Rothwell Headspace II MC Headamp
The Headspace II is a moving coil headamp (also known as a pre-preamp) which does a similar job to a step-up transformer, ie raises the output of moving coil cartridges up to moving magnet level, but does so with transistors rather than transformers. The benefits of the transistor approach are the ability to set the gain and the load impedance independantly, and the extremely wide bandwidth. The Headspace has four gain settings and eight load settings so a very wide range of cartridges can be accomodated.
Uses for a headamp
1) To allow low output moving coil cartridges to be used with moving magnet phonostages.
This could be anything from a budget mm-only phonostage right up to a high-end valve phonostage – the Headspace will not be out-classed by even the most expensive of ancilliary equipment.
2) To add flexibility to an mm/mc phonostage.
A phonostage with no ability to adjust the gain or load impedance can be set to mm operation and the Headspace used as a pre-preamp to allow the optimum gain to be set for the cartridge in use and the load impedance can be set independantly of gain for the best performance.
3) To improve the signal-to-noise ratio of an mm/mc phonostage.
Phonostages which are noisey on the mc setting can be improved by using the Headspace as a pre-preamp with the phonostage set to mm operation. The Headspace's low noise design makes it very quiet, with extremely low hiss and hum – better than many mc phonostages.
4) To boost the signal from high output moving coils.
Some moving coil cartridges which are classed as “high output” still have a much lower output than a typical moving magnet cartridge. The Headspace has a low gain setting (10dB) which is ideal to give those cartridges the extra lift required to match them to an mm phonostage, and the Headspace's highest load impedance setting (1.5k) is ideally suited for high output moving coils (even if the manufacturer's recommended load is 47k). The Denon DL-110 is an example of such a cartridge.
design
The Headspace uses discrete transistor circuitry throughout, including the proprietry low noise voltage regulator.
The transistors used to amplify the audio are selected low noise devices and audiophile resistors and capacitors are used for the lowest noise and best sound. The circuit configuration is an unusual variation on the complementary feedback pair giving the Headspace superbly detailed performance with good separation and a wide and deep soundstage.
gain settings:
Four gain settings are available for cartridges with output voltages within each of the specified ranges:
- 0.7mV - 02.5mV, 10dB (x3.2)
- 0.2mV - 0.7mV, 20dB (x10)
- 0.1mV - 0.35mV, 25dB (x18)
- 0.05mV - 0.3mV, 27dB (x23)
load impedance settings:
Eight load impedance settings are available:
- 55 ohms, 65 ohms, 80 ohms, 100 ohms, 140 ohms, 200 ohms, 360 ohms, 1.5k
The range of load impedances allows the Headspace to be used with a wide variety of low output and high output mc cartridges..
specifications:
Gain: 10dB, 20dB, 25dB, 27dB
Input impedance: 55R, 65R, 80R, 100R, 140R, 200R, 360R, 1.5k
Output impedance: <100 ohms
Headroom: >20dB
Power supply: 24 volts DC, center +ve
Mains voltage: 100V - 250V AC
Power consumption: 1W
Dimensions: 60 x 155 x 92 mm
Weight: 570g (exc. psu)
Packed weight: 770g (inc. psu)
