2. amps-preamps
  3. 195077-47456

I changed a Tube and…

I liked it!
 Have a Rogue Audio Cronos mag lll bought it years ago as original Cronos Mag  sent it in last year for the upgrade to lll .  Never changed any of the original tubes .

The amp was lightly used due to my changing amps like regularly. Decided to stick with Cronos and and have really enjoyed it . 
Playing vinyl for the majority of time and seem satisfied with Triode mode .  Amp runs perfectly no noise at all but thought about all the threads regarding tube rolling  especially the center 12au7 . 
pulled out the stock JJ and found a Genalex  Gold Lion ECC82/B749 (12au7)  bought them 7-8 years ago .  
Put the GL into center position and was thinking “am I going to really hear a difference “???   Figured I listen to a few LPs and maybe I’d notice something different good or bad Maybe ? after all it’s just one tiny tube !

Well I was blown away !, 30 seconds in listening to “two of a mind “ Desmond /Muliligan  things just got a whole lot more musical 🎶. Hard to describe everything seemed improved , midrange was wow ! Soundstage was better , etc .

Went to another familiar favorite Grant Green “ Idle Moments “   Oh yes the magic is here too 

Is this even possible or am I under a placebo delusion  lol 

Now I’m really wondering what about the other 2  12au7’s  and even the 2 -12ax7’s

what else am I missing ? 

 

 

 

mfm22
atmasphere's avatar
atmasphere
12,138 posts
 

@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!

larsman's avatar
larsman
2,357 posts
 

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. 

knotscott's avatar
knotscott
1,136 posts
 

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.

mfm22 OP
39 posts
 

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. 

 

buellrider97's avatar
buellrider97
618 posts
 

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. 

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