The mono power amplifier at the top of the Chord range
Chord ULTIMA is the reference monophonic power amplifier from Chord Electronics: 780 W RMS into 8 Ω, 1,405 W RMS into 4 Ω and, according to the manufacturer, 2,500 W into 2 Ω. Sold as a single unit: a stereo system needs two amplifiers. Each unit weighs 66.7 kg.
The manufacturer conceived it for the highest-end systems, those which by their nature use large, demanding and difficult-to-drive loudspeakers, and presents it as the most accomplished amplifier in its 34-year history. The stated peak output current exceeds 500 A.
A new topology with academic roots
ULTIMA uses an all-new circuit, the first completely new design since the company was founded. Its dual feed-forward error correction stems from a technical paper by Malcolm J. Hawksford, emeritus professor at Essex University, later refined by Bob Cordell of Bell Labs.
To this foundation John Franks added his own solutions for ultra-high-frequency power supplies. Each amplifier uses 64 proprietary MOSFET power devices; the drive circuit is an ultra-low-distortion, high-voltage amplifier operating at 300 V per microsecond, with both feed-forward and feedback compensation techniques. Operation is class AB with sliding bias.
Connections, chassis and dimensions
The inputs are balanced XLR and unbalanced RCA, in both cases with one inverting and one non-inverting socket. The loudspeakers are reached through two pairs of gold-plated, high-current terminals, suitable for bi-wiring; a 12 V trigger input handles automatic start-up (the Chord Electronics Auto Start function).
The chassis is solid aluminium, convection cooled, with the top light ring included and dimmable lighting. The Integra side legs are included and bring the dimensions to 480 × 305 × 750 mm (W × H × D); with the side blocks, available as an option, the size is 420 × 285 × 750 mm. Stated consumption at full power is 3,500 W.
Technical data
- Type: mono power amplifier. Sold as a single unit: a stereo system needs two amplifiers.
- Output power: 780 W RMS into 8 Ω; 1,405 W RMS into 4 Ω.
- Inputs: balanced XLR inverting and non-inverting; unbalanced RCA inverting and non-inverting, gold plated.
- Trigger: 1 × 12 V input (Chord Electronics auto start).
- Outputs: 2 pairs of gold-plated, high-current loudspeaker terminals (bi-wireable).
- Operating class: AB with sliding bias.
- Power devices: 64 proprietary MOSFETs.
- Frequency response: 0.2 Hz - 46 kHz (−1 dB); 0.1 Hz - 200 kHz (−3 dB).
- Total harmonic distortion: 0.005 %.
- Signal-to-noise ratio: better than −90 dB.
- Input impedance: 100 kΩ (unbalanced and balanced); output impedance: 0.04 Ω.
- Gain: 30 dB.
- Power consumption: 3,500 W at full power; 10 W in standby.
- Dimensions with the included Integra legs: 480 × 305 × 750 mm (W × H × D).
- Dimensions with the optional side blocks: 420 × 285 × 750 mm.
- Weight: 66.7 kg.
- Finishes: black or silver.
- Included: 15 A IEC mains cable.
