INPUT SCENARIO

Electro-Voice RE20 through a Warm Audio WA73 preamp

An outboard preamp changes where the gain comes from — and where the interface knob should sit. The calculation shows the split and the input the signal must land on.

Gear in this setup:electro-voice-re20 focusrite-scarlett-solo-gen4 macbook-pro-m2 warm-audio-wa73

Signal Chain Compatibility Matrix

Select gear and parameters for live gain, impedance and SPL calculations.

Input Equipment Setup

Input Source Category

Select Microphone / Transducer

Intermediate Gear (DI Box / Preamp / Booster)

Select Audio Interface / DAC

Select Host Device / OS

Source Sound Level (dB SPL)85 dB SPL

PASS: Optimal Signal Chain

Requires minimum +60dB of clean pre-amp gain. Most budget entry interfaces max out at +50dB to +56dB and introduce hiss at max pot. An inline preamp booster (Cloudlifter CL-1 / FetHead) is strongly recommended.

Gain Staging (Required Gain)

+57 dBInterface max: +69 dB

Inline Booster Status

Direct connection OK

The interface preamp provides sufficient headroom.

Chain Budget (new vs used)

2026

Total chain MSRP (new)

$538

Secondary market estimate

$405

-25%

Potential savings buying used:~$133 (25%)

Expert Audio Engineering Commentary

Tonal & acoustic characteristics: Flat, wide-range frequency response for clean music and speech. Smooth, warm acoustic character with air-suspension shock isolation.

Technical advisory: With +69dB max gain, the Gen 4 Solo can drive demanding dynamics like the Shure SM7B natively without requiring an external inline booster.

Physical Interconnect Topology

Input Chain (XLR / USB)

Stage 1: Input Source

Shure SM7B

Output Port:XLR / 1/4" TS

Stage 2: Intermediate Gear

Direct Cable Connection (No Intermediate Box)

1x Shielded Balanced XLR Cable (3-Pin XLR Male to XLR Female)

Phantom Power:+48V Ready

Stage 3: Interface / Host

Focusrite Scarlett Solo (Gen 4)

Host: Apple MacBook Pro (M1/M2/M3/M4)

Input Terminal:Combo XLR / 1/4" TRS

Signal and impedance metrics are calculated from hardware specs.