A valve amplifier against a solid-state one. They are not really rivals: they differ in character, in what they will drive and in what owning them involves, so start there rather than with the watts.
| Area | Better | Why |
|---|
| Power | A | PS Audio BHK Signature 250 has more power - 250W against 150W into 8 ohms. That is about 2.2dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Grip on hard loads | A | PS Audio BHK Signature 250 holds up better into a 4-ohm load: its output nearly doubles to 500W, where the other increases strongly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Built-in DAC | B | Cambridge Audio Evo 150 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | B | Cambridge Audio Evo 150 takes more analogue sources - 2 against 1. |
| Phono stage | depends | Cambridge Audio Evo 150 has a built-in phono stage (MM) and PS Audio BHK Signature 250 does not. Decisive if you own a turntable, completely irrelevant if you do not - and an outboard phono stage is easy to add later either way. |
| Use with a TV | depends | Only Cambridge Audio Evo 150 has HDMI ARC, so the television can drive it directly and one remote controls the volume. If the system is for music only, this changes nothing. |
| Headphones | depends | Only Cambridge Audio Evo 150 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier type | depends | PS Audio BHK Signature 250 is Hybrid and Cambridge Audio Evo 150 is Solid State. Valve designs are usually warmer and softer at the limits and need their tubes replaced eventually; solid state is the lower-maintenance choice. This is a taste and ownership decision, not a quality one. |
| Shelf space | depends | Cambridge Audio Evo 150 takes up about 23% less shelf area (1190cm² against 1544cm²). |
| Price | B | Cambridge Audio Evo 150 costs less - $3,249 against $4,249 at list. |
| Watts per dollar | A | PS Audio BHK Signature 250 is the cheaper watt - about $17 per watt against $22. 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 Cambridge Audio Evo 150
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?
The usual trade-off: PS Audio BHK Signature 250 measures better, Cambridge Audio Evo 150 costs about 24% less. With most speakers in most rooms that gap is smaller in practice than it looks here. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - PS Audio BHK Signature 250 is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. 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 Signature 250 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 150 watts is already more than most people ever use, and the extra 100 watts would be headroom you pay for and never hear - we rate PS Audio BHK Signature 250 poorly for near-field use for exactly that reason.
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.