These are not the same size of amplifier: PS Audio BHK Mono 600 has roughly 2.4x the power of PS Audio BHK Signature 250. That is about 3.8dB, so it is a question of room size and how hard your speakers are to drive, not of one being the better amplifier.
| Area | Better | Why |
|---|
| Power | B | PS Audio BHK Mono 600 has more power - 600W against 250W into 8 ohms. That is about 3.8dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Noise floor | B | PS Audio BHK Mono 600 is the quieter design on paper - 100dB against 85dB. Audible mainly with sensitive speakers in a quiet room. |
| Analogue inputs | evenly matched | The same number of line-level inputs (1). |
| Price | A | PS Audio BHK Signature 250 costs less - $4,249 against $14,999 at list. |
| Watts per dollar | A | PS Audio BHK Signature 250 is the cheaper watt - about $17 per watt against $25. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A PS Audio BHK Signature 250 B PS Audio BHK Mono 600
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both amplifiers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
PS Audio BHK Mono 600 is ahead, but on only 1 of the measured areas, and it costs about 3.5x the price. That is a lot of money for a narrow margin - PS Audio BHK Signature 250 is the sensible buy unless a specific feature above decides it for you. Start with the room. In a large or open-plan room, or with speakers that are hard to drive - low sensitivity, or an impedance that dips - PS Audio BHK Mono 600 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 250 watts is already more than most people ever use, and the extra 350 watts would be headroom you pay for and never hear - we rate PS Audio BHK Mono 600 poorly for near-field use for exactly that reason. Think about the whole system: the roughly $10,750 saved by taking the cheaper one would buy better speakers or a subwoofer, which does more for the sound than the difference between two competent amplifiers.
What a spec sheet cannot show: how either sounds with your speakers, how the controls feel day to day, and what the app is like to live with - which is where most all-in-one amplifiers are actually won or lost. Power figures are the manufacturers' own and are not measured to a common standard, so treat small differences as noise. If you can hear both, that will tell you more than any row above.