Chord Electronics Ultima

The Chord Electronics Ultima is a 780-watt mono reference power amplifier capable of driving loudspeaker impedances down to 1 ohm. It is the most powerful amplifier Chord has ever built, using their ULTIMA dual feed-forward error correction topology, proprietary matched MOSFET output transistors, a high-frequency switch-mode power supply operating at 70 kHz, and a fully balanced circuit from input to output. Sold as a pair, two Ultima mono blocks are designed for loudspeakers that most amplifiers cannot properly control.

Key Features

• 780W into 8 ohms (mono), stable into loads down to 1 ohm
• ULTIMA dual feed-forward error correction
• High-frequency switch-mode power supply operating at 70 kHz
• Proprietary MOSFET output transistors (closely matched)
• Fully balanced XLR and single-ended RCA inputs
• Fully balanced circuit from input to output
• ULTIMA Reference range
• Sold as a pair (price is per pair)

Why We Carry Chord Electronics

Chord Electronics has been doing digital conversion differently since 1989. While every other manufacturer buys off-the-shelf DAC chips, Rob Watts designs custom FPGA algorithms with tap lengths that dwarf anything from ESS or AKM. Their proprietary Pulse Array technology, MOSFET amplification stages, and high-frequency switch-mode power supplies are all designed and built in Kent, England. From the portable Mojo 2 to the flagship DAVE, every product runs code that Chord wrote themselves.

780 Watts Into 1 Ohm

The Ultima's headline specification is not just its 780 watts into 8 ohms. It is the amplifier's ability to drive loads down to 1 ohm without shutting down, distorting, or overheating. Most loudspeakers are rated at a nominal 4 or 8 ohms, but impedance varies with frequency. A speaker rated at 4 ohms might dip to 2 ohms at certain frequencies, and some complex multi-driver designs present loads below 2 ohms at their impedance minimum. These are the speakers that cause conventional amplifiers to current-limit, clip, or engage protection circuits. The Ultima does not. Its output stage and power supply are built to deliver whatever current the speaker demands, at any impedance, without compromise.

Chord Electronics Ultima and ULTIMA Topology

Dual feed-forward error correction runs a dedicated error correction amplifier alongside the main signal amplifier. The correction amplifier monitors the output at two points in the circuit, comparing it against the input signal and correcting any deviation before it reaches the speaker terminals. At 780 watts driving a 1-ohm load, the output transistors are pushing massive amounts of current through the circuit. Maintaining signal accuracy under those conditions is the hardest test any amplifier topology can face. The dual feed-forward approach catches distortion that single-loop negative feedback designs miss, keeping measured performance consistent from milliwatt levels to full rated power.

Chord Electronics Ultima Power Supply

The Ultima's switch-mode power supply operates at 70 kHz, charging its capacitors up to 70,000 times per second. An amplifier rated at 780 watts needs enormous current reserves to handle dynamic peaks, and the SMPS architecture delivers that current faster than any conventional toroidal transformer. The high switching frequency keeps the power supply's operation well above the audio band, eliminating the magnetic interference that 50-60 Hz transformers generate in the exact frequency range the amplifier is trying to reproduce. The result is an amplifier that combines the current delivery of a massive conventional power supply with the speed and noise rejection of Chord's proprietary switch-mode design.

Proprietary MOSFET Output Stage

Chord designs and closely matches their own proprietary MOSFET output transistors. At 780 watts into loads as low as 1 ohm, the output stage is handling peak currents that would destroy off-the-shelf devices with inconsistent characteristics. Close matching between all transistor pairs ensures equal load sharing, equal thermal distribution, and consistent performance as the devices heat up during sustained high-power operation. The fully balanced circuit topology carries the signal from input to output with no conversion between balanced and single-ended stages, maintaining common-mode noise rejection throughout the entire amplification chain.

The ULTIMA Reference Range

The Ultima is the reference amplifier in Chord's lineup, paired with the Ultima Pre reference preamplifier for a complete no-compromise signal chain. The Ultima Pre's three dedicated outputs, frequency EQ adjustment, and eight-input routing provide the control complexity that a system at this level demands. For digital source, the DAVE DAC with Hugo M Scaler represents the reference front end. Balanced XLR connections between the Ultima Pre and the Ultima mono blocks allow the amplifiers to sit near the speakers with long interconnect runs and short speaker cables. Available in black or silver finish.

The Listening Room Difference

At The Listening Room, we don't just sell high-end audio, we provide a level of service that's as refined as the products we offer. When you invest in a mono amplifier like the the Ultima, you're not just making a purchase, you're making a commitment to world-class sound, and we match that commitment with world-class service.

Owner Michael Hoaston will personally deliver the Ultima to your home, anywhere in the country. This isn't a curbside drop-off. Mike will painstakingly ensure that every detail of your setup is dialed in perfectly. From room placement and fine adjustments to full system integration, he'll work to optimize the Ultima's performance within your space. When you buy from The Listening Room, you're getting the expertise and dedication of someone who truly understands what it takes to bring a system to life.

Chord Electronics Ultima Specifications