7 Best DC-Coupled Audio Interfaces (For All Budgets)

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  • Learn what a DC-coupled audio interface is
  • Why a DC-coupled audio interface might benefit you for modular synthesis
  • How to use the CV (Control Voltage) inputs and outputs on your synth
  • While you’re here, also check out our separate post on the best professional audio interfaces.

Ever looked at the back of your synth while plugging in your USB MIDI cable and wondered what that CV port is for?

CV stands for Control Voltage and was a predecessor to MIDI, usually found on modular synthesizers.

Just like MIDI, it’s another way for the different parts of a modular synth to communicate.

Since CV uses DC (or direct) current, you need a DC-coupled audio interface for it to work correctly. In this article, we go over 7 of the very best picks across a variety of price points.

What Are The Best DC-Coupled Audio Interfaces?

Our top pick is the PreSonus Studio 1824c. This 18-in/18-out USB-C audio interface has many ways to connect your gear and includes Studio One DAW software.

If you’re on a budget, the less expensive PreSonus Studio 26C is a contender due to its simple design.

If you can spend more, Universal Audio’s Apollo x8P 16×22 Thunderbolt 3 interface is a studio standard with state-of-the-art AD/DA conversion.

Without further adieu, let’s explore the best DC-coupled audio interfaces on the market today.

  1. PreSonus Studio 1824c USB-C Audio Interface (Our Pick)
  2. PreSonus Studio 26c USB-C Audio Interface (Best Value)
  3. Universal Audio Apollo x8p 16×22 Thunderbolt 3 Audio Interface with UAD DSP (Premium Option)
  4. RME Fireface UCX II 40-channel USB Interface
  5. Native Instruments Komplete Audio 6 Mk2 USB Audio Interface
  6. MOTU M4 4×4 USB-C Audio Interface
  7. Universal Audio Apollo Solo Heritage Edition USB-C Audio Interface with UAD DSP

1. PreSonus Studio 1824c USB-C Audio Interface

Presonus Studio 1824c

Loaded with 18 simultaneous inputs, including eight sweet-sounding XMAX preamps, the PreSonus Studio 1824c is tailor-made for project studios that record full bands, including multichannel drums.

Why We Love It:
  • Accessible layout
  • PreSonus DAW software included
  • Top-tier audio quality
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This versatile USB-C audio interface has 18 inputs and 18 outputs with many connection options, including ADAT, SPDIF, MIDI, and more.

It comes with the Studio One Artist DAW software package, including the Studio Magic plugin suite.


  • It has 8 XMAX mic preamps
  • It has a DSP-based monitor mixer for zero-latency recording
  • It runs on 12V DC power (power supply included)


If you want to record a full band without spending a lot, the PreSonus Studio 1824c will get you there.

Not only do you get plenty of inputs and outputs for the money, but it comes with Studio One Artist DAW software and Studio Magic plugins, as well as the UC Surface software to save your mixer settings.

The XMAX mic preamps really elevate the audio quality because they run on 30-volt power rails, whereas most audio interfaces in this price range use 10-18 volts.

The extra voltage gives you more headroom and a cleaner, fuller signal and sound.

2. PreSonus Studio 26c USB-C Audio Interface

PreSonus STUDIO 26C

Loaded with two sweet-sounding XMAX-L preamps, the PreSonus Studio 26c is tailor-made for DJs, mobile musicians, and electronic musicians who want excellent audio quality in a sturdy,

Why We Love It:
  • Award-winning XMAX preamps
  • Studio One Artist included
  • Convenient A/B monitoring
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This little interface is quite the piece of gear for about $200 – if not slightly less, depending on where you get it.

It has the same XMAX preamps as the other PreSonus Studio interfaces and has A/B monitoring for headphones so that you can switch between two different mixes.


  • Its digital converters go up to a resolution of 192kHz
  • It has 5-pin MIDI I/O, so you can easily connect older MIDI gear
  • Studio One Artist and the Studio Magic plugin suite are included


If you don’t need a lot of inputs and outputs, but you still want the quality that comes with PreSonus Studio interfaces, the 26C will do the job at a fraction of the price.

It has two inputs and four outputs, with low-latency direct monitoring and the ability to cue up two different mixes when listening on headphones.

It comes with all necessary USB-C cables, including USB-C to USB-A.

3. Universal Audio Apollo x8p 16×22 Thunderbolt 3 Audio Interface

Universal Audio Apollo x8p Heritage Edition

Place the Universal Audio Apollo x8p at the center of your studio, and it's guaranteed to turbocharge your productivity

Why We Love It:
  • 50% more processing power
  • HEXA Core processing
  • Packed with pro-features
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This 16-in and 22-out interface from Universal Audio is a solid option for studio owners who want an audio interface to track a full band without spending five grand or more on a new setup.

It has a 6-core HEXA processor for faster processing than previous Apollo gear and supports 7.1 surround sound monitoring.


  • It comes with UA LUNA recording software
  • It has eight Unison mic preamps (combo mic/line) and two 1/4″ instrument preamps
  • UA LUNA software gives you a completely integrated tracking, editing, and mixing environment


This generation of Apollos has 50% more processing power thanks to their 6-core HEXA processor so you won’t have any latency issues.

It fits right in at the studio with built-in talkback and the option to select +24dBu operation to get the most out of your analog gear.

The included UA LUNA software suite lets you record, edit, and mix, and it has everything from control surface software to tape emulation and more.

With the Toslink I/Os, you can even chain multiple Universal Audio interfaces together.

4. RME Fireface UCX II 40-channel USB Interface

RME Fireface UFX II

The RME Fireface UCX II packs a lot into its rugged half-rack housing. 

Why We Love It:
  • Great latency
  • Plenty of built-in effects
  • 20-in/20-out audio interface
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40 channels?! Yes, you heard right.

The Fireface also has two reference-quality mic preamps, stable clocking thanks to its SteadyClock technology, and onboard control and mixing software TotalMix FX.

With DC-coupled outputs, you can easily send control voltage signals to your modular synths without issues.


  • It fits in a half-rack space, so it doesn’t take up too much room
  • It has eight balanced line-level I/Os
  • Connect MIDI, ADAT, AES, SPDIF, and headphones easily


For such a small unit, the RME Fireface UCX II is very powerful.

In addition to a whopping 40 channels via the DURec port, which can record directly to any hard drive up to 2TB, it uses SteadyClock technology to cut down on jitter and latency issues, so you get the cleanest possible audio signal.

TotalMIX FX is an onboard DSP mixing and monitoring system with built-in effects, including 3-band EQ, reverb, a compressor, and more.

It also comes with an optional USB remote with assignable buttons so you can control the interface from your computer.

5. Native Instruments Komplete Audio 6 Mk2 USB Audio Interface

Native Instruments Komplete Audio 6 MK2

Greater resolution, more comprehensive I/O, and a sleek new tabletop design make the second-generation Native Instruments Komplete Audio 6 the perfect front end for your stage and studio performance setup. 

Why We Love It:
  • Heaps of I/O
  • Great preamps
  • Included software suite
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This ultra-portable 6-channel USB interface is great for musicians or producers on a budget who still want a decent amount of I/O options, including SPDIF and MIDI.

It also comes with Ableton Live 10 Lite and the Native Instruments software suite.


  • It has four analog I/Os, digital SPDIF, and MIDI
  • There are two 1/4″ headphone outputs, so more than one bandmate can listen
  • It’s USB bus-powered


Whether you’re looking for a small, secondary audio interface to record rehearsals and live performances, or you’re just starting and want something simple.

This sleek audio interface from Native Instruments won’t break the bank.

It has four DC-coupled analog outputs so that you can use it with your modular synths and also comes with digital SPDIF and MIDI connections.

In addition to Ableton Live 10 Lite, it comes with the Native Instruments software suite and will work flawlessly with your Maschine or any other Native Instruments hardware.

6. MOTU M4 4×4 USB-C Audio Interface

MOTU M4 4x4 USB-C Audio Interface

Looking for a high-quality audio interface that won’t break the bank? The MOTU M4 fits that description to a T. 

Why We Love It:
  • Affordable
  • Top-tier sound
  • Low latency
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This fun-sized MOTU USB-C interface has four ins and outs, including two mic preamps.

It uses ESS Sabre32 Ultra DAC technology for crisp audio with low latency.

It has a full-color LCD screen on the front for monitoring, so it’s easy to use in any setting, whether studio or live performance.


  • It has MIDI in/out as well as USB MIDI
  • It comes with MOTU Performer Lite and Ableton 10 Live Lite software
  • It has two DC-coupled 1/4″ monitor outputs and two DC-coupled 1/4″ line outputs


The MOTU M4 comes with everything you need to get started recording audio and MIDI without putting a serious dent in your wallet. I

n addition to the hardware, it includes MOTO Performer Lite, Ableton 10 Live Lite, and an exclusive loops and sounds bundle.

It’s also great as a secondary audio interface if you want something to work specifically with older analog gear and modular synths.

7. Universal Audio Apollo Solo Heritage Edition Audio Interface with UAD DSP

Universal Audio Apollo Solo USB Heritage Edition Audio Interface

Universal Audio’s Apollo Solo Heritage Edition brings a USB Apollo to Windows users at the lowest price ever. This USB-C audio interface is the real deal.

Why We Love It:
  • Portable
  • Access to industry-standard plugins
  • Easy-to-use design and system
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The Universal Audio Apollo Solo Heritage Edition audio interface is available as a USB-C or Thunderbolt 3 interface.

It’s compatible with UA LUNA software and has two Unison mic preamps. It includes Universal Audio’s Realtime Analog Classics plugin bundle.


  • It’s Thunderbolt 3, so it has very low latency
  • It uses UAD-2 processing power on its plugins for extra speed
  • It has two Unison mic/line inputs, one instrument input, two analog outputs, and a headphone output


If you love Universal Audio’s plugins and hardware but want something affordable, this interface is a great introduction to their products and will still give you plenty of what you need.

It’s portable, and since the UA plugins come with it, you can take it to other studios or live performances and still have what you need to keep working.

The built-in free UA LUNA software gives you monitoring and mixing tools such as the Shape Creative Toolkit.


How do I know if my audio interface is DC-coupled?

If it doesn’t say in the specs, you can use a volt meter set to measure DC voltage and check the outputs.

If you don’t have a meter, contact the manufacturer to find out.

Why does CV need DC coupling to work?

AC, or alternating current, is the most common current in audio equipment and its power sources.

Since unexpected DC current can sometimes damage audio equipment, AC-coupled current is designed to block DC.

However, Control Voltage uses DC current. So for Control Voltage to work properly, we need an audio interface that won’t block DC.

Specifically, we need a DC-coupled audio interface. DC coupling allows both AC and DC current to pass to and from a circuit.

What is Ableton CV Tools?

CV Tools uses Max For [Ableton] Live, meaning you can use your modular synths with Ableton Live.

These ten tools generate and receive pitch, clock, control, and trigger information from CV inputs and outputs.

How do control voltages work?

Control voltage works by using an input that listens for a certain amount of DC voltage and then responds by changing various parameters on your synth. It can even be used for lighting rigs.

Why do modular synths still use control voltage?

MIDI is essentially a programming language capable of 128 steps with nothing between them, whereas control voltage gives you more nuances, making it ideal for modular synthesis.