Vintage amp needs some mods

[Don Borro]

I bought an ELKA trz 20 for very only 240 euro. Its a full tibe amp with 2 EL84 and 3 12AX7, also 2 reverb tubes. First thing I wanne do to the amp is make it to have more bottom end en the biggest problem: the gain! I think It doenst have a good natural overdrive and I whant to have some more gain out of it when fully cranked and cleaner at volume 6. The EQ also needs some tweaking. Any help? its an nice amp from 1967