The Carl Martin Bass Drive is a great sounding tube (12AX7) overdrive that can be set from clean to heavily overdriven tones. With its treble, middle & bass controls, it allows you to dial in the exact clean or overdriven tone that you want. I upgraded this one with a vintage RCA 7025 (a low noise 12AX7A equivalent) and, IMO, it sounds A LOT better than the stock chinese Ruby tube that it came with. It is in MINT condition with its original box, manual and AC power cord. These have street price of $280 with the chinese tube, and vintage RCA tubes sell for $40-$80 alone. I will also ship it with the original tube if you'd like.
