First off, welcome to the board, Pat.
 
I have experienced a similar voltage / performance issues with other devices. Fuzz units in particular seem to be sensitive to this.
 
I have also found that the Bass Driver Deluxe produces a fairly high output - high enough to overdrive the power amp of a traditional bass amp (when used in the effects return jack) or the power amp used for a PA system or powered monitor.
 
Dialing in a strong (but not too strong) output signal is key to optimizing its performance.

I would also check into the Eden WTDI. Great tone from a crazy small DI and built like a tank. If you're using effects, the Zoom B3 is an interesting option to consider as well. It's got a good DI plus amp/cab simulations and several types of EQ.

Coop I agree about the Zoom B3, I pre programmed mine for each song in the set list as according to how it sounds live. It's a great piece of kit with so many applications, DI, looper, recording interface, cab & amp simulators. Although some people say it's not as good as Boss/Roland stuff it is actually much more versatile and switches faster.

A friend has a REDDI available for $500.
http://www.adesignsaudio.com/reddi-all-tube-direct-box.htm

great quote on REDDI website
 
The exceptional brightness of the LED was intentionally provided for easy visual confirmation that the REDDI is powered on, and also to temporarily blind annoying A&R reps lingering in the control room.