Cary SLP-05 with Pass Labs X-250

Your X.250 has an input impedance of 11kohm this would give trouble to many tube preamps that have high output impedance.
But your lucky as the SLP-05 has a low output impedance of 400ohms which is a good match for the X.250, maybe it has a solid state output buffer or has a maybe cathode follower tube buffer.

Cheers George

boisehomes,

Interesting, I owned the Andra 2, Pass Labs X-10, Cary SLP-05 and a Pass Labs X350.5.

First off, I did not like the Cary SLP-05 at all. The Pass Labs X-10 was better.

But, better yet would be to get a Pass Labs X250.8 Amp.
It has a much warmer sound and improved sound quality over the X250.

ozzy

George, per Stereophile’s measurements the 400 ohm spec is not accurate:

The SLP 05’s output impedance is specified as a usefully low 400 ohms. However, I got significantly higher values for the unbalanced output of 1500–1600 ohms in the midrange and treble, rising to 3400 ohms at 20Hz, with similar if slightly lower figures for the balanced output. The Cary preamp needs to be used with power amplifiers having input impedances of 10k ohms or greater if the bass is not to sound a little lean.

... And given those measurements I would consider JA’s suggestion of a 10K minimum load to be optimistic.

That said, the 22K **balanced** input impedance indicated in the manual for the X250 would seem to be a fairly reasonable match for the SLP-05 in terms of impedance compatibility, given also that the SLP-05’s output impedance has much less variation over the frequency range than in the case of many other tube-based preamps.

Regards,
-- Al