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 6 responses by lowrider57

For your next tube roll, try using a pair of RCA Cleartops in the gain stage. These tubes have incredible air and openness, but are completely neutral, so use a warm tube as a follower. They are also very affordable.

The Brimar longplate will have similar sonics to your Mullard; warm, laid-back, with a liquid midrange.
JB, careful placement of Cleartops is key. Too many may result in brightness. Use in combination with a warm tube like the Mullard.
I look forward to hearing about your results.
Sure, try 4 Cleartops in various positions. They do have good bass slam, and air on top. It will be interesting to see what happens when using them with the Mullard EL’s. Realize that Mullard reissues are brighter and more forward than NOS Mullards.
@jbhiller ,
If the Mullard CV4003 is too laid-back for you, the 12AU7 Mullard or Brimar longplate square getter is more dynamic, yet still has good warmth and sweet mids.
The Amperex (Holland) 7316 is a rare and expensive tube. Have you tried any 1950s Amperex Bugle Boys yet (Holland 12AU7)? Very musical, incredible 3D imaging, dynamic with air on top...IMO more realistic than Cleartops.
@samzx12 ,
ECC82 /12AU7 Mullard longplates, square getter, 1950s vintage, Great Britain.
Found on Brent Jessee site...
These are all the older long narrow plate version, with the rare early SQUARE top getter, with the 1950s date code. These are incredible tubes with a fine soundstage, clean top end with a touch of midrange warmth. Rare.
The different types of Mullards and year produced results in different sonic signatures. CV491 military and CV4003 are warm, textured, and laid-back. The ECC82 square getter is a more open tube, so is the ECC82/12AU7 Mullard longplates, halo getter.

Mullard reissues have nothing in common sonically with NOS Mullards. The Mullard name and trademark have been acquired by the New Sensor Corporation (Russian factory); same comany that makes new Tung-Sol, Sovtek, Electro-Harmonix.

(I have never tried Cifties).