I have nothing but praise for this little wonder- Duesenberg's Gold Boost. A good clean booster, which has a gain focus, should not affect volume once it's in use. If this is the case, the increase in volume influences the gain/ drive structure you hear over at your amp. The GB does all this without colouring the final output of your amp's driven/ distorted voicing- it preserves the frequency response between your guitar & the amp. If there are any such tamperings, then I didn't hear them, which is a good thing isn't it? But it's a little pricey... please refer to Musicark for the GB's exact retail price.
My thanks to brother Firdaus (aka SicBarney) for the excellent customer service- salute!
