HP-1: Ultra-High End Headphone Amp

Rated 5.00 out of 5 based on 1 customer rating
(1 customer review)


Ultra-high end 3 W headphone amplifier with vanishingly low distortion.

SKU: N/A Category:


The Neurochrome HP-1 is an ultra-high end headphone amplifier capable of producing up to 3 W into a 20 Ω load at vanishingly low distortion. The HP-1 will drive even the most challenging headphones with the utmost fidelity and natural sonic profile. It is designed to be as close to a straight wire with gain as technically possible. In addition to providing the ultimate technical performance, the HP-1 also provides peace of mind as it contains advanced protection circuitry which will protect your headphones in case of various fault conditions.

Key Features

  • Fully optimized 4-layer circuit board.
  • Total harmonic distortion: 0.000017 % (200 mW, 600 Ω).
  • Total harmonic distortion: 0.000032 % (200 mW, 300 Ω).
  • Total harmonic distortion: 0.000050 % (200 mW, 32 Ω).
  • Total integrated output noise: 1.0 µV RMS (A-weighted, 20 Hz – 20 kHz).
  • Output power: 3.0 W (32 Ω).
  • Output power: 450 mW (300 Ω).
  • Output power: 230 mW (600 Ω).
  • Gain selectable (+6, +12, +20 dB) by front panel switch to accommodate a wide range of sources, including smartphones, tablets, DACs, and CD players.
  • 1/4″ phone and 4-pin XLR output connectors.
  • Balanced (XLR) and unbalanced (RCA) inputs.
  • ±0.1 % tolerance Susumu RG-series resistors used in critical parts of the circuit to ensure the best possible performance.
  • All signal switching is accomplished using relays with gold plated switch contacts.
  • ALPS RK097 volume control potentiometer.
  • Well filtered switching power supplies followed by onboard low noise linear post-regulators ensuring the highest power supply performance.
  • Protection against DC voltage on the amplifier output.
  • Integrated mains soft start and 320 Joule surge suppressor.
  • ON indicator emitting a subtle and pleasant blue glow.
  • International mains voltage compliant (85 – 264 VAC @ 47 – 440 Hz).
  • All aluminum chassis made in Canada.

The HP-1 is available in various options ranging from a bare circuit board (no components included) for DIY assembly to a fully and assembled and tested product.

Please follow this link for the full circuit description, specifications, and performance measurements: HP-1 Product Description Page.

1 review for HP-1: Ultra-High End Headphone Amp

  1. Rated 5 out of 5

    Keith (verified owner)

    Neurochrome HP-1 Headphone Amplifier
    Build: February 2017
    BMF Flyer
    Pictures, below…


    I like a lot of different amps. I enjoy building DIY amps and it’s fun “rolling” amps, so to speak…solid state, all tube, and hybrids. So, which one sounds best? Well, for me it depends… on the day, the music genre, the mood, the quality of the recording, and the headphones to mention some of the variables involved in producing “sound quality” and audio pleasure.

    What one person hears and describes may be heard and described very differently by others. Objective measurements can help but don’t guarantee you’ll like what you hear. It comes down to opinions, personal preferences and simply, “what sounds good, sounds good.”

    I had the opportunity to participate in SBAF’s Neurochrome HP-1 tour. Before my week with HP-1 was up, I knew I wanted to build one. I ordered the PCB, custom enclosure, volume knob, and RCA jacks from Tom Christiansen, an electrical engineer and designer of HP-1. The HP-1 components arrived within a few days of receiving the BOM from mouser.com I had ample time to sort and label all parts corresponding to Tom’s excellent build guide and BOM. I completed my HP-1 build over the course of two weekends. I really took my time and proceeded carefully. I double-checked each component against the BOM and schematic and measured each and every one both before and after soldering them in place. Patience and attention to details paid off…when I flicked the On switch, the soft blue LED lit up…and there was no smoke! I ran it through the setup and testing procedure recommended by Tom. The DMM showed 200 mW RMS and 0.00 VDC offset on the outputs. OK, time to take HP-1 for a test drive.

    Gear Chain

    Lossless and FLAC files > iMac 7 > OPPO HA-1 DAC > HP-1 > HD-650, HD-600, AKG 7xx, Beyer 990, OPPO PM-1 and PM3, Yamaha YHD-1

    “A Few” Eclectic Test Tunes I know very well put amps through their paces requiring complex bass, sweet acoustic/vocal mids, and treble details:

    Anna Maria Jopek and Pat Metheny – Are You Going With Me?
    Beck – Blackbird Chain
    Bill Evans – Piece Peace
    Cake – I Will Survive
    Charlie Hunter Trio – Wizard Sleeve
    Donald Fagen – Maxine
    Gorillaz – Dare
    John Mayer – Slow Dancing in a Burning Room
    Jon McConnell – Sober
    kd lang – Save Me
    Smetana – Ma Vlast mvt II
    Shostakovich Symphony No 5 mvt iv
    Lucinda Williams – Essence
    Mana – Mariposa Traicionera
    Marcus Miller – Redemption
    Metallica – Whiskey in the Jar
    Miles Davis – So What
    Muse – Hysteria
    Norah Jones – I Wouldn’t Need You
    Patricia Barber – Too Rich for my Blood
    Perlman – Bach Double Violin Concerto
    Punch Brothers – Missy
    Radiohead – Jigsaw Falling Into Place
    Steely Dan – Babylon Sisters
    The Tao of Groove – Multatica Mia
    Vlatko Stefanovski & Miroslav Tadic – Kajesh Anjo
    Willie Nelson – Vous et Moi
    Wynton Marsalis – The Magic Hour
    Yes – Long Distance Runaround
    Yo-Yo Ma – Quarter Chicken Dark


    The background is Black and dead quiet. There’s no hum, buzz, or other noises when not playing music, and none during silent passages of songs at any volume pot setting.

    I agree with Tom, Armaegis, fishski13, and others that HP-1 is “a straight wire with gain.” Parsimony Rules: HP-1 delivers a flat FR. No part of the FR is emphasized or cheated. HP-1 is balanced from bass, through the midrange, and into the higher frequencies.

    Bass is fast, textured, and well extended. I really like how HP-1 “does” acoustic double bass harmonic layering and decay. Kick drums have punch. Tympanis have authority.

    The midrange is fantastic and neither forward nor recessed. Vocals and acoustic instruments sound beautifully rich while remaining clear. I love HP-1’s rendition of jazz trumpet, tenor sax, and female vocals.

    HP-1’s treble extends into the upper frequencies providing accurate micro details, “air,” and shimmer without any sibilance or pierce. Harmonics from chimes, triangles, and cymbals add sparkle and nuance to the sound quality. Hearing female singers inhale between phrases and the delicate sound of exhaling on the extended final syllable of the last word enhances the emotional impact of the song.

    The width of soundstage and instrument placement is in the Goldilocks Zone…not too narrow, not too wide…just right.


    Previously, I thought there was no discernable difference between HP-1 and QRV-08. After spending a good deal of time with them head-to-head using a Quick Switch adapter and SPL matching, I have concluded that there is a noticeable difference. HP-1 is rather more resolving, cleaner, and more enjoyable. I can voice this opinion with some authority given I’ve built 3 QRV-08’s And I really do like QRV-08…it’s no slouch to my ears and I like it a lot! It’s just that HP-1 ups the ante. HP-1 also competes with other amps I’ve auditioned, own, and/or have built including, in no particular order:
    GS-X mkII
    Liquid Carbon
    OPPO HA-1
    EHHA Rev A
    Kameleon v2
    Single Power MPX3
    Some other TOTL amps


    I had a lot of fun building HP-1. I’m having more fun listening with HP-1. Many thanks to Tom for creating HP-1, as well as a bit of technical assistance…he’s “on it!”

Only logged in customers who have purchased this product may leave a review.