All of these are guitar preamps with effects. The Profex is older, I don't know anything about it. The Profex 2, Bassfex, Tubefex and Transtubefex are all capable of having the "Newman Presets" loaded into the the user banks of 127 settings.
I do not know how Jeff accumilated all the settings from different steel players (including Hughey's settings), but they are a wonderful piece of work. You can buy many preamp processors on the market and spend countless hours trying to put together your own settings for steel guitar or guitar. Most processors have "Factory Settings" that are virtually useless to anyone except the rock and roll, grunge, rap markets, etc.
The Profex 2 and Bassfex are identical units, except for the logo and factory presets. All the units have a card slot for a PCMCIA type card to load presets. All units have midi ports for sending and receiving data. I use an older Peavey Midi-Filer, one rack space unit, to load and save settings. I can buy one of these for about the price of a card and I have limitless amounts of files I can then put on a 3.5" floppy. Both these units have a volume control (hands on type) for input and output levels.
The Tubefex was the next newer device and the Trantubefex was the last of this family to be made. They offer an optional preamp of the tube type (2 each 12AX7 in the Tubefex) or "Transtube Technology". They have their preamp volumes set via "Global Commands" using the buttons and cursors on the front of the unit. The tube or Transtube preamp effect can be added to any setting and adjusted on the fly with the fronts knobs (input, low, mids, treble, output). Both these units offer a built in chromatic tuner. In my opinion, the tuners do not work well, tend to freeze up, etc. Version 2.0 fixed this problem and is worth the money spent just to get the tuner up to par. Both these units have balanced XLR outputs for a mixer. The Transtube offers an output selection pot for "Speaker Cabinet Simulator" that affects the XLR outputs only.
The Transtube also has an excellent headphone output as well as an input for CD player or other line level device.
I hope that helps a bit.[This message was edited by Ken Fox on 27 October 2002 at 08:59 AM.]