What a pre-amp! You can use this two (or more!) ways. First, stick it straight into the power amp section of your amp via the FX loop, bypassing the internal pre-amp, and enjoy it's delights. Secondly, use the emulated output straight to a PA and forget about lugging your amp in the first place... your back will love it. These have quite the reputation for being an exceptionally warm and articulate high-gain metal distortion, but it's equally at home on the crunch or clean settings. Могучий звук!

Model: AMT SS-20 Guitar Pre-Amp
Made: Russia, recent model
Type: dual channel pre-amp
Power: 12v negative supply, 1.25A, power supply included, 12AX7 valve 
Equivalent new street price (approx): $549aud
Mods: velcro added
Accessories: non-original box, power supply included (Australia 240v)
Condition notes: used, few very minor marks, very good condition