Lesson in Tube Rolling:: My confirmed need for "air on top" via 12au7 ECC82 5814a tubes


I thought that I would share something that I learned in my first 90 days of tube rolling. 

I knew and still know that I don't like harsh treble.  I thought NOS Mullard CV4003s would be perfect for me.  I realized, though, that the very quality I like about them I also do not like about them--they are laid back and mellow.  But, when I move to other tubes, e.g. RCAs, Ciftes, Amperex, GE, of the same tube equivalent I feel they may be a bit too forward.  

I don't really know much but what I know is that I need a touch of air on top.  The Ciftes and RCAs helped but if I went to a full bay of those it became too bright or top end extended.  And, just as with the Mullards, what I liked about the Ciftes and RCAs was exactly what came to tire me.  

I'm happy to find that mixing preamp tubes seems to do the trick.  If I run 2-4 Mullards with 2 Ciftes (6 preamp tubes total) in the front slots of my amp it adjusts the tone just right.  

This may not be a revelation for advanced tube rollers. It is, however, reassuring because I am able to get very much closer to the tone that I want in my mind's eye (or mind's ear), and I still hear value in the various NOS tubes that I bought. 

As an aside, these experiments worked so well that now I have faith in some reissue Mullard EL34s again and when I swap back in my Gold Lion KT88s, I may go 4/6 Mullard to chill things out a bit.  

I hope this helps other novice tube rollers.  

PS  I would like to try some NOS Brimars to see what kind of air and extension they put on top.  If I roll 4/6 tubes with Ciftes it starts to get to be too much.  
jbhiller

Showing 2 responses by aniwolfe

I use 12au7 in my Primaluna Integrated Amp. I have tried several combos with the Mullard Reissue El34’s and GL KT77 Russian. I much prefer the KT77 sonic balance over the Mullard.

What I have found is that the Mullards have too much midrange forwardness and the KT77’s are much better balanced from top to bottom. More extension top to bottom,.the midrange is clearer and not forward.

For the Preamp section I like the combo of either the (2) Cifte or Tungsram in the Gain stage and the (2) NEC/Mullard in the first Driver Stage. The second driver stage I use the stock (2)12au7 Chinese tube.
I have not heard all the 12au7's created. But out of the 10 or so I have tried, the Cifte/Mazda Gray Plates have become my favorite 12au7 tube.