I changed a Tube and…

I've seen plenty of threads & videos about tube rolling and guess I was a bit skeptical about actual results . 

Guess I have seen the truth , pretty amazing results . 

There is a downside to this , how much will I be wondering about ' maybe this tube is even better ?   etc. 

JJ small signal tubes are the poorest SQ I’ve ever experienced. I have multiple Rogue items but not yours. In my M180’s each has a 12AX7 and 2- 12AU7’s, the 12AX7 is the phase tube and has a pretty strong influence on gain. I currently have 12AT7’s in that slot as they have a lower Mu ( gain ). There are about 4 different tubes that you can run in the slot. 12AY7 (45), 12AT7 (60) 5751 (70), 12AX7 (100)  with the corresponding mu. Your 12AU7 has a gain of 100. Rogue often recommends Mullard NOS tubes but I’m not a fan of their sound. I’m not well versed with new production 12AU7’s , but for nos in Rogue I like RCA and Tekefunken which are unfortunately expensive. I recently had my amps serviced and upgraded by Rogue. They were retubed with new production Tung Sol 5751 gold pins for the 12AX7 slot and they sound VERY NICE ! I actually preferred them over nos Telefunken. I have nos GE 5 Star and Sylvania Gold label for that slot too. I would avoid any of the JJ’s even the higher grade ones. Not sure in your amp if you would effect overall power  going to a 5751 , being lower gain it imparts less noise. But with new production input tubes averaging $40-50 each I’d change them all. BTW what power tube are you running ? Happy Listening, Mike B. 

For fun go to Brent Jessee and pick up singles of these 12au7 tubes...

RCA early grey plate (organ stock) - $15

RCA black plate (butt ugly) - $30

Amperex World Logo Holland $59

You might also pick up 2 of the $15 jobs to try as drivers.

Aside from Mullard you will be able to sample the sound of my favorite 12au7 tubes.

I’m not keen on Seimens, Telefunken and Mazda (except for the early Mazda).

DeKay

I have the original kt120 tubes -   I do have a bunch of tube 12au7 & ax7's 

bought a few years back thinking i'd change / roll - never got to it .

found the Gold Lions in a Box with some Mullard EL34'S [ For Dynaco ST70] 

and figured i'd try one - being new I wouldn't have doubts on the wear .

not sure about those prices from Brent - ? 

I picked the reasonably priced tubes that give you a good taste of RCA and Amperex.

I’ve used all of them in my preamp with good results.

I generally run late 60’s Mullard Blackburn 12au7’s (short plate/round getter), but he didn’t have any, plus they would be $150+ a pair if he did.

I prefer a 3D presentation with some weight/color.

Oh, since you have spares try them in the driver positions.

DeKay