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[review] Mu-FX (by Mike Beigel) Tru-Tron 3X (by Bieke)

In the beginning of 2013, Bart told me that he discovered that Mike Beigel - founding father and chief designer of Musitronics Corporation -  had filed a couple of trademarks at the USPTO. So the wait began...

A couple of months later Mike announced that he started a new company – Mu-FX™ – and that he was nearly ready to release a first pedal, the Tru-Tron 3X™,an envelope filter, very similar to the original Mu-Tron III he designed about 40 years ago.

Now, the Mu-Tron III was originally meant to be part of a Guild synthesizer, but Guild stopped this project and not much later Mike Beigel formed Musitronics together with former Guild electronics engineer Aaron Newman. They developed a pedal using the Timbre Generator section of the Guild synth, and this became the Mu-Tron III, the first envelope controlled filter pedal. Bob Moog helped to file a patent application.

The Mu-Tron III was a big hit, it was an effect that had many applications, and a lot of talented artists incorporated it into their music, Bootsy Collins used it on bass, Stevie Wonder used it on keys, Jerry Garcia used it on guitar...

Beigel eventually got his patent granted and Musitronics licensed the Mu-tron III circuitry to Univox, Monacor and others in the seventies.

ARP Instruments bought Musitronics in 1979, they continued making the Mu-Tron III until they went out of business about a year later. In the 1990s, there was a "reissue" - the HAZ Mu-Tron III+, but Mike Beigel did not have any connections with this reissue and the circuit was different to that of the original Musitronics Mu-Tron III.

However, in 1995, Mike Beigel teamed up with Electro-Harmonix to recreate the Mu-Tron III and this cooperation resulted in the creation of the infamous Electro-Harmonix Q-Tron.

Jump to 2013, Mike Beigel starts production of the Tru-Tron 3X™ and announces: "The unit, although smaller than its predecessor, the Musitronics Mu-Tron III, is bigger in features and equal or better (my opinion) in sound and versatility.”

This calls for a review.

Mu-FX Tru-Tron 3XThe looks

Well, it looks nothing like the original Mu-Tron III.

It has a light gray casing, which is shaped like the Mu-Tron III, but smaller and much lighter.

Layout of the controls is totally different with 2 control sections on a black background.

Top row is Preamp with two controls labeled Mu and Pre, a mini toggle to select between these and 2 overload indicating LEDs for envelope saturation and audio distort and on the right there is a mini toggle to select up or down envelope drive. 

Bottom row has controls for Peak and a 4 position control for Filter Mode and a toggle to select Hi or Low filter range.

The controls are soft touch pointer knobs, each one with a different colored indicator line, and the settings are white numbers, the higher ranges are in red and upon close inspection, there are red U markings for the Mu and Pre controls, apparently these are to indicate the unity gain setting.

On the top panel, there is a socket for the power supply, the Tru-Tron only works with a 12V AC power supply, and the in- and output are reversed, just like the original Mu-Tron III, so you have your input on the left and output on the right.

A footswitch of course, where you expect to find it, I think it is true bypass switch and an FX status LED, green when the unit is powered and blue when the effect is on.

Mike Beigel is going a production run of 1000 units, the first 100 units are signed by the man himself, and the serial number is hand written on a bit of adhesive copper foil.

No CE or RoHS complaint labels. Who cares ? It is all about the sounds.

So without further ado...

The soundsMu-FX Tru-Tron 3X demos

It sounds just like the Mu-Tron III.

It can also sound just like the EHX Q-Tron.

It can also sound just like the Moog Low Pass filter.

It can do a lot more sounds, very subtle and smooth to very extreme and in our face. I mean ears.

It is quite something, it had endless applications as it can be used on everything, guitar, bass, synths, drums, vocals,...

Really, I cannot describe all the sounds, but it is a very intuitive pedal (at the time I am writing this, there is no manual available yet). Also, since some of the critical components of the original Mu-Tron III are no longer made, it would seem virtually impossible to get that Mu-Tron sound, but with the switch set in "MU" mode, it sounds pretty similar to the Mu-Tron III or the Q-Tron. The MU knob controls the signal gain to the filter and the envelope. The peak knob controls the resonance peak of the filter effect and this one goes to 11, just to say, it has an incredibly wide range.

With the toggle switched to PRE, the MU control still controls the envelope sensitivity, but the audio level to the preamp is then controlled by the PRE knob. In the PRE position, you have independent control of Envelope Drive and audio level. This really opens up the filter effect and gives tons of useful filtered sounds. You can blast the PRE control (it also goes to 11) into distortion territory and then have the filter add more even distortion (into fuzz territory).

The 4 position Filter Mode switch is similar to that of the Q-Tron and selects between lowpass, bandpass, highpass and Mix settings, the latter being a mix of the dry signal and the lowpass filter.

The Envelope Saturation overload LED lights up when the envelope signal shifts into saturation, and it gets brighter and stays lit if the envelope is fully overloaded. If it does not light up, the envelope always follows the shape of the loudness of your instrument signal. This LED responds to the input signal and the setting of the MU control. The red numbers on the dial tell you that almost everything you play will be overloaded.

The Audio Distort overload lights up when the audio signal to the filter hits clipping, the higher you set the MU control, the louder the audio signal gets, and be warned, this pedal can get very loud. If the loudness is boosted so that it distorts, it not only mimics that gnarly sound of the Q-Tron, but it can also produce some sublime filtered distortion sounds, especially in lowpass and bandpass modes.

The Mu/Pre switch at is a huge add-on and it is not to be found on the Mu-Tron III.

If you want the Mu-Tron sound, flick it to MU, if you want to take it to the next level, switch it to Pre.

The Envelope and Audio Level are independent. MU controls the envelope drive and  PRE controls the audio level, so that you can get exactly the envelope drive you want (and the LED lights up on louder notes) and everything else you play will be in the "dynamic filtering" range. And you can set the audio level from clean to distorted.

The verdict

I am a big fan of the EHX Q-Tron. The Q-Tron has its limitations, it is a temperamental envelope filter, it will never sound just like I want it so sound, and it often sounds muffled and gets lost in the mix or just quacks and clips strumming a little too hard. It is a demanding effect.

The original Mu-Tron III is rare and vintage. Sounds great, but even if I had one, I would certainly prefer to use it, but would be reluctant to gig with it. What if it breaks?

Tru-Tron 3X  solves it all. It has far better control and is less finicky as compared to the Q-Tron, it can sound just like the Mu-Tron III and on top of that, it does a lot more. Sounds great on everything, sounds great with dirt in front.
It is perfect. Or wait, nothing is. But this comes very close.