Best 12AU7 Type Tubes for a Preamp

I was recently asked a couple of questions related to this thread so I will partially answer here.

Q: Any update on how the new tubes sound in your system ?

• New Tubes: Amperex PQ 7316/ECC186 Holland Short Plate O-Getter 1965 Ct5. I have had these in the Hattor Tube Active Stage for a couple of weeks now and the tube stage is sounding the best it ever has. While the tube stage does not seem to be terribly sensitive to the tubes being used, the Amperex tubes seem a little more musical with maybe a little more definition than the new stock Mullards I was using. However, I could have lived with the sound from the Mullards.

Q: What changes does the tube buffer makes over the Big Preamp?

• I need to do more listening to answer this. As I remember it, I was impressed with the sound through the internal NewClassD op-amp active stage of Hattor’s The Big Preamp. The drive, dynamics, and clarity were very good but I need to make the time for a direct comparison with the Amperex loaded Tube Active Stage before I answer the question. However, as with the tube question above, my recollection is that I could live with either option, either the tube stage or the internal op-amp stage. BTW, my preferred gain with the internal active stage as I recall was +6dB. I will report back on this comparison after I listen some more.

Just 3 days ago I got a package from Brent Jesse. It contained the 1960s Mazda ladder plates 12AU7 for my Backert Labs Rhumba. I installed them and kept the preamp ON for 2 hours and sat down for a serious auditioning. I am not going to say "blow out of water" or "I was blown away", etc etc, lest I jinx them. All I will say is that comparing the Mazdas to the Psvane ART series tubes is like comparing a 23 year old man/woman with a 40+ man/woman respectively. Hope you get it. I was told that they need at least 48 hours to sound nice. They sound nice right now. I am not going to keep them ON for a long time just to let them "burn in".

Yes, the Mazdas are pricey, but they are keepers. Mind you, the Psvane ART series are not bad at all. In fact of all the current production tubes, they are THE BEST. Only after listening to the Mazdas, did I realize that the Psvanes produce excess bass that is a bit bloated. The Mazda bass is very tight. Also the Psvanes do not extend and light up the treble the way the Mazda does.

Excellent thread. About two weeks ago decided to shuffle the pre amp tube line up on my Raven Nighthawk/Blackhawk modified, and pure magic was the result. (User experiences may vary) Front row went Volvo/Mullard 3 hole ECC81 (12AT7 equivalent), , row two CBS Hytron 12AU7( USA) , and row three Tungsram ECC82 (12AU7 equivalent) (Austrian).. This is more revealing than any combo tried yet. Tried all low gain 12AU7's throughout but lost details. Kicked the RCA clear tops out of the line up. Blurry (May have been an off pair.) For customers of Raven Audio, Dave and James are tube heads and provide personal help and tubes for their devotees. Very nice , tested, graded, and guaranteed High frequencies now are dreamy.

if this will help

british    mullards- warm, detailed, good dynamics

german   telefunken, siemens, open, airy, good head room, great sound top to bottom

holland   amperex, phillps good sound staging, 3 dimensional, good top end, bass may be a little sloppy with some. ( bugle boys are my favorite)

tung sol, rca , slyvania, electric harmonics or any of the us made tubes are all about the same to me and lower cost.  depends on your listening taste

talk with andy at vintage tube svcs in mich  616 454 3467 very knowledgable and helpful.   tell him damon from atlanta sent you....