Warm Audio WA73-EQ 1 Channel British Preamp with EQ

A '73 channel for everyone

If there is one style of preamp that professional engineers recognize as defining the tone of pop/rock records for decades, it is the revered '73-style microphone preamp. '73-style preamps have been massively used in recording and live applications for years, and are still considered the “Holy Grail” of preamp choices. The Warm Audio WA73 family includes one- and two-channel models (with or without EQ), paying tribute to British audio history.

When Warm Audio decided to launch the WA73-EQ, it was essential to meet vintage expectations in design and performance. The sweet tone and character that vintage '73-style preamps deliver are so unique and familiar that our only wish was to create faithful sonic replicas. After years of research, reverse engineering, and many hours of testing, the WA73-EQ was born.

The WA73-EQ is a boutique “desert island” preamp, but also a workhorse for studio and live performances. Classic '73-style preamps are versatile and work with all types of microphones: condenser, dynamic, and ribbon. The WA73-EQ shines on all sources: vocals, acoustic and electric guitars, bass, drums, percussion, orchestras, keyboards, and even as a tool to shape tonal character of partial or full mixes. With 80 dB of gain and a fully discrete, balanced signal path with Carnhill transformer, there is no recording, mixing, or engineering task the WA73-EQ can’t handle.

Custom UK Carnhill Transformers

Enthusiasts get excited about the components used in classic British '73-style preamps. Signal transformers are a recurring topic. Vintage units used different versions over the years, but the earliest versions are the most coveted. They are considered the most desirable for their smooth, forgiving nature. They saturate sweetly when pushed and have made engineers cry hearing the beauty of their mixes through them.

Warm Audio worked closely with Carnhill Transformers in Cambridgeshire, UK, to design faithful replicas of these sought-after early transformers. We have yet to hear a modern '73-style preamp that sounds as sweet and musical as our WA73-EQ with these beautiful custom transformers.

Capacitors and signal path

An important yet little-discussed aspect of classic British circuits is the different types of capacitors and output transistors used. We consider it essential to maintain design integrity by using tantalum and polystyrene capacitors in the signal path, and a much softer output transistor choice in high gain settings than typical modern '73-style reproductions.

Blore Edwards Dual-Concentric Switch Potentiometers from the UK

A '73-style circuit that sounds great must be as reliable as it sounds good. The complex dual concentric switch potentiometers in the WA73-EQ’s EQ sections are made in the UK by Blore Edwards, who produce military-spec potentiometers and switches. Including Blore Edwards components is no small matter for a '73-style preamp-EQ at this price range.

Hand wiring and assembly

Classic '73-style preamps were hand-wired, just like the WA73-EQ. Experts say part of the much sought-after classic British tone comes from hand wiring. The WA73-EQ is hand-wired and assembled, including all PCB-mounted components soldered by hand.

Technical specifications

• Single channel, class A, British '73-style preamp with EQ
• Carnhill transformers made in the UK
• Blore Edwards dual-concentric switch potentiometers made in the UK
• Hand wiring and assembly
• 80 dB gain – stepped resistor gain switch
• Fully discrete
• Tone button – changes input transformer impedance to vary tone
• Polarity switch
• 48V phantom power
• 3-band inductor-based EQ