Sony MDR-7506: the same 16 dB between dongle and desktop DAC, and it changes nothing
The 7506 needs 0.40 V and 2.51 mW for a 110 dB peak. The lowest-output dongle in the catalogue finishes 9.5 dB above target, the most powerful desktop DAC 25.6 dB. Both answers are «yes», and one of them costs $76.
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)
Yes to both, and the gap between them is wasted money. KA13: 119.5 dB. DX3 Pro+: 135.6 dB. Target: 110 dB.
Sony rates the MDR-7506 at 63 Ω and 106 dB/mW, which converts to 118.0 dB/V — the highest voltage sensitivity in this catalogue. A 110 dB peak therefore needs V = 10^((110 − 118.0)/20) = 0.40 V, drawing 2.51 mW and 6.31 mA. The KA13 delivers 1.188 V into 63 Ω after its own output impedance takes its share: 9.5 dB of headroom. The DX3 Pro+ delivers 7.588 V: 25.6 dB of headroom, i.e. 16.1 dB you will never use, because using it would mean listening at 135 dB.
This is the same comparison that ruins the ATH-R70x, with the opposite result. The two sources are 15.9 dB apart no matter what is plugged in; whether that gap matters depends entirely on where the headphone's requirement sits. The R70x needs 2.73 V and the cheap dongle fails by 7 dB. The 7506 needs 0.40 V and both sources clear it before the volume control leaves its first third. «Which DAC is better» is not a question about DACs.
The pearl: at these levels the volume control becomes the weak link. 0.40 V of the KA13's 1.22 V ceiling is peak level; ordinary listening sits 20-25 dB below that, i.e. in the bottom eighth of an analogue potentiometer's travel — exactly where channel-balance error on cheap pots is worst. With a sensitive headphone the audible problem migrates from the amplifier to the attenuator, which is why a high-output DAC can measurably worsen a 7506 while measuring better on every other test.
Damping, checkable here. FiiO publishes <1.7 Ω for the KA13 and Topping <0.1 Ω for the DX3 Pro+; against 63 Ω that is a ratio of 37 and 630 against the 8 the rule asks for. Both are clear. This is the exception — most manufacturers publish nothing at all, and then no one can say what the output impedance is doing to the bass.