Randall MTS RM50/RM100

For the gotta-have-more tube amp lover
For the gotta-have-more tube amp lover

After trying to get together for several years, in 2002, tube amp guru Bruce Egnater officially joined forces with Randall Amplification. The result? Randall’s MTS guitar amps!

With its interchangeable all-tube preamp modules, the MTS line is essentially “amp modeling” done the old-fashioned way. Using one of three chassis designs and Randall’s 14 preamp modules, one can achieve most any tone.

Flagship of the line is the RM4, a two-space rackmount frame with tube-buffered series/parallel effects loop that holds four preamp modules. It’s mated with the RT2/50 power amp that features two channels – one with a pair of Ruby Tubes 6L6s, and the other with a pair of Ruby EL34s – as well as individual volume, presence, and density controls on each channel. Channels on the RT2/50 are MIDI footswitchable between the pairs of power tubes.

Next in the line is the RM100, a three-module/100-watt head that features four Ruby 6L6s, MIDI footswitch, master volume, presence and density controls, and series/parallel effects loop with a mix control.

The combos feature room for two modules, single-button footswitches, master volume, presence and density controls, and the same effects loop. The bigger of the two is the RM80, which has two Ruby 6550s producing 80 watts through two 12″ Celestion G12T-75 speakers. The smaller combo (which we tested) has two Ruby 6L6s producing 50 watts through a single Celestion G12T-75 speaker.

The modules slide in and out of the chassis on nylon rails and are held in place with knurled thumbscrews. Swapping them out takes about 30 seconds (most of which is spent waiting for the amp to go into standby). A contact strip at the back of each module slips into a port in the chassis, which eliminates fumbling with multi-pin connectors.

We plugged several modules into the RM100 running through a Celestion-loaded Randall 4×12″ cab. All MTS amps feature adjustable power-tube bias and fuse protection for the power tubes, as well as high-quality transformers, components, and Baltic birch plywood cabinets (excluding the RM4). And all MTS amps have three preamp tubes that are not part of the modules; one is a phase inverter, one buffers the effects loop, and one runs the input.

Cosmetically, the MTS combos have a clean, simple look, with black tolex and metal corners, with anodized black knobs and highly polished chrome faceplates on the modules. The modules include four “California-flavored” units – Tweed, Blackface, DLX, and Recto. U.K.-style modules include the SL+, Plexi, Top Boost, and JTM. With a little imagination, you can decipher the tones these modules are chasing. The Ultra, Ultra Lead, and Modern modules cover the heavier/high-gain U.S. sounds.

Finally, the Brown and Clean modules cover everything the others don’t. All modules use the same controls – gain, master volume, bright switch, and controls for bass, middle and treble. Each module has a pair of 12AX7 preamp tubes, some Ruby, others Electro-Harmonix. Randall encourages the user to try different preamp tubes, i.e. 12AT7s in the California modules for less gain, and a more vintage tone.

To test the modules, we used a ’59 Fender Esquire, an early-’80s Ibanez Artist with Wolftone pickups (VG “Gear Reviews,” August ’03) and a Strings-n-Things classic single-cut.

To keep it interesting, we grouped the modules by flavor, with the appropriate guitar(s), i.e. Tweed, Blackface, an DLX with the Esquire and the Strings-n-Things, while the Plexi, SL+, and JTM were teamed with the Ibanez. And to ensure we were hearing exactly what the preamp modules were doing, we limited our adjustment of the chassis’ presence and density controls.

We got rolling by installing the Blackface and Tweed modules, and plugging in the Esquire. Straight away, we were pleased; the amp offered a nice, round low-end and crisp high-end for which vintage SoCal amps are famous. The Blackface stayed pristinely clean and crisp with a big, wide-open sound, while the Tweed had a tighter, slightly darker tone with more mids that we were able to overdrive without having the tone get mushy. The Tweed also produced plenty of musical overtones that gave the preamp more attack and note clarity without getting harsh.

Swapping the Deluxe for the Blackface, it was immediately apparent that it fit right in the middle, tone-wise, with the added mids and drive of the Tweed module. But it retained the “open” quality of the Blackface.

The Recto definitely offered the most aggressive of the California-style modules, with plenty of crunchy overdrive and smooth midrange. The bright switch added noticeable life to the tone, without getting buzzy.

Switching to the Ibanez and popping in the Plexi and JTM modules, we started checking out the U.K. flavors.

The Plexi offered a very tight, focused sound with a lot of sustain and punchy mids, while the JTM’s tone was more loose, with the mids pulled back just a touch. When we pushed it hard, the JTM did get a bit mushy on the low-end, while the Plexi stayed tight and punchy, even with the gain cranked.

We swapped out the JTM for the SL+ and found it also very focused and tight-sounding, but with considerably more usable gain. In fact, with the gain cranked, the SL+ sustained nicely as it rolled into sweet musical feedback! The only downside compared to the Plexi module was that it did lose some of the clarity and note separation.

Our final U.K.-style modules were the Top Boost and Brown, which fit somewhere between the Plexi and the SL+. Both retained good note separation like the Plexi, but had more sustain and overdrive, like the SL+. The Brown was like a hot-rodded version of the Plexi, while the Top Boost had a more loose, somewhat “trashier” sound.

Using the Ibanez, we checked out the Modern, Ultra, and Ultra Lead modules , in both the RM50 combo and the RM100 head with the Randall 4×12″ cab. These three are definitely for hard rock and metal, with gobs of gain, thumpy lows, and sizzling highs – just enough of that trashy sound to make it fun! All had similar gain characteristics, but with obvious individuality. We ran the Plexi in the RM100 through the 4×12″ cab with a Fender American Strat, and it produced a great “Smoke On The Water” tone with lots of singing sustain and crunchy highs that cleaned up nicely when we rolled back the guitar’s volume knob.

Last up was the Clean module, which for the most part had a flat response; a good platform to add without over-coloring the tone.

An especially pleasant feature with the RM4 chassis and the RM100 head is the MIDI channel switching. This makes it easy to incorporate into a larger rig with a MIDI footswitch for controlling other processing, instead of having separate footswitches.

The Randall MTS 50 combo is extremely versatile, and each module has a distinct, high-quality sound, accurate to the classic from which it was inspired. And, as versatile as the combo is, one can surmise that with the RM4, a handful of modules, the RT2/50 power amp, and a couple cabinets, one would have a very satisfying rig for either studio or stage.

Randall MTS Guitar Amplifiers
Type of amp All-tube chassis with preamp modules.
Features Interchangeable tube-driven preamp modules, Accutronics spring reverb, Ruby Tubes 6L6s, parallel and series effects loops, Celestion G12T-75 12″ speaker.
Price $699 to $1,299 for the amps, $249 for each module (retail).
Contact Randall Amplifiers, 444 East Courtland Street, Mundelein, IL 60060, phone 800-877-6863, www.randallamplifiers.com.

This article originally appeared in VG‘s June ’04 issue. All copyrights are by the author and Vintage Guitar magazine. Unauthorized replication or use is strictly prohibited.

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