Well, I'll give you some... advice
First is the Ampeg preamp pedals. Should work fine with a clean amp like the TC, or if you bypass the head's preamp.
Next, Tech21 Sansamp VT. I believe it was designed to give that SVT type sound. It's also a DI pedal, very handy.
Another option is a multi-effect unit. The Zoom B1 Four has an Ampeg SVT sim (and other amp sims), along lots of other effects (preamps, chorus, octave, distortions, reverb, delay, cab sims etc), a looper, and a tuner. It's cheap, easy to program, and far more versatile than the preamp pedals. My guess is it will have the least accurate SVT reproduction, but probably good enough for a cafe or bar where no one really cares.
The above might fit your budget with the TC BAM200.
Last but not least, find a used Ampeg head.
Thank you - greatly appreciated.