Finally circled back to giving this a shot. Seems that like most things, there was a few issues here.
Initially, moving to parallel and only using 1 channel didn't help, and it was shutting off more frequently than I remember, and this was at bedroom volumes. Kind of made me wonder about the preamp, and I recalled that I never had this issue when I used a VT-Bass pedal as a preamp.
Gave a shot to using the -20db function of the preamp, and that appear to have cleared up the issue. I guess the preamp just hit the input too hard.
Again, sincere thanks to you all. Looking forward to putting it through its paces this week at practice!
The non-DSP versions of the Prolite 2.0 and 3.0 (I had a 2.0 for awhile) are more sensitive than a lot of racked poweramps -- they are easy to drive (don't require that much juice) from a preamp to reach full power (the 3.0 requires only 0.74 volts from the preamp when driving a 4 Ohm load).
Datasheet:
User manual Crest Audio Pro-LITE 3.0 (English - 40 pages)
This matches up pretty well with a lot of bass instrument pres, actually, though some can put out a good deal more juice depending on how hard you hit them.
The manual for the SVT IIP says it'll put out "1 Volt RMS maximum, 3.5 V RMS with EQ." (EQ is just another frequency-limited gain stage.)
I don't know what that looks like with peaks or what other factors might influence its output (aside from the input signal and how you EQ it), but it looks capable of clipping the front-end of the Pro-Lite without too much trouble. I also don't know if clipping the front end of the 3.0 is enough to shut it down or merely make ugly clipping sounds.
If the -20 dB pad for the balanced output on the back helps, by all means use it. You can also play around with gain-staging between the first volume control, the +/- 10 dB on the graphic EQ, and the attenuators on the Pro-Lite to see what gives you the best results (best sound, S/N ratio, dynamic response).
Non-bridged, with proper gain-staging, running 800 or 900 watts off a side into a 4 Ohm load, though, the 3.0
should be able to drive either of your 4 Ohm cabs (810 or 8x8) to its limits. 100 Hz HPF on the back of the amp (2nd order, per datasheet -- should be 12 dB/octave, not 24) would typically be employed for tops/subs, not a stand-alone bass cab (pretty high for that).
Again, I don't know how the amp behaves if you simply hit the front end too hard (that it was shutting down at bedroom volumes and then stopped when you engaged the 20 dB pad on the pre is suggestive). Have you tried the unbalanced outputs? It might be that, with your bass and EQ settings, you don't have to turn the preamp master up very high at all to drive the power amp to full power.
Good luck at practice this week -- hope it works well for you and that some simple gain-staging is enough to sort it out!
If the amp is still shutting down, you might have other issues. (Worth making sure that the fans are running well and unobstructed.)
