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

This is very interesting to me. I owned the Pass Labs 250.5 for a short time, and really disliked it's sound with 4 different speakers. I was using the Morrison Elad preamplifier with it. Now I'm thinking that it may have been an impedance mismatch after all. Any thoughts Al?

Hi John (Roxy54),

No, I don't think there would have been an impedance compatibility issue using the Morrison Elad with the X250.5, or with most other power amps.  See the info provided in the PM I sent to you on 3/3/2017.

Best regards,
-- Al

Thanks Al. I guess that just wasn't the right amp for me. 

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,

Almarg is right, I got the 400ohms from the Cary website.
This is why Stereophile is such a good site for seeing what's really going on with products, as their measurements can't be disputed.
In this case your Cary is not a good match for the Pass X-250. either get a pre with low impedance across the whole audio band, or get an amp that has 50kohm or more input impedance. 

Cheers George 

Well, I can not help you with the preamp and amp you have suggested.  However, I can let you know what I have used both previously as well as currently with my EgglestonWorks Andra II speakers.

I used to use a (solid state) Ayre K-1xe (full function) preamp with a pair of (hybrid) Lamm M2.2 (220 wpc) monoblock amps.  (FYI:  I should state I like to run my system fully balanced, from my phono cartridge to my amps.) The sound was very good.  The imaging and soundstaging was quite good.  The bass response was great, (both deep and tight). The mid-range was very good. The treble was slightly dark, although substituting some NOS 6922 tubes (there is one per amp) helped here.  All in all, it was a very good sounding system.

Then a friend sold me a great phono preamp, (an ASR Basis Exclusive 2010 gold board version), for a great price.  So, I figured it was a good time to sell the full function Ayre, and buy a line stage preamp.  Since I liked the hybrid Lamm amps, I thought I would try a hybrid preamp.  Luckily, I found a lightly used VTL TL-6.5 Signature preamp for a good price.  This preamp combination was a step up over the Ayre, especially in the phono stage area.  The background was still as deep and dark as the Ayre, but the soundstaging and imaging was even better.  The frequency response was flat and well extended, similar to, and slightly better, than the Ayre.

Shortly thereafter one of my Lamms died, (after "only" ten years, which was annoying, but I was the 2nd owner, so "oh well"), so I started looking for a new amp.  My friend, (the same one I mentioned earlier), had previously auditioned half a dozen amps with me there over a few years, but the one I always remembered was the VAC Phi 300.1 (150 wpc) stereo tube amp.  Luckily I found one for a great price, (although I had to have it shipped from Canada, but the exchange rate at the time was 72 cents on the dollar - hence the great price!). Anyway, the sound is incredible.  The sound staging and imaging is the best I have ever heard.  The bass is very good, (especially so for a tube amp), but not the very best, but close enough.  The mid-range is almost liquid like, it is so good, (again, the best I have ever heard).  And the treble is very well extended and refined, (and yes, once again, the best I have ever heard).  The only downside to the amp, apart from merely "very good" bass response, is buying tubes for it.  (It takes 8 KT88 power tubes and four 6SN7 tubes, so it costs several hundred dollars to retube it every few years.).  And since you runs subs with yours, the bass response is not much of a consideration.

Anyway, that is my two cents worth.
Good luck in your search.

@dpac996 What you are hearing are the stock Electro-Harmonix EH-6SN7 tubes.  Tube rolling is the Cary yields great results

dpac996
  did many thing right but the overall balance was too hot / forward in the upper midrange.

As with the OP's amp it will roll of early in the bass, not quite as much as the OP's amp, as your friends x250.5 is a little higher input impedance at 20k balanced, but still not a great match with the Cary's 3.4k output impedance at 20hz. This could be the reason for sounding "hot". Tube rolling as little effect on this type of impedance matching problem.

Cheers George   

I have the SLP-05 and the Andra II. I have tried a few amps. The best one so far has been the CAT JL-2 Black Path with KT-120's. Incredible match.