Lyra Kleos Mono
This is a special, built-to-order, mono version of Kleos for real mono playback of monaural/monophonic (mono) microgroove, vinyl records. It is recommended that the Kleos Mono is used with high-gain, low noise phono stages, or alternatively a step-up transformer designed for phono cartridges of 2 – 3 ohms or less.
On mono records, the vertical axis of the groove contains no musical information, but it will frequently have noise, in the form of groove damage and dirt. The Kleos Mono has therefore been designed to be completely insensitive to the vertical axis, which greatly improves the signal/noise ratio without any downside on monaural records.
The coil former is a square permeable plate oriented parallel to the record surface rather than the 45-degree angle used for most stereo cartridges, while the coils are wound so that they only generate a signal when there is horizontal movement of the stylus and cantilever when tracking a record.
Two totally separate monaural coils are used in the Kleos Mono, since most monaural cartridges are used with stereo amplifiers and stereo speakers. The separate coils also help avoid possible ground loops and hum problems that could otherwise be caused if a single coil is fed into a stereo two-channel amplification system, thereby tying the two channels together electrically.
In addition to parallel mono connection to a stereo system (two amplifiers and two speakers), it is also possible to leave one set of connections unattached for pure mono playback with a single amplifier and a single speaker. However, it is also possible to connect the two mono channels in series for additional output when used in a pure mono system. Use a short cartridge headshell lead wire with female pin-connectors to connect either the Kleos Mono’s upper right pin with the lower left pin, or alternatively the upper left pin with the lower right pin. Then use the two remaining unused pins for connection to your single amp RIAA input (alternatively a transformer input). The two internal channels are now “chained” in serial-connection for additional output and energy when you only use a single amplifier and a single speaker.
Specifications for Lyra Kleos Mono
- Designer: Jonathan Carr
- Builder: Yoshinori Mishima (final build, testing), Akiko Ishiyama (preliminary build)
- Type: Medium weight, medium compliance, low-impedance moving coil cartridge
- Stylus: Lyra-designed long-footprint variable-radius line-contact nude diamond (3um x 70um), slot-mounted
- Body: Nickel-plated duraluminum
- Cantilever system: Solid boron rod with short one-point wire suspension, directly mounted into cartridge body
- Coils: 2-layer deep, 6N high-purity copper, square-shaped chemically-purified high-purity iron former, 5.4ohm self-impedance, 9.0uH inductance
- Output voltage: 0.5mV@5cm/sec., zero to peak, 45 degrees (CBS test record, other test records may alter results)
- Frequency range: 10Hz ~ 50kHz
- Compliance: Approx. 12×10-6cm/dyne at 100Hz
- Cartridge body: One-piece machining from solid 7075 alloy billet, with reduced-surface higher-pressure headshell contact area, partially non-parallel shaping, phase-interference resonance-controlling mechanism, and body threaded directly for mounting screws
- Cartridge mounting screws: 2.6mm 0.45 pitch JIS standard
- Distance from mounting holes to stylus tip: 9.5mm
- Cartridge weight (without stylus cover): 8.8g
- Tracking force: 1.65 ~ 1.75g (1.72g recommended)
- Recommended load directly into MC phono input: 95.3ohm ~ 816ohm (detailed guidelines in instruction manual, finalize by listening)
- Recommended load via step-up transformer: Use a step-up transformer designed for 1 – 3 ohms cartridge impedance (step-up transformer’s output must be connected to 10kohm ~ 47kohm MM-level RIAA input, preferably via short, low-capacitance cable)
- Recommended tonearms: Medium to Medium-High mass arms recommended, which is bulk of tonearm market