Short answer
Both are desktop DAC/amps, $3500 against $2499.
The Questyle CMA Fifteen reaches 100 dB on 567 of the 567 models here, the Marantz SACD 30n on 552.
| Specification | Marantz SACD 30n | Questyle CMA Fifteen |
|---|---|---|
| Power into 32Ω | 50 mW | 1.5 W |
| Power into 150Ω | 11 mW | 344 mW |
| Power into 300Ω | 5.3 mW | 188 mW |
| Power into 600Ω | 2.7 mW | 94 mW |
| Output impedance | not published | not published |
| Output noise | not published | not published |
| Price | $3500 | $2499 |
| Headphones it reaches 100 dB on out of 567 | 552 | 567 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | Marantz SACD 30n | Questyle CMA Fifteen |
|---|---|---|
| Socket | no separate rating | 4.4mm + 4-pin XLR |
| Power into 32Ω | — | 2.0 W |
| Power into 300Ω | — | 765 mW |
| Output impedance | — | not published |
| Output noise | — | not published |
| Headphones it reaches 100 dB on out of 567 | — | 567 |
Only the Questyle CMA Fifteen has a separate balanced rating from its maker; through it, it reaches 100 dB on 567 of the 567 models here. The Marantz SACD 30n may still have a balanced socket — its spec sheet simply gives no figure for one, so there is nothing to put beside it.
| Load | Marantz SACD 30n | Questyle CMA Fifteen |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Published |
| 600 Ω | Derived | Derived |
Both makers publish a power rating. Marantz SACD 30n publishes at 32 Ω; Questyle CMA Fifteen at 32 Ω and at 300 Ω. The other rows are worked out from those.
So the two columns are not equally firm row by row: at 300 Ω only the Questyle CMA Fifteen figure is the maker’s own. On those rows the derived number is the one to doubt first.
15 headphones reach 100 dB on the Questyle CMA Fifteen but not on the Marantz SACD 30n — HiFiMAN HE-6se V2, HiFiMAN HE6 Remastered, HiFiMAN Susvara, 12 more.
552 of the 567 models here reach 100 dB on both.
Headroom is at a 100 dB SPL peak.
The widest gap on the list is the Sennheiser HD 600: Questyle CMA Fifteen has +15 dB of headroom there against -1 dB. 15 dB is about 35 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Marantz SACD 30n and Questyle CMA Fifteen because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Marantz SACD 30n headroom | Questyle CMA Fifteen headroom | Marantz SACD 30n hiss | Questyle CMA Fifteen hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +25 dB | +40 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +5 dB | +20 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +15 dB | +29 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +10 dB | +25 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +7 dB | +22 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +3 dB | +19 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | -1 dB | +15 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | -3 dB | +12 dB | not published | not published |
The Marantz SACD 30n costs $1001 more than the Questyle CMA Fifteen, and on these three axes the money buys nothing: among the 567 models here there is not one that the Marantz SACD 30n handles and the Questyle CMA Fifteen does not — not on power, not on the one-eighth rule, not on hiss. The traffic runs the other way: the cheaper Questyle CMA Fifteen drives 15 models to 100 dB that the Marantz SACD 30n does not.
Only published figures count here; blank axes are counted separately.
Each in full: Marantz SACD 30n and Questyle CMA Fifteen.