I have been using a groovetubes brick for bass DI and also for getting some sweet guitar sounds when recording miked vox ac30 in my home studio. But I cant get the thing to brake up and give me some nice tube distortion when recording bass. This must be because it only has input gain nob and not output like a UA solo610 for example. Is there anyway to get round this? - pads? - swapping the tubes? -running into another preamp?