Ruby, as Groove Tubes, doesn't manufacture tubes...they buy tubes that are available directly from the manufacturer, test them, and put their brand name on them.
Ruby sells SEDs, Sovteks, JJs and other brands....so comparing a pair of JJ E34Ls to a pair of Rubys could be comparing the same tubes.
Each of Ruby's products has an alphabetic suffic which denotes the country of origin. This can help sort out what you're actually getting.
Ruby, as Groove Tubes, doesn't manufacture tubes...they buy tubes that are available directly from the manufacturer, test them, and put their brand name on them.
Ruby sells SEDs, Sovteks, JJs and other brands....so comparing a pair of JJ E34Ls to a pair of Rubys could be comparing the same tubes.
Each of Ruby's products has an alphabetic suffic which denotes the country of origin. This can help sort out what you're actually getting.