I'm not all that happy with my Ampeg SVP-Pro lately. I think I've just grown out of the tone it delivers which to me seems more distoreted and thinner than what I want at this time. Sure it's great for some stuff where you want a good grind. I've had this pre for about 2 years and I'm still happy with the veriability in tone - which is why I bought it. I used to use a Hartke 3500 head, but went to a QSC2450 for power. For a short time I used the Hartke as a preamp...I really loved the tone. Very thick and clean. No distortion clear across the spectrum. I sold that off though and got the SVP-Pro to save some weight. I've noticed that now my sound to me just seems dirty. The drive channel is turned all the way off but I still get grungy sound. I experimented. I ran the DI from my practice amp (Hartke Kickback 12) into on channel to use it as a pre amp. I tried both channels that way _ one with a BagEnd S15B-D and the other with a BagEnd D10B-D. I really loved the tone. Super juicy, thick, clear (only I had no EQ since it's running from the DI to the amp). I realized my cabs are fine and my amp is fine. I'm not sure if my Pre is bad, but I'm certainly not happy with the overall tone. I was trying other pre's before I bought this one. I really liked the tone I got from a TraceElliot V-type and Warwick Quadruplet. I also recently used a Demeter (model?) through basically the same rig otherwise and loved that too. I'm wondering if I can get any benefit by replacing the tubes in the pre. I really like the controls on the SVP-Pro, I felt I got more tonal variety at a lower cost than the others I tried out. Any advice? I play jazzy rock.