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Should I upgrade my Tubes

I have a Rogue Audio Magnum II which is 100 Watts per channel paired with Vandersteen Treo CT speakers. My tubes seem to be shot as suddenly I get no amplification (just very low level audio). The 4 power tubes are TUNG-SOL KT120. I have been reading about getting "better" tubes but every discussion seems to get into "depends how you like the sound" types of comments similar to every other audio component - LOL.

So what's a man do ?
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oldhvymec
5,101 posts
 
Check them at least, ay. Do you have a way, or know someone?

It will also tell you how much is still there, and when you might need to change them, or at least be looking for some good replacements.

Panic buying is no fun, over a valve. A spare or two is never a bad idea,
and you really don't want to let them FAIL, before replacing...
It can cause more than a valve to fail.. ok...

The Tubes, what a crazy band.... :-)

Regards
rodman99999
6,159 posts
 
An easy, more noticeable (generally) and less expensive way to enter the tube-tasting whirlpool, than swapping power tubes: a change of the preamp tube.      There are a number of nicer 12AU7/ECC82 tubes, that will change the Cronus’ presentation.        Mention your tastes to any of the tube mongers I’ve listed.      They can easily guide you to sonic bliss (kinda flowery, but- yeah).      Some opinions, here: http://hktubeaudio.homestead.com/files/best_of_the_best_12au7.htm      One nice thing; many of the better NOS, nine-pins are rated for 10K hours.       That tube will need to be tested/certified for low noise.      Any good seller will know that and provide such.
readheads OP
6 posts
 
After some research and calling Nick at Rogue Audio, he told me that the biggest impact will be by tube rolling the center (of 5) preamp tube 12AU7. He mentioned the Mullard 12AU7 NOS made in England for the military. Anyone have experience with it ?
rodman99999
6,159 posts
 
http://www.audiotubes.com/12au7.htm
ronrags's avatar
ronrags
281 posts
 
readheads,

I agree with Nick at Rogue that tube rolling the center with a Mullard 12AU7 NOS will give you the biggest impact since that is what I’m using on my Magnum 3. Great detail, bass and quite smooth without any edgy brightness. Call Andy at Vintage tubes and he’ll be more than helpful plus he tests every tube he sells. The 12AU7 should cost around $120.


I also purchased my Magnum 3 with Golden Lion KT77s instead of the standard KT120. The KT77s are a great all around tube and will cost around $200 for the quad. The KT77s also need to be biased at 25 to 30 instead of 35 for the KT120. I found no sound difference setting it at 25 which makes the tubes last longer.
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