Mullard E188CC - but with tight bass?

I just digged into tube rolling a bit as my dac (Lab 12 Dac 1 Reference), which is using ECC88s and variants in its output stage, needs a shot of energy and atmosphere.

The stock tubes were 6922 Electro Harmonix. Well, they were okay but nothing special and lacked a precise bass. I changed over to the legendary Amperex bugle boys. My dear, that was an excellent, precise and powerful bass, but the mids were too upfront and I couldn’t relax with them.

Next one was a pair of Siemens E188CC from 1966. Excellent tube, great dynamics, but a bit too cold and lean for my taste and the bass wasn’t as good as from the bugle boys. Finally I now got some RTC E188CC from the early 70ies. Wow, that was the midrange I was missing all the time. Absolutely rich, voluptuous and full of textures. Really amazing, just like the 3D soundstage. The only thing that bothers me is the bass. Again it’s not 100 percent tight and precise enough. Maybe on par with the Siemens but not with Amperex (I have to admit I just used them for 3 days now. Maybe the burn in process will improve the bass but who knows).

So my question is - is there ANY tube out there with such an impressive rich, involving and delicate midrange like the RTC E188CC combined with a tight and precise bass like Amperex? What about the Mullard E188CC - or is it the exact same tube? Valvo, Genalex? Open to anything but I’m not looking out for a compromise regarding the midrange.
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The tightest bass is typically associated with Tele's but you give up some midrange they don't tick all my boxes  You may want to try the Mazda 7308/E188CC from the early 60s.
Digitalviper, I don't think so.. ;] my Abyss 1266 PHI TC already IS a subwoofer and the First Watt F6 dual mono can kick his ass. It's more about fine-tuning. I don't just need a massive bass, it has to be tight!

@tvad Thanks for the link. That's really helpful. What are the exact differences between the mullard you mentioned and the E188cc?

@three easy payments. Yeah that's the trick. Don't want to miss the mullards cozyness in the mids and of course I know this is usually associated with a tubey bass. Is the Mazda as thick and rich as the mullard with a better bass? 
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