Audient ASP8024-HE Heritage Edition

The Audient ASP8024-HE is a large-format console featuring world-class Audient mic preamps, 56 to 152 inputs, 14 aux buses, 8 stereo subgroups, Retro Iron mix-bus processing, John Hardy 990C summing amps, split-able EQ, mix-bus compressor, and more.  

The ASP8024 Heritage Edition is a new incarnation of the original ASP8024, designed and built by David Dearden. Backed by his 40 years of console design experience, which includes consoles for MCI, Soundcraft, DDA, and Midas, the ASP8024 became a modern classic having provided the foundation for Audient’s leadership in the field of cost-effective, high-quality recording desks. After 20 years in production, Audient has taken that foundation and reimagined the ASP8024 with new features and enhancements that offer a surprising level of workflow flexibility as well as new sound-shaping options on top of the ASP8024-HE’s great-sounding preamps and John Hardy 990C summing amplifiers. Based on the ASP8024’s legendary circuit blocks, Audient has returned to designer David Dearden’s roots to release the definitive version of the ASP8024; the ASP8024 Heritage Edition.

Audient ASP8024-HE—Just the Facts:

• World-class Audient mic pres, 56-152 inputs, 14 auxiliary buses, 8 stereo subgroups
• Variable mix bus
• John Hardy 990C summing amps
• 4-band split-able EQ
• Mix-bus compressor
• Inline architecture
• Comprehensive monitor control
• Monitoring-grade headphone output
• Modular construction
• Whisper-quiet power supply
• Impressive “Black Raven” vintage/modern look

ASP8024 optional extras:

• Patchbay
• Dual-layer control (DAW and analog automation)
• Producers desk
• VESA mount option

Audient ASP8024-HE—Beneath the Surface

Audient console mic preamplifiers

Not only is the Audient mic pre renowned for being clean, punchy and musical, it is often regarded as one of the most versatile mic pres available. Its impressive dynamic range enables faithful reproduction of the sound source, with greater realism in the audible range and better blending of instruments, plus just enough color to give the signal some character.

The Audient ASP8024-HE mic pre is an all-discrete, high-grade op-amp design that delivers low noise, low distortion, and high common mode rejection (CMMR) at all gain levels, which is part of the secret of Audient design. According to designer Dave Dearden, “A successful mic pre doesn’t just have to amplify a low-level signal up to something more usable. It must also be protected against an external attack such as static, phantom power, and radio frequency interference (RFI). This is where component choice is vital, especially the low-noise transistors and even passive elements such as resistors and RFI filters.”

Audient is the only company that uses the same Class-A mic pre design throughout their entire product range. There is no upsell or down-market “based-on” preamps. When you buy Audient, you’re getting full-on Audient sound, whether you’re in the studio with an Audient console, or on the road with an iD4 interface.

Discrete John Hardy 990C summing amps

The mix-bus summing amplifier on a console, where all signals come together to play nicely is the most crucial part of the console design. Cutting corners here results in what Abbey Road engineers called a “ship fight.” (Imagine a fight breaks among the entire crew of a battleship at sea, leaving no place to escape.) Audient upgraded the ASP8024’s summing amplifiers to the renowned American John Hardy 990C amplifiers. The 990 discrete op-amp was designed by studio tech legend Deane Jensen in 1979, which continues to be regarded as the finest op-amp available for audio applications. In 2018, the 990 discrete op-amp was inducted into NAMM’s prestigious TECnology Hall of Fame. Interestingly enough, Deane’s company, Jensen Transformers, never made the 990. There were manufactured by The John Hardy Company in 1980-81—hence the name John Hardy 990C.

These discrete transistor amplifiers are the pinnacle of op-amp design, offering increased dynamics and punch while simultaneously halving the noise of the console. For example, a 72-channel Audient desk now measures like an old 36 channel!

Retro Iron Variable Mix Bus

Moving through the signal path and coming after the 990C op-amps, the Heritage Edition provides new tonal options with the Retro Iron output card. As David Dearden has stated in his design philosophy, the transparency of Audient enables you to add color as you choose. Thanks to the Retro Iron card, now you don’t have to go outside of the ASP8024-HE to get it. Before we get into the details lets have a look at Retro Iron's inspiration.

The “Big Iron” legacy

Included in the ASP8024-HE, the Retro Iron card is inspired by two of David Dearden’s first console tech experiences at Advision Studios*, London circa 1970. After a stint with David Manley (founder of Manley Labs) at his studio building a tube console mainly comprising Telefunken V72 preamps, David joined Advision as in-house tech and engineer to specify, build, and maintain equipment for the studio, with notable session clients such as Emerson, Lake & Palmer, Shirley Bassey, David Bowie, Fleetwood Mac, Eddy Offord (Yes), Gus Dudgeon (Elton John), and many more.

Back in those days, there were three major players in console manufacture: Neve, API, and Quad-Eight/Electrodyne (SSL came later). Of the three, Quad-Eight didn’t survive due to poor financial management, but it’s sound quality stood up against its competition at a significantly lower price (Boston’s “More Than A Feeling” and Pink Floyd’s The Wall were mixed on a Quad Eight).

Two of “the big three” consoles were in service during David’s first few years at Advision; one was a 20-channel desk designed and built by Rupert Neve, the other was a Quad-Eight (for whom Deane Jensen was chief engineer). The Quad-Eight featured Jensen’s AM4 hybrid op-amp (later refined into the 990) and custom transformers built by Ed Reichenbach, who built transformers for Altec Lansing and founded Reichenbach Engineering, the leading maker of transformers for the audio industry in America. Jensen sold Reichenbach transformers as retrofits for the big-name consoles, and later founded his own company, Jensen Transformers by Reichenbach Engineering. (Pay attention, there’ll be a quiz on this later.)

*PAD Pro Fun Fact: Advision Studios, as the name suggests, started out recording voice-overs and jingles for television commercials. The studio could accommodate a 60-piece orchestra, hence the addition of the Quad-Eight, perhaps the world’s first automated console, used by major film studios including 20th Century Fox, Universal, and Lions Gate Films. However, Advision didn’t do much feature film scoring, rather it found its niche as the center of progressive rock in London since the large room could accommodate the stacks of equipment brought in by bands such as ELP and Yes.

Design Inspiration

Now, back to our regularly scheduled broadcast: The Neve console was mostly class-A with a weighty low-frequency response from its large iron transformers (hence the phrase, “big iron sound of the ’70s”). The Quad-Eight console, on the other hand, had clean, clear midrange with sparkle and speed, largely running class-A/B with smaller but more transparent steel/nickel transformers.

Audient’s Retro Iron card is inspired by both consoles, combining the best sonic features of each. The discrete class-A/B transistor amplifiers are based upon the Quad-Eight, but with each transistor selected by ear to offer incredible detail, speed and subtle harmonic excitement of 2nd-order distortion.

These amplifiers are coupled to large un-gapped Carnhill transformers made in the UK to Audient’s specifications to improve the response found in the original Neve console. These transformers are over-engineered and free from sluggish DC core saturation.

When these two stages combine they produce a punchy, weighty sound that’s harmonically exciting and slightly gritty. Perfect for adding character to your mixes, the output transformers provide just the right growl in the lower midrange for guitars.

Operating ahead of the discrete amplifiers, there is a powerful and delicately tuned EQ that changes the energy levels delivered to the harmonic output stage to sweeten and “tilt” the response of the console to the style of music you are working on. This EQ is based upon legendary Baxandall peaking filters with broad curves, using high-quality capacitors and exceedingly smooth, low distortion modern amplifiers - the LM4562.

Retro Iron is engaged via switches in the master fader section, and when inserted into the mix bus signal path, provides +28dBu headroom into 600 ohms at the mix insert send output, perfect for driving a vintage mix-bus EQ or Fairchild compressor.  You should try engaging the Retro Iron features half-way through a mix to give you a little lift.

There are 4 modes of “tone shaping” operation, controlled by the 3 switches on the right-hand side of the master fader panel:

• Retro Iron
• Retro Iron + Low Bump
• Retro Iron + Air Lift
• Retro Iron + Low Bump + Air Lift

Mode 1 adds the discrete circuitry & transformers to the mix-bus and provides delicate enhancement and punch. Mode 2 increases the weight of the low end at 60Hz, resulting in more core saturation and a fatter response that suits Hip-Hop and EDM. Mode 3 opens up the top of the console for a pretty sound that really suits Ballads and Pop music, whilst Mode 4 scoops the midrange slightly and adds weight to the lows and sparkle to the highs, which really loves Rock music. Experiment, sometimes you might leave the entire card off and enjoy the tight, clean response of just the 990C mix amps!

These “tone shaping” options should be looked at as creative mix enhancement tools or as a way to offer simple corrective rebalancing if you find that you always mix a “bit bass light” or a “bit bright”.

The vintage circuitry uses period correct axial BC electrolytic capacitors, high-quality polypropylene film bypass capacitors from Wima, along with expensive Polystyrene high frequency and Panasonic Polyester EQ capacitors for seriously tight bass and 3D air.

For the tweakers there are jumpers on the circuit board so that you can set 0.5dB, 1dB, 2dB, or 3dB EQ levels for the Low Bump and High Lift modes. The card is set to 2dB but due to the filter design is not too aggressive and perfectly suited to a wide range of program material and genres.

Short faders, long reach

Above the 24 long-throw faders and pan controls is a row of 24 short faders. Herein is where a great deal of the 8024’s flexibility resides. The short faders can be used to monitor signal coming from and going to the record busses, which enables them to be used for fader rides going in (we know you’ve been dying to make a “riding the short bus fader” joke, so go ahead, get it out of your system, we’ll wait . . .). This exceptional feature (now you’ve got us doing it) enables you to do much more.

The short faders can act as a B section, providing an additional 24 inputs, and when used in conjunction with the channel EQ split function, can control high-and low-frequency shelves, or the parametric midrange section. This feature can come in real handy for cue mixes, when you need to boost bass and highs for a vocalist, for example, without affecting the recorded signal. The short faders can also act as a secondary trim control for the preamps when sending the signal to tape.

You can also use the EQ with the short faders and send the equalized signal to the record busses. Initially, you can monitor tape out through the long faders, like an old-school workflow, and apply EQ, which has no effect on what’s going to tape. If you like what you’re hearing, you can switch the EQ settings from the long to the short faders to commit to tape, and hear no difference while still monitoring tape return via the long faders. You can also bus effects into tape or disk on the same channel, as in the case of a snare with plate reverb as a single instrument sound, or record the effect onto different channels for greater control during the mix.

The copy button on each channel takes what’s happening in the long faders (tape return) and copies it to the short faders, which in turn go to the routing bus. Essentially, what this means is that you can build a separate mix, send it to outboard and have it return through the eight stereo group returns for parallel processing. For example, you could have a separate drum kit mix in the short faders specifically created for a compressor with less kick drum so low frequencies don’t pull down the entire kit. And since you can apply EQ to the short faders, you can tame cymbal wash going into the compressor, or control transients so that the compressor doesn’t punch holes in the drum mix responding to hard transients. In essence, the short faders give you up to 24 channels of parallel processing.   

ASP8024-Heritage Edition's classic 4-band parametric EQ

David Dearden had one design philosophy: “Move the microphone first and you need less EQ”, thus the ASP8024 equalizer has been designed with this approach in mind. The ASP8024-HE will encourage you to work harder to get it right at the source. The payoff is less phase shift and more open-sounding results, turning the EQ into a more powerful creative tool rather than a corrective one.

ASP8024-HE features the classic David Dearden 4-band console equalizer, which is something unique among console EQs. Offering two dual-band equalizers that can be split individually to the short (SF) or long (LF) fader paths, the ASP8024-HE provides all input channels with tone control adjustment. Most other 4-band console EQs can only be moved entirely to the short or long fader “inline” signal paths, but the ASP8024-HE is unique in that you can split the EQ in half or use it as a standard 4-band EQ on a single path for more traditional operation. For example, in split mode, you can “ring out” a snare mic to tape with the dual mid bands while using the dual shelving stage on the short fader tape return to EQ another source on playback—talk about flexibility!

The low- and high-frequency shelves

The passive sounding low-shelving EQ features 50Hz and 100Hz switchable frequencies, while the gentle and smooth high-frequency shelving EQ features 10kHz and 18kHz (AIR) both with ±15dB gain range.

The shape of these filters is classic with a small dip at the corner which means they do not get harsh or too muddy. The circuitry is very pure, with only one op-amp per band, thus they sound very much like early passive EQs despite being active. It’s best to describe these EQs as tone controls with a response that works on well-recorded sources or even sub mix stems (due to their clean, simple signal path). These are not aggressive LF/HF controls.

Low mid-frequency and high mid-frequency parametric EQs

The dual mid-bands are fully parametric and offer unusually large ranges so that they can provide double duty as both normal LMF/HMF controls or extra LF/HF bands if required. The real trick lies in the fact that these are also a minimal signal path design and offer a tight, punchy sound that can carve resonances and add edge without sounding overly processed.

Tight and surgical or broad and musical

The LMF band offers a sweepable range of 50Hz to 1.5kHz and can be used to EQ bass or kick drum fundamentals or easily scoop resonances in snare drums or boxiness from a vocal performance with adjustable bandwidth control and ±15dB gain range. The bandwidth or “Q” adjustment for both mid bands can create a subtle bell or a narrow, sharp surgical move in either band with a range of 0.6 to 3.7.

The HMF band offers an enormous sweepable range of 450Hz to 20kHz and can easily create a bell type air boost or become a surgical mid-band for corrective use when required. For example, it can get low enough to act as a “box-removal" band on kick drum, leaving you the LF/LMF bands to work in tandem on the source below 450Hz to do some real bass enhancement. Plus, you still have the HF shelf to add air or presence. Alternatively, you can reach towards 8-16kHz and add great sparkle and shine.

A powerful sculpting tool at your command

The mid-bands are the perfect compliment to the smooth shelving EQs, and in total there are only 3 dual op-amps in the entire 4-band EQ, meaning that it sounds very natural and musical without the grit or grain found in many state-variable EQ’s that use 10 amplifiers or more.

Combining the LF & LMF in an overlapping fashion can effortlessly add point to the bottom end of a kick drum with the LMF band, while using the LF shelf to taper subs below 50Hz, or alternatively, you can combine the two to create the famous “boost & atten” trick of 50’s passive EQs by boosting the 50Hz LF Sub-band and cutting with the LMF around 250Hz. Grab hold of the unique ASP8024-HE EQ and hear what it can do for you.

VCA Bus Compressor for analog “glue”

Apply that magic mix bus glue all over your mixes with the classic ASP8024-HE VCA bus compressor. Designed in the spirit of some of the most classic bus compressors of all time, this circuit features great stereo imaging, density, and a mid-forward bite with smoother make up gain compared to the original.

The 2:1, 4:1, and 10:1 ratios also adjust the threshold for different program levels. The 2:1 ratio is designed for lower threshold smoothing, whereas 10:1 is designed for higher threshold peak limiting on hot program material. By design, the higher ratios result in slightly less compression until you adjust the threshold.  

Bass Expand—don’t let the bass drag you down

The ASP8024-HE bus compressor is outfitted with Bass Expand, which is a sidechain high-pass filter set to 350Hz with 6dB/octave roll-off. This awesome feature gives the bus compressor a completely different personality. Instead of reducing compression just on kick drums and extreme low end, the higher frequency choice allows the entire low and lower mids of the mix to breath, sounding more natural and relaxed.

Gain-reduction meter

A beautifully illuminated gain-reduction meter makes it easier to dial in subtle compression and achieve that perfect “needle bounce” mix glue. Along with its impressive looks, the meter is finely calibrated for accuracy below 8dB—perfect for your 2-bus.

Inline architecture

The inline architecture of the ASP8024-HE enables you to start building your mix as you are tracking. You can create separate record and monitor balances on one channel strip via the long and short faders, all while being able to access the console’s split-able EQ and aux sends, perfect for getting it right going in. Experience the classic large-format console workflow and take your mixes to the next level.

Comprehensive monitor control

The ASP8024-HE boasts a full-featured monitor control section, with artist communication, remote talkback control, an additional engineer headphone output, powerful source selection, and loudspeaker control with a short passive signal path for incredibly clear and accurate monitoring. Since you’ll be reaching for the monitor control knob a lot, Audient added the phenomenal-feeling Alps “Blue Velvet” pot and custom aluminum knob for a touch of class during everyday use.

Reference headphone amplifier

ASP8024 Heritage Edition comes with a high-current reference headphone amplifier provided as the ALT3 monitor output destination. The new design features a 250mA high-current output stage based upon class leading Burr-Brown and LM4562 high-speed amplifiers. The output is entirely DC-coupled with very low output impedance for all types of headphones. There’s only one main capacitor in the signal path for very low distortion and enhanced sonic performance.  

Green power

Saving you money in more ways than just electric bills, the ASP8120 Ultra Power Supply is not only incredibly efficient, it’s also whisper-quiet, enabling it to be situated in the control room without disturbing your workflow—no need for an expensive and air-conditioned machine room. With a low noise transformer and low RPM fan cooling system our power supply is a safe choice for years to come and has helped make the ASP8024-HE more reliable than ever.

Impressive look and feel

Studios are often chosen by sight rather than by sound, as many owners have come to realize—and there’s nothing more impressive than a large-format console. And the modern/vintage look of the ASP8024-HE says, “studio to reckoned with.” Building on the modern classic as well as taking inspiration from classic pieces of gear, Audients “Black Raven” color-way, vintage knobs, chunky fader caps, and British design theme not only make the ASP8024-HE a visually stunning centerpiece but also make it more intuitive than ever.

Audient ASP8024-HE Options

Patchbay

While the patchbay is technically considered an option, it’s an essential one. Not only does it bring all of the ASP8024-HE’s functions into one convenient location, including insert points, it also provides other very useful features, such as level control between +4dBu and -10dBV sources, artist fold-back, alt speakers, stereo FX returns, 144 tie lines for outboard, and the ability to send up to three parallel signals from a single source. Additionally, all connections are carried via DB-25 connectors, making Cannon or Elco crimping tools, soldering iron, and raw fingers a thing of the past. Plus, and this is a big plus, Audient has reduced the price on the patchbay to make it even more cost-effective and easier to include with your console. The savings in studio (wo)man hours alone is worth the investment.

*PAD Pro Tip: When you consider purchasing a console, always budget for a patchbay plus the cost of wiring it to your studio. Think of it as part of the cost so that you don’t end up “console poor” when the time comes to install and configure a patchbay—and we can assure you, even with a small amount of outboard, that time will come.  

Producer’s desk

The Producer’s Desk provides extra real estate on your console to place a keyboard, mouse, or even a control surface at the center of your console or to one side for a second engineer. Traditionally, a producer uses one (hence the name, “producer’s desk”) to take session notes or annotate music scores alongside the engineer. There are many ways to use this option and take advantage of the beautifully included walnut script tray.

If you have two PD modules side-by-side (Double PD) it allows you to accommodate larger control surfaces, such as the Slate Raven or Avid S3 controller.

Dual Layer Control

Dual Layer Control (DLC) was designed to seamlessly integrate with your DAW and let you combine both your analog and digital workflows on the ASP8024-HE giving you complete hands-on control over your mix or recording session. It integrates seamlessly with Pro Tools, Cubase 9, and Logic X DAWs.

DLC provides you with a range of useful DAW control features within easy reach, including 8 bankable faders, transport control, track record enable, pan control, aux sends, and plug-in selection/editing—all of which enable you to navigate your session with ease.

DLC’s automated faders give you a wide range of creative options. Whether you’re adding realistic and accurate vocal rides to your mix or simply bringing your drum group up in the chorus, DLC allows you to avoid staring at the screen and painstakingly drawing in your automation levels and instead lets you work fast and efficiently.

VCA Automation

By using DLC’s 8 channels of VCA automation you add movement and finesse during your console mix balances. The VCAs can be individually routed to subgroups 1-8 or independent DB25 i/o that can be patched to any console insert point for creative use. Try riding your hardware compressed drum parallel in the chorus or automated pre/post insert effect for wild automated distortion control with your outboard gear.

Simple and intuitive control via Faderlink

DLC is connected via Audient’s proprietary Faderlink plug-in (64-Bit AAX, VST & Audio Units) to record, edit, and recall 8-channels of VCA automation directly from your DAW session, providing visual automation of level and mute. DLC is connected via HUITM protocol. Supported DAW’s include: Cubase, Nuendo, Logic Pro X, and Pro Tools.

5.1 Surround-sound mixing

Whether you’re working on film scores or simply mixing in 5.1, the ASP510 surround-sound monitor controller integrates seamlessly with your ASP8024, providing you with an efficient, powerful and intuitive 5.1 surround sound workstation—all while using only one connection.

What the pros are saying about the ASP8024-HE

I'd prefer to have an audient console in my studio than the money equivalent of several fancy vintage rack boxes. I like the audient. I really like it. It's a powerful tool. — PETE TOWNSHEND (Who? Yes, that Pete Townshend)

It was hard to imagine an improvement to the asp's already clean and punchy sound, but the new john hardy 990 op amps give it extra zing and crystal clarity. — RUSS RUSSELL (Napalm Death, Dimmu Borgir)

About Audient

Audient was founded in 1997 by David Dearden and Gareth Davies. Dearden started his career in 1968 as an assistant to David Manley (original founder of Manley Labs) and later became a junior maintenance engineer for Advision Studios, which led to work with studio designer Eddie Veale, building a custom console and private studio for John Lennon’s Imagine sessions, as well as studios for George Harrison, Ringo Starr, Gus Dudgeon (Elton John, David Bowie), and Chris Squire of Yes. Dearden met Audient co-founder Gareth Davies while the pair were working at Soundcraft. Upon hearing of a possible financial downturn for Soundcraft, they decided to jump ship before the pinks slips arrived, founding DDA (Dearden Davies Associates) consoles in 1980.

Not only did David Dearden design DDA’s most highly regarded consoles, (many of which are still in use), he also designed consoles for Midas after Klark Teknik took over DDA (now you know why older Midas live-sound consoles were being used in studios for their preamps). After his tenure at Midas, Dearden and Davies teamed up once again to resume doing what they did best, founding Audient with the goal of creating high-quality, cost-effective pro audio consoles and outboard.     

If you really want to do recording and mixing right, there’s no substitute for an Audient ASP8024-HE console. For more information, contact your PAD  Studio Integrator today.

Frequency Response:

• Mic input to mix output: ±0.3dB (20Hz to 20kHz with 6 to 40dB gain)
• Line input to mix output: ±0.3dB (20Hz to 20kHz with 0dB gain)
  

THD + N:

• Mic XLR input to any output: < 0.005% @ 1kHz, +22dBu output
• Line input to any output: < 0.005% @ 1kHz, +22dBu output
• Tape input to any output: < 0.003% @ 1kHz, +22dBu output
  

Noise:

• Mic EIN (20-20kHz, 150? source): < -127.5dBu
• Bus Noise (No Inputs Routed): < -93dBu
• Bus Noise (36 Inputs Routed): < -81dBu (990C mix amps)
  

Crosstalk & Mute Attenuation:

• Short fader mute: > 90dB @ 1kHz
• Long fader mute: > 90dB @ 1kHz
• Mix assign: > 90dB @ 1kHz
• Bus assign: > 90dB @ 1kHz
  

Mic CMRR:

• Min Gain (6dB): 70dB
• Max Gain (66dB): 75dB
  

Maximum Input Level:

• Mic: > +21dBu (min gain)
• Line: > +30dBu (min gain)
• Insert returns: > +21dBu
  

Maximum Output Level:

• Mix output: > +26dBu into 2k ohm
• Bus output: > +26dBu into 2k ohm
• Aux output: > +26dBu into 2k ohm
• Insert send: > +20dBu into 2k ohm
• Monitor, studio, and F/B outputs: > +20dBu into 2k ohm
  

Retro Iron Heritage Card specifications:

Frequency Response:

• Retro iron engaged on main mix: ±0.1dB (10Hz to 80kHz)
• Hard-wire bypass: Relay switched — no loading effects
  

THD + N:

• 0dBu into 600 ohm: < 0.016% @ 1kHz (2nd & 3rd)
• +24dBu into 600 ohm: < 0.033% @ 1kHz
  

Noise:

• Retro iron on, EQ off: < -92dBu (20Hz to 20kHz unweighted)
  

Maximum Output Level:

• Carnhill line driver: +28dBu into 600 ohm
• Insertion loss: 1dB into 600 ohm (transformer loading)
• Output gain: ±0.5dB load dependent
• Output impedance: 600 ohm
  

Dynamic range: 120dB

• Crosstalk: < -82dB 10Hz to 10kHz, typ. -88dB @ 1kHz
  

Tone-Shaping EQ:

• Low bump: +2dB wide bell @ 60Hz, Baxandall type
• High lift: +2dB wide bell @ 20kHz, Baxandall type
• Gain adjust jumper positions: +0.5, +1, +2 (default) or +3dB options
  

Audient ASP8024-HE headphone amp

Frequency Response:

• Input to Output, load independent:±0.1dB (20Hz to 20kHz)
  

THD + N vs. Load:

• THD into 600 ohm @ 1kHz: 0.0013% (0dBu), 0.0009% (+18dBu)
• THD into 150 ohm @ 1kHz: 0.0010% (0dBu), 0.0012% (+18dBu)
• THD into 60 ohm @ 1kHz: 0.0024% (0dBu), 0.0016% (+18dBu)
• THD into 32 ohm @ 1kHz: 0.0040% (0dBu), 0.0077% (+17dBu)
  

Noise:

• Reference headphone stage: < -104dBu (20Hz to 20kHz unweighted)
  

Maximum Output Level

• Load-dependent: +22dBu, typically +18dBu into all phones
  

Maximum Output Power:

• Power into 600 ohm: +22dBu @ 0.0010% THD = 317mW
• Power into 150 ohm: +21dBu @ 0.0012% THD = 1W
• Power into 60 ohm: +20dBu @ 0.00