PS Audio’s NuWave Phono Converter

The PS Audio NuWave Phono Converter (NPC) is a fully balanced analog phono preamplifier, but also has a built-in Analog-to-Digital Converter (ADC) as an optional way of using it. For a phono cartridge, it can handle both Moving Coil or Moving Magnet. I have been using an NPC for some months now, ever since I started reviewing and using turntables -- after a 30 year lapse. At first I borrowed an NPC from a friend; but I eventually bought one for my system, being suffciently impressed to do so.

The purpose of this article is to offer an overview of what the NPC can do, how to use it and why it is a very important high-end audio device as we continue to steam ahead with an increasingly digital future. It is an amazing unit that deserves some attention and quite frankly has been fascinating me ever since I first began using it. It almost seems magical.

Using the option of ADC allows one to pass on (on the fly) the created digital signal to your Digital-to-Analog Converter (DAC) for play or even record the file as a PCM or DSD file (to play on DACs upon demand). If this sounds a dash confusing, don’t worry, it should, and so I will carefully explain all of this in more detail in what follows.

Physical Specs

The NPC unit is 14”(L) x 8.3” (W) x 2.4” (H) and weighs 14 pounds. You can use your own power cord if you wish. It comes in black or silver, and retails for $1899 [Price update as of March 18, 2016; $999 and sold factory direct only, making this the analogue deal of the century! - Ed]. Those with a PS Audio NuWave DAC might recognize its looks because it uses the same case (14”(L) x 8.3” (W) x 2.4” (H)); but this NPC is a very different animal.

The front has a small blue power light in its upper left corner (alerting you that the unit is powered on), while more centered is a black monitor surrounded by four small control buttons for selecting/controlling the various functions/modes for use such as adjusting the gain or choosing digital versus an analog path. When a button is pressed, the monitor shows blue text, which then goes off (to save energy) after a pre-specified amount of time (20 seconds for example). The power switch is on the back, as are all inputs and outputs, and as with most PS Audio products, it is suggested to always leave the unit powered on. It emits no noise.

Using the NPC as an analog phono preamplifier for playing vinyl

Used in this manner, the NPC is a high-end passive EQ 3-stage architecture based on a THAT 1532 programmable input stage (e.g., a very fine programmable operational amplifier). Analog input for a turntable (labeled ‘phono’) is via RCA. For analog out (phono (turntable) only), there is one pair of balanced (XLR) and one pair of RCA for going to preamplifiers (or a mixing console); you can connect both at the same time. There is a ground binding post in the upper right corner for attaching a ground wire from a turntable. Cartridge loading options (a wide range) are dealt with by flicking DIP switches up or down in pairs (one for the right channel, one for the left). As mentioned earlier, both Moving Coil or Moving Magnet cartridges are supported.

Note: In addition to the phono input, you can also connect a second analog input at the same time (such as a tape deck, or FM tuner) using the second pair of RCA inputs (these are not for using a turntable they are not labeled ‘phono’). If you have both inputs in use, you can select which of the two inputs you wish to use from the NPC’s front panel. Analog out from the NPC is reserved solely for a turntable (phono) input, not another analog input; the other one is for digital out only. More on why one would want to do that will be discussed later in the digital sections.

Using the NPC as an Analog-to-Digital Converter (ADC) for playing vinyl

Once your turntable is connected to the RCA analog phono inputs of the NPC, instead of going analog all the way you can opt to have the NPC convert (on the fly) the analog while playing live on your turntable to digital which in turn is sent directly to your DAC for play. This is how I use it. This is where the magic begins. The digital formats can be chosen as either PCM or DSD from the front panel and you can choose the resolution desired too (up to 24/192 PCM, and single or double rate DSD). [Oh, how I'd like a shootout with the similarly-priced, all analogue Rega Aria phono stage I just reviewed - Ed]

As stated in the user manual, the NPC ADC converter ‘is based on the Burr Brown PCM4222 Delta Sigma Analog to Digital Converter. This architecture runs as a core DSD converter, sampling at a constant rate of 352,800Hz (5.6MHz), for any analog input signal.’

For best sound performance it is highly recommended by PS Audio (and confirmed in my experiments) that one should use 24/96 for PCM, and for DSD use single rate. Moreover, you can even ‘rip the LP’ by connecting the NPC with a USB cable to a computer and saving the digital file created (amazing); more on that in the next section.

Why would one want to use the NPC in a digital way you might ask?

Because it can dramatically simplify/streamline your audio system and do so without (in my opinion) losing quality of sound: it helps rid us of this ‘analog versus digital’ controversy, and does so in a way that can satisfy both sides of the aisle — I now have a wonderful VPI turntable and can use it on my system; I can play vinyl again without going thru all the additional hoops, hurdles and cost of analog only -- and the sound is divine. And for analog purists, one can go all analog using the NPC if they so wish. My DAC (as with many others) has an internal volume control, and hence no external preamp is required. By then going direct to amps from the DAC, in the end I only need one pair of analog interconnects (as opposed to 3 pairs if I were to use an external preamp!). My DAC serves as the preamp/volume control for running both my digital music server (Mojo Audio upgraded Mac-Mini) and my turntable (an upgraded VPI Scout). I can choose on my DAC which source I wish to play. Need I say more?

There are two digital outputs for going directly from the NPC to a DAC: S/PDIF, and I2S (using an HDMI cable). The method of sending the I2S with an HDMI cable was developed by PS Audio and is the superior way to go (because I2S is the native protocol for digital audio used in all DACS, CD players and transports; S/PDIF is not). But it can only be used if your DAC can accept I2S with an HDMI cable (it is a non-standard use of such cables); PS Audio’s DirectStream DAC does so, and that is how I use it. But you can just use the S/PDIF otherwise; essentially all high-end DACs allow that. Warning: Although there is a USB output, it is not to be used for going to a DAC: It is only for connecting to a computer (Mac or PC) for recording the digital output as a file.

Ripping vinyl

By connecting the NPC to a computer using a USB cable, one can save the converted digital output of an analog input as a file that can then be played on a DAC anytime you so wish. By far (as usual) it is so much easier to do such things on a Mac versus a PC, so I only report on that here since I have never been able to use a PC (for any purpose) without getting hopelessly frustrated. I also will only focus on doing so with a turntable as analog source. (One can make digital copies from an FM tuner for example, too.)

Minimal software is needed, besides the Mac’s own always provided Audio MIDI Setup app (found in the Utilities folder), and the NPC is only connected to your turntable and computer to succeed. All else of your audio system is irrelevant (e.g., your speakers, amps and DAC are not involved), and I strongly suggest isolating the three needed components so as to avoid additional ‘noise’ issues; and turn off all non necessary software and turn off wireless and bluetooth. To isolate further, I used my MacBook Air instead of my system’s Mac-Mini, and tried to keep it as far from the turntable cartridge to reduce any buzzing; grounding the turntable is crucial.

Connect the USB cable from the NPC to your Mac, and make sure to ‘enable’ the USB via using the front panel of the NPC (always keep that USB enabling off otherwise). Choose what you want PCM, or DSD on the front panel of the NPC. At this point, if you chose PCM, the PCM resolutions desired (24/96, etc.) and PCM file format (AIFF, FLAC, etc.) are then up to your computer software for choice (not the NPC), so, be careful what you do. I mainly used PCM (as opposed to DSD) since then I could more easily share my ‘masterpieces’ with friends who might not be able to play DSD files. I kept the resolution as 24/96 and used uncompressed FLAC or AIFF as the final product. An album ripped this way can easily be at least 1 GB in size. If you wish to save space, using 16/44.1 is just fine sounding.

I have been using Audacity 2.1.2 as the recording software; it is free and does the trick; there are others for sale that are more sophisticated. Another free external software required is LineIn.app, which is explained here in the PS Audio NPC owners manual, as is the required set up for using Mac’s Audio MIDI Setup app.

With Audacity, you choose the ‘PS Audio USB 2.0 Audio in’ as input (as opposed to ‘Built-in Microphone’), create a new project and push the record button when the needle is on the record (or right before) [I'd suggest after needle has dropped. Karl sent me a converted AIFF of the recent Haydn 45 rpm I reviewed, and the it began with an almighty bump of the needle hitting the vinyl - Ed]. After side A of an LP is over, you can push the pause button wile you flip the album to continue; just push the pause button again to re-start. When finished, stop recording. Then use ‘Export Audio’ under ‘File’ to save/convert the file; it is at that point where you will be able to choose AIFF, FLAC, etc., give the file a name, and add in any metadata info.

An example

My favorite reference LP recording so far is one recently suggested by my Editor, a 45 RPM Supercut of Haydn’s Symphony 101 in D major, Robin Ticciati, Scottish Chamber Orchestra (Linn Records 2015). Perhaps one of the very finest LPs I have ever heard; I love it. The natural timbre of instruments, the air around and separation of instruments is out of this world, and the performance is remarkable, too. But I now have a 24/96 digital copy, and I love that as well.

Summary

Suffice to say that I could not tell a significant difference between playing my turntable digitally, and using a pure analog path; the NPC performs a terrific job either way. Typically, people visiting (including audiophiles who prefer vinyl) never knew I was using the turntable through my DAC unless I told them; and sonically they claimed to hear ‘analog’ when vinyl was playing digitally. (Those familiar with the outstanding DEQX products, which have both a ADC and a DAC built in, will perhaps have had similar experiences.) I also sometimes played a 24/96 copy and often too could not tell the difference between playing that and playing the record. Sometimes my own digital rip (of an outstanding LP) sounded better to me than a CD of the same piece. This all continues to amaze me; I hope it will amaze you, too. And one can always use a separate preamp (for a pure analog path) if they so wish; I sometimes will want to do so when reviewing equipment side by side or perhaps reviewing a preamp itself. Bingo.

Further information: PS Audio