Octave Audio • HP 300 SE Preamplifier

by Mark Blackmore | November 21, 2025

I was discussing the Octave HP 300 SE with a friend, and he said that it seems like "a quiet luxury piece." I wasn’t sure what he meant, but after a quick Internet search, I realized that he was correct. Octave’s design philosophy shares a lot with the fashion-design concept of quiet luxury, which refers to products having understated elegance, excellent craftsmanship, and the use of high-quality materials. Additionally, these products feature a minimalist design with sustainable consumption in mind; the products last a long time, yet they remain timeless. That perfectly describes the HP 300 SE, Octave Audio's entry-level preamp.

Andreas Hoffman, founder of Octave Audio, adds two more requirements for his designs: they must use tubes for their “exceptional sound performance,” and all products must be reliable and repairable. To address reliability, Octave's Power Management and Soft Start circuitry ensures long life from tubes and electronics. These two circuits “gently ramp up the heating and supply voltages to minimize wear and tear on the components.” Furthermore, “In the event of a problem, the Power Management’s protection system disconnects the unit from the power supply.” The Soft Start circuit mutes the preamp for 90 seconds at startup, and also mutes the output for 30 seconds when changing the gain setting.

Because of these circuits, the owner’s manual states that tubes may last five to ten years without needing replacement. Andreas Hoffman goes further: "Five to ten years, in my opinion, this is at best a run-in period; in reality, significantly longer operating times are achieved. Many customers believe that tubes age rapidly and become sonically unusable. This is a factor that depends on the circuit design, not on the tubes themselves. Regardless, the power management system isn't just responsible for the tubes; it's also about extending the lifespan of the device itself, or rather, preventing unnecessary failures and consequential damage. In this respect, I expect a lifespan of 15 to 20 years without servicing."

The HP 300 SE is a hybrid design that shares some electronic design elements with Octave’s flagship Jubilee line. Audio signals are routed through two tubes, an ECC81/12AT7 and a 6N6, and then through a “super-gain semiconductor circuit” acting as a buffer to drive an amplifier. Hoffman indicates that this buffer circuit maximizes the preamp’s sound quality, regardless of amplifier or cabling used. The HP 300 SE is powered and switched on by an outboard power supply, keeping electrical noise to a minimum. The satin-black review piece (silver is also available) included the optional moving-coil phono board. Upon request, a moving-magnet board is also available.

It should be noted that every transformer used in Octave products is made in-house. That includes power transformers, matching transformers used in the XLR connections, and even the step-up transformers used in phono stages. Before Hoffman designed audio gear, his family business began as a transformer-winding shop, and they continue this practice today.

A visually minimalist design, the HP 300 SE has just three front-panel knobs, but there are some not-so-obvious features included in its design. The left knob controls muting, home-theater bypass, and three levels of gain. This last feature is somewhat rare; it allows you to change the gain structure of the tube circuit to better match the preamp with amplifiers of differing input sensitivities and gains. The gain selector was helpful in matching the three amps I used for this review, as well as being instrumental when evaluating the phono stage.

A larger central volume knob has good rotational feel, and volume changes are appropriate -- neither too small nor too large in use. The excellent handheld remote has only two concave buttons for volume up and down, but the feel is perfect, and the sensor’s wide angle of acceptance and good rate of volume change makes adjustment easy. I enjoyed the remote control so much that I rarely used the actual volume knob. On the right side of the front panel is the input selector knob for three RCA inputs, one XLR input and the phono stage.

The preamp’s back panel has a large connector for attaching the outboard power supply, two sets of RCA outputs for easy biamping or subwoofer use, and two sets of XLR outputs: one for amplifier connection and one for the home-theater bypass. The HP 300 SE isn’t a true balanced preamp, but Octave does use coupling transformers to eliminate ground loops and ensure “unsurpassed sound characteristics.” Users must enable the home-theater bypass for use via a small switch inside the preamp, but the excellent owner’s manual makes it a simple procedure if needed.

My initial impression of the HP 300 SE's sound was easily summed up in three words: bass, space, and pace. Bass notes were weighty, with good speed of attack and no overhang. There was no sense of bloat, just solid bass response with plenty of power. Interestingly, that bass character was similar with all three of my test amps, with power ratings ranging from 1 to 300 watts. The Altec Valencia speakers were able to pressurize the listening room in heavy bass passages, and even the little Falcon LS 3/5as were more robust and energetic on bass lines. The HP 300 SE's tight bass made music sound peppier, with lots of toe-tapping and head-bobbing.

Spatial cues were precise, with a good sense of hall acoustics, but did not extend as deeply into the soundstage as with my BorderPatrol Control EXD 0.5 preamp. One aspect of the HP 300 SE that was clearly better than my reference preamp is image height. Because of the generous soundstage height, one guest thought the HP 300 SE gave the best sense of soundstaging that he’s heard in my listening room. The HP 300 SE was also fast- and nimble-sounding, excelling at PRaT (pace, rhythm and timing). As we will see, this pace and timing contributed to what I heard from vinyl playback.

After the initial break-in period, I began more specific testing of the HP 300 SE with the title track from Anouar Brahem’s Blue Maqams [Qobuz ECM 5767265 24 bits/96kHz]. This track is a reliable check to quickly assess new audio gear. I listen for a component’s ability to lift the music out of its dreamy, contemplative nature that can border on that of elevator music. One key aspect to listen for is Jack DeJohnette's drumming, along with his use of timpani mallets on his drum set. The HP 300 SE gave his drumming real depth and energy, and his floor toms excited the recording studio’s acoustics. Instead of dreamy and sluggish, this cut now had drive and pulse, creating interest.

Listening to Andras Schiff’s Das wohltemperiete Clavier [Qobuz ECM New Series 001733702 24 bits/44.1kHz], I heard why so many listeners love this recording. The HP 300 SE, in addition to its powerful low bass, imparted the impression of a bit of midbass richness, giving the piano more heft from the left-hand notes. Schiff’s right-hand treble notes sounded clear and clean without any unnatural glare. The preamp’s clarity made it easy to hear Schiff’s sparing use of rubato while still managing musically satisfying phrases. With the exception of the noted slight bass warmth, the HP 300 SE did a good job of keeping consistent piano tone throughout all octaves.

For a completely different portrayal of recorded piano, I chose Nikolai Lugansky’s recording of Debussy's Suite bergamasque [Qobuz Harmonia Mundi HMM 902309 24 bits/96kHz]. Harmonia Mundi put the piano sound in a midhall perspective, which let the HP 300 SE’s handling of hall reverb and space shine. Piano tone was somewhat distant, but its harmonic overtones and the captured hall space were well preserved. The Schiff recording was an excellent-sounding studio recording, but the Octave preamp’s reproduction of space and reverb allowed Lugansky’s recording to feel like the listener is attending a concert performance.

“Life goes on: Life goes on” from Carla Bley’s new album of the same name [Qobuz ECM 003160802 24 bits/96kHz] is a slow-burn blues that begins with solo piano. The HP 300 SE’s sound had bass richness, extension and texture, even when played back on my little Falcon LS3/5a speakers. I have heard this cut on different systems lately, and the HP 300 SE had the best bass texture on Bley’s opening solo. Soundstaging had good image placement on this recording, but comparing different amplifiers with the HP 300 SE revealed a characteristic that I found intriguing.

To explain: transparency is traditionally used to mean (among other things) that a piece of gear resolves low-level detail and reveals new information in a recording. The HP 300 SE is transparent in the traditional sense but also transparent or uncolored enough to allow downstream gear to be more easily identifiable. I utilized three vastly different amplifiers during my review period. The first was the Innersound ESL solid-state amp that I retain because of its indifference to speaker load or sensitivity. It can drive almost any speaker ever made without breaking a sweat, but its downfall has always been a slightly cool, clinical timbre. While the Octave preamp couldn’t banish its slight coolness, it managed to give the amp some extra bounce and life, making it sound far better than usual.

The second amp is the 6C33-tubed BAT VK-60, which maintained its velvety sound and dark, almost chocolaty tonal balance. The HP 300 SE didn’t diminish that luscious sound, but it did reveal that the BAT amp has a noticeably softer, slower treble attack while also displaying the widest soundstage of all three amps used.

Finally, I partnered the HP 300 SE with the flea-powered Yamamoto A-08, easily the most textured and holographic amp I own. The Octave preamp also clearly revealed how much smaller the soundstage width and height of the Yamamoto amp were when compared to my two previously mentioned amps. All of these amps should sound different, and most preamps will hint at these sonic differences, but the Octave preamp made each amp sound vastly different from the others, yet completely interesting and engaging.

I’ve saved the HP 300 SE’s best for last. The optional MC phono stage adds a third tube (ECC81/12AT7) to the signal path. To change cartridge settings, one has to remove eight screws to access the phono board. The phono section has a switchable subsonic filter, a gain switch for moving-coil cartridges above or below 0.5mV, and load switches allowing sixteen different settings, ranging from 37 ohms to 1000 ohms. It should not be an issue finding suitable load and gain settings for almost any moving-coil cartridge. The factory setting is high gain and 100 ohms, and I found it to be a fine match for my Ortofon SPU-A and Yamamoto YC-03S cartridges. While listening to digital, I used the preamp gain settings on low or medium to better match the volume’s range to my amplifiers. But because both of my phono cartridges have very low outputs, I decided to compensate for that by switching the preamp's gain to high.

I have been using “Engravings II” from A Winter’s Solstice [Windham Hill HW-1045] to assess changes to my vinyl setup before doing any serious listening. I find this cut helpful for quickly evaluating different phono stages and cartridges, and changes in cartridge alignment. This track’s opening melody is played on an English horn, later accompanied by piano, and the test is to hear if the English horn sound has enough body so as not to be mistaken for an oboe, and if its timbre is maintained once the piano enters. The combination of my Ortofon SPU-A and the HP 300 SE's phono stage passed this test easily, with spot-on tonality and better-than-average separation of English horn and piano unisons.

Listening in earnest, I chose George Crumb’s Ancient Voices of Children [Nonesuch H-71255], conducted by Arthur Weisberg with the marvelous Jan DeGaetani as soloist. Even though this album was recorded by the dream team of Marc J. Aubort and Joanna Nickrenz and mastered by Bob Ludwig, I just don’t remember hearing it sound so good. It wasn’t that the HP 300 SE's phono stage was revealing more soundstage cues or low-level sounds, but, rather, it that it made the recording compelling and interesting. Listening to the amplified piano clanging away, with DeGaetani’s vocal part swooping and shrieking, was absolutely spellbinding. Not one audiophile term came to mind, and all I wanted to do was hear track after track. I was so excited about this recording that I dug out two other Crumb recordings and listened to them all the way through. Quite an afternoon of listening joy and certainly more George Crumb than I had heard since cramming for my college music-history exams.

Even messy and confused recordings like Don Ellis’s Autumn [Columbia CS9721] were more tolerable and kept my interest. Every Don Ellis recording has sound-quality issues, but the HP 300 SE managed to make better sense of his music and rekindled some long-forgotten memories of trying to play his compositions in college.

For quite some time I was perplexed as to why this phono stage was so enjoyable, so much fun to listen to. After listening to a number of albums, I believed it was the nimble approach to timing and rhythm that made the phono stage stand out. John Quick, (VP of Sales and Marketing for Dynaudio and North American distributor for Octave) informed me that the preamp's high-gain setting uses less negative feedback. Maybe that was what gave vinyl the toe-tapping energy and pace to keep me listening and discovering more albums. Using the low- and medium-gain settings, the analog playback was good, but high gain was where I began to really enjoy vinyl. Trying high gain with digital playback showed some similar improvements, but it was vinyl playback using my Ortofon SPU-A cartridge that brought so many smiles. I encourage you to read Guy Lemcoe’s review of the solid-state Octave Phono EQ.2 for his reaction to that phono stage. It closely mimics my experience with the tube-based phono stage of the HP 300 SE. He, too, found himself listening to recording after recording; obviously, Octave is doing something very right with their phono stages.

There were some drawbacks while using the Octave preamp and, while minor, still deserve mentioning. First, the power switch is located on the separate power supply, so the power supply must be in an easily accessible spot on your equipment rack. The length of the umbilical between preamp and power supply is generous, at five and a half feet, so this may not be an issue. Second, the remote control has only volume up and down, and many competing preamps offer source selection, balance, mute, and maybe even back-lighting. If those are must-haves for you, then this remote will not satisfy. In the remote control’s favor is its excellent ergonomic feel, ease of getting just the right volume setting, and that it works no matter how I pointed it at the preamp from across the listening room.

One final thought is about warm-up time. The review sample of the HP 300 SE was delivered with, reportedly, many hours of use, but I was not totally comfortable with the sound until the unit had been on for at least an hour. The sound when first turned on wasn't harsh or bass-shy, but rather unnaturally fast and insistent. I can’t say these made music unlistenable, but as soon as I discovered the sound of a fully warmed up HP 300 SE, I always turned it on an hour or two before listening, and I strongly recommend you do the same.

Is the Octave HP 300 SE “a quiet luxury piece”? It is certainly minimalist in its outward appearance, but the sound of the preamp is anything but muted or reserved. Fully warmed up and on the high-gain setting, the HP 300 SE sounded energetic and musically engaging, urging me to seek out new listening material. Bass response was tight and extended, and recording spaces wrapped around my listening seat. Octave’s HP 300 SE preamp made listening just plain fun.

Price: $8250 for line stage; add $1500 for either moving-coil or moving-magnet phono input.

Warranty: Three years parts and labor on electronics and workmanship from Octave Audio. Two-year warranty extension from Dynaudio North America with registration within 60 days of purchase.

Octave Audio
Industriestrasse 13
76307 Karlsbad
Germany
www.octave.de

North American distributor:
Dynaudio North America
500 Lindberg Lane
Northbrook, IL 60062 USA

Associated Equipment

© www.theaudiobeat.com