Aesthetix Calypso or Pass Labs Preamp

Terryakhan - I think you have very good tubes. I can recommend you try Telefunken 12AX7 smooth plates to get another perspective.

In the 6922 slot's, I've been happy with Amperex orange label, but preferred the older & more expensive Amperex (Phillips branded) white label SQ's. Currently using IEC Mullard's white label from the mid 60's with very good success (not commonly available). So I can recommend all three listed above and feel you can't go wrong with Amperex... they are readily available, albeit not cheap.

In the 12AX7 slots I've had good results with the following:
- Telefunken smooth plates (these are the best IME... awesome mid's, dynamic & liquid but slightly shrill high's on some notes)
- Mullard CV4004 Platinums (very good, balanced all-around sound)
- Mullard / Bogen branded white labels (very warm, good bass & lower mids, strong with vocals, but erring far on the warm/dark side of neutral)

I tried Amperex Bugle Boys, but found them to lack focus... maybe just had some mismatched tubes... hard to say. I also tried the much heralded & mega expensive Mullard 10M gold pins, but found them to be too warm and veiled for my taste... once again, maybe the tubes were note well matched, nor did I buy them from a reputable dealer. I also tried new production tubes from Sovtek & Mullard New Sensor, but they all sucked, to be blunt.

Ultimately, I think there are many good tubes / choices, but think it probably pays to buy closely matched tubes from reputable dealers or at least from an Audiogon member that can verify the tubes came from a good supplier (i.e. Tubeworld, Vintage Tube Services, Upscale Audio).

So I just finished a multi day direct A/B of the Pass XP10 and a Aesthetix Calypso. The sessions were in my home with the only changes being the pre amps, including level matching. The pass has more detail but ultimately I chose to stay with the Calypso because it sounded more realistic and had more depth to the sound stage. It was kinda like listening to a live band with a slight vail over the band. When switching to the xp10 the vail was lifted but suddenly the band disappeared and I was left with a couple speakers. The pass sounds good but just doesn't convey the depth and realism of the calypso. I plan to buy the XP20 in the next year or so. I figure the 20 may give me the added warmth and depth of the calypso while maintaining the detail of the xp10.

Associated gear:
Magnepan 3.7's on myestands
Esoteric SA10 SACD player
Pass Labs XA100.5 amps

I think that Calypso may perform even better with a high input impedance poweramp.