Will a Scarlett Solo drive 250 Ω DT 990 Pro headphones?
The answer forums give is yes or no. The arithmetic gives a third one: 0.2 dB short of a 110 dB peak target, and entirely comfortable at 100 dB.
Signal Chain Compatibility Matrix
Select gear and parameters for live gain, impedance and SPL calculations.
Input Equipment Setup
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.
The interface preamp provides sufficient headroom.
$538
$405
-25%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
Shure SM7B
Direct Cable Connection (No Intermediate Box)
1x Shielded Balanced XLR Cable (3-Pin XLR Male to XLR Female)
Focusrite Scarlett Solo (Gen 4)
Host: Apple MacBook Pro (M1/M2/M3/M4)
Beyerdynamic quotes 96 dB per milliwatt for the 250 Ω version. Converted to volts — the unit an amplifier actually delivers — that is 102 dB per volt: for 250 Ω the conversion adds 6 dB, and confusing the two formats is the single most common mistake in this question.
From there the arithmetic is short. Reaching a 110 dB peak (85 dB of comfortable listening plus 25 dB of crest factor for uncompressed material) needs 2.51 V RMS. Focusrite publishes +10 dBu for this output, which is 2.45 V. The Solo lands 0.2 dB short — not a failure, but not the headroom the marketing implies either.
What that means in practice: at a 100 dB target the same pair has 9.8 dB to spare and is entirely comfortable. At 115 dB, for wide-dynamic classical or film material, it falls 5.2 dB behind. So the honest answer is neither "yes" nor "no" — it is "yes for most listening, no for the loudest peaks of uncompressed material".
One number is missing and we do not invent it: Focusrite does not publish the output impedance of this jack. Without it, nothing can be said about whether the bass resonance of a dynamic headphone gets lifted — so the calculator above says exactly that instead of guessing.