Short answer
Both are desktop amplifiers, $2395 against $1800.
The Cayin HA-6A reaches 100 dB on 567 of the 567 models here, the Bryston BHA-1 on 566.
| Specification | Bryston BHA-1 | Cayin HA-6A |
|---|---|---|
| Power into 32Ω | 500 mW | 3.0 W |
| Power into 150Ω | 358 mW | 1.5 W |
| Power into 300Ω | 445 mW | 900 mW |
| Power into 600Ω | 667 mW | 450 mW |
| Output impedance | not published | 2 Ω unverified |
| Output noise | not published | 25 µV unverified |
| Price | $2395 | $1800 |
| Headphones it reaches 100 dB on out of 567 | 566 | 567 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | Bryston BHA-1 | Cayin HA-6A |
|---|---|---|
| Socket | balanced | no separate rating |
| Power into 32Ω | 500 mW | — |
| Power into 300Ω | 445 mW derived | — |
| Output impedance | not published | — |
| Output noise | not published | — |
| Headphones it reaches 100 dB on out of 567 | 566 | — |
Only the Bryston BHA-1 has a separate balanced rating from its maker; through it, it reaches 100 dB on 566 of the 567 models here. The Cayin HA-6A may still have a balanced socket — its spec sheet simply gives no figure for one, so there is nothing to put beside it. Derived figures are worked out from the loads the maker did publish.
| Load | Bryston BHA-1 | Cayin HA-6A |
|---|---|---|
| 32 Ω | Published | Unverified |
| 150 Ω | Derived | Unverified |
| 300 Ω | Derived | Unverified |
| 600 Ω | Published | Unverified |
Cayin HA-6A publishes no electrical specification at all. That is true of 10 of the 280 sources here, and the figures in that column come from independent measurement rather than from a maker document — which is not worse, but it is not the same thing, and it cannot be checked against anything the maker will stand behind.
The Bryston BHA-1 column does stand on a power rating its maker printed, at one of these four loads at least. Reading the two straight across sets one kind of claim against another, and nobody has written down the conditions of both side by side.
1 headphone reaches 100 dB on the Cayin HA-6A but not on the Bryston BHA-1 — Symphonium Titan.
566 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 Campfire Audio Andromeda 2020: Cayin HA-6A has +23 dB of headroom there against +15 dB. 8 dB is about 6 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Bryston BHA-1 and Cayin HA-6A because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Bryston BHA-1 headroom | Cayin HA-6A headroom | Bryston BHA-1 hiss | Cayin HA-6A hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +35 dB | +43 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +15 dB | +23 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +27 dB | +34 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +28 dB | +32 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +17 dB | +25 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +26 dB | +26 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +18 dB | +21 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +9 dB | +16 dB | not published | not published |
The Bryston BHA-1 costs $595 more than the Cayin HA-6A, and on these three axes the money buys nothing: among the 567 models here there is not one that the Bryston BHA-1 handles and the Cayin HA-6A does not — not on power, not on the one-eighth rule, not on hiss. The traffic runs the other way: the cheaper Cayin HA-6A drives one model to 100 dB that the Bryston BHA-1 does not.
Only published figures count here; blank axes are counted separately.
Each has a page of its own with a full headphone list and the provenance of every figure — worth opening here, because Cayin HA-6A has published no electrical specification at all and everything above comes from independent measurement: Bryston BHA-1 and Cayin HA-6A.