I have had one of these for many years. It's powered by a QSC RMX-850. I've tried going back to head/cab, and combo set ups, but I always return to the DB 659.
There may be better preamps available, but this one has to be one of the best. I LOVE the tone. Someone needs to jump on this one. New, they sold for around a grand.
I rarely see them for sale. You won't see mine for sale.
Someone buy this. You won't regret it.