Sunn Beta preamp too loud

[Guzz]

http://tagboardeffects.blogspot.com/2016/03/sunn-beta-preamp.html

Hi there, so after building two of these (one without the master daughter board and one with) I've had the same issue twice, it is way too loud. It's WAY past unity when any of the level/master pots are more than a quarter of the way up, after that it's not realistically playable. It is in fact so loud that it can drive a 12 inch speaker on its own.

Is there anything I can do to tame it down?

Thanks.