2. amps-preamps
  3. 1210026207

Is upgrading stock tubes standard proceedure?

I'm just wondering if I'm the last guy to realize just how enormous an improvement can be had by upgrading stock tubes to NOS. Most of my system has been in place for some time now and I've sought to improve it's performance by tweaking. Tube changes have resulted in noticeable but subtle results; most of the time involving trade-offs... until now. I just upgraded the 6922s in my cj Premier 17LS to Amperex 6DJ8s with stunning results. I can't find any trade-offs, everything desirable in audio is improved IMHO. This is the kind of improvement I would have been looking for if I bought a new preamp and spent twice the money. As much as I've read about tube rolling, based on what I'm experiencing now, there isn't enough emphasis, especially by professional reviewers.

So, I guess my purpose in writing this thread is two fold:

1) Why don't tubes receive at least the same attention as the equipment they're in.

2) Just a heads-up in case there is anyone else out there who thinks they can't justify $100 or more for a small tube.
phaelon
audiofeil
4,011 posts
 
A few hours, perhaps 10, at the most.

Dave Mitchell posted the following and he is spot on. It is quite excellent in its explanation:

07-26-07: Davemitchell
The answer depends upon whether you are referring to the tubes themselves or an entire tube-based circuit.

First, lets clarify that the popular term burn-in really refers to forming dielectrics. This is where electrons find and groove a path of least resistance through the insulation materials surrounding the conductors. Dielectrics (teflon, polyethylene, glass epoxy boards, etc...) act as an impediments or road blocks to the free flow of a signal.

The actual vacuum tubes themselves require little or no burn-in because they have so little dielectric material to form in the first place. The conducting elements are surrounded primarily by a nearly perfect vacuum, which is a superior dielectric to all others including air.

Tube circuits like all circuits which contain capacitors, resistors, wire and circuit traces, require significant burn-in because all of those passive parts contain all kinds of plastic dielectrics which need to form to sound best.
jmo
115 posts
 
Thanks a lot this is very good info.
jmo
115 posts
 
The NOS Mullards 12AX7 just awakened my sleeping giant, my VTL 7.5 preamp never sound so good.
jmo
115 posts
 

I just purchased another set of NOS Mullards 12AX7 & (1) GE 5751 for the phono stage of my CJ PV-12. With all of the recent modifications I had completed to the phono stage the CJ will rock even more. :O)
unclejeff
1,313 posts
 
While it is true that McIntosh amps don't show as much improvement when changing power cords, I beg to differ on tubes.

My McIntosh 2102 amps do embrace NOS tubes and yes it does show...perhaps not as much as with my Audio Aero Capitole amp, but anyone still running the stock Chinese Tubes with this amp needs to go shopping for NOS.
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