First posting in 12 years

Hi all, I`ve been reading posts , buying and selling on Audiogon for 12 years and this is my first posting because I really need help. I bought a Forte model 40 pre a little while back and the seller told me the person he bought it from replaced the capacitors. Using it in rotation with 3 sets of speakers I`m noticing it`s very bass heavy. Perhaps he used oversized caps? I don`t know. I looked everywhere for a schematic with no luck. I hear Jon Soderberg doesn`t do repairs anymore. Any thoughts? Thanks, tominredbank
Whats the rest of your system?
The rest of the system is a Quad 909 amp. Dahlquist DQ 20 speakers ( noted for being bass shy) and a Rega Apollo CD player with Speltz anti cables and interconnects. Since my post I removed the preamp cover and see what looks like all factory caps ( judging by images I`ve seen online) Elna`s,,,, all 470 uf / 35 volt,,, all 28 of them. Maybe he messed with the power supply.
Also other system I`ve used it on is McCormack 0.5, Arcam dv-27a and Dynaudio audience 42. Tried on Cain Abbys also with better results because they`re so bass challenged to begin with