As New Two Rock Bi-Onyx 50 watt guitar amp head. Currently running EL34 tubes. Has the ability to switch to 6L6 Tubes with switch flip on the back PLUS re biasing for tube change. Very flexible as you have separate Volume/Gain, Treble, Middle, Bass, Master, Channel Boost, Reverb and Contour FOR EACH CHANNEL! Hence the name Bi-Onyx. Never switch channels to a volume or tone you don't like. You set them separate and independent. A channel switcher dream amp! Great Reverb on each channel (independent). Great Effects loop (Send/return). Very loud 50W head with footswitch to control channels and separate boost settings for each clean and lead channels. These amps are built like tanks! Can run 2 separate cabs at multiple impedance choices. This amp with EL34's LOVES 4x12 cabs. Very articulate. Can do a John Mayer clean tone and even more so with tubes changed to 6L6. My starting bid is less than half the new price. Go to Two dash Rock dot com for manual download. No low feedback bidders! Shipping only to US Continental 48 States. Paypal only. No Returns! No part Strippers!. Bid with Confidence! Amp will ship as soon as funds transfer to my paypal account. See my feedback! Get an incredible deal on this boutique amp now! Location: Round Rock Texas.