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Rek-O-Kut Professional Phono Preamplifier mk II & Re-Equalizer II Review

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RekOKut PMMPii Phono Preamplifier Moving MagnetThe 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.

Re-Equalizer II: Oh! So That’s What They Meant!

The other half of this story is the Re-Equalizer II and what it can do for the record collector. Most casual record collectors don’t have the needed styli (line contact, truncated elliptical, spherical, etc.), cartridges (stereo, mono, high compliance, low compliance), or specialized phono preamps to hear what tens of millions of records should sound like. Played back with a moving-coil, in a high resolution system, a 60-year-old mono LP can sound like a 747 crashing into a light bulb factory. To understand what’s going on, you have to familiarize yourself with the history of the LP, and the disks that came before the LP.

Way before the advent of the LP, almost all disks were cut with varying amounts of bass attenuation that would be corrected when playing back the record. The reason for this was that unattenuated bass would cause the cutter head to cut into adjacent groove walls, destroying the lacquer. The cutter heads were “constant velocity”* devices, meaning that without some kind of EQ, treble grooves would be increasingly tiny and bass grooves would be increasingly large. When the “long playing” record was proposed by Columbia (here in the US), they came up with a playback curve that allowed storing a lot of music on one side, and that minimized the effect of surface defects and wear/tear. On playback, the consumer’s electronics would cut treble and boost bass. Because you are cutting the boosted treble to get it in proper proportion to the bass, you are also reducing the high frequency noise that comes from pressing defects, damage and mistracking. Creating a precedence that would continue to the digital age, RCA proposed a competing EQ curve for its new 45rpm, a curve which RCA based on earlier curves. They had proposed the 45 rpm format that was basically a miniaturized 78 (the LP was something much more radical in approach, which allowed an entire symphony to be recorded on one disk). The result was that the 33rpm LP and the 45rpm EP had different playback curves.

*The difference between constant velocity and constant amplitude can be understood when you think of how fast a stylus must move when playing 20,000 Hz versus 20 Hz. The stylus has to switch directions 1,000 times more often at 20KHz than at 20 Hz, which means the stylus is moving much faster to cut or reproduce treble. Hence the importance placed on low mass styli, cantilevers, iron, coils, etc If a cutter is a constant velocity device, the rate of travel of the cutting stylus must always be the same, whether it is going back and forth at 20 Hz or 20KHz. The consequence is that for a stylus to move as fast at 20 Hz, when compared to 20KHz, the distance traveled by the stylus must be many times larger to keep going the same speed. If the distance traveled by the stylus were to be limited somehow, the stylus would travel slower at low frequencies. This wasn’t possible (the cutting head is not a constant amplitude device), so the only workable solution was to reduce the bass so that the amount of distance traveled by the stylus would be similar to the highs, allowing the cutter to cut more narrow grooves, and the playback stylus to more easily reproduce the signal. If that explanation isn’t that clear, it’s because I’m not a physicist. It took me a long time to understand the difference between constant amplitude and constant velocity.

If it were just two different curves, then there wouldn’t be much of an issue. Unfortunately, when including the various practices going back to the days of Edison, there are over 100 different playback curves used by various record manufacturers. Some kind of standard had to be set so that everyone was on the same page. Though many had legitimate claim to having the “best” curve, only one would be standardized, which happened to be very close to the RCA curve – not hard to understand why if you realize how powerful RCA was at the time. After the RIAA adopted the standard, all equipment manufacturers adopted the new curve into their designs and it would eventually be the only playback curve offered. So what to do with the old records? After the adoption of the RIAA standard, several manufacturers continued to include the various curves, notable examples of which are the McIntosh C8 and Harman-Kardon Citation I. These multi-curve units had many more capacitors, resistors and switches, so they were usually the most expensive preamps offered. Gradually, the multi-curve units died out completely. The solution, for most people, was to hunt down a Citation I, or similar, restore it, and use it for playing back the various odd-ball records in their collection.

One weakness of those older units was that the switching and parts needed to accomplish multiple curves caused poorer performance. Subjecting a tiny signal to dozens of contacts, solder joints and stray capacitances created a lot of noise and distortion. One possible solution, one employed by a number of archivists, is to amplify the signal to line level, but without any EQ at all. The resulting signal is recorded to a digital file where various EQ curves can be applied to find, objectively and subjectively, the best curve for that recording. Well, that all seems like a lot of work for a regular record collector, not to mention that many of us don’t want our precious analog signals sliced and diced and converted to digital, another source of distortion.

The solution from Esoteric Sound, the Re-Equalizer, one that seems to adopt “best practices,” is to apply a corrective filter after your pre-existing phono stage. If your phono stage does an adequate job of doing the RIAA curve, the Re-Equalizer will reshape the signal into various curves by using a set of selectable filters. The result is that you can have audiophile sound from your audiophile pressings, and by flipping a switch, you can play back just about any record by adjusting the knobs on the RE-EQ. The Re-Equalizer sums to mono, which is not a problem for most listeners. However, there are stereo records cut with non-RIAA curves, not to mention that some detail is lost when summing a stereo signal to mono, because the two coils of a stereo cartridge are slightly out of phase with each other, causing the signal to partially smear or cancel out, something a true mono cartridge will not do. Esoteric does offer a price break for people wanting two units for stereo. That would also allow you to select the inside or outside groove of a mono record when using a stereo cartridge, something done by most archivists, who pick the quieter of the two channels, and use it as the basis for their work.

Some Important Info:

Re-Equalizer Features

* Supplied with eleven page manual including recommended compensation settings for any vintage record – including acoustics. This is the most extensively researched chart ever produced.
* In “BYPASS” mode, signal is hard-wired input to output – no compromise to any audiophile unit
* Passive equalization design & film capacitors assure low TIM and transparent sound.
* High input impedance for use with both tube or solid-state amplifier outputs.
* Accurate record compensation from any source using your preamp.
* Connects to hifi systems like any ordinary graphic equalizer.
* Works with phono, tape recorder outputs – any source.
* 8 settings of Turnover and 8 settings of Rolloff.
* Gold-plated RCA connectors.

Playing a record with the wrong EQ is the worst of possible fates, regardless of what an extra box does to the signal, whether it is another set of interconnects, more RCA jacks, solder, wire, PCB, switches, resistors, capacitors, or active devices. The resulting deviation from flatness can be much worse than modern cartridges and speakers. Some records will sound extraordinarily bright, others very dark, and the overtone structure of real instruments will be knocked out of whack. One instrument can be mistaken for a different instrument, details can be rendered inaudible, and relative prominence of a musician in the mix (like a soloist) can be lost. If you are primarily a record collector, what distortions are introduced by the inner workings of the Re-Equalizer are far outweighed by hearing the records played back with the correct equalization. When bypassed (Re-Eq switched out of the circuit), I heard no noise or veiling with the Shure V15iii. When in-circuit, I did hear just a bit of opacity, which is the result of more gain stages, resistors and capacitors. A high-end moving coil’s signal will be slightly compromised, even when the Re-Eq is bypassed, just because of the extra jacks and switch. So, you might look into a second arm/table, or another arm if you have a plinth that allows for it. What route you choose depends on whether you are a collector or an audiophile.

Hearing old vinyl played back correctly for the first time can be revelatory. Many of my mono records are not RIAA, so every record can be an adventure in EQ tweaking. After a while, you get faster at finding the right curve and you become aware of trends from certain labels and even certain countries. One possible solution is to print some address labels and keep track of which settings you preferred (put them on protective outer plastic sleeves). In daily use, I never felt like I was being robbed of information or suffering extra distortion. I was able to hear, for the first time, what the mastering engineer intended on records that had sounded dreadful without compensation. Just remember that it isn’t an exact science. The tapes and transcription disks used to master old vinyl were also subject to EQ errors (both need EQ). The EQ preemphasis introduced in the mastering process could have been poorly implemented (wrong values, bad parts quality and even poor design). Some of the records will be in “the crack,” like the singer who can’t find a key that is comfortable, being somewhere on the piano that doesn’t exist (the crack between two piano keys). Pick whatever sounds most natural, the curve that makes it sound real. That is what a good mastering engineer or archivist would do.

There are buyers who only purchase audiophile reissues, so the Re-Equalizer probably won’t be useful in those systems. It’s a shame to say, but it’s not expensive enough for a lot of audiophiles to take it seriously. Well, you should. The assumption that “if it’s cheap, it must sound cheap” is moronic. I’ve heard $100 moving magnets sound better than $1,500 moving coils. If you buy lots of used vinyl, the money for the RE-EQ is well spent. Maybe we can get a gold plated version for audiophiles, just so they will buy it.

Buy More Records

To give you an idea of what you are missing, I will recount my shellac “road to Damascus.” Thinking all 78 rpm disks sucked and were good only for shooting skeet, a record collector buddy said “why don’t you listen to this one.” This record was BN 543, Thelonious Monk – ‘Round Midnight b/w Well, You Needn’t, a mint 10” 78 rpm Blue Note from 1947. Yea, verily I say unto thee that I did heareth ambience, the tapping of the foot, and nuance of music, which is the breath of life. No crackle and no hiss to be heard. Get the hence evil noise! The thing which clinchethed the argument was comparing the LP reissue, cutteth from 78 master to 33 lacquer. Verily, I say unto thee, that the extremely expensive LP was much worse than the meek and gentle 78. Hosanna on highest!

I’m very enthusiastic about what both these units can do. The prices aren’t only affordable, they are downright cheap (especially the phono stage). Sound quality, while using both units, was always good and, with the RE-EQ, sometimes better than my reference setup. Summing to mono, then finding the correct EQ, turned some dogs into winners. If you buy lots of used vinyl, especially mono, and if you have a high output cartridge, then you might find a place in your system for both of these units. You certainly can’t complain about the asking price. For people who are interested in exploring and enjoying music, both these components can satisfy, and leave money for more records.

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