Pass Labs preamp with Krell Evo amp. Anyone..??

I used a Pass Labs Aleph P for many years with several Krell Power Amps with great results. The X2.5 is a decent pre-amp but I found that the Aleph P was a better pre-amp in my system. I now have a Pass Labs Xp 10 which is much better than both the Aleph P, X1, and the X2.5. I have tied many different Krell power amps in my system, but not an EVO 302. I got try an Evo 402 and it did not sound as good in my system as my current amp, a Pass Labs X350.5. I hear that the EVO 302 is sonically much better than the EVO 402. A freind who is a Krell dealer said he liked the EVO 302 better than the EVO 402. The output voltage, output gain, and the input impedance are all very similar between all the Pass Labs and Krell pre-amps and they are all very compitable.

@Thesoundhouse, thank you - this is a very insightful reply.

Have you had any experience with other brands of preamplifiers - say, Ayre, Electrocompaniet, Audio Research, Parasound (JC-2) in combo with Krell power amp..??

Btw, it is not the first time to hear similar impressions regarding Evo 302 superiority over bigger Evo 402.

I have a reservation concerning 302 vs 402 comparison. How come same design one with the less watts is sonicaly superior to same one 100 watt more? or number 300 sounds more sympatic than number 400? In auto industry there is a belief that manufacturers never use ''4 or derivatives'' as model numbers.Maybe Krell made wrong and used 402 as model number.....

The specs for the two models do indicate that they differ signficantly. Note that the 402 burns a LOT more power, even in standby, indicating that it's biased more heavily into class A.

On the other hand, the 302's slew rate is faster, and it has a higher damping factor.

So it does make sense that they should sound different.

Also note that at $0.10/kWH, the 302 costs $130 per year in standby, while the 402 costs $320 per year. Not much money compared to the amps themselves though :)

302
Power consumption
Standby: 150 W
Idle: 320 W
Maximum: 3400 W
Slew rate
120 V/µs
Damping Factor (referred to 8 ohms)
>200 at 20 Hz, referred to 8 Ω
>150, 20 Hz to 20 kHz, referred to 8 Ω

402
Power consumption
Standby: 370 W
Idle: 570 W
Maximum: 3800 W
Slew rate
100 V/µs
Damping Factor (referred to 8 ohms)
>145 at 20 Hz, referred to 8 Ω
>125, 20 Hz to 20 kHz, referred to 8 Ω

Turns out the 402's standby and idle power consumption was overstated due to a typo. Krell has updated their site:

402
Power consumption
Standby: 260 W
Idle: 390 W
Maximum: 3800 W
Slew rate
100 V/µs
Damping Factor (referred to 8 ohms)
>145 at 20 Hz, referred to 8 Ω
>125, 20 Hz to 20 kHz, referred to 8 Ω

Mert,
More does not mean it is better. I see you have an EVO 402 and it is a fine amp and I am sure it makes your speakers sing. In most cases it is easier to make a less powerful amp sound good as opposed to more powerul amp. The more output devices and more complex an amp design is the more difficult it is to make sound good. That is why many of the pure class a biased amps are low wattage with lots of current. Simple is best and less sometime is more. Since my last posting I have been able to put some ear time on a Krell Evo 302 and it is better than the 402 in my opinion. It is much more musical and I liked what it does in the bass and if I did not own a Pass Labs X350.5 I would probably buy an Evo 302.