The Ultimate Rack and Recording Tool! Randall Amplifiers and legendary amp guru Bruce Egnater have joined forces in designing the MTS series. Introducing the RM4 modular tube preamp, the first edition of the new MTS series, with more modular products on the way. Now you can change your amp tone as often as you like, simply by plugging in your choice of any of the 13 available tube preamp modules. This 4-channel preamp gives all the flexibility of any digital modeling amp, but does it with all-tube circuitry, based on the original circuit specifications. The RM4 also allows you to hot swap, and customize any combination of the 13 classic to modern real tube tones. Set up your rig with any range of sounds from the classic country tone of a Fender® Deluxe, to full out metal tone with the new Ultra. No longer do you have to dream of having your ultimate collection of tube amps, it's all available with the RM4 modular all-tube preamp.