"... one of the best ­ if not the best ­ headphone amplifiers money can buy."

Alan Sircom Hi-Fi+ Iss94

  HFC 933 HiFiPlus933 SoundStage! Hi-Fi HiFi Philosophy

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Trilogy 933 Amplifier for Headphones

The task of moving the delicate membrane of a headphone driver is a very different to energising the reactive complex impedance of a multi driver loudspeaker. With much less mass to move and without the masking of listening environment and room interaction, the small signal integrity of an amplifier becomes even more critical than that of a regular power amplifier.

A different approach to design is required. This has led us to a very different solution to most accessory mass market offerings.

The Trilogy 933 is a clean sheet design with the same natural presentation and vibrant musicality found in our award winning pre and power amplifiers. Its a subtle, but crucial distinction: we like to think of the Trilogy 933 as an amplifier for headphones, not a headphone amplifier.

933 Pack Iso MkII PSU with cans mr

HFC Excellence
Polish Hi-Fi Choice Editors Choice

The svelte amplifier enclosure is machined from a solid billet of aluminium. Its hefty 1.3kg mass provides outstanding physical and electrical isolation for each of the active circuit elements as well as a stable thermal base for heatsinking the output devices.


The 933's amplifier is pure single ended Class A, employing active constant current sources. Each channel has just one continuously biased output device. The output waveform is therefore completely free from crossover distortion and has excellent small signal integrity.

DC coupling removes capacitors in the signal path, enhancing detail even further. The discrete topology is implemented with carefully selected audio grade components to deliver amazing resolution and drive capability for any high quality headphone.

933 Int
mr 900 MkII RH Iso

The improved external power supply can be remotely sited to keep stray electromagnetic fields at bay. A generously rated, faraday screened transformer and soft recovery rectifier diodes are complemented by a custom wound input choke.

The choke input topology smooths out the current pulses demanded by the premium Mundorf reservoir capacitors, much like a flywheel, keeping the power supply's dynamic noise very low

The rear panel offers the user two selectable stereo inputs via high quality gold plated phono connectors.

The 933 can stand alone as the cornerstone of a headphone based system or connect easily to any existing preamplifier.

933 Rear mr
933 Detail mr

Volume, mute and balance which are all accessed by the supplied remote control only.

The front of the amplifier has an arc of LEDs which conveniently display the chosen settings which are stored for the next time the 933 is powered up.

The amplifier is monitored for safe area operation at all times and is automatically muted for power on and off.


In combination the 933 elements form a whole greater than the sum of its parts. The Trilogy 933’s performance bears all the traits you would expect from a full sized Trilogy amplifier: coherence, precision, resolution and effortless musicality. The Trilogy 933 is truly a class leading amplifier for headphones.


Chameleon Colour System LogoAvailable in natural silver as standard. Extra cost finish options are our standard paint finishes, and almost unlimited custom colours through our Chameleon System.


Download a PDF Product Sheet


Download a User Manual



 Size (933 Amplifier)  150*220*38 (W*D*H)
 Size including connectors (933 Amplifier)  150*235*38 (W*D*H)
 Weight (933 Amplifier)  1.8 Kg
 Size (PSU)  132*225*57 (W*D*H)
 Weight (PSU)  2.85 Kg
 Packaged Size (combined)  330*290*195
 Packaged Weight (combined)  5.7 Kg
 Power consumption  22 Watts
 Inputs  2 Stereo line 4 RCA phono sockets
 Input Impedance  ≥20KOhms
 Gain (max)  19dB
 Frequency response  15-120KHz +/- 0.5dB
 Output impedance  ≤ 3 Ohms
 Output Power

 800mW into 300 Ohms
 250mW into 60 Ohms

Distortion (THD) ≤ 0.05% 10mW into 300 Ohms
Signal to Noise Ratio ≥ 85dB A Weighted
 Phase  Phase correct (non inverting)
Specification subject to change





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