Shuguang EL34B
Electro Harmonix EL34
Reissue MULLARD EL34
Reissue Gold Lion KT88
Treasures 6ca7-z
Ei KT90 (Not in production)
Groove Tube EL34m , 6CA7(no longer listed on groove tube webpage).
First i have to say i have tested or listen to the above tube either in my own system, friends or in dealer system and not the result is not conclusive.
I would categories them under 2 batch distinctively by the origin of the tube.
I found even with the claim of different design I still find the sound characteristic is almost the same.
The first batch will be from China Shuguang that are more tonally pleasant but with bloated bass and sound “dirty” at the high.
This category of power tube is more suitable for small speaker or speaker with tight bass.In my system base on ls3/5a, i tends to favour this group.
This including the:
Treasures > GT 6CA7 = > GT EL34m(1ST BATCH) => SHUGUANG EL34B
The second category will be from Russia.The sound is thin withn tight bass.Full range or big speaker tends to favour this group of power ube.
I also put the EI kt90 under this category as the sound is much closer to this category:
Ei > Gold Lion => mullard > EH
> BETTER
=> EQUAVALENT OR BETTER.
I found that more better i rank is usually improve on the dynamic and sound less "dirty".
This might lead to improve imagimg , soundstage and etc.Tonality is usually the same even with the claim of different design.
KLau