Ross Martin PCM4222 ADC <- Pics and Audio Sample!

Snapped a couple pictures tonight of the PCM 4222 ADC. Samples coming soon!

Here's one sample of how the PCM 4222 ADC sounds:

Don Slepian - 'Reflections'


This was my Zyx R100H on my Denon turntable, going through the Audio Research PH5 preamp and into the PCM 4222 ADC via RCA to XLR adapters. The gain was set to max on the PCM 4222. The coax output was sent to my Focusrite Liquid 56 and recorded at 96K/24bit. This is the raw audio with no post processing or cleanup.

The sound quality seems to fall between the Presonus Inspire and the Apogee Rosetta AD. I guess I should remember that it's brand new and will need some time to break-in.

I'll post more samples tomorrow with the Zyx Omega G.

I'm considering to buy a Ross Martin PCM4222. How are you getting on with yours? How does it compare to the Apogee Rosetta? The PCM4222 doesn't cost the earth but should I consider anything else for around the same cost? I am looking to transfer some of my precious vinyl collection with it. Any chance for some more samples from yours? Many thanks.

Hello, and welcome to the forum!

After using my PCM4222 for the last few months, I have to say that I prefer the Apogee Rosetta by a wide margin over the PCM4222.

First, the PCM4222 uses +4dB XLR inputs, which is a problem when recording vinyl directly from most phono preamps, which use the more familiar -10dB RCA outputs. You can buy a converter box (Like a Radial ProAV2) that will step up consumer, line level (-10dB) signals to professional level +4dB, but since I'm a purist when it comes to audio fidelity, I don't like the idea of placing extra equipment between the source (turntable -> phono preamp) and my recording interface, which can alter or color the sound quality. The XLR and 1/4" inputs are wired for +4dB (TRS on the 1/4"), so using a RCA to XLR (or RCA to 1/4") adapter will yield the same results; which is, the signal will be too low to record with decent dynamics; even with the levels cranked all the way up. (Especially when using a low-output moving coil cartridge)

Second, the internal wiring is somewhat of a concern to me, since the implementation of the PCM4222 chip is pieced together from an 'evaluation' board, wired haphazardly to other home-made boards and wired together with not much concern for signal path lengths or signal degradation. The engineering philosophy of Ross Martin seems to be that wire choice, wire routing and component quality don't matter, but I strongly disagree. I think he would be of the mindset that believes interconnects and speaker cables along with film caps over electrolytics is hogwash; and the internal wiring and design of the PCM4222 reflects this. Remember, the PCM4222 is not a single board design, the heart of it is the PCM 4222 evaluation board available from T.I., which is then hard wired to his own 'home-made' support circuits; which isn't the cleanest of designs. From my auditioning, the result is mild hiss and background noise and a slight loss of low level detail.

Third, I've had some issues with the clock connections (BNC connectors for clock master/slave), specifically, when using it with long cable runs (more than 25 feet). If I use a 30 foot BNC to BNC to pass the master clock signal from the PCM4222 to my Focusrite Liquid 56 recording interface, my interface has a problem locking on to the signal. The same issue happens when I use the RCA SPDIF digital output, the signal is too weak to be used with a cable longer than 15 feet. For comparison, my Apogee Rosetta's clock can easily be locked onto through 30 foot of cable, as well as the RCA SPDIF digital output. Plus, I've yet to see the PCM4222 lock onto an external clock - it just sits there, silent. Maybe my PCM4222 is defective, I just never found the time to contact Ross Martin and send it back for repair.

Fourth, the sound quality is nice, but when I critically compare recordings made by the Apogee Rosetta and the PCM4222, to me at least, the Rosetta sounds more refined in the mid-range with much cleaner and sweeter highs. The bass of the Rosetta is excellent (very deep, pure with plenty of 'weight'), but it can sound a tad 'phasey' (detached from the midbass) and 'monochromatic' compared to my Presonus Inspire, which sounds quick and punchy. The PCM4222 has very good bass extension as well, but it sounds flat and dull compared to the Rosetta or Inspire. Both the Rosetta and Inspire have better weight and presence to the bass than the PCM4222. Overall, the sound quality of the PCM4222 falls between the Rosetta and the Inspire.

Fifth, the LED level meters on the PCM4222 are not calibrated which makes it impossible to use them to adjust the input level accurately.

By comparison, the Apogee Rosetta is much better suited for recording vinyl than the PCM4222. First, the input sensitivity can easily be changed from +4dB to -10dB by flipping a DIP switch on the back of the unit. Second, the input levels on the front are multi-turn pots which gives you finer control of the input level and better channel matching. Third, the Rosetta has a built-in limiter which helps prevent clipping on vinyl with noisy clicks and pops. Fourth, the LED level meters are calibrated and feature two LED's to notify you if a channel has clipped. If a clip is detected, they stay lit until you press the reset button. The PCM4222 has two clipping LED's, but they simply flash when a clip is detected, which is not very helpful. Fifth, the component selection and clean, professional layout of the Rosetta's internal design lends itself to better sound quality. There's no jumper wires and the signal path is short and symmetrical.

Overall, the PCM4222 is nice for the price, but IMHO, the Apogee Rosetta is a much better unit. It's easier to use with line-level (RCA equipped) gear and the sound quality - even at 48K/24bit - beats the PCM4222. It's a perfect match for archiving vinyl. 

When I get a chance in the coming days, I'll try to post a few more samples. What types of music do you prefer to hear?

Thanks for such a detailed reply!
I'm using a Burmester 838 preamp (I have replaced the opamps with Burr Brown ones which improves the sound in every way) This has dip switches to adjust the gain and even with my low level output Van Den Hul MC10 Cartridge, it puts out plenty of signal, which will probably be enough for the RM PCM4222. I am concerned about some of your comments about it though. There is very little written about this unit apart from it sounding so good. I have a limited budget at the moment and wouldn't be able to spend much more than what the PCM4222 costs.  Any ideas what else is worth a look for similar money, new or used? I still haven't ruled out the PCM4222. Many thanks.

My Ross Martin PCM4222 ADC is for sale - click here!