Linn Asak Cartridge
Manufacturer's Specifications:
Type: Moving coil
Frequency Response: 10 Hz to 50 kHz, ±3 dB.
Output Voltage: 0.2 mV. Channel Balance: ±0.5 dB.
Channel Separation: 27 dB. Impedance: 3.5 ohms.
Compliance: 12 x 10-6 cm/dyne.
Tracking Angle: 20°. Stylus Type: 0.2 x 0.8 mil elliptical diamond.
Weight: 6 grams.
Price: $425.00.
Linn Ittok LVII Tonearm
Manufacturer's Specifications:
Overall Length: 284 mm (11-3/16 in.).
Effective Length: 229 mm (9 in.).
Overhang: 18 mm (11/16 in.).
Length Behind Pivot: 50 mm (1-15/16 in.).
Friction: Less than 20 mg.
Effective Mass: 1 1.5 grams.
Cartridge Weight Range: 2 to 10 grams with main weight only, 5.5 to 15 grams with additional weight.
Recommended Stylus Force Range: 0 to 3 grams, in 0.1-gram steps.
Price: $520.00.
Company Address: Audiophile Systems, 6842 Hawthorn Park Dr., Indianapolis, Ind. 46220, USA.
Linn Products, Ltd. is a Scottish company which is probably most famous for their Sondek LP12 turntable (Audio, Nov. 1983). The LP12 has earned a reputation for excellent performance when used with high-quality tonearms, but Linn felt that they could design a tonearm which combined the best of modern design ideas and advances in precision manufacturing. The Ittok LVII tonearm and Asak cartridge are made in Japan to Linn specifications. Since this combination of arm and cartridge was meant to complement the LP12 turntable, I used this turntable during my evaluation.
The Linn Ittok LVII tonearm has some features similar to those of the Sumiko MDC-800, which I reported on in the Sept. 1983 issue. The Sumiko tonearm provided exceptional performance, so I expected great performance from the Linn Ittok LVII; I wasn't disappointed.
The Ittok LVII has a straight arm tube with the necessary offset provided by slots in the headshell. The Asak cartridge is a moderate-output moving-coil type which is designed to be mounted in a tonearm with a wide, rigid mounting surface in the headshell, such as the Ittok. While both the arm and cartridge may be purchased separately, there is every indication that they are designed to complement each other.
Although the names of these Linn products appear strange, they do have a rationale, based on persons, places and companies which were significant to the products' design and development. "Asak" comes from Asakura Brothers, who build the cartridge. "Ittok" comes from Mr. Ito, the Japanese engineer from the company which makes the arm; the “k" was added to harmonize with "Sondek" and "Asak." The ''LVII" designation stands for the design specification meeting between the people from Linn and the Japanese manufacturing company, which took place in Las Vegas during a Consumer Electronics Show (it appears more goes on at these shows than one might imagine); the "II" stands for Ito and Ivor Tiefenbrun, Linn's Managing Director. (And you thought audio people had no sense of humor!)
First Impressions
The appearance of the Ittok LVII is one of simplicity and style. It gives the immediate impression that it is a well executed, no-nonsense tonearm that will do exactly what it is designed to do, without being fussy in operation. The bearings feel smooth and friction-free, without any excess play, and the finish is quite good. The headshell appears a bit strange at first, since it lacks the usual offset, but closer examination reveals that the offset is supplied by the cartridge mounting slots. The tonearm retainer is separate, and must be mounted on the front of the tonearm base. The instructions for the Ittok are very detailed, and it is evident that Linn is more than a little concerned that you obtain the best possible performance from their tonearm. The use of both a counterweight to balance the tonearm, and a calibrated spring tracking-force control, means that the Ittok LVII can be dynamically balanced. This provides good isolation from outside forces which can adversely affect performance.
The Asak cartridge reminds me a bit of European cartridges of the past, such as the ELAC, and has a bulky appearance even though it is actually quite small and compact. The front of the cartridge has a little red indicator that looks like an LED-one almost expects it to light up!
Features
The bearing system is probably the single most important part of the Ittok LVII design. The goal of stability between the cartridge stylus and the record surface dictated the use of the same material for the bearings, bearing housing, and arm pillar. Since the coefficient of expansion is the same for all three parts, changes in temperature affect them identically and therefore are cancelled. The tonearm tube is relatively large in diameter but is made of very thin aluminum. This gives the tube great rigidity while requiring less mass than smaller tubes with thicker walls.
The headshell is made of magnesium/aluminum alloy, and it is permanently attached to the tonearm tube. While admitting that this makes rotational adjustment of the head shell impossible, Linn feels that rigidity is more important than being able to make such an adjustment, and that the Ittok's design makes such an adjustment unnecessary. This is because the arm's bearing axis is not perpendicular to the shaft, but is 'offset at the same angle as the axis of the cartridge mounting screws. According to Linn, this allows the stylus to remain perpendicular to the record even when arm height is changed to adjust vertical tracking angle, provided that the cartridge is mounted parallel to the head shell.
The counterweight has two parts. The main weight is used alone when cartridges weighing less than 6 grams are mounted. For cartridges over 6 grams, a smaller ring is attached to the main weight, and locked in place with two hex screws. The counterweight is used to adjust the balance of the tonearm, not to apply the tracking force. Since the tracking force is applied separately by a spring, the arm can be dynamically balanced. This means that the tracking force is not a function of gravity and that a record could be played with the turntable upside down, or even by astronauts in outer space! The use of a dynamic balancing scheme like this has a more practical advantage, however, since it isolates the tonearm from other outside forces besides gravity. This means that external vibrations will have little effect upon performance. The spring that applies the tracking force is controlled by a calibrated knob. The side thrust compensation is also applied by a spring controlled by a calibrated knob.
The arm height can be adjusted to compensate for different turntable platter heights by sliding the arm pillar in the arm base. The tonearm pillar has a slot running up one side.
A large setscrew in the tonearm base is locked against the outside ridges of this slot after the proper height is set. A right-angle connector plugs into a keyed socket on the bottom of the arm pillar, and the shielded signal cable is carefully dressed and clamped along the path to the exit point, which is at the center rear of the turntable base.
The Asak cartridge is designed to couple any excess energy from the record groove which is not used by the stylus, cantilever and coils directly to the tonearm and into the mounting base, where it can be dissipated. To accomplish this, the cartridge body has a flat upper mounting surface which is wider than usual. Instead of mounting ears, such as are found on other cartridges, the Asak has mount ing holes which run directly through the cartridge body. This allows the cartridge mounting screws to be tightened very securely.
Mounting the Asak cartridge to the Ittok LVII tonearm is very simple, but, as Linn recommends, this should be done while the arm is removed from the turntable. Changing cartridges therefore is not simple, but for most users this will not be a major consideration. Mounting the tonearm to the turntable is also relatively simple, but the detailed instructions should be followed carefully and patiently in order to obtain the best performance. There are a number of small details in the process which can affect performance, and these are well covered by the instructions.
Measurements and Listening Tests
I am convinced that pursuing the relationship between audible effects and technical measurements is very worthwhile. Since it is difficult to remain objective, especially if one is trying to prove one's own hypothesis about something, I always use a listening panel to evaluate the sound quality of the components upon which I report. The panel consists of persons who are used to listening to excellent sound reproduction and who also attend live musical events. Many scientific investigations of sound phenomena are conducted using untrained listeners, in order to determine effects which can be perceived by average persons.
Fig. 1--Frequency response and interchannel crosstalk of arm and cartridge,
using B & K 2010 test record.
Fig. 2--Low-frequency tonearm/cartridge resonance is at 9.5 Hz, with a "Q" of
3.8 (B & K 2010).
Fig. 3--Interchannel phase of Talisman Sapphire cartridge of previous report.
This test was run to determine if the phase difference between channels
could be zeroed out (see text).
Linn Asak Cartridge--MEASURED DATA
Linn Ittok LVII Tonearm--MEASURED DATA
When testing high-quality audio equipment and attempting to correlate subtle audible effects with technical measurements, I feel that the use of experienced listeners is as important as the use of the finest test equipment.
Fig. 4--Interchannel phase of Linn Asak cartridge and Linn Ittok LVII tonearm
vs. frequency (B & K 2011, pink noise). Maximum phase shift is 38° at
20 kHz, equivalent to 5.3 µS.
Fig. 5--Interchannel phase of arm and cartridge, left vs. right channel
(B & K 2011, band 7, pink noise).
Fig. 6--Mistracking of a 1-kHz signal begins at 15.5 cm/S lateral modulation,
with 1.8-gram tracking force (B & K 2010).
Fig. 7--Spectral components caused by slight mistracking of 1-kHz signal
in Fig. 6. Level of third harmonic (3 kHz) is 0.56% in left channel, 0.88%
in right. Note low levels of upper harmonics.
Fig. 8--Arm/cartridge response to 10.8-kHz pulse test (Shure TTR103) at
30 and 15 cm/S.
The object of a technical report, such as his one, is to supply valid information about the equipment, including the subtle details. The most rational way to do this is to try to correlate the comments about the sound quality by a listening panel with various artifacts in the data gathered from measurements. Since it is always easier to find things wrong with equipment, no matter how excellent it is, the reports tend to emphasize the faults rather than the virtues. (Editor's Note: This is true to a great extent with all reviews, and it is an unfortunate fact of an editor's life that we will have very little to say about the very best equipment. -E.P.) It should be remembered, when reading my reports, that the listeners are experienced and that the reference system used is considered to be of the highest quality.
The amplitude versus frequency response and interchannel crosstalk curves of Fig. 1 indicate that the Ittok-Asak combination is well-matched, and only a slight discontinuity at about 90 Hz is evident. This is probably due to the headshell-to-arm-tube connection which, while it is very good, is not perfect. Any mechanical discontinuity in the path between the cartridge and the base of the tonearm can cause delayed energy to be reflected back to the cartridge stylus, where it is mixed in with direct signal. This can cause the sound to be muddy or unclear. During the listening sessions, no negative comments were made by anyone on the panel that could be attributed to this discontinuity.
The crosstalk of the left channel into the right channel is down by at least 30 dB from 500 Hz to 10 kHz, which is excellent. The crosstalk of the right channel into the left channel, while it is even lower through most of this same range, does show a sharp increase around 5 to 6 kHz.
During the listening sessions, comments were made, after playing certain types of program material such as solo guitar, about an upper-midrange "brightness"; this puzzled me, because it didn't seem to be consistent. On other program material, such as the Sheffield Drum Record, some of the panel members would comment that the reference system was "brighter." This bundle of crosstalk energy around 5 to 6 kHz may only be heard sometimes, and at other times not be triggered at all by the program material.
Figure 2 shows the tonearm/cartridge resonance, which is relatively very well controlled. It occurs at 9.5 Hz with a "Q" of 3.8, which is very good. This is probably an area of tonearm and cartridge design where effort to lower the "Q" would most likely result in improved performance. The subjectively perceived results of this rise in low-frequency output can be correlated with comments about the difference in the bass range compared to the reference system. The reference system has a slightly lower and much more narrow rise in output at about the same frequency. Some panel members commented that the Ittok/Asak combination had more bass when playing such discs as the Sheffield Drum Record and Pink Floyd's Dark Side of the Moon.
I have done more investigating since I first began to measure the interchannel phase of phono cartridges. The first phase data was shown in the report on the Sumiko Talisman S cartridge, and although I thought that the amount of interchannel phase differential was a little high (130° at 20 kHz), it represented only a 19.2-µS difference, which would probably be very difficult to hear. The inter channel phase differential measurement is for the complete system, including the pre-preamp used between the cartridge and the magnetic phono input. The input of the pre-preamp is very low in impedance; in the case of the Talisman S and the Asak cartridges it was set at 100 ohms. Prior to testing the tonearm/cartridge combination, the complete system was tested electrically by feeding a signal from a 600-ohm generator into the pre-preamp's input. Under these conditions, the interchannel phase difference was less than 2°. It was discovered later that, when the extremely low impedance of a moving-coil cartridge was connected to the pre-preamp's inputs, there was an increase in the inter channel phase differential. This was traced to a difference in capacitance at these inputs. After this was corrected, the interchannel phase was tested using an even more elaborate procedure, which included running the turntable in forward and reverse directions. The total difference for the Sumiko Talisman S is 13° (1.8 µS) and is shown in Fig. 3.
Since investigating interchannel phase differential in more detail, I have been even more careful in setting up phono systems, particularly with regard to determining the proper offset angle and checking the effects of input loading upon low-impedance moving-coil cartridges.
Figure 4 shows the interchannel phase difference for the Linn Asak moving-coil cartridge and the complete system, which includes the B & K 2011 test record, the pre-preamp, and the control preamplifier. It is quite good, since 38° represents a time differential of only 5.3 µS at 20 kHz. Figure 5 is a measurement over a period of 2 S, using the same record, displayed as left versus right channel. A perfect cartridge and system would show a straight line at 45°. The amount of "blooming" is an indication of the amount of interchannel phase differential. This pattern is considered very good and indicates that the coherence between channels is excellent. The listening panel was very impressed by the way the Linn Ittok LVII and Asak cartridge presented the stereo images on well-recorded program material. Some multi-track and/or multi-microphone-type recordings were presented in such a clear way that their faults were not hidden, and comments regarding poor stereo could be traced to the recordings and not to the playback system.
Figure 6 shows the effects of slight mistracking in the left and right channel when playing a 1-kHz tone at 15.5 cm/S. This is a fairly high level, indicating that the Ittok LVII and Asak will reproduce most recordings without difficulty. Figure 7 shows the harmonic distribution of the distortion under the same conditions. The cursor at 3 kHz indicates that the third harmonic distortion is 0.56% (45.1 dB) and 0.88% (41.3 dB) for the left and right channels, respectively. The seventh harmonic in the right channel is 0.22% and might be heard if not masked by the program material. Perhaps this could be a partial explanation for the comments made about the sound of the guitar, which some panel members considered a little bright.
Figure 8 indicates a slight amount of compression when reproducing the extremely high-level, 30 cm/S, 10.8-kHz tone burst of the Shure TTR-103 test record. Figure 9 shows the amount of low-frequency output which is present at this level. The listening panel made comments about a very slight "congestion" or "lack of clarity" when reproducing crescendos in symphonic-type program material. This might be related to the production of lower frequency energy by the Ittok/Asak combination when trying to reproduce high-level, high-frequency energy from cymbals, etc.
The 1-kHz square waves shown in Fig. 10 corroborate the amplitude versus frequency response data shown in Fig. 1, since the high-frequency roll-off is shown as an upward slope on the top of each positive cycle.
Fig. 9--Spectrum of distortion products for 10.8-kHz tone bursts of Fig.
8, for 30- and 15-cm/S signals. Frequencies between 200 Hz and 2 kHz are
down 20 dB, even with 30 cm/S signal.
Fig. 10--Arm/cartridge output for 1-kHz square wave, CBS STR-112, 5 cm/S
lateral modulation.
Conclusions
The Linn Ittok LVII tonearm and Asak cartridge is an excellent combination, and I definitely recommend that they be used together. The Ittok LVII tonearm seems particularly well suited to medium-compliance cartridges and should also offer excellent performance with cartridges other than the Asak. There is some indication that the Ittok performs best when mounted on the Linn Sondek LP12 mounting base, which tends to absorb some unwanted energy, preventing it from reflecting back into the tonearm. Mounting the Ittok LVII to a base made of different material, especially of metal, would certainly change the sound character. The comments of the listening panel and my technical measurements both indicate that the combination of the Ittok LVII tonearm and Asak cartridge, when mounted on the LP12 turntable, is worthy of its excellent reputation.
-Edward M. Long
(adapted from Audio magazine, Mar. 1984)
= = = =
Also see:
Linn Axis Turntable (Equip. Profile; May 1987)
Linn Sondek LP12 Turntable (Nov. 1983)
Linn Basik LVX Tonearm and K9 Cartridge (Equip. Profile, Nov. 1987)