For one, I would like to say that Im EXTREMELY surprised that this pedal doesnt get much recognition on these boards. Well I would like to be the first to bring the Electro Harmonix LPB 2ube the glory and attention it overly deserves. I do believe that this might be one of the best little pedals a bassist can buy thats not looking for a radical change in tone, but to add thickness, beef, and some coveted tube warmth and natural harmonics/dynamics to a Solid State Rig. This pedals core is two stages of 12AX7 Tube gain. It comes with Sovtek 12AX7-WBs in it. Both stages have a drive control and a volume control. The drive control obviously drives the tubes, and the volume is the master for each stage. The LPB 2ube also has an input level switch for high output/low output instruments. HANDS ON: I wanted to make sure that I was getting maximum control over both stages so I ganged them up, and had the output of the left going into the input of the right, and having that output into my amp. This way, you can have full control over both stages gain and master volume. With the option of driving both stages of tubes and having the master volume which can push the next stages gain even more, you have a wonderful pallet of Tubey goodness you can obtain. You can push this as an overdrive pedal in MONO mode and get nice tones from it if thats your desire, but I mind you, you do get a natural compression that Im not fond of. My personal use, Im just using this to add a little thickness, warmth, and wonderful harmonics. (Who doesnt want more harmonics?) I push it pretty hard, but light enough not to get an overdriven sound. Once its set up to that degree, you will hear your tone instantly get fuller, warmer, thicker, and richer over all. You will also notice a nice addition of harmonics and definition that only tubes can offer. It doesnt alter your instruments or amps tone whatsoever either. Thats what I love about this thing the most. Ive tried tube emulators pedals (Tech21, amongst others) and they IMHO totally re-voice your instrument and amp. The LPB 2ube doesnt at all. It just makes everything sound bigger and more dynamic. This is the real deal, real tubes and no emulation. Another wonderful thing about having this pedal is that you can get different 12ax7 tubes, (Groove Tubes, EHX, Sovtek, JJ, Tung-Sol, RCA ect, ect .) and introduce a new sound to your rig each time you switch. Switching out 12ax7s in the LPB 2ube is just another awesome thing about this unit. You can purchase many, there pretty cheep, and see how each have their own signature voice to them and enjoy, all for pretty cheap. Preamp Tubes usually arent much more then $10-$15. If your looking to add warmth, thickness, harmonics, definition and dynamics to your rig, with the option of pushing the gain stages to get a little grit n growl, I recommend trying this pedal.