FS: Woo WA234MKII Monoblock Headphone/Speaker Amplifier

Price: $12,950
Currency: USD
Ships to: Local Pickup Only (Southern Florida)

Selling my WA234 MKII Mono Block Headphone/Speaker amplifiers; most of my listening time is on speakers now.

They are in like-new condition, with no scratches, dings, dents, scuffs, nor any other marks I can see, and have always been kept in a pet and child free home.

You can read on, below, for more details about this very powerful, flexible, and amazing-sounding amplifier (or you can look at the product page at Woo Audio).

I’ll post additional pictures, of my actual amplifiers, as I get a chance/when I get a serious inquiry.


  • 2x WA234 MKII Mono-Block Amplifiers
  • Original “Stock” set of Tubes (2x 13EM7, 2x 300B, 2x 5U4G) – < 10 hours
  • 12x (6 matched pairs) of 13EM7 driver tubes, all NOS and unused
  • Cased set of “switching keys” and dual ¼” TRS mono to single ¼” TRS stereo cable
  • All original packaging

An additional $1,000 will get you the optional tubes as well (about $2,800 worth); see below.

I will NOT ship this; so, any transaction will be in person.

You don’t want to buy something like this without auditioning it anyway. So, you’re invited to visit and spend a day listening, both to audition and verify everything works, with no commitment. If you’re not local, you’re welcome to stay with us rather than dealing with hotels.

If you need to ship it once you’ve bought it, I can help, and I have all the original packaging. But understand that you will be shipping your amplifier, and all costs, risk, and any issues that arise from shipping, will all be on you.

Price is firm (MSRP is $18,000, and comes with a multi-month build-time despite the 6-8 week claim); I’m not in any hurry, nor do I need to sell these, they’re just not getting used.

Not really looking for trades, though I might consider a recently built DNA Stellaris + cash.

Amplifier Details

This is a true class-A, SET, transformer-coupled mono-block amplifier. Volume is set individually on each channel using a 42-position stepped attenuator (so it’s easy to match levels between left and right channels). You can also set volume to maximum to bypass the resistors and use a variable-output source to control the volume instead.

It uses 1x 13EM7 driver tube and 1x 5U4G/274B rectifier tube per amplifier, and your choice of 2A3, 300B or 45 series power-tubes. You can select either plate (high power) or cathode (lo power) drive, and high or low impedance output. These features are selected by inserting “switching keys” into sockets on the top of the amplifier.

It has plenty of power for every headphone I’m aware of, including the AB-1266 Phi TC (8.2W into 47 ohms, at 127.2 dB/SPL) and the Susvara (6.5W into 60 ohms, at 121.1 dB/SPL), while still easily handling low impedance cans, all the way down to things like the LCD-5 and Stealth at ~14 ohms).

I’ve used it to drive the RAAL SR1a via the TI-1a interface from the WA234’s speaker taps, to excellent effect.

8W of SET power is available to drive speakers.

They have 2x RCA and 1x XLR inputs, and 3-pin XLR and ¼” TRS combo outputs.

Optional Tubes

Optionally, for an additional $1,000 total, if purchased with the amplifier:

  • 2x Sophia Electric Princess Punched Plate 274B rectifiers (originally $500) – 500 hours
  • 2x Emission Labs Mesh 274B rectifiers (originally $706), 250 hours
  • 2x WE 300B [late 2020] (originally $1,499), unused (bought as spares)