Rogue amps-- try 5751 instead of 12ax7

On my M180s I was using an RCA 5751 and RCA clear tops in the 12AU7 position. That combination worked great with my monitor speakers. I later went to larger, 3-way speakers and it didn't sound good. I replaced the 5751 with a Telefunken 12AX7 ribbed plate and the improvment in dynamics was incredibly better. I subsequently put Telefunken ribbed plates in the 12AU7 positions and the clarity of the system has been greatly improved.

When I originally went with the 5751's I chose them over a Telefunken 12AX7 smooth plate. With the monitor speakers I had at the time I liked the 5751 better, but with the change in my system the all Telefunken set is working really well. That's just my experience with my system.

Sebastien1 - yes realized you were interested in the KT77s not the 88s was just trying to give you a sense of a possible alternative based upon what I'm hearing when comparing the 2 KT88s - enjoy!

Hi Facten,

Just to make it clear, I was talking about KT77 not KT88. KT77 are an exact equivalent of the EL34. I have no experience regarding Genalex KT88.

Since you suggest me the Shuguang Black Treasures El34, I'll consider them and maybe give them a try someday.

Sébastien

I use GE triple mica black plate 5751's and made a big difference in my Tempest II. The Sovtek 12AX7's sounded fuzzy and the GE's sound much more focused and clear.

Here's a copy of what I posted a little while back concerning my "tube swapping" for my Rogie Audio Cronus. Mark and Nick at Rogue have always been extremely helpful. My system makes beautiful music.......
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04-03-11: Adam18

For me, my Cronus, being fed by my Rega P3-24/Exact 2/TTPSU and Rotel RCD-1072, through my Vandersteens, sounds better after I did the following : an RCA NOS 5814 to replace the center EH 12AU7 gain stage tube, a pair of GE NOS Five Star 5751 "goldpins" to replace the Sovtek 12AX7 input tubes, and a pair of GE NOS 12AU7A's to replace the EH 12AU7 driver tubes. I then replaced the original Svetlana EL-34's with a beautiful matched quad of Genelex Gold Lion KT-77's.

All this "tube rolling" was done after some pretty nice conversations with Mark and Nick at Rogue Audio, and I'm glad I followed their advice. They are a pleasure to work with.
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So, Dhcod..... I'm glad you're enjoying your Atlas. Happy Listening !

I am going to try kt 120s on my rogue m180s next, I have gold lion 12au7s and 12ax7s on the way from rogue , should have them in a couple of weeks, but I was interested in the kt77s, what do they sound like? has anyone compared kt77s vrs kt120s? thanks, Chris

I have used both RCA and sylvania 5751's in my Rogue M-180 with Golden Lion KT-88 reissues for several years to good effect. The GL KT-88 are getting a little long in the tooth, i might have to try the Shuguang Black Treasures,

The 5751 is a well-known sub for the 12AX7 that works in MOST circuits. My experience is that the 3 mica black plate versions are the best of the bunch. My favorites are the early RCAs and GEs that have silver clips (looks kind of like braces) on the ends of the plates. Highly recommended!

Use NOS Tungsol 5751s in my Cronus Magnum

Sebastien, take this for what it's worth as I am not partial to EL34s,I recently swapped GL KT88s out of my Ayon Spirit for Shuguang Black Treasures - to my ears they take the music up a few notches, more detail & dynamic -prior to these I found the GLs the best KT88s I used. There's a Black Treasure version of the EL34 , haven't heard it, but if it is as good as their KT88 it might be something to keep in mind at some point if you're interested

On my side, I've received one week ago a pair of GE 5751 1960's (grey plate, triple mica, 5 stars). I placed them in my Cronus instead of the 12AX7 and they are wonderful. Surprisingly, it adds an improvement on bass. Plus, voices are beautifully separated when there are back vocals. All in all, these tubes are very musical and I don't hear any of the bad things that some say about NOS tubes.

Another thing, on the suggestion of Mark O'Brien at Rogue, I replaced the EL34 by KT77's Genalex Gold Lion reedition. Just a big WOW !

Enjoy your sound,

SÉbastien

I use them in my Tempest II Magnum with outstanding results.