signals coming in from many separate sources. Your receiver, tuner, CD player, tape player, record player, as well as a host of other components can be part of your audio-video system. It is up to the pre-amp to tell what signal it is receiving, where to send its sound. For middle to low end systems, the pre-amp built into most receivers suffices to switch the various signals to various amplifiers in the system. For higher end systems, however, the complexity of amplifiers and signal sources demand that a higher level of control be attained.
In addition to providing a ‘switching’ system for all your components, a good pre-amp will also allow the user to customize the voltage (or gain) of signal going to each amplifier. Pre-amps do not send power out like one would think of as the wattage in an amplifier, instead they send as pure of a signal as possible with virtually no wattage going to the amplifiers. While this may be only one or two watts of signal, the voltage of that signal can be adjusted to best match the amplifier’s sensitivity. In layman’s terms, one can match the quality of the signal going from the pre-amp to the amplifiers. Too much voltage, will result in a distorted sound, while too little will result in the full impact and quality of the sound not being experienced.
I specifically chose NAD components for my pre-amp, two of my amps, and my receiver because they were the highest quality I could find with out pushing my system budget into the six-figure range. The C160 only cost $600.00, yet I found it to have the same features and quality that are found in $1,000 to $5,000 components from Adcom and B&K. I also received a discount through a local retailer on most of my components, which sweetened the deal even further.
The C160 is the flagship component pre-amp that NAD makes. Its simple design hides the fact that this is a complete component pre-amp. The controls on the C160 go back to the rotary knobs that one would find in vintage Luxman and Marantz equipment, forgoing the overly-complex digital controls that most of the major audio manufactures have gone to. I actually have missed having rotary knobs, especially for my volume control, as it seems far easier to find that ‘sweet spot’ in your sound, versus punching an up or down arrow button for the right ‘number’. Although the remote does not mimic the simple control found on the pre-amp, it still does not waste the users time with unnecessary controls. Source selection also gives us a flashback of vintage high-end components, using simple buttons to select each component. In addition to the source selection and volume controls, the receiver also has your obvious treble, bass, voltage (gain), and remote on/off switch. One important part that I found necessary is that the tone controls on the pre-amp can be bypassed for use with external equalization. Although this is a simple feature, it saves a lot of problem when adjusting your sound.
One problem I had with the C160 is that it does not have the standard side mounting brackets found in many other components. Even though it is light, at only ten pounds, this will have to be placed on a shelf, instead of mounted to brackets. Currently all my components are just on a shelf, but I hope in the future to have a professionally made mounting system.
The C160 includes 6 line level inputs, two tape in/outputs with dubbing facility, two line level pre-amp outs, independent headphone amplifier bass and treble controls with tone defeat switch, and most importantly a 12-volt trigger. The 12-volt trigger automatically switches the pre-amp to a preset device when that device is powered on. All of the connectors are gold plated, giving the best contact with the least resistance (ohms).
Using the highest quality components, the C160 offers a very strong link in the audio chain. The C160 utilizes completely new, innovative circuit topology that allows for investment in high specification, close tolerance components. Metal film resistors, polypropylene capacitors, hermetically sealed relays and the Alps "Blue Velvet" motorized volume control are a few examples of this. Special attention was given to the power supply section of the C160. The toroidal transformer has 4 separate secondary windings followed by 6 main low-noise regulators. From here no less than 6 super low-noise subsidiary regulators and active filters are used to maximize supply rejection for all sections of the C160 to more than 100dB.
To give an accurate test of the difference in the sound quality of the C160 I subjected the system to a comparative test with and without the preamp. For this test I used only the Phase Tech Tower 10 main speakers connected to two NAD C320 amplifiers and the Phase Tech Power 15 subwoofer connected to the Audire Monarch Mono block 1200. I bypassed the surround speakers as well as the rear channel speakers, using only a direct signal from my receiver. For all of the tests I used a Boston Acoustics audio test CD and an old System 824 RTA/SPL meter. I also set all gain and equalization settings flat so there would be no change based on these additional factors.
First I listened to the first two selections on the test disk with the preamp bypassed. Adding in the preamp their was a noticeable difference in the quality of the sound. Overall the sound had a fuller, richer feel to it and the bass was much stronger. I also had the opinion of increased depth to the sound. To see the overall system difference on my RTA meter, I set the disk to repeat a track of ‘pink noise’. The readings on my RTA meter confirmed what my ears were telling me. On the lower end I picked up almost .5db in the 10-50hz range and 1db in the 100-250hz range. On the upper end I had even greater gains in the 5,000hz range, acquiring over 1.5db. By using the preamp in its proper fashion and adjusting the gain settings back to what was optimum for my system, (I used a little piece of tape to keep note of what my optimal settings were during this test), I was able to pick up another 2% in decibels over the aforementioned flat settings. There was a noticeable decrease in THD on the lower end when using the preamp and overall the harmonic curve was much smoother.
For all those people who wish to know every ohm and volt, I have included some technical specifications of the C160. I have only included the specifications that I find important in choosing a pre-amp, however, the manual will go into much greater detail on the included specifications for each channel and each possible setting independently.
Input impedance 47k ohms + 470pF
Input sensitivity 2.10mV MC
Signal/Noise ratio 80dB (1k Source)
THD (20Hz - 20kHz) and IM distortion
Line Level Inputs (CD, Video, Tuner, Tape1, Tape2, Aux)
Input impedance 500k ohms, 320pF
Input sensitivity ref. 0.5V 150mV
Signal/Noise ratio ref. 0.5V )100dB
Frequency response 20Hz-20kHz
Line Level Outputs
Output impedance Pre Out 75 ohms
Pre out2 (Variable) 350 ohms
Controls (Volume Setting @ 12:00 position)
The manual on the C160 is actually far more complex than the component itself is. As I have stated, every possible technical specification for every possible component arrangement is included. Although this seems like overkill, when building a high end system of many components, often times from separate manufacturers, it is important to match the voltage to each component for optimum performance.
Normally I would go into the instillation and set up of a product, but in the case of a high-end audio system, every instillation will be different depending on the components that a part of your system.
For the short time I have been using my system, I have been very pleased with the performance of the NAD C160. In a chain of components, this is proving to be a very strong link tying my audio system together. Stay tuned for the future installments of a series of reviews on my new audio-visual system. I will also be eventually including photos of the instillation on my profile page so everyone can see how the system comes together as a final package.
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Amount Paid (US$): 600.00
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