Yes, I built The Queen May Treble Booster - featured at generalguitargadgets.com - it certainly boosted the treble, but there was a lot of hiss and hum, however I discovered that I was getting other hum problems when recording - due to my Amp being too close to my computer - unfortunately I sabotaged the treble booster as I needed the box and the input jacks to move the Amp.
I intend to rebuild the Queen May and hope that a lot of the hum has now gone ?