I changed a Tube and…

No delusion. Replacing stock JJ tubes almost always elicits this reaction. 

Based on a quick check

 center 12au7 is the gain for both channels.

The other 2 are L/R are  driver and probably won't make  a noticeable difference.

@mfm22  Changing a tube in an amp or preamp is a classic way to change the sound and/or get it to sound better. The difference is not only audible, it can be quite measurable too. This is why there is such a market for NOS vintage tubes!

I replaced Gold Lion 300B tubes on my headphone amp with new WE 300B's, and it sounded like the next highest amp in the company's lineup, if they'd had one. $1200/pair are expensive tubes, but in this case, it was well worth it for me. 

Tube rolling is a great way to fine tune a tube amp to your liking.  You can swap driver tubes and output tubes....all can make a notable difference.

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

Pop in a Telefunken, Amperex bugle boy, Mullard, RCA blackplate, or sleeper giant Raytheon black plate, you’ll be even more impressed.  NOS 12AU7s cheaper than NOS 12AX7s so you can experiment on a lean budget. 

I have a set of NOS preamp tubes I used for 2 months before I sold the Rogue Cronus Magnum II.  I bought them from Brent Jessee of AudioTubes.com.

3 Mazda 12au7, 2 GE 7025 (12ax7)  $450

The change from stock was extremely dramatic in all aspects.  Detail, soundstage, cleaner highs, punchy lows.  My thought was what amp is this and what did you do with the Rogue.

These tubes are just sitting in my drawer.  Feel free to DM me with questions 

"not sure about those prices from Brent - ?"

What do you mean by that - too inexpensive?

The new production tubes you are using currently retail for $60+ per tube.

The tubes I mentioned are cheap as chips and they may further rock your world of tube rolling.

DeKay

I’ll be trying other tubes for sure. 
always looking for larger soundstage , and warm midrange

these Gold Lions are a big step up from the JJs but I can hear that they are a little brighter 

“What do you mean by that - too inexpensive?

The new production tubes you are using currently retail for $60+ per tube.

The tubes I mentioned are cheap as chips and they may further rock your world of tube rolling.”

I’ll revisit the site , last time I looked prices seemed higher but then all nos tubes are getting $

I’ll look for ones you mentioned ….thanks for advice

NOS ( new old stock vintage tubes) are expensive relative to new production but in my experience the sound quality is far superior.  Brent happens to be the most reasonable priced NOS tubes.  He has a vast knowledge of what tubes work best in specific amp/preamp applications and you can return them within 30 days if they don’t work for you.  You can call him directly.
My experience has been a few hundred $ in NOS preamp tubes has saved me spending thousands more on a new amp or integrated to get improvements in overall sonics, soundstage, depth, and clarity.  
But that’s my experience which doesn’t mean …. in the big picture.

Mine are available 

Not trying to rain on your parade, but if you think Russian made GL reissues are good, dive into NOS. Brent Jesse should be your guy. It doesn’t have to be more expensive. Look at Baldwin 12AU7 too to get some lower cost ideas.

He lists every tube he has in detail on his website. Spend some time there, then email him rather than call.

The implementation matters though, so experimentation is required. For example, I have a DAC and a phone stage that both use a pair of 12AX7. $300 Tele’s sound better in the PS than $450 Mullard’s, and vice versa.   

Brent Jesse is the second best tube seller I know of, Andy at vintage tube services being number one.

@invalid Wrote:

Brent Jesse is the second best tube seller I know of, Andy at vintage tube services being number one.

I agree!

Mike

I have a nearly new Cronus Dark in my second system. Like you, I recently began some tube rolling, only the center preamp slot, because my experience in tube rolling with a CM2 was that the other tubes make only a negligible difference. 

Mostly I have been playing with new-production tubes because I generally find they tend to perform better than NOS tubes. That has been a recurring pattern in almost every tube-based product I’ve owned. Perhaps that’s only because I don’t purchase the NOS tubes that go for like $300 each.

Anyhow, I recently purchased a low-noise, matched-triodes Genalex Gold Lion 12au7 from Tube Depot. I also purchased the same JJ preamp tube that Rogue  used to supply in the CMII. Previous to these I purchased a NOS Telefunken smooth-plate. In playing with all these, this is how I would rank their performance:

Best: gold pin JJ ECC82 that came stock with the CM Dark.

Next Best: JJ ECC802S that Rogue used to equip in the CMII

Next: NOS Telefunken smooth plate.

Least Good: Genalex Gold Lion

Yup, the Gold Lion has been the least enjoyable of these, and by a rather wide margin. It could need more hours, but within the 10 or so hours I tried to tolerate it, the sound was closed in, with a very recessed midrange.

The Tele was a little grainy relative to the JJs, but then I didn’t buy a $200 example from VTS, rather a $100 one I found on ebay. 

I too will vouch for Andy at VTS: great tubes at mostly reasonable prices. Where he and I greatly differ is his appreciation for NOS RCA tubes. Every time I go with that recommendation I end up disappointed. Personally, I would only pick from his stock of Amperex, Teles, Siemens or Mullards. 
 

I have had some unpleasant experiences ordering from Brent Jesse. Two of the half dozen or so orders I received from him were total duds, completely unusable on arrival. I have had no such issues with any of the other popular tube vendors. 

helomech -Interesting take  appreciate the info . 

I had the Gold Lions sitting new for years [ forgot i had  them ]  So it was an easy choice to use one of them .

I went digging deeper into my cabinets & found all kinds of  NOS tubes  .

Most being 12au7 & 12ax7's  these were bought 2015 / 2016 - must have thought I'd tube roll down the road  ?   Have Mullards , RCA Clear tops , Telefunken , Sylvania  etc..   

I had some receipts - sellers were Brent Jesse / Andy VTS / Bryce ? 

Do not want to go down the tube rolling Hole - did that with Amps / Speakers and wind up listening to equipment not Music 

I can see the logic in new production being reliable  but sonics are tricky with any thing  NOS vs New .  I'll probably pick up the Gold Pin as that was mentioned by Bill at Rogue - he did say NOS / Vintage could be better and mentioned Jesse & Andy .

Just a thought - The Gold Lions I have are 10 yrs old - I wonder if there is a quality difference to current production ?

Seems like everything made today suffers from less quality control / cheaper materials  etc.  [ everything = TV's, Refrigerators , Washer / Dryers , AC'S / Cars , EVERYTHING!! ]

Being in my 70s and having gone to rock concerts and having front row or very close seat...like Black Sabbath 1972 the old Academy music on 14 st NYC....I never noticed the changes...

Not sure how to link to the thread about AI’s use for HiFi, but therein you’ll find my input/driver/rectifier tube story.  In summary I have rolled tubes (mostly 300B), talked to folks, bought better amp and rolled more tubes, etc.  I landed on a fine sounding SET with WE300B power tubes, but as a friend’s insistence used my setup and asked ChatGPT which input/driver/rectifier tubes to try.  I had to describe my system a little further (speakers, inputs, cables, etc), but in the end I got a very specific suggestion (mfg, year, identifying markings, reputable sellers like Brent) for 12AU7, 12BH7, and 5U4G tubes that sound amazing to me in the real world.  

I share this to agree with your observation that the little tubes matter and that you’d probably be surprised how much difference the plate driver and rectifier tubes can make.  The AI reference isn’t any kind of endorsement or recommendation...

Enjoy the experimentation!

I bought a pair of NOS 1957 ECC83 long plate Bugle Boy for my Pro-ject DS2 Tube Box. They cost more than the DS2. 
 

They were worth it. A dramatic difference. 

Changed the GL out for a Telefiunken 

yes it’s even better , midrange sweet , overall is smoother than GL. Seems like imaging is excellent 

these tube sockets are pretty tight , little patience and wiggles needed

Telefunkens are the best for clean (neutral), airy, transparent sound.

I’m going to leave it be for a week or so 

hoping they have lots of hours in them 

it was like finding a treasure chest a bunch of NOS tubes . 
Maybe a good thing that sockets are so tight , discourages user from excess swapping  lol

OP

Welcome to the world of Tube Rolling 

My first experience is tube rolling the Shiit Freya+ a few years back. OMG, you can hear what swapping different brands of tubes do. 

So, when I got my Linear Tube Audio Microzotl, I did not take chances. i used Telefunken 12ax7 medical grade and Kenrad VT231 for the 6SN7 driver

For my power amp, I use NOS Bigboy's for 6SN7 and Elrog 845

the downside is $$$$$$$

But I think they last, so make a choice

But again, welcome to Tube Rolling

I had all tube systems for over 50+ years. Two years ago, I found a superior although expensive alternative: Westminster Labs REI mono amps and Quest2 pre-amp.  Solid state Class A that remain on all the time using minimal power and always ready.  Neutral but high resolution, full bodied dynamic sound.  With 96 db speakers, fantastic.  No more tubes or tube rolling or waiting 20 to 45 minutes for warm up either.  

Solid state is great , but I prefer Tubes for now .

I have no problem with warm up time and some  minor tweaking [ check bias , change a tube etc.. ]  It's all part of the process . 

I'm not looking for Neutral , Looking for warmth / emotion .

I have a solid state  set up as well [ Exposure 2510 + ] - it's very nice and probably a bit on the warmer side - to my liking .

@trivema 

If it's a true NOS British made GEC/Genalex B749 it's doubtful any of the tubes you mention would hold a candle to it. If it's a Russian made tube a grilled cheese will outperform it.

@noromance 

"Telefunkens are the best for clean (neutral), airy, transparent sound."

I respectfully disagree. Everyone thinks Telefunkens aer the best for clean (neutral), airy transparent sound. They aren't.

Telefunken makes a bunch of really good tubes and a few great ones. Valvo makes a bunch of really great tubes and a few good ones. Siemens, too. They are the tubes that the people that buy Telefunken think they are buying when they buy Telefunken tubes.

If you aren't familiar with the Valvo Long Plate mC series tubes I reckon you'd find them quite interesting — in a far superior kind of way.

@chickenoregg  Are you suggesting diamond base Telefunkens are made by Seimens and Valvo? Are the Telefunkens I use in 3 phono amps something else? 

They are the tubes that the people that buy Telefunken think they are buying when they buy Telefunken tubes

@noromance 

No. I am not suggesting that at all. 

It is established fact that Siemens produced a great many tubes for Telefunken. They are labelled for Telefunken but do not (in my years of experience in selling tubes) have the diamond on the bottom. They instead have a number embossed in the glass as is characteristic of Siemens made tubes.

But that wasn't my point.

What I am saying is that Telefunken tubes aren't as great as people think they are. They think that when they buy Telefunken they have somehow bought the defacto best tube out there and in one fell swoop dismiss every other tube as inferior, often without ever having heard many (or in some cases any) other tubes out there. The only thing they've heard are people just like them talking about how great Telefunken tubes are. Truth is, if you secretly swapped out their Telefunken diamond on the bottom tubes with some Ei tubes (aka "Fake Telefunkens") hardly any one of them would notice.

I think Telefunken tubes are good. Very good even. Rarely great. Telefunken made three types of 12AX7, 17mm Smooth Long Plate, 17mm Ribbed Long Plate and the frame grid ECC803S; with the latter often being made by Tesla or Siemens under contract for Telefunken. The ECC803S is a great tube. The garden variety Telefunken 17mm plates are very good, but they are not great.

If you look at the number of variations that Valvo and Siemens made for 12AX7 such as the E83CC, E283CC, and the mC series of long plate tubes (e.g. mCp, mC1, mC2, mC3, mC4, mC5, mC6) and then the variations within each of those (for instance Valvo made three types of mC1 tubes alone – 45º Halo Getter (1957), 45º Foil Getter (1956), and Tilted Square Getter (1956-7)) there are dozens and dozens of different tubes that do all the things that Telefunken tubes do and do them better.

And listen, I don't know you, maybe you know all of these other tubes intimately well and still feel that way. I would respect that tremendously. 

In any event its late, I'm tired, and tired also of seeing the same old Telefunken propaganda out there and chose to vent my frustration on a stranger that I am sure has far better things to do then engage with an exhausted, temporarily disgruntled tube dork.

Have a wonderful night.

@chickenoregg  Perhaps I should have been more clear in my recommendation. I meant original Telefunken not the newer stuff. With diamonds–I know of no other. Included in that are those branded Fisher and Dynaco. While I am no expert, I have rolled hundreds of tubes over almost 40 years. I have found Siemens E83CC to have some of the characteristics of the Telefunkens but lacking the dynamics. Indeed my recommendation was in the context of the OP’s post of them being a new roller and may not be in the market for relatively rare and expensive Valvos. However, I do agree Teles are not the pinnacle of the clean and transparent. I use Teles in the regulators but a different tube in the phono amplification stage which has aa the benefits of the Teles but with more finesse. 

Anyone know why there are different getter shapes?

It makes sense for manufacturers to put cheap and available tubes into the gear they market.  The tubes they offer must be common and easily replaceable.  Because not everyone's taste and system characteristics are the same, there is no clear consensus on what constitutes and upgrade, so why should a manufacturer spend extra on fancy tubes that may make the sound "worse" to certain buyers?  This does leave it up to the customer to experiment and hunt for "better" tubes.  A local dealer in my area carries a wide array of vintage and new tubes and customers frequently borrow tubes to try in their gear to find what sounds best.  This dealer offers recommendations based on what the customer says he wants to change about the sound and discourages obsessive tube rolling (this damages tube sockets), but he knows that some swapping and matching may be needed by his customers.

@thecarpathian 

My understanding is that different shaped getters were used to guide/control where the barium patches ended up. I've always though of them like a wine glass that's designed for specific type of wine to maximize how that particular wine hits your nose and tongue; e.g.. like how a Bordeaux glass differs from a Burgundy glass.

They are also indicative of a date of manufacture. But after the vacuum is created during the production process, they really serve no purpose. I have tubes with huge foil getters that broke off at the post were it meets the mica and it rattles around in there like a maraca. They work fine, like more prone to issues down the road, but a tube with a broken getter is far from a horse with a broken leg.

@larryi 

But this starts with the false, outdated presumption that each specific model of whatever piece of gear must have the same tube as every other piece of gear with the same model number. In the age of co-creation where you get to pick the kind of wood you want your amp built with there is no reason you cannot specify also an NOS tube that is to your taste. The manufacturers that embrace this instead of fighting it I think will be better for it.

@noromance 

Let's talk more about tubes we like. I expect we have a lot of overlap.

I also like the Siemens 3-Mica E83CC short plates. I had a quad or two of some long plates that were nice but didn't do much for me.

I very much like the Siemens mC3 and mC5. The mC6 is a bit lush for me. And the mC1 can feel a bit too airy, but has moments of brilliance. 

My two favorite 12AX7 are hands down the Valvo mCn/mCp tubes and the second one isn't even a 12AX7 - it's the GEC A2900.

I don't run 12AX7 much these days, I favor octal tubes with adapters for the most part. The GEC/Osram/Marconi B36 is one of the best values in audio tubes, period.

I just sold my entire system and am rebuilding it around a VAC 200iq that shall soon be two VAC 200iq's. I am currently experiencing the unique torture that is picking new speakers, preamp, and DAC.

The only thing i can tell anybody about "new" Telefunken tubes is that there is no such thing, unless you are referring to Ei tubes, which is 2/3 of a thing.