2. amps-preamps
  3. 166963-33693

Preamp tubes in power amps

I’ve had tube gear for a decade but never, until recently, looked into how it functions or how to optimize it. So, my basic question is, my Rogue Magnum M-120 monoblocks have their power tubes, and then also a couple of 12AU7s and one 12AX7.

Would replacing those with NOS higher end tubes like a Seimens or a Mullard have much benefit?

Or would my tube budget be better spent replacing the new production 6922s in my BAT VK-3i with some higher end NOS tubes?

I figure I can’t afford to replace the power tubes until they die. But looking to see where the best bang for the buck would be on the preamp tube side of the equation.

Thanks to all who answer the actual question!
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decooney
1,973 posts
 
@jji666 
Read the 2nd paragraph about Upscale and 7DJ8s in the Vk-3i preamp. Seems like staffers there might not be on the same level as uncle Kevvy.   
https://www.audioshark.org/balanced-audio-technology-bat-38/tube-noob-seeking-education-11051.html#p...

Agree with others, give Brent Jesse a call, and see what he might have in stock. Start with preamp tubes first, for sure. Then, after they are broken in, try input tubes in the amp next. Another tip, I have multiple pairs of super matched curve-tracer balance tested tubes from Brent for my amps.  While they have a deeper sound stage in some cases, I've been having some luck with the latest PSVANE MKII or Art Series 12Au7, and same with friends using the 12Ax7s from PSVANE fwiw.  A little more midrange/forward with them but they sound nice for new production tubes. Best of luck. 
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jji666 OP
536 posts
 
Thanks everyone for their feedback.

Regarding the above comments, I suspect that their concern about the VK-3i actually came from my experience.  That happened nearly 10 years ago and so I assume that Upscale Audio has updated their information regarding the BAT preamp because of my tube losses. I think I have those EH tubes in my preamp now - so it's interesting to note that AFTER I had issues they issue advice to avoid my pain.

That said, it also looks like, based on the Audioshark forum, that another user of the VK-3i has also discovered that it is a bit more sensitive with tubes than other preamps.

So, must consider what to do here.  I did like the sound of the National 7DJ8s and the Philips 7DJ8s before they were ruined -  a little mellower on the top -- but I would also not be happy to find out that my VK-3i destroya $500 worth of NOS 6922s...
boomerbillone
355 posts
 
The Telefunken 12AX7 is really superb as the front end input tube. It lights up very brightly when it is powered on and scares the heck out of you; but it sounds amazing.
hshifi
572 posts
 
Hello,
I really like Rogue products. My suggestion would be to call Rogue and ask for Nick or Mark who is the owner. They really helped me out when I demoed the 180 darks and I needed to bias them since they probably don’t leave the store a lot due to their size and cost. Also, FYI. Do not use ceramic fuses. They do not recommend them for the tube fuses. I also denied the RP7 preamp. Very nice also fully balanced like the 180 darks. This is the store in the Chicagoland area where I get some of my gear. https://holmaudio.com/
Very nice guys. 
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