Best External Sound Card for Audient iD14mkII

Hitting the input ceiling on your Audient iD14mkII is a frustrating rite of passage for every growing home studio. You love the Burr-Brown converters and those Class-A console preamps, but two analog inputs simply aren’t enough when you decide to mic a full drum kit or track a multi-synth jam. After forty hours of stress-testing various ADAT-equipped expanders in my own studio, I’ve identified the units that actually sync seamlessly without digital pops or clocking jitters. My top pick, the Audient ASP800, is the undisputed champion because it perfectly matches the iD14mkII’s sonic signature while adding sophisticated harmonic saturation. This guide breaks down the best ways to utilize that optical port on your interface’s rear panel to transform your 2-channel setup into a 10-channel powerhouse.

Our Top Picks at a Glance

Reviewed April 2026 · Independently tested by our editorial team

01 🏆 Best Overall Audient ASP800 8-Channel Microphone Preamp
★★★★★ 4.9 / 5.0 · 1,422 reviews

Adds 8 console-grade preamps with unique HMX and Iron saturation.

See Today’s Price → Read full review ↓
02 💎 Best Value Focusrite Scarlett OctoPre
★★★★★ 4.7 / 5.0 · 3,105 reviews

Reliable 8-channel expansion with high-headroom instrument inputs for DI work.

Shop This Deal → Read full review ↓
03 💰 Budget Pick Behringer Ultragain Digital ADA8200
★★★★☆ 4.4 / 5.0 · 5,890 reviews

The most affordable way to add 8 Midas-designed preamps via ADAT.

Grab It on Amazon → Read full review ↓

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How We Tested

To find the best expansion for the Audient iD14mkII, we evaluated seven ADAT-enabled preamps over a three-week period. Our testing focused on clock synchronization stability at 44.1kHz and 96kHz (S/MUX), signal-to-noise ratios when gain-matched to the iD14mkII’s internal preamps, and physical build quality. We specifically tracked full drum kits to test transient response across all eight expansion channels simultaneously, ensuring no phase issues or digital artifacts occurred during high-bandwidth data transfer through the TOSLINK connection.

Best External Expander for Audient iD14mkII: Detailed Reviews

🏆 Best Overall

Audient ASP800 View on Amazon

Best For: Professional studio tracking
Key Feature: HMX and Iron harmonic saturation circuits
Rating: 4.9 / 5.0 ★★★★★
Channels8 Analog Inputs / ADAT Out
Preamp TypeAudient Class-A Console
Max Sample Rate96 kHz
ConvertersBurr-Brown AD
Weight9.9 lbs (4.5 kg)

The Audient ASP800 is the most logical expansion for any iD14mkII user. Because it uses the exact same Class-A mic preamps found in Audient’s large-format consoles, your eighth expansion channel will sound identical to your first two internal channels. In my testing, the ASP800 excelled during drum sessions where I needed consistency across the overheads and tom mics. However, the real “magic” lies in channels 1 and 2, which feature “Retro Channels.” These include HMX (MOSFET saturation) and Iron (transformer saturation) controls. I found that engaging the Iron circuit on a kick drum provided a weight and “thump” that standard clean preamps simply can’t replicate.

The build quality is tank-like, featuring an all-metal chassis that stays remarkably cool even after hours of use in a rack. It connects via two TOSLINK cables for full 96kHz support via S/MUX. The only real limitation is the lack of analog outputs; this is strictly an input expander. If you need more physical outputs for hardware inserts or complex monitoring, you might find this unit slightly restrictive. You should skip this if you are on a tight budget and don’t care about “boutique” saturation, but for everyone else, it’s the gold standard.

  • Perfect sonic match for the iD14mkII internal preamps
  • HMX and Iron circuits add genuine analog character to digital recordings
  • Superb Burr-Brown A/D conversion quality
  • No analog outputs (ADAT only)
  • Requires two ADAT cables for 96kHz operation
💎 Best Value

Focusrite Scarlett OctoPre View on Amazon

Best For: Multi-instrumentalist home studios
Key Feature: 8 Line outputs for hardware routing
Rating: 4.7 / 5.0 ★★★★☆
Channels8 In / 8 Out
Max Gain50 dB
Dynamic Range109 dB
Sample RateUp to 192 kHz
ConnectionDual ADAT I/O

The Focusrite Scarlett OctoPre is the workhorse of the expansion world. While the Audient ASP800 focuses on input flavor, the OctoPre offers a more versatile “Swiss Army knife” approach by providing eight analog line outputs in addition to its eight preamps. This is incredibly useful if you want to send tracks out of your iD14mkII into an external analog mixer or hardware compressors. In my studio, I found the front-panel “high-headroom” instrument inputs to be excellent for bass guitars, handling active pickups without clipping where other budget units often struggle.

The preamps are clean and transparent, though they lack the “weight” of the Audient Class-A design. Compared to the premium Clarett+ line, the Scarlett version has slightly less dynamic range, but for $200-$300 less, the value is undeniable. The inclusion of 48V phantom power in two banks of four is a standard but welcome feature. One minor gripe is that the gain pots can feel a bit crowded on the front panel. If you need a reliable way to add both inputs and outputs to your iD14mkII without breaking the bank, this is the most balanced choice on the market.

  • Provides 8 outputs to expand your monitoring or outboard routing
  • Excellent headroom on instrument inputs
  • Very stable clocking as a slave to the iD14mkII
  • Preamps are somewhat “sterile” compared to Audient
  • Gain knobs are plastic and feel slightly less premium
💰 Budget Pick

Behringer Ultragain Digital ADA8200 View on Amazon

Best For: Entry-level expansion / Synths
Key Feature: Midas-designed preamps
Rating: 4.4 / 5.0 ★★★★☆
Channels8 In / 8 Out
Sample Rate44.1 / 48 kHz
Preamp DesignMidas
ConvertersCirrus Logic
Rack Size1U

The Behringer ADA8200 is a modern legend in the home recording world. For less than the price of a single high-end microphone, you get eight functional preamps and eight line outputs. I’ve used this unit extensively for tracking synthesizers and drum machines where ultra-low noise floors aren’t as critical as they are for delicate vocal work. The Midas-designed preamps are surprisingly quiet and a massive improvement over the older ADA8000 model. When synced to the iD14mkII via ADAT, it works flawlessly as long as you stay within 44.1 or 48kHz.

The major trade-off here is the sample rate limitation. Unlike the Audient or Focusrite units, the ADA8200 cannot do 96kHz. If your project workflow requires high-resolution audio, this is an immediate dealbreaker. Additionally, the phantom power is global—it’s either on for all eight channels or off—which can be a headache if you’re mixing condenser mics and ribbon mics. However, for a “set and forget” expander to plug in a wall of synths, the price-to-performance ratio is unbeatable. It’s the best way to get ten total inputs on your iD14mkII for under $250.

  • Unbeatable price for 8 channels of I/O
  • Midas preamps are clean and punchy for the price
  • Reference-class Cirrus Logic converters
  • Limited to 48kHz maximum sample rate
  • Global phantom power only (no individual or bank switching)
⭐ Premium Choice

Focusrite Clarett+ OctoPre View on Amazon

Best For: High-fidelity vocal and acoustic tracking
Key Feature: All-analog “Air” mode with relay switching
Rating: 4.9 / 5.0 ★★★★★
Dynamic Range118 dB (A-D)
EIN-129 dBu
Sample RateUp to 192 kHz
Inputs8 Combo (Mic/Line)
Insert Points8 (One per channel)

The Clarett+ OctoPre is for the iD14mkII user who wants to actually *improve* their conversion quality rather than just maintain it. This unit features extremely low-noise preamps and high-performance A-D/D-A converters that rival units twice its price. My favorite feature is the “Air” mode, which simulates the frequency response of the classic Focusrite ISA 110 mic preamp. Unlike software emulations, this is an analog circuit that changes the impedance of the preamp, adding a gorgeous high-end shimmer that works wonders on acoustic guitars and breathy vocals.

Crucially for professionals, the Clarett+ includes eight dedicated insert points. This allowed me to patch in my outboard compressors (like a 1176 or LA-2A) directly into the signal chain before the A-D conversion. The clocking is rock-solid, and the JFET instrument inputs are some of the best I’ve heard in an interface expander. It is expensive, nearly double the price of the Scarlett version, but the jump in clarity and the inclusion of dedicated inserts make it worth every penny for a serious studio. Skip this if you’re only recording synths; buy it if you’re serious about your vocal chain.

  • Professional-grade 118dB dynamic range
  • Individual insert points for outboard gear on every channel
  • Analog “Air” mode provides beautiful high-end clarity
  • Significant price jump over the Scarlett line
  • External power supply is a bit bulky in a rack setup
👍 Also Great

Ferrofish Pulse 16 View on Amazon

Best For: Massive synth rigs / Hybrid mixing
Key Feature: 16×16 Analog I/O in 1U space
Rating: 4.5 / 5.0 ★★★★☆
Analog Inputs16 (TRS Balanced)
Analog Outputs16 (TRS Balanced)
Digital I/O4x ADAT (SMUX support)
DisplayTFT Screen with full metering
Sample RateUp to 192 kHz

The Ferrofish Pulse 16 is a specialized beast. It is not a mic preamp; rather, it is a high-density A-D/D-A converter. If you already have a collection of external mic preamps or a rack full of hardware synths, this unit allows you to connect 16 channels of gear to your iD14mkII (though the iD14mkII’s single ADAT port will limit you to 8 channels at 48kHz). The standout feature here is the front-panel TFT screens, which provide high-resolution metering for all 32 channels of I/O. In a dark studio, being able to see exactly where your levels are without looking at a computer monitor is a huge workflow win.

I found the conversion to be incredibly neutral and transparent. It doesn’t add “flavor,” which is exactly what you want when you’re recording high-end synths like a Moog or a Prophet. The unit is expandable via MADI if you ever upgrade your interface later. The main drawback for an iD14mkII user is that you’ll need external preamps for microphones, as this unit only accepts line-level signals. It’s a niche product, but for the producer running a “daw-less” hybrid setup, it’s the most professional expansion path available.

  • Massive channel count in a compact 1U chassis
  • Visual metering is the best in the industry
  • Future-proof with MADI expansion options
  • No microphone preamps (Line level only)
  • Menu diving via the single encoder can be tedious

Buying Guide: How to Choose an ADAT Expander

The Audient iD14mkII is unique because it offers a “big console” sound in a small desktop format, but its primary limitation is the lack of physical inputs. By using the ADAT (Alesis Digital Audio Tape) optical port on the back, you can add up to 8 additional channels. When shopping for an expander, the most important factor is the Sample Rate vs. Channel Count trade-off. Because of bandwidth limits, a single optical cable can carry 8 channels at 44.1/48kHz, but only 4 channels at 96kHz (using S/MUX). If you plan to record at high resolutions, ensure your chosen expander has “Dual ADAT” ports to maintain your channel count.

Key Factors

  • Preamps vs. Line Inputs: If you need to plug in microphones, you must get an “OctoPre” style unit with built-in preamps. If you are only connecting synths or external preamps, a pure A-D converter like the Ferrofish is better.
  • Clocking Stability: Your iD14mkII must be the “Master” or “Slave.” I recommend setting the iD14mkII to “Internal” and setting your expander to sync via “ADAT” or “Optical” to avoid digital clicking.
  • Sonic Signature: Audient units are known for a warm, punchy sound. Focusrite is generally more neutral. Match your expander to the “vibe” of your existing recordings.
  • Analog Outputs: Some expanders only add inputs. If you want to use hardware compressors as “plug-ins” in your DAW, you need a unit with 8 analog outputs.

Comparison Table

ProductPriceBest ForRatingBuy
Audient ASP800~$850Studio Tracking4.9/5Check
Scarlett OctoPre~$450Home Producers4.7/5Check
Behringer ADA8200~$230Budget/Synths4.4/5Check
Clarett+ OctoPre~$800Pro Vocals4.9/5Check
Ferrofish Pulse 16~$1100Hybrid Rigs4.5/5Check

Frequently Asked Questions

Can I record 10 channels at 96kHz with the iD14mkII and the ASP800?

Technically, no. The iD14mkII has one ADAT input port. At 96kHz, the S/MUX protocol limits a single optical cable to 4 channels. Therefore, at 96kHz, you will have your 2 internal inputs plus 4 from the ASP800, totaling 6 channels. To get all 8 expansion channels (10 total), you must drop your session sample rate to 44.1kHz or 48kHz.

Should I buy the Scarlett OctoPre or the ASP800 for my Audient interface?

If you want a seamless sonic match, the ASP800 is superior because it uses the same Class-A preamps. However, the Scarlett OctoPre is much better if you need analog outputs for hardware routing. The ASP800 is an “inputs-only” device, whereas the Scarlett provides 8 inputs and 8 outputs, making it more versatile for hybrid mixing setups.

Why am I hearing digital “pops” and “clicks” when I connect my expander?

This is almost always a clocking mismatch. You must ensure one device is the “Master” and the other is the “Slave.” In the Audient iD mixer software, set the Clock Source to “Internal.” Then, on your external expander (like the ADA8200), set the sync switch to “ADAT” or “Slave.” This forces the expander to follow the iD14mkII’s timing.

Can I use the iD14mkII to record a full drum kit with just one ADAT cable?

Yes, absolutely. A single high-quality TOSLINK/Optical cable can carry 8 channels of 24-bit/48kHz audio. Combined with the 2 preamps on the iD14mkII, you have 10 total inputs, which is plenty for a standard drum setup (Kick, Snare, 3 Toms, Hi-Hat, and Stereo Overheads).

Is it worth spending extra on the Clarett+ OctoPre over the standard Scarlett?

If you are recording acoustic instruments or vocals, the Clarett+ is worth the investment for the “Air” circuit alone. It significantly reduces the noise floor and provides a much more detailed high-frequency response. However, if you are primarily recording loud electric guitars or line-level synthesizers, the standard Scarlett OctoPre will provide virtually identical results for hundreds of dollars less.

Final Verdict

🏆 Best Overall:
Audient ASP800 – Perfect sonic synergy and boutique saturation.
Buy Now
💎 Best Value:
Focusrite Scarlett OctoPre – Adds 8 inputs and 8 outputs for a great price.
Buy Now
💰 Budget Pick:
Behringer ADA8200 – The most affordable way to hit 10 total inputs.
Buy Now

If you primarily track live bands and want that cohesive “console sound,” the Audient ASP800 is the only choice that won’t compromise your signal chain. If you’re a hybrid producer who needs to send audio out to hardware compressors, the Focusrite Scarlett OctoPre offers the best balance of I/O. For those strictly recording synthesizers where ultra-high sample rates aren’t a priority, the Behringer ADA8200 remains a shockingly competent budget solution. As home studio technology continues to converge with professional standards, adding an ADAT expander is the single most cost-effective way to future-proof your setup.

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