I have this amp I took off a guy a year ago and was wondering if you guys could answer a few questions for me. I'm doing some research on it now. The amp is a Challenger series. Model CHA 10. Series J-39. I can't tell exactly who it is made by because of some slight cosmetic damage, but it looks like it says "David Bogen Co. Paramus N.J." I can't find a date on the thing, but I know it is very old. I'm not sure if the tubes are original or not, but they are as follows: (1) RCA 6L6GB, (1) Sylvania 6AU6, (1) Ratheon 6AV6, and (1) RCA 6BW4/EZ81. The 6AU6 and 6AV6 are both shielded. I'm guessing its close to 25 watts because of the one 6L6 and it looks like someone tampered/replaced a midi in for a microphone. It has a tone knob with settings "Deep Bass, Mellow, Crisp, Brilliant." Do you guys think that with some minor ajustments it could become a small practice bass amp?