This is my first "proper" review on Head-Fi. I'd be remiss if I didn't post one, though, as the Ray Samuels Audio ("RSA" from here) Apache is a relatively rare amp, and has limited coverage online. As a new owner, I feel pretty strongly that it deserves further praise and information posted about it, in case Ray ever gets enough parts to start taking further orders!

First, I should note that my rating of 4.5/5 is simply to leave room for the mega-buck amps in the price class above $ 3,000 USD, and I would presume those can achieve more on a larger budget. That said, within my experience, the Apache safely earns a 5/5. I certainly can't imagine ever wanting more in an amp.

Second, some additional context: This is my first high-end solid-state amp, though I have some experience with "mid-fi" solid-state amps, having owned the Burson HA-160, SPL Auditor, and the Violectric V200. I've also owned the entry-level Creek OBH-11, which got me initially hooked on head-fi, with the Burson acting as the springboard into what I consider "proper" headphone amps a couple of years later.

I also own the Woo Audio WA2, which now has been equipped with top-notch tubes and is my end-game tube amplification for years to come. However, for shorter listening sessions, I felt a strong need to invest in a solid-state amp to match. The prospect of causing added wear and tear on my tubes when powering up the WA2 and shutting it down again after a short listen made me hesitant enjoy music as often. And we can't have that!

As a result, I started hunting for a solid-state amp that would serve a proper foil for the tube-based WA2: It needed to be quiet with low power consumption, should act as a high-quality preamp for my stereo setup, have precise volume control, and have several sound signature traits that mimic an OTL tube amp. Oh, and it needed to play nicely with high-impedance headphones as I own two ZMFs (the Eikon and Verite Closed) and plan to purchase my final (?) ZMF pair in a few months (the Atrium Closed). Not a tall order at all, right?

Using a budget of $ 2,000 USD as my ceiling and shopping among new and pre-owned units, I initially (among others) had the Pass Labs HPA-1, Kinki THR-1, and Violectric's new 2-- series in mind, while their mid-range amps generally either were too expensive or were described by owners as more neutral in tone. However, I also came across very favorable reviews of Ray Samuels Audio amps, including strong statements that they were excellent-sounding with ZMF headphones. Testimonials supporting this included Zach Mehrbach's own notes, which weighed into my purchase decision.

After considering the RSA HR-2, I stumbled over an RSA Apache in the Head-fi classifieds that turned out to be available. I was also fortunate enough to buy it from an exceptional community member who shares my Norwegian roots (@cinisi ), and we had many pleasant exchanges via PM in addition to a smooth transaction.

As the Apache unit was 230 Volts, I needed to get it switched to 120 Volts for my use, and thanks to great advice by the esteemed @John Massaria , I had cinisi ship from Europe to Ray Samuels directly after letting Ray know it was coming.

Ray is both a gentleman and a scholar, as they say. He only charges a nominal fee for op-amp upgrades, something I requested as he has continued to improve the Apache topology with newer, more sophisticated and high-quality op-amps that fit his design. He overhauled the amp and power supply as well, restoring the Apache to as close to as-new state as possible. I cannot speak highly enough of Ray's customer service!

I received the amp yesterday, and due to Ray's burn-in and testing before shipping it to me it sounded excellent out of the box. However, I needed more time today to try it out with a range of music and to listen more critically.

I have connected it to my Schiit Audio Gungnir Multi-bit via balanced Harmonic Technology Pro-Silway interconnects, and used the supplied high-quality vibration-mitigating spikes and additional protection discs (after all, who wants to mar the gorgeous black case finishes?).

Listening notes with my pair of ZMF Eikons (Bocote LTD, Norne Einvaldi Reference cables):

• Great horizontal soundstage. It extends well beyond the cans, which is unusual with the Eikon unless it’s driven by an excellent amp.
• The bass sounds like it emanates from space. The bass depth and clarity puts good tubes on my WA2 to shame, and I don’t say that lightly. The Apache has phenomenal bass control- with stops/starts happening on a dime, so to speak. This is visceral bass with a headphone that has full range like the Eikon.
• The Apache is FUN FUN FUN to listen to! The music grabs you by the lapels and drags you into the music. You want polite background music? Get another amp.
• The Apache is dead silent- this helps contribute to micro detail and the overall feeling of space.
• When listening, it's hard to not nod along or tap your feet with the rhythm- a true sign of great PRaT.

Track samples from my listening:

• H.E.R.: “We Made It”:
  • This track is a great test of bass depth and quality. Bass as diffuse pulses, speedy beats, or waves spreading outward- the Apache does it all without the bass getting overcooked or bloated. This amp controls the biocellulose driver of the Eikon magnificently! In addition, the bass does not spread into midrange.
  • The Apache also does not get harsh in the treble despite the song's slightly hot mix with somewhat overemphasized highs.
• Elbow- "One Day Like This":
  • This track showcases a delicate piano portion, which the Apache renders with grace and clarity.
  • Singer Guy Garvey floats steadily in center of stage, rock solid without wavering.
  • The track then introduces a bassline that thrums underneath without interfering with the rest of the song.
  • Later in the track, you can hear the bows moving across the massed strings, and plucked strings resonate with body.
• Arctic Monkeys- "Arabella":
  • For a fairly gritty rock track, this track has bass that is incredibly detailed and tuneful, and the Apache shows off its chops with relish. The bass drum has punch and you can hear the drum's skin resonate with capital "R".
  • The drum kit's high hat is clear, and you can hear the trailing ring shimmer in the air.
  • In the midrange, it is very clear when the mix uses deliberate distortion on the lead singer's vocals.
• Royal Blood- "Typhoons":
  • I am hearing more details in this track's mix than ever, including detailed ringing of metal in the opening's percussion.
  • As I noted when listening, this is a "Great amp for rock"!
• William Fitzsimmons- "Good Morning (Pink Ganter Remix)":
  • This is a song that has great channel separation, and the low noise floor and dual-mono topology of the Apache represents this exceptionally well.
  • Fitzsimmons' trademark breathy voice is well rendered, really bringing him to life.
  • I can REALLY hear into the mix, which has a lot of great details that are showcased without being overwhelming.
  • Stereo pans are CRYSTAL clear
• Death Cab For Cutie- "Doors Unlocked and Open":
  • This song proves the Apache's capability to propel driving rhythms forward with gusto!
  • Ben Gibbard's distorted voice is detailed, but not harsh to listen to.
  • I am now hearing more extended echo/reverb detail than ever before on other amps, which is impressive.
  • Great horizontal sound stage is also really noticeable.

At this point I simply stopped taking notes- it was too fun to listen!

I can only tip my proverbial hat to Ray Samuels for building an incredible amp that I will treasure for many, many years to come. The Apache is a perfect counterpoint to my Woo Audio WA2, and I will not miss its charms when I use the solid-state part of my system- which is exactly what I hoped for.

The Apache has delivered that in spades, and if I someday have to downsize to a single amp, the Apache is likely to be "the last amp standing". It is that charming, keeping enough of the beauty of tubes while injecting the dynamics and detail of solid-state, literally without missing a beat. To say I'm pleased with my purchase would be a severe understatement, and if you get the chance to buy an Apache whether in pre-owned or new state, I'd wager it will hold its own against amps at a higher price point as well.

[Minor edits made August 16, 2023 to clean up formatting and a few typos]