Too bad about all these active basses with super hot outputs. It seems a lot of folks have issues with too much gain from them going into their amps; I could easily live without the input pad on my Tone Hammer 500. I have yet to get the amp to light it's clip indicator no matter how hard I play my basses, all great sounding passive instruments, and I have never gotten anywhere close to cranking the amp it is so loud.
Can you reduce the gain, internally, of the Spector preamp (or, just turn the volume control down on it)? The Tone Hammer preamp pedal and the Tone Hammer 500 have pretty much identical front ends (barring the superior Drive function of the amp vs. the AGC circuit in the pedal) so I am surprised you find the sound that different between them. What are you currently running the pedal into for power?