A ways back, you and I had a good chat about the NAD C 298 amplifier, miniDSP products, and the merits of sub-sat systems. Well, one thing I can tell you is that I’m definitely a sub-sat believer! I added a KEF KC62 to my KEF LS50 Metas, ran a low-pass filter to the sub and a high-pass filter to the mains, time-aligned the system using Room EQ Wizard, and otherwise straightened things out via Dirac Live room EQ. I know the KC62 is not a be-all, end-all sub, but wow! It lifts my setup to a whole different level and absolutely brings out the best of the LS50s. My listening volume and distance are about perfect for these speakers. Thanks for the encouragement to take sub-sat systems and room EQ more seriously.
I now have the miniDSP SHD preamp. I had one reliability problem (the unit bricked itself) and received poor customer service from both miniDSP and the dealer, but, over the course of several months, they got me a replacement unit. I would (and maybe should) have cut my losses, but the miniDSP does things that I cannot find in any other device: great DAC, amazing I/O flexibility, and full control over DSP with the available quick presets (I use one for loudspeakers with a digital source, one for loudspeakers with vinyl, one with heavy parametric EQ correction for my headphone amp, and one I leave completely untouched as my control).
At this point, I can’t imagine thinking through my signal chain and saying, “the DAC warms it up a little, but then my cables cool it down, and my amp makes everything just right for my speakers which are warm, and then my room . . . destroys everything I worked so hard to achieve.”
Once again, thank you, and sorry for the length of this preamble. I look forward to seeing more content on the SoundStage! Network.
Anyway, now for my question. For my phono preamp, I’m auditioning the iFi Audio Zen Phono and found your measurements, which are the only ones out there. I’ll cut to the chase (and I don’t expect a treatise at all): Focusing on the moving-magnet (MM) section, do you consider these measurements to be solid? I gather the signal-to-noise ratio (SNR) is a decent amount short of spec and that the THD+N isn’t anything to write home about, but the latter is mostly due to noise floor and not distortion. RIAA accuracy and overload margin look great. I just don’t know how to rate the whole package in terms of competency and whether it belongs in a serious system, where all the other parts carry their weight and then some (NAD C 298, miniDSP SHD, and KEF LS50 Metas plus KC62 sub). One thing that clouds my judgment is the obvious noise floor and distortion of the vinyl medium itself, and whether that renders any hesitation about the Zen Phono itself moot.
One complication for me is that I’m using the one gain setting you didn’t chart—the MC High (48dB gain/47k ohm input impedance) setting for moving-coil cartridges, which I can only hope performs more like the MM setting than the MC Low and MC Very Low configurations. I’m using it with a MM cartridge and the 48dB gain matches the TAS gain formula, and what I’m seeing in my miniDSP SHD’s input meters show it’s kosher in terms of signal strength (any more gain would likely be a problem, but it’s not clipping and the signal is strong, with no discernable electrical noise—like ground hum—at all). I’m using the 4.4mm balanced output into dual XLRs into the miniDSP preamp.
Sorry for the long message. No worries if you’re too busy to respond, and even the briefest interpretation would be appreciated. In any case, thanks for doing these measurements.
First, it’s great to hear you dove headfirst into the world of bass-managed, room-EQ’d sub-sat systems. Welcome!
Coincidentally, I currently have miniDSP’s SHD Power integrated amp on the SoundStage! test bench. I must say, I’m blown away by the level of customization it has. It took me a while to wrap my head around everything the SHD Power does so I could explain it properly in the introduction to my measurement report.
To answer your question, the Zen Phono measured great overall, and especially for MM. You’ve hit the main points—super-low THD, extraordinarily flat RIAA frequency response (FR), and plenty of headroom. For the MM setting (and I would presume MC High would be very close, with a slightly higher noise floor), everything is pretty much state-of-the-art in terms of performance, except the noise and intermodulation distortion (IMD). These measured results were OK, but not great—but for the price, still pretty darn good. I would stress how great the FR is on the Zen. I almost never see ruler-flat adherence to the RIAA curve from 5Hz to 50kHz. If you experiment with different cartridges, turntables, or other components and hear FR changes, you will always know that your phono preamp is dead neutral with the iFi Zen Phono.
As for noise, I’d just see if you can hear any hum/noise from your seat at a reasonable volume without music playing. If you can’t, then it’s all good. As for IMD, well, it is what it is, as they say. Here’s a point of comparison with an expensive phono preamp I measured recently, the Saturn Audio 401. For IMD at 3kHz/4kHz and 18kHz/19kHz, the Saturn measured -108dB/-104dB to the iFi Zen’s -96dB/-77dB. For SNR, the Saturn measured 100dB (A-weighted) to the iFi Zen’s 89dB. Would you hear these differences? Maybe. I do think that IMD numbers are often overlooked in favor of pure THD—or, even worse, THD+N—which is silly, because music is not a single tone, but multiple tones.
The bottom line is that I don’t think you can go wrong at the Zen’s price point.
Let me know what you decide.