Looking for a softer tube

Mullard 12au7 "box plate", without a doubt.

NOS RCA 12au 7 Black top or clear top will work, and they are not as expensive as Mullards. I also believe their softer. In no way am I knocking Mullards, just differentiating.

You might try a 6211 if you can find them. It's a lower gain 12AT7. I'm also with the Mullard guys as far as finding them to be warm.

Hi all ! Telefunken smooth plates are , well , smooth sounding . Or , I have great success by going with Jim McShane's advice .

Siemen e82cc/12au7. It has a vivid and clear midrange. Excellent dynamics and a controlled top end. Check Upscale Audio for exact description.

I will be selling my backup MQ in platinum grade that I no longer need and was purchased from Upscale.

BTW, Philips e88cc SQ is one of my favorite tubes.