Marshall Time Modulator 5002 'A' System

An extraordinary piece of kit for sale serviced by us and in superb working order. One of two...

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An extraordinary piece of kit for sale serviced by us and in superb working order. One of two different versions we have available at the time of writing.

Condition of the unit for sale is very good with some signs of age – the usual rack rash and one missing knob cap.

Supplied with a custom power supply built by us that will be set up for either 240 or 120v operation as required.

Inputs and output are via the ¼” jack sockets on the front panel.

Serviced, tested and in full working order.


It took me years to find one for our studio – not many were made, and they don’t come up for sale very often as people tend to hang on to them. Being a modulation freak, it was always high on my wish-list – ours is going nowhere, but this one is available.

Designed in the late seventies by Steven St. Croix, this is a truly legendary effect that represents the pinnacle of analogue circuit design – see below for some of the history of how it began as a bet (really).

Not always the simplest effect to operate – the various delay/phasing/flanging type effects from this analogue rack seem limitless and unlike other modulation/delay racks we’ve used – controls interact in unusual ways and are not necessarily intuitive. It rewards perseverance with some amazing sounds, but treat it with extreme caution and operate at modest volume levels – the levels of feedback that can emanate from this thing can destroy speakers, not to mention your eardrums! 

Our own MTM was used by Reinhold Mack on the recording of Queen’s ‘Another One Bites The Dust’ (not the one for sale here), and I suspect Tony Visconti used one on David Bowie’s late 70s recordings (eg the main ‘Ashes To Ashes’ riff). It’s a very versatile and fabulously-deep box of tricks that will surprise and inspire you: by no means is this just another me-too flanger.. 

Intelligent devices have this to say about it: (they make a Marshall Time Modulator plug in version – find it here)

Before there was much “digital” anything, and before records were considered something anachronistic and nostalgia evoking, back when “Dark Side of the Moon” was new and Hip-Hop kind of a distant dream, Stephen St. Croix had an idea: What would happen if you took the the longest analog delay line possible, gave it the greatest signal to noise ratio in a piece of outboard gear, and then made the modulation of it possible over such a wide range that it could effect sound in ways sublime AND outrageous. Something so utilitarian and necessary that it could fit in equally well on Stevie Wonder’s “Songs in the Key of Life,” or as the means of giving extra gravitas to the sound of a bad acid trip. Stephen called it: The Marshall Time Modulator. You’ll call it “indispensable”. 

From the Studio Electronics Marshall Time Modulator page(they service and supply parts):

The MTM is an analog effects unit that Steve developed in the late 70’s. It doesn’t truly modulate time (you can’t go back and buy Apple stock for $15!) It does however modulate and manipulate audio delay time, producing many unique and amazing effects. The input signal passes through two analog delay lines. The delay time is adjusted by manual control, a wide range LFO circuit, or (for most effects) a combination of the two. Dry and delayed signal are combined, with feedback added to taste.

This simplified description may sound quite dull, but the sounds produced by the MTM are utterly amazing. Effects include positive, negative, and resonant flanges, cardboard tube echo, automatic double (and triple) tracking with pitch and delay dithering, circus vibrato, arpeggio, pitch quantizing, and many more. The MTM was used on many hit records.

In an interview with the Device Newsletter in 1979, Steve said that he developed the very first prototype in 1975, to win a bet. He brought it into a studio to try it out in session, and everyone was blown away. The AES Convention happened to be a few days away, and everyone encouraged Steve to produce a finished demo model and show it, which he did. His booth was mobbed at the AES and the Time Modulator instantly got lots of great press. Initial prototype runs were produced, with early batches going to Stevie Wonder and Sound 80 Studios in Minneapolis. Wrestling with improvements and tweaks, it was another two years or so to before Steve went into production. But when the 5002 Time Modulator was finally released it scored rave reviews in Studio Sound, REP, and Modern Recording, and sales took off.

The 5002 was followed by the 5402, which featured a new control set and greatly extended delay times. Steve also developed the AR-300 Tape Eliminator, which simulated delay at various tape “speeds”. It included a tape-like EQ curve and natural sounding tape compression — just like the boxes released today. Of course, he beat all the new guys to it, by 20 years or so!

It’s worth repeating that these were analog boxes, totally free of quantization noise and other digital artifacts. The MTM had a signal to noise ratio of 95 db! This was an amazing and unheard of feat, that most modern gear still can’t equal. Steve was a real perfectionist.


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