ART Solo MPA

Product overview

The ART Solo MPA is a single-channel multivoice microphone preamp that offers both a clean solid-state and a warm tube signal path, with a Voice knob to blend the two.

The Solo MPA belongs to the ART Solo Series, a range of all-analog, single-channel processors with flexible tone shaping, intuitive controls and the sound of real tubes. The Tilt EQ balances lows and highs, the sweepable Low Cut filter removes rumble and tightens bass, and the variable microphone impedance tailors the preamp response to the microphone, be it a dynamic, a studio condenser or a low-level ribbon. A 20 dB boost, phase reversal, 48 V phantom power, input and output gain controls and a VU meter complete the channel. The rear panel has XLR and 1/4 inch connections, and the front 1/4 inch High Z input lets the Solo MPA work as an instrument DI. It is housed in a 1U rack chassis with a CNC milled aluminium front plate and an internal power supply.

Key features

• Discrete class A FET input microphone preamplifier
• Hand selected 12AX7 tube
• Variable Voice control: blend of the tube and solid-state stages
• Adjustable input impedance, 600 Ω to 80 kΩ
• Flexible Tilt EQ (±12 dB) and tunable Low Cut filter (10-200 Hz)
• +20 dB gain switch, phase invert and 48 V phantom power
• Analog VU meter with front accessible meter trim
• Front mounted Instrument / DI input with very high input impedance
• +4 dBu / -10 dBV output level selection
• Low THD and wide frequency response

Solid-state, tube or a blend

The Voice control blends the solid-state and tube stages. The Gain switch adds 20 dB in the tube circuit, which drives the tube harder and makes it the dominant source of gain and overload character. Input gain runs from 0 dB (for line level signals) to 40 dB; with the +20 dB switch and the output control (+15 dB) the total reaches 75 dB. ART notes that more input gain, the +20 dB switch and less output gain give more tube sound.

Tone shaping and microphone voicing

The Low Cut filter is a single tuned high pass filter from 10 Hz to 200 Hz that removes pops and other low frequency content while preserving some low end. The Tilt EQ emphasises high presence or low-end warmth. The Impedance control sets the load on the XLR mic input: ART describes lower settings as focusing the sound and rejecting more cable noise, and higher settings as giving a more open sound. The instrument input is not affected by it.

Inputs, outputs and metering

The front 1/4 inch instrument input takes up to +17 dBu and disables the rear balanced input when a plug is inserted, so the rear input can stay patched. Balanced outputs on XLR and 1/4 inch TRS reach +27 dBu balanced (+20 dBu unbalanced) with an output impedance below 47 Ω. The rear +4 dBu / -10 dBV switch matches 0 VU on the analog meter to the system level.

In the box

• Solo MPA multivoice tube preamp

ART Solo MPA: frequently asked questions

Can I use the Solo MPA as a DI?

Yes. The front 1/4 inch High Z instrument input lets the Solo MPA serve as an instrument DI.

Which tube does it use?

A hand selected 12AX7 tube, which reaches operating temperature within one to three minutes.

Does it have phantom power?

Yes, 48 V phantom power on the XLR microphone input, switched from the front panel.

What mains voltage does it need?

ART specifies 100-120 V 60 Hz / 220-240 V 50 Hz, with an internal power supply and a fused IEC connector.

Where can I buy the ART Solo MPA in India?

The ART Solo MPA is available from Shivansh Electronics, Kolkata, West Bengal, India, with delivery across India.

Workflow 1: Vocal recording with tube character

Home and project studios recording vocals.

Connections

Setup

1. Set the +4 dBu / -10 dBV switch to match the interface.
2. Switch on phantom power for a condenser microphone.
3. Set the input gain and blend the Voice control between solid state and tube.

Tip: More input gain and the +20 dB switch with less output gain give more tube sound.

Workflow 2: Voicing a ribbon or dynamic microphone

Engineers matching the preamp to a particular microphone.

Connections

Setup

1. Start with the Impedance knob centred (20 kΩ load).
2. Turn it lower to focus the sound or higher for a more open sound.

Tip: Phantom power should be off with dynamic microphones.

Workflow 3: Instrument DI

Guitarists and bass players recording direct.

Connections

Setup

1. Plug the instrument into the front input: the rear input is disabled automatically.
2. Set the input gain, Tilt EQ and Voice.

Tip: The rear input can stay patched; unplugging the front jack returns to it.

Workflow 4: Cleaning up low end

Close miked vocals and speech.

Connections

Setup

1. Sweep the Low Cut control between 10 Hz and 200 Hz to remove pops and rumble.
2. Use the Tilt EQ to add presence or warmth.

Tip: The single tuned filter preserves some low frequency content, so its use is less obtrusive.

Workflow 5: Feeding a mixer at -10 dBV

Setups with consumer level inputs.

Connections

Setup

1. Select -10 dBV on the rear I/O level switch.
2. Set the Output control while watching the VU meter.

Tip: The outputs keep the same level whether they are used balanced or unbalanced.

Workflow 6: Fixing phase between two microphones

Multi-microphone recordings.

Connections

Setup

1. Engage the Phase switch on the Solo MPA channel.
2. Listen for an improvement where the two microphones cancel.

Tip: ART notes that some microphones sound different depending on the phase chosen.