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Newproduction power tubes: Reliablity

There  isa topic going on  concerning power tube issues in his PL amp, 
Some of us have power amps with 4-12 power tubes,,  the higher number of the tubes in a amp means the more demand for  reliability.
The 2 countries making  the most power tubes are china and russsia, So basically we can say this is a Russia vs China shootout.

China has come out with incredible numbers of power tubes, varieties and styles. These are the SET tubes. Russia has a  far superior selection in the push pull category.
IMHO , as i do have a  push pull amp, I favor the russian labs as far as reliability. 
Here is where it counts, As we know, its no fun having a   multiple power tube amp, and hearing 1 or more tubes going bad. 
A  good tech is not cheap, nor so easy to locate.
So in terms of reliability/push pull, I have to side with the russian labs.
The one exception on russian power tube relaibility, is the russian KT150,, its a new tube and we have not yet had long term performance testing. It is  not a tube I am the least bit interested in. 
. 

mozartfan

Showing 2 responses by johnss

johnss
564 posts
 
@mozartfan, This is quite the post. I have bought dozens and dozens and dozens of both Russian and Chinese made power tubes (mostly KT88s, but also many others). China has come a long way in their power tube reliability issues of previous years. Today's Chinese made tubes are much better than those of 5-10 + years ago.  Would still say the Russians are better for long term reliability. Have had to replace fewer of them in my amps over months of use.

As for sonic qualities, the best sounding most organic output tube is the Shuguang Western electric Plus series (WEKT88; same series available in  6CA7. 300B, 845,. etc); This tube family blows everything else into the weeds sonically.

But the reliability on these shuguang tubes is not as good as the  Russian made tubes (GL KT88 for example). So if you are going to run Chinese tubes, need to stock up on lots of spares, but you will get a nice sonic improvement by doing so. 

The Shuguang factory is in the process of moving so only real option for chinese tubes today is PSVANE, which are also good. Check out their KT88 gray glass tubes.  

From the Russian side, the GL KT8s are my favorite. do not sound as natural as the Chinese Shuguang WE varieties but are more reliable, and last longer.

For input tubes, really hard to be the PSVANE T-II 12A_7 series. They are reliable and sound exceptionally good.

for 6SN7 types, the Shuguang WE variety tops all, even NOS types.

best

johnss
564 posts
 
have not tried the JJ KT88s or svetlanas, so can't offer any opinion on them. But have tried dozens each of  the electro harmonix KT88 and 6550, the Mullard KT88, and Tungsol 6550 all from Russia. All are pretty reliable, have some sonic differences, Mullards are a bit warmer sounding, EH KT88 a bit more open, etc. The Tungsol re-issue 6550s sound pretty close to the original US made Tungols.

The Shuguang factory has done their homework on plate and cathode construction materials and now understands how these affect the sound of the valve. Shuguang used to make the PSVANE tubes, but now PSVANE has their own factory so is making their own valves.

If you like the sound of the GL KT88s, you may want to try the PSVANE gray glass KT88s, more open, and detailed than the GLs, but will not last as long.

Should also state my amps are not stock. All have Jensen copper foil caps installed in the coupling caps and power supply locations, which also will affect the sonic attributes of the TUT (tubes under test).



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