Yesterday night Norman was at my place and we had a small tube rolling session with my newly arrived GG2.5 (as we named it - and Norm can maybe explain this better).
Tubes we rolled were Elrog 300b, KR242, RK 300b and for the sake of fun National Union 45.
Firstly I have to mention, due to the fact that I was "suffering" with high output voltage with my previous GG overdriving my preamp, this thing is in the new DAC solved to the extent that with each different tube type output gain is almost the same, so for example inserting famously high gain 242 we still had to play it on almost the same level as for example 300b or 45 which for me is something I was looking for. Recti tube we used was RK 5u4g.
I can easily say that all tubes had their own magic and for non I can say that it sounded as crap in this particular GG as for the opposite in several other GGs for example Elrog 300b sounded really really bad.
45s had a great mids and were shining in vocals while LFs were a bit wobbly and undefined. Overall extension in HF was not really top notch but still it as very pleasant tube for low volume late night listening sessions.
300b - Elrog splendid performer in all domains, huge soundstage, precise deep bass, extended HF, very nice layering and portraying the performers. RK - same comments as for Elrog but a bit more forward sounding tube and also maybe a bit tighter and extended LF.
242 - I was expecting miracles to be honest (despite the fact that in Norms GG it sounds nervous I would say due to gain mismatch, while in Chris GG and now Demo Pacific it sounds sublime) and was close to it but still not that far from both 300b. It is super dynamic, surgically precise, extended in both directions and creating a grand staging.
To sum up I can live with all 4 of them more than happily and it is just the matter of the mood, which one will plugged in, at the particular time of day/month. I can not avoid taking into account visual effect of all of those 4 as 242 and 45 look rather pathetic vs both RK and Elrog 300b and I take also this into account when plugging in the tubes as I personally enjoy looking at my gear
and especially tubes.