10 db or 20 db attenuator?

I hooked up a Transporter direct to an Ayre amp and getting too much signal at the low end of the dial.  I've got this in the bedroom so want to be able to play low volume.  It looks like an attenuation device might do the trick.  Was thinking of trying a balanced rothwell, and I can get either -10dB or -20dB.  Would like to buy correctly the first time.  Would anyone happen to know given the pieces above which version might work best for me?  Thanks