Developments in Step-Up Devices for Moving-Coil Cartridges (Vol.2, No.2: 1979)

Further Developments in Step-Up Devices for Moving-Coil Cartridges: Denon AU-340; Denon HA-1000; Marcof PPA-1 (Improved) ; RWR Audio MCT-1 ; Signet MK12T .

The latest crop includes an almost-SOTA transformer at an attractive price, a major improvement in what was already the best-per-dollar pre-preamp, plus the usual quota of new mediocrities.

After our experience with the Audio Standards MX 10A (see pages 62 and 63 of the last issue), we have the deepest suspicion of any kind of laboratory test of a pre-pre amp or transformer. That was as close to a straight wire with gain as we had ever seen on our lab bench, and it didn't mean a thing. We tracked through the same tests on the present batch of step-up devices, but whatever we observed has little bearing on our conclusions as reported in these reviews. Only in the case of the RWR transformer (see below) was there any correlation between a particular electronic test and an audible effect. Even in that instance we can't be absolutely sure.

All of the listening tests were performed by inserting the step-up devices one by one into our ''Reference A' system (see updates in this issue). The slight differences in gain introduced this way were compensated for by careful calibration of the main volume control of the system. No A-B switching system was used, as we know of none that will work properly at MC cartridge output levels.

Denon AU-340

American Audioport, Inc., 1407 North Providence Road, Columbia, MO 65201. Denon AU-340 Audio Step-Up Transformer, 3410. Tested sample on loan from importer.

This is an attractive and obviously well-made trans former, with switchable inputs for two separate pickups, front-panel choice of 3-ohm or 40-ohm connection, plus bypass. Sonically it rates fairly high but is no match for either the Cotter or the RWR. By comparison, it's a little edgy, especially on strings, and also has a relatively unobtrusive but definitely perceptible midrange coloration. If nothing better were available, the AU-340 would have to be considered quite clean and transparent, however.

Denon HA-1000

American Audioport, Inc., 1407 North Providence Road, Columbia, MO 65201. Denon HA-1000 MC Cartridge Head Amplifier, 3440. Tested #110157, on loan from importer.

Another solidly built unit from Denon, with head amp and power supply on two separate chassis connected with an umbilical cord. The sound leaves a great deal to be desired, though. Much more edgy than that of the AU-340 trans former, it hardens and brightens to the point of nastiness on certain string passages and transients. We suspect feed back-related time modulation effects; not recommended.

Marcof PPA-1 (Improved)

Marcof Electronics, 7509 Big Bend Boulevard, Webster Groves, MO 63119. PPA-1 moving-coil pre-preamplifier, $124.95. Two year warranty. Tested #006603, on loan from manufacturer.

Three new things have happened to our ' Reference B ' pre-preamp since the original review in the last issue. There has been a minor circuit change. The price has gone up five dollars. And the metal box is now black instead of blue. The net result is a considerable improvement in the sound, which of course was already excellent. (Must be the new color-or the extra money.) That slight trace of zinginess on top and looseness on the bottom are completely gone. The sound is now firmly controlled, beautifully focused and smooth as silk. The only thing that still separates the Marcof from SOTA quality is a lack of ultimate transparency and definition. Next to the Cotter transformer it sounds ever so slightly veiled and blunted, although its basic sonic character is very similar. At the price, nothing else comes even close. At twice the price, we still don't know of anything better. One of the great buys in audio today.

RWR Audio MCT-1

RWR Audio Ltd., Box 3080, Station D, 340 Laurier Avenue, Ottawa, Ont., Canada KIP 6H6. MCT-1 Moving-Coil Transformer, $299 (direct from manufacturer). Five-year warranty. Tested two preproduction samples, on loan from manufacturer.

Who would have thought it? A completely unknown little firm in Canada has come up with the only challenger to the supremacy of the Cotter transformer-at half the price and with six different switchable strapping configurations! In our opinion, the Cotter survives the challenge, but it remains on top by a very, very narrow margin. It took us long sessions of agonizing A-B comparisons to decide that the Cotter MK-2L (the best of all Cotter transformers so far) sounded just barely smoother and more neutral on top, with perhaps half a hairsbreadth more clarity, if that much. Nothing could have been closer except total identicalness.

And that's not all. The remaining minuscule difference may be due to quality control rather than design. We examined two RWR transformers, with a total of four channels.

Each channel was slightly different in square wave response.

The best channel had a small overshoot followed by quickly diminishing ripples, which is the correct response. The worst channel had an abrupt wrinkle right after the leading edge, indicating some kind of sharp glitch at around 130 kHz. The remaining two channels were between these extremes.

Unfortunately, the best and the worst channel were in one transformer; the second best (which was almost right) and the third best (somewhat faulty) in the other. The two trans formers didn't quite sound alike. We tried to listen to the best and second best channels in stereo but couldn't eliminate a hum caused by a ground loop between the two simultaneous ly used transformers. We have a feeling that a single trans former incorporating these two channels might have sounded identical to the Cotter. Our final conclusions were based on the slightly better-sounding of the two transformers, which was the one with the second and third best channels. The glitches are caused by something wrong in the windings, we believe; Cotter has such problems completely solved. We also suspect that the dip switches that select the strappings in the RWR are not as trouble-free as the less convenient soldered strapping connections used in the Cotter line.

Despite these minor problems, the RWR must be rated as a sensationally good product at a reasonable price, which at present is maintainable only by direct-to-user sales. More conventional distribution will undoubtedly raise the price in the end. We still consider the Cotter to be a more carefully made, better finished and marginally more accurate trans former, but the RWR is also very attractive in all these respects and still a lot better than any electronic MC step-up device known to us, regardless of price.

Signet MK12T

Signet Division, A.T.U.S., Inc., 33 Shiawassee Avenue, Fairlawn, OH 44313. MKI2T Transformer for MC Cartridge, $300. Tested #934, on loan from dealer.

Another well-built Japanese transformer, with 3-ohm, 20-ohm and 40-ohm connections (plus bypass) switchable from the front panel, the MK 12T doesn't quite make it to the top sonically. By itself it sounds reasonably transparent and neutral, but in comparison with the Cotter or even the RWR, which costs a dollar less, it has a somewhat hard and glassy quality. On dynamic peaks rich in high-frequency energy, the sound begins to approach nastiness but never really gets there. A possible though far from certain explanation is that the high-frequency resonance of the transformer is no higher than 54 kHz, which may be too close to the audio band for comfort. This is probably as good a transformer as most people are likely to hear in the course of their audio shopping in most places, but the very best it isn't.

Recommendations For the first time, there's an obviously right choice at three different price points. As you know, we firmly believe that MC cartridges are the only way to go; therefore you should own one of the following in our opinion, no matter what your system consists of.

Best step-up device for moving-coil cartridges, regardless of price: Cotter MK-2 transformer.

Close to the best at a much lower price: RWR Audio MCT-1 transformer.

Best MC step-up device per dollar: Marcof PPA-1 pre-preamp (improved version).

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[adapted from TAC]

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Also see:

Cartridge / Arm / Turntable--Briefs and Interim Reports: DB Systems DBP-10 Protractor; Dennesen Geometric Soundtracktor; Denon DA-401; Denon DL-303; Denon DP-80; DiscFoot Isolation System; Fidelity Research FR-14; JVC MC-1; JVC TT-101 JVC UA-7045; Kenwood KD-650; Linn-Sondek LP12 (reappraisal); Ortofon MC30; Thorens TD 115; Wheaton 240 Type 2

Why We're So Mean, Vindictive, Arrogant, Negative--and Truthful

Various audio and high-fidelity magazines