Originally Posted by CoiL
Sharing some impressions with tubes. HP`s used for listening test: Superlux HD-681 (mkII filter) & HD-662F (custom filter)
I like this tube very much and if you don`t bother to mess with tubes, then its good to go as "stock". It has wide spacious soundstage. Well spread out instruments and easy to concentrate on details. Great sence of air. Has more highs and bass depth/reverb than 6N23P. Great tube for towards "fun" sounding HP`s like HD-681 for longer music listening sessions.
Great with different genres but better for electronic music.
Amperex ECC88/6DJ8 (1969, GAC, large dimple disc getter on a single leg support, NOS)
Similiar to 6922EH. Both have wide soundstage, airy sound, very well spread out instruments and easy to concentrate on certain details/instruments. Amperex has less highs and bass is more tight, making it littlebit less airy. More life in mids, bringing vocals more into "sight". I personally find this tube better for rock/metal than 6922EH but sounds great with different genres and is good also good with flat sounding HP`s.
6N23P (Reflektor logo, from Mike @ rockgrotto)
Has narrower soundstage than tubes mentioned before and instruments are less separated. Less air, space and more foward sounding. Good tube for flat sounding monitoring cans. Personally I prefer Amperex with HD-662F for music listening. For studio monitoring 6N23P is propably better.
Brimar ECC88/6DJ8 (late 70´, round large halo getter, "cinemascope" logo)
Not good with Aune T1. It is quite bright and narrow sounding, dry, no liveness, bass is lost.
Tungsram PCC88/7DJ8 (1972, made in Hungary, NOS)
This tube is very similiar to 6922EH. It is hard to compare those 2 and find differences. All I could figure out with my ears is that both tubes have exactly the same soundstage, space and instrument separation.
With 6922EH there is tinybit more bright top-end and thus makes 6922EH only fraction more airy/detail.
Bass is littlebit more punchy and tighter on Tungsram but again, only a fraction.
Atm, for me, it`s the best tube for HD-681 (mkII).
Overall, for me, the best tube for different genres & cans is Tungsram PCC88/7DJ8.
Will make more comparing between Amperex and Tungsram later.
Also ordered one Tesla PCC88/7DJ8 (NOS, Yellow 32 Factory Code for Tesla Rožnov n.p. Závod Vrchlabí plant)
Will update soon.