MANUFACTURER'S SPECIFICATIONS:
Type: Ribbon (velocity) magnetic.
Frequency Response: 20 to 30,000 Hz.
Effective Mass of Stylus Cantilever Assembly: Less than 0.5 mg.
Output Voltage at 1 kHz: 0.04 mV, 5 cm/S; 4 mV via HA9000 head amplifier.
Channel Separation at 1 kHz: More than 25 dB.
Channel Balance at 1 kHz: Less than 1 dB.
Dynamic Compliance: 7 x 10^-6 cm/ dyne.
Output Impedance at 1 kHz: 3 ohms.
Recommended Cable Capacitance: 200 to 500 pF (not critical).
Tracking Force: 1.6 to 1.8 grams--optimum 1.7 grams.
Vertical Tracking Angle: 24°
Recommended Load: 10 to 30 ohms.
Stylus Tip: 0.4 x 0.8 mil; special elliptical, nude, solid diamond with 0.15mm square shank.
Cantilever: Titanium (crystallized).
Weight: 19 grams.
Replacement Stylus: RS HV9100.
Price: $220.00.
In recent months the adherents to the moving-coil cartridge mystique have had much to rejoice with the introduction of the Nagatron HV9100 ribbon (velocity) magnetic cartridge. The HV9100 is a true ribbon cartridge, quite similar in operation to the transducing principle of the ribbon microphone. However, the less-than-full-turn metallic ribbon "coil" acts in a magnetic field not unlike the standard multi-turn coil commonly used in moving-coil cartridges. Its frequency response is not affected by wide variations in resistive and capacitive loading. An important feature is that its output is inherently phase linear.
Unlike moving-magnet and variable-reluctance cartridges, the ribbon design concept does not rely upon varying the magnetic field in order to induce a voltage. Instead, the mag net is fixed, and the two flat strands of metallic ribbon (one per channel) move in direct proportion to the stylus-tip motion within the constant magnetic field. In this way, magnetic flux density is always constant and directly proportional to actual stylus-tip velocity. The magnet is a rare-earth samarium-cobalt structure yielding a magnetic flux density of 10,000 Gauss that produces a nominal output level of 40 microvolts (0.00004 volts). The ribbon is made from a special silver alloy, which includes zinc, nickel, platinum, and other elements, resulting in excellent conductivity, not just on the surface, but throughout the entire metallic ribbon body.
The stylus and cantilever assembly is quite different from the usual systems. The exclusive one-point support eliminates rotational shifting at the pivot axis by utilizing a square-shaped damping panel and high-elasticity damping compound. IM distortion is thus kept to a minimum. The cantilever, made of crystallized titanium, is a straight-line tapered cantilever tube which precludes spurious local resonances that usually arise in curved-cantilever shapes. The elliptical nude diamond stylus is cut from a solid, square diamond. Moving-coil cartridge enthusiasts should be quite pleased to learn that the stylus is user-replaceable, thus eliminating part of the high cost of stylus replacement.
Many cartridges are becoming available already mounted in a standard headshell, thus eliminating the vexing problem of properly mounting the cartridge. Nagatron has gone one step further and built the cartridge into a headshell, all as one unit. It would be nice if the manufacturer placed a vertical (6 mm) white index line on the center front of the shell for easier cueing. Although the overhang cannot be adjusted, it should cause no serious problem in tonearms using the universal four-pin plug since their head shells are designed for a 51 ±1 mm spacing between the stylus tip and bayonet base, which is an EIAJ standard. It is strongly recommended that no attempt be made to correct the overhang error, which is not off by more than 1.5 mm, through any tone arm adjustments or other means.
The headshell-cartridge combination is quite heavy, weighing 19.3 grams. However, we found that some other standard headshell-cartridge combinations weighed as much. It may be necessary to add additional weight to the counterweight on some tonearms so that the arm-cartridge combination can be properly balanced prior to adjusting the tracking force.
Measurements
All measurements and listening evaluations were made using the Mark Levinson JC-1DC moving-coil cartridge preamplifier at its high gain position. We checked out the JC-1DC to ascertain that it would not affect any of the measurements. The gain of the JC-1DC at 1 kHz was 48 dB, while the frequency response was down 1 dB at 20 Hz, flat to 20 kHz, and down 1 dB at 60 kHz. Moving-coil cartridge transformers currently available cannot be used with the HV9100 because of insufficient gain.
During the test period the average room temperature was 70° F± 1° (21.11° C) and the relative humidity was 55 percent, ± 3 percent. All measurements were made at the recommended 1.7 grams tracking force and an anti-skating force of 2 grams.
Frequency response of the Nagatron HV9100 cartridge, using the Columbia STR-170 test record and our reference tonearm, an Audio-Technica AT-1009, mounted on a Technics SP-10 turntable, is flat within +0.5 dB from 40 Hz to 6 kHz, ascending to +5.5 dB at 12 kHz, and +6 dB at 20 kHz.
Separation was 18 dB at 1 kHz, 17 dB at 10 kHz, 18 dB at 15 kHz, and 13 dB at 20 kHz. This separation is more than adequate inasmuch as a good stereo effect is evidenced with as little as 15 dB separation between channels.
Fig. 1--Frequency response and stereo separation with the Nagatron HV9100
Cartridge.
Fig. 2--Response to 1-kHz square wave.
Over a period of many years we have used just about every test record commonly available and a few not so easily avail able. One thing they all had in common was that no two gave identical results, particularly in cartridge frequency response and separation measurements. We have frequently compared the various cartridge test records and continue to be amazed how different a simple measurement can be between all the test records, using the same cartridge for all measurements. Recently, our colleague, Julian D. Hirsch, of Stereo Review, wrote an excellent review of this problem. It should be required reading for all involved in using test re cords or interpreting results obtained from them. The article appeared in Stereo Review, January, 1979, and we highly recommend it to the readers of Audio. Further, since phono cartridge measurement standards do not exist, either domestically or internationally, we would like to propose that such a committee be formed for the purpose of establishing standards for the measurement of phono cartridge performance.
Returning to the HV9100, the square wave response has a large overshoot, followed by a few cycles of well-damped ringing that rapidly decreases to near nonexistence. Arm-cartridge resonance was +1 dB at 9 Hz. Intermodulation distortion was the lowest we ever measured.
The following test records were used in making the reported measurements: Columbia STR-170, STR-112, STR-100, and SQT-1100; Shure TTR-103, TTR-109, TTR-110, and TTR-115;
Deutsches HiFi No. 2; Micro-Acoustics TT-2002, and Nippon Columbia Audio Technical Records (PCM) XL-7004.
Wt. 19.3 gm; tracking force 1.7 gm; opt. anti-skating force 2.0 gm; output 2.1 mV/cm/S; IM dist. (4:1) +9 dB lateral, 200/ 4000 0.85 percent, +6 dB vertical, 200/4000 0.38 percent; crosstalk (using Shure TTR-109)-30 dB; ch. bal. 0.75 dB; TTR-103 trackability: high freq. (10.8 kHz pulsed) 30 cm/S, mid freq. (1000 + 1500 Hz lateral cut) 31.5 cm/S, low freq. (400 + 4000 Hz lateral cut) 24 cm/S; Deutsches HiFi No. 2 300-Hz test bands tracked to 86 microns (0.0086 cm) lateral at 16.20 cm/S at +9.66 dB and 55.4 microns (0.00554 cm) vertical at 10.32 cm/S at +5.86 dB.
The Nagatron HV9100 encountered no difficulties in playing all tracking and transient ability bands of the Micro-Acoustics TT-2002 musical test record, including tracing the computer-generated high, low, and high/low mixed frequencies.
The Shure Obstacle Course--Era 111 was no challenge to this cartridge except for a hint of stridency at level 5 of the violin band. With the new Shure Obstacle Course test record-Era IV, both the orchestral bells and the flute were just beginning to sound harsh at level 4, but this was not evident when playing the combination of orchestral bells and flute through level 5. The harp alone or the harp and flute combi nation presented no problem. Only an occasional cartridge can claim to be able to play all levels of the instruments on the Era III and IV test records without encountering some difficulty.
Listening and Use Tests
As always, our listening tests were performed both before and after laboratory testing of the Nagatron HV9100. Upon prolonged listening, using both the records listed below and some reported in previous reviews, we concluded that the cartridge sounded excellent. We could not detect any audible coloration or brightness due to the rising frequency response at the high end. Transient and tracking ability were excellent, particularly when playing the high recorded levels present on many direct-to-disc recordings. Sonic clarity was beyond reproach, and bass response was excellent. The HV9100 encountered no difficulties in tracking warps that are nowadays apparently considered a must in record manufacture.
We are certain that the Nagatron HV9100 ribbon (velocity) magnetic cartridge will undoubtedly find a top niche among the best moving-coil cartridges available today.
--B.V. Pisha
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Evaluation Equipment and Records
The equipment used for the listening evaluation included a Technics SP-10 turntable with the Audio-Technica AT-1009 tonearm, Crown IC-150A preamplifier, a pair of Crown DC-300A amplifiers used in the monophonic mode, a pair of stacked Duntech DL-15B speakers in each channel, Mark Levinson IC-1DC moving-coil cartridge preamplifier, and a Columbia SQL-400A SQ decoder. Each pair of speakers was connected to the amplifiers with Polk Audio Sound Cables, using Polk's RC terminating network at the speaker end.
The following records, along with many listed in previous reviews, were used to aurally evaluate the Nagatron HV9100.
Stereo
Haydn: The Creation, Dorati, Royal Philharmonic Orchestra--London OSA 12108.
Rimsky-Korsakov: Scheherazade, Stokowski, Royal Philharmonic Orchestra--RCA ARL1-1182.
Shubert: Symphony No. 9 in C major (The Great), Mehta, Israel Philharmonic Orchestra--London CS 6948.
Respighi: Feste Romane, The Pines of Rome, Maazel, Cleve land Orchestra --London CS 7043.
Bernard Herrmann Conducts lane Eyre and Other Film Scores--London Phase Four SPC 21177.
Walton: Belshazzar's Feast, Coronation Te Deum, Solti, London Philharmonic Choir and Orchestra -- London OS 26525.
Sibelius Masterpieces, Kord, New Philharmonia Orchestra-- London Phase Four SPC 21155.
Roussel: The Spider's Banquet, Op. 17, Petite Suite Pour Orchestre, Op. 39; Honegger: Pacific 231, Ansermet, L'Orchestre de la Suisse Romande --London Treasury Series STR 15395.
The One for Me, Acker Bilk his clarinet and strings --PYE NSPLX 41052.
Direct to Disc
The First by Sleepy, H. Matsumoto--Toshiba LF-95008 (distributed by Audio-Technica).
Big Band Jazz, Rob McConnell and the Boss Brass--Umbrella UMB-DD4 (distributed by Audio-Technica).
Big Band Jazz, Volume 2, Humber College Jazz Ensemble--Umbrella UMB-DD7 (distributed by Audio-Technica).
Emergency, Count Buffalos --Toshiba LF-95002 (distributed by Audio-Technica).
Buddy Spicher and Friends, Yesterday and Today--Direct Disk DD102.
Cal Tjader, Huracan--Crystal Clear Records CCS-8003.
Arthur Fiedler and the Boston Pops--Crystal Clear Records CCS-7003.
Pulse Code Modulation (PCM)
Bach: Orgelmeisterwerke, H. Rilling (Organist) --Denon OX--7027-ND (distributed by American Audioport, Inc.).
Bach: Orgelchorale durch das Kirchenjahr, H. Rilling (Organist)--Denon OX-7023-ND (distributed by American Audioport, Inc.).
Quadraphonic--SQ
Donizetti: L'Elisir d'Amore--Columbia M3 34585.
Puccini: Edgar--Columbia M2 34584.
Go for Your Guns, The Isley Brothers-T-Neck Records, Inc. PZQ34432 (distributed by Columbia).
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(Source: Audio magazine, May 1979)
Also see:
Thorens TD 115 Turntable / Ortofon TPO-70 phono cartridge wand (Dec. 1982)
Nikko Gamma I Stereo FM Tuner (May 1979)
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