Rek-O-Kut Professional Moving Magnet Preamp mk II:
Sensitivity: 3.5 mV
Rated Output: 300 mV
RIAA Deviation: +/- 0.25 dB
Sub-Sonic Filter: 6 Hz
Signal/Noise: Better than 80 dBA
Input Impedance: 47 kOhms, and 220 pF
Output Impedance: 600 Ohms
Overload: 35 mV
Maximum Output: 2.9 Volts
Crosstalk: 45 dB at any frequency between 20 - 20 kHz
Dimensions: 5- 5/8" X 1-1/2" X 3-1/4"
Shipping weight: 2 Lbs
THD: Less than 0.02%
Hum & noise: 85 dB below rated output
Response: 20 to 20 KHz +/- 0.5 dB
Max input: 3.5 volts rms
Turnover: FLAT, 300Hz, 400Hz (AES), RIAA (NAB), LP, 629Hz, 800Hz, 1000Hz
Rolloffs: FLAT, -5dB, BBC, -8 dB, -10 dB, -12 dB (AES), RIAA, NAB
Input Impedance: 100 k ohms
Power requirements: 120/240 VAC, 50/60 Hz
Dimensions: 19" X 1.75" (rack mounted)
Rek-O-Kut Professional Moving Magnet Preamp mk II: $69.95 + $7.50 Shipping
The current state of the music and consumer electronics industry is pretty much total chaos. I stopped keeping tabs on which digital format was “best,” or which digital connection was “best,” or the infighting between factions (rearranging the deck chairs). I’ve probably missed entire formats after I stopped caring about “state of the art” hardware and software. Not that analog didn’t have growing pains, false starts, and odd detours. It’s true that learning the history of the analog disk can be confusing, especially if you are a true collector. There are archivist, mastering engineers, musicologists and collectors who will get into long arguments about some bit of minutiae. But it’s not like you can’t play a 1950 Columbia LP with a 2011 Koetsu. Regardless of who recorded it, mastered it, or pressed it, analog will continue to do its intended job for the foreseeable future. The technological basis for the analog disk is superior to digital. With one turntable, and one cartridge, you can play every disk-shaped record ever made (the cylinder is a different story). You can get dozens of styli for moving magnets that will satisfy every possible scenario of groove size and condition. When we can’t figure out how to play a CD in 100 years, the analog disk will still be viable media. With such clever marketing as “download included,” we have rendered a silver disk irrelevant. If I can put it in a MP3 player or music server, I don’t need to put a disk in a player. And, when I really want to enjoy it, I’ll put it on the turntable.
Besides the official history of audio, according to the guys with the money, there are hundreds of stories that are forgotten, sitting in the back of trade publications from before your parents were born. But it matters little. Those guys are mostly dead. What we are left with is an amazing legacy of recorded sound that evolved, changed, and occasionally improved, to the present day. With so many recordings, so many people mastering and pressing records, a certain amount of confusion can be expected. If it were left up to the high end dealers, you would have a really expensive rig that sounds great with expensive audiophile reissues, but not so good on everything else. Well, there are buyers like that, but many of us find records at thrift stores, garage sales, eBay and from friends and relatives. How do you get the most from your records? What do you do if it sounds bad? Throw it away because it sounds bad, or try to figure out why it sounds bad in the first place? Does it really sound bad, or are we forgetting something? For those of us who are interested, there are solutions.
The subjects of this review are so inexpensive that I fear most people would assume they are “junky”. It’s a mantra worth repeating in every review: Just because it’s cheap, doesn’t mean it’s junk; just because it’s expensive, doesn’t mean it’s good. Non sequitur (it does not follow). The Rek-O-Kut Professional Moving Magnet Preamp mk II, and Re-Equalizer II weren’t built with audiophiles in mind, though the designer did not purposefully take short cuts, or build a unit with low quality the goal. You won’t find input and output jacks that could double as grape-shot, or face-plates that weigh more than the fully stuffed circuit boards. What you will find is pragmatic engineering, with carefully chosen circuits and parts.
Between The Lines
While I completely embrace antique technologies, and believe that some pieces were designed to be as good as they could possibly be, I don’t deny that more recent developments can offer solutions that equal or better a classic design. Modern vinyl formulations are very good; regulated power supplies are quiet; exotic tonearms and cartridges can be miraculously revealing, and (gasp) transistors can sound really good (which really isn’t a modern technology—being proposed in 1925). Considering the asking price of the Rek-O-Kut Professional Moving Magnet Preamp mk II (or PMMPii), it was a good idea to use transistors. By its very nature, tube equipment is more expensive to build, and a cheap tube design will probably suck because of shortcuts.
The PMMPii does have respectable numbers for a budget piece:
*Highly accurate RIAA record compensation.
*Includes 39 inch 43 pF/ft interconnect cable.
*Input matched to most high-quality pickups.
*6 Hz subsonic filter to cut ultra low rumble.
*Includes cable for computer soundcard.
*High-quality, gold-plated RCA jacks.
*Discrete component design.
*Power: 120 VAC/60 Hz.
*Low hum steel case.
There are some measurements on Esoteric Sound’s page that compare the noise and RIAA accuracy of their little black box against a rebuilt McIntosh tube unit, and a later transistor model. If you look at the charts, it would give you the impression that the Rek-O-Kut is “as good as” the two McIntosh units. To some extent, I disagree. The PMMPii is better than the Mac tube unit, based on my experiences. The McIntosh C20 uses the 12ax7 as the phono tube. All of the golden era 12ax7 phono stages I’ve heard have relatively poor low-level resolution, poor dynamics, high levels of spurious noise, sluggish bass, and a gelatinous soundstage. The measurements don’t tell the whole truth, to the detriment of Esoteric Sound. It’s interesting that the noise figure of the PMMPii is similar to a restored McIntosh C20. I’ve had several tube McIntosh pieces and none had a noise floor as low as the PMMPii. I’m at a loss to explain why they would have similar noise figures, unless the test equipment or setup was somehow limited.
You might say I’m venturing out on a limb with the following statement, but I will stand by it: This little preamp is better than most “classic” 12ax7-based phono stages I’ve heard. Over the years, I’ve listened to, worked on, built, rebuilt, tweaked, tweaked, tweaked some more, and got rid of every 12ax7 phono stage that came through the system. I think the biggest problems with those designs are the tube itself, such as low current, high plate resistance and higher noise. The circuit components are no better: high resistances are used, which create several types of noise, some of which are endemic to all resistors, regardless of how much you spend.
I’ve seen audiophiles do just about everything possible with a 12ax7 to get detail, dynamics, sound-staging, etc, but be frustrated with the results. The strength it has in gain, it gives up in noise and distortion. You might imagine that the lower gain of the 6dj8 puts it at a disadvantage to the higher gain 12ax7 , but that’s not always the case. It has plenty of useable gain because the high tranconductance and lower plate resistance means less noise, better dynamics, better drive, etc.. I’ve had good luck using medium output moving coils with phono stages using the 6dj8 (and variants). Then there was the rediscovery of industrial tubes, like the 417a, E810f, d3a, etc.. A carefully selected 12at7 with a constant-current-source load would be better than a 12ax7. The bottom line is that you shouldn’t waste your time restoring or modifying a Dynaco PAS when you could have better sound with the PMMPmk.2, which costs less than one NOS Telefunken 12ax7. It has none of the golden ooze, or noise, of a “classic” tube unit, while largely avoiding the sterile sound that is the trademark of hyper-fi transistor units.
So, even though the PMMPii doesn’t present itself as an audiophile component, Esoteric Sound took time to compare it to units specifically marketed to audiophiles (the two McIntosh units). If you read between the lines, Esoteric Sound is implying that it’s good enough for an audiophile. The marketing literature does say “designed for both home as well as broadcast and studio applications”, and I believe it. The output impedance is 600 ohms, the standard for professional work. That means it can drive extremely long cables and any preamp or amp you could produce. Where some tube phono stages would be compromised driving a transistor preamp, the PMMPii can drive anything, outside of something that is a very poor design, or broken.
I won’t tell you anything about the insides other than it is all discrete, and Mike at Esoteric Sounds says it was “tweaked forever.” There is no superfluous stuff here, and not much of anything that the traditional audiophile would see in a pricey unit. That doesn’t mean anything, though. Most of the expensive capacitors are made on the same equipment, using the same techniques and materials that make the “cheap” capacitors. Mike’s goal was to make a good, clean phono stage, which can be used both by archivists and regular music lovers, and the result was the PMMPii.
I’m not going to blab on and on about how this phono stage is a revelation, and kills phono stages costing thousands. The sound is very good. There are better sounding units, and they are all significantly more expensive. To compare it to a relevant “rival,” by price-point, I tried listening to the little NAD phono stage. The NAD can’t touch the Rek-O-Kut. The NAD was borderline unlistenable at times, where the Rek-O-Kut provided pleasurable listening.
The PMMPmk2 is fundamentally honest, with very low distortion. Background noise was totally absent in my system. At 11 o'clock I could hear some 60Hz buzz, but it was so far down as to be irrelevant. Not to mention that the 60Hz might have been in the preamp, or induced by poor component placement, or by cable dressing, or even the slings and arrows of outrageous fortune... Bass is very tight and relatively deep, not thuddy or overripe. Records with good soundstage width were served well, though depth was a little shallow.
There are limitations to the unit. It doesn’t have crushing dynamic impact of bigger/badder transistor relatives. Though the bass is tight, the bottom octave was a tad soft. The unit includes a subsonic filter, starting appreciably below what would normally be considered “audible” bass. Is it causing a slight rolling near the audible range? As much as I’d like to find out, it’s a trivial issue. It’s possibly a power supply or capacitor thing. On a couple tracks, loud passages were a bit compressed. I noticed occasional brightness in bells, cymbals and loud brass. It’s very possible that it was the Shure making “noise,” but I didn’t have a better moving magnet on hand to double check. The PMMPmk2 didn’t have the high gain necessary for my moving coils. Besides, it makes more sense to partner this phono stage with a Shure V15 than a fiddly $5K moving coil. The Rek-O-Kut doesn’t have the microscopic resolving power of extremely sophisticated transistor units, especially the balanced ones.
There isn’t the three-dimensionality and depth of finer tube units. However it does a good job of placing images outside the speakers, and better than most tube units it seems. In tube units, unless parts are carefully matched, including the tubes, the ability to cast images outside the speakers is greatly diminished; this is easier to accomplish with transistor units. It doesn’t sound sterile or lugubrious, the two possible extremes in phono stage characters. The vestigial power supply is probably a limiting factor (and probably the capacitors, too). It would be a rewarding experiment to replace the wall-wart with batteries, and then replace the capacitors with Muse, Cerafine or other high performance capacitors. Or it might be a waste of time. If I get around to it……..
Tickets for three to an amusement park? Twelve extra value meals? A bottle of cologne? One tank of gas? Music can be enjoyed, and for only $70. Considering you will use this phono stage longer than a day-pass to an amusement part, that it doesn’t give you heart disease, and that you don’t have to stand in line, it seems that the Rek-O-Kut is a better use of your money.