[Dracule1]

I was interested in these new KT88 tubes from Northern Electric which has carbon plates.

http://www.thetubestore.com/Northern-Electric-KT88

I was told by the distributor they are made by Full Music to higher tolerance than the "standard" Full Music KT88.

However, according to this website, carbon plates drastically reduces tube life.  Need to go about 1/3 down the page to see the reference to Full Music carbon plate tubes.

http://www.jacmusic.com/KT88/kt88.htm


Anyone have any opinions?  According to some, the NE tubes are some of the best sounding KT88 ever made.

http://www.canuckaudiomart.com/forum/viewtopic.php?f=23&t=26891&start=45

[FullRangeMan]

I read on Emission Labs site that Carbon plates are suited for big Triodes only as they run with Thoriated cathodes at 2500ºC.
At this hi temperature the impurities of metals and gases that adhere to graphite are burned and collected by the getter, which does not happen with low temp tubes as 300B and this KT88 you mention.
Oxide cathode tubes run only at 1200ºC which is insufficient to remove the impurities.
The general opinion is for 300B and Pentodes the best sound are metal plates, mainly the mesh plate.

About Chinese grapite plates you may like read the second paragraph:
http://www.jacmusic.com/nos/GM70/
As a user, all you can do is wonder why your 845 tubes develop this whisker noise sounding like "shhhhh...." and it comes and goes.