QUAD PA-One+ Headphone Amplifier and Preamplifier Sneak Peek

I’m old school in many, many ways, but I’m also a fierce adopter of new technology as well – just at my own pace and in my own way. I’m not on anyone’s bandwagon, I tend to march to my own drummer.

So, when an old-school company starts coming out with new gear, I tend to pay attention because I feel – like me – they’ve taken a beat to assess the latest and then come out with something in their own way and in their own time.

Venerable British hi-fi manufacturer QUAD is just such a company in my experience. They don’t rush into anything, rather they take a measured approach and since they are no stranger to my ears, as it was their 1957 electrostatic-paneled ESL-57 loudspeaker (hence the naming protocol) that got me back into high-fidelity nigh on close to 10 years ago.

Their PA-One Headphone Amplifier and Preamplifier has been on my radar for review since hearing it a couple times at shows last year and coming away impressed with what I had heard, so when Mo-Fi Distribution asked if I’d be interested in reviewing their freshly updated version – the PA-One+ – I gave them an emphatic thumbs-up.

So, what’s new in the “+” version? According to QUAD it’s sporting:

  • Re-engineered circuit topology for better freq. response and S/N Ratio.
  • Improved circuitry for better transparency
  • Better DAC: ESS Sabre 9018 K2M DAC up to PCM 384kHz & DSD256
  • Lower price point - now $1,299 USD vs $1,799 USD

Specifications:

Valves:

2 x 6SL7 amplification valves. 2 x 6SN7 amplification valves.

Analog Connections:

  • Gold plated RCA input.
  • 6.3mm headphone jack.
  • 4-pin XLR balance headphone input.
  • 3-pin XLR balance input.
  • Gold plated RCA Pre-out (use as Pre-amp).

Digital Connections:

USB, gold-plated coaxial, optical.

The PA-One+ has an input impedance of 50kΩ, outputs 500mW (at 32Ω) has a listed output impedance of 32Ω~300Ω, an input sensitivity of 500mW (at 32 Ω) and a frequency response of 20Hz~20kHz (+0dB,-0.5dB). Distortion is 0.5% at 1kHz, channel balance of ±0.5dB, a signal/noise ratio of 90dB and weighs in at 7kg.

The PA-One+ ships with a power cord, batteries, remote control and user manual.

I’m going to be burning this unit in for the next couple weeks as QUAD recommended to give as much break-in as possible before critical listening as in their haste to get it into my sweaty palms they shipped it without factory run-in.

Look back for the full review here.

COMPANY INFO
Quad
IAG House Units, 13-14 Glebe Rd, Huntingdon PE29 7DL, United Kingdom
+44 1480 452561

COMMENTS
Simply Nobody's picture

May be Rafe could also review the Schiit Audio Mjolnir headphone amp ($849) .......... It is both tube and transistor capable ..... It has no digital connections :-) ...........

Rafe Arnott's picture
I'd love to review Schiit gear!
PAR's picture

" has a listed output impedance of 32Ω~300Ω"

I don't think that can be correct. If it is then this would be an unusual amplifier and one that would not be very successful at driving headphones given such a high output impedance and one that varies so hugely, presumably with frequency. Should it not, instead, read something like " Output is suitable for headphones of between 32 and 300 ohms impedance"?

I look forward to the full review.

Rafe Arnott's picture
I am quoting from the spec sheet from QUAD. If you have issue with their nomenclature, I suggest to take it up with QUAD. Also, From the PA-ONE+ owner's manual:

"The PA-ONE+ is able to drive both high and low impedance headphones, selected via switch on the rear panel. 'High impedance' means 100 Ohms and above; 'low impedance' is below 100 Ohms. (Typically, high-impedance headphones are 200Ohms or 600Ohms, while low-impedance types are 32 Ohms.)

Hope that helps.

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