Today the Sylvania 6CB6As arrived:
I did a quick A/B with my GEC CV4014s and yes, these Sylvanias seem to have the same level of gain as the EF91s. I think the GEC's bass is a bit bigger, but not by much, and the GEC's upper midrange is a bit brighter. However, I find these Sylvanias very balanced and musical. I think it is great to finally have a good selection of cheap tubes available that can be used with the EF91/2 settings.
Oh.. The blue line you see on the tube is some kind of reflection. It is not on the tube itself.
Great, this is getting interesting! So, would you say these sound somewhat like a higher gain CV4015 (balanced and musical, but maybe a bit more punchy)? Out of curiosity, did you order any other brands too? Any date code on these, just to get a feeling of what time period they were made in?
Acapella, yes you understood what I'm trying to do here. I will make my MK IV drive orthos properly, whether it wants to or not! Well, at least I'll try... Since there is no doubt my CV4015 just aren't giving enough power to the power tubes in my amp to drive HE-500 correctly (I get all the nice OTL perks, holographic soundstage, dynamics and liquidity, but I can tell the bass is just not keeping up like it was even on the HD650 or even the HE-400). Whereas, my GEC CV4014 seem to be *just* enough to drive the HE-500 to maybe 80-90% of what it can do, and still has all the OTL goodness.
Anyway, interesting endeavors. I feel a whole dimension just opened before me.