Stax SRD-7 transformer box question

[dlaloum]

Hi folks,
 
I have an SRD7 (unknown vintage) on the way to me from Japan...
 
Just wondering how I can tell whether it is multi-voltage or 100/110V only... 
 
I believe that some of the jp units were labeled only 100V but were in fact multi-voltage.
 
Any help appreciated
 
thanks
 
David

 

[scott16]

I got a Stax SRD7SB (self biasing) and its very good I love it with my standard bias Stax Sigmas
but with the Lambda Pros the sound is about 1/2 as loud as it should be (the bass is fine it's just the volume isn't as loud as it should be)
 
Is there some way to modify it  to add a Pro Bias side to it?