I also have VTL 2.5 preamp and find it difficult to replace below a certain price point. As others suggested, if you are going for SS preamp, then better be prepared to spend more to get better sound compared to the VTL 2.5. What tubes are you using? Hera are a few suggestions that might help you to get more out of your VTL 2.51. Try Amperex Bugle Boy 12AT7 and 12AU7 (Holland). You get deep and tight bass, do wonders to the voices, and extended highs2. Alternatively, RCA 12AU7A ECC82 clear Top
"D" Getter also give excellent results.
3. If you haven't done already, may be it is time to cleanup the contact points of the tree knobs used for source selection, balance and volume control. With age, they begin to make poor contacts and will require some cleaning. Use DeoxIT D5 or similar product. Please do not use WD-40. This will also improve your sound.
Hope this helps to keep VTL 2.5 until you find a suitable replacement.
3. If you haven't done already, may be it is time to cleanup the contact points of the tree knobs used for source selection, balance and volume control. With age, they begin to make poor contacts and will require some cleaning. Use DeoxIT D5 or similar product. Please do not use WD-40. This will also improve your sound.
Hope this helps to keep VTL 2.5 until you find a suitable replacement.