Muir Audio Design's Silicon Steel Output Transformer Overdrive is a distinctly unique Silky Smooth Saturating Overdrive with exceptional dynamics
The two things about the Silicon Steel Overdrive that immediately presented themselves for me were just how beautifully smooth and sustaining the core tonality and texture of this pedal are - and how superb its dynamics and guitar volume gain cleanup are in particular. In fact it’s near Boss BD-2 levels of gain roll-off where you can go from fully saturated to near enough clean with a deft flick of your guitar volume knob. And similar to the BD-2 - with the guitar volume set just right your pick attack can really impact the nature of the output where softer playing yields cleaner outputs, and then you can dig in when you need more!
As I was playing the pedal for the first time - the smooth lilting tones of Carlos Santana came immediately to mind - in particular the key melody heard on the song Europa! And I imagined how great a demo Alberto Barrero or Bjørn Riis could make with this pedal - there deft and nuanced style of playing would be just perfect for this Silicon Steel - all those names popped instantly into my head as a reaction to what I was hearing.
There’s a lot about this circuit which is fairly conventional in the nature of its construction - while the finer calibration here and the interplay between certain key elements of the circuit are what make this overdrive so special.
There are essentially 3 distinct but overlapping gain generating elements here, the core Opamp, the twin silicon clipping diodes, and the orange-shell-covered high-fidelity audio output transformer. So as you crank up the Drive knob - the circuit dynamically blends gain generation between opamp, diodes and the beautifully saturating output transformer. You have a total gain range of around +30dB from minimum to maximum settings.
The ’Silicon Steel’ moniker is derived from the metallurgical composition of the coil of the transformer - which particular formulation generates more magnetic resonance. The pedal could also have been called ’Satin Steel’ - for that matter - specially formulated silky smooth steel panels used in high grade automotive manufacture - as that is so indicative of the core tonality and textural characteristics / nature of this pedal!
Controls - Level, Drive, Bass, Treble.
Engineer Colin Muir paid particular attention to how the pedal saturates and how the circuit progressively hands over gain duties to the output transformer. While the 2-Band EQ was another area which had a major focus on getting the calibration just right - such that you have the perfect centre-frequencies and sweet spots for the Bass and Treble controls - to deliver really precise Mids profiles also - with highly complementary Mids Boost and Scoop - when you dial the two controls up or down in tandem - so not only can you accentuate the Low and High frequencies, but the Mids also!
Similarly to exactly how the output transformer saturation works, the precise calibration of the tone-stack (and its centre frequencies) will remain a trade secret - where both those elements took a lot of engineering focus in order to combine so beautifully and expansively.
When listening to typical Carlos Santana recorded tones - his upper register is really quite bright - so the Treble here should be fairly elevated when attempting such - near max in many scenarios to achieve those sparkly highs - while the Bass is so potent that I typically have that dialled back at around 9 o'c. Note that I play almost exclusively humbucker guitars where there is plenty of range on all the dials here to accommodate all styles of pickup and guitar.
In fact my core settings for this pedal are mostly with Level and Drive at Max, Bass at 9 o'c or thereabouts, and Treble between 3 o'c and 5 o'c. I slightly over-egg the settings for my ideal preferred maximum extent - and then dial back the guitar volume to reach the appropriate level of gain / saturation. The nature of the saturation adds a really elegant sustain to the output.
As I mentioned at the start - you really have BD-2 levels of gain cleanup here - so you can go from a very potent Mid Gain saturation to near clean - with a sort of quarter twist of your guitar volume knob.
Everything about this pedal softly screams next level quality - from the neat symmetry of the circuit internals / arrangement and elegant transformer cover, to the gorgeous silver sparkle enclosure with its Colin Muir custom-designed knobs - whose markers have been hand-inlaid with resin / enamel.
And all this next level engineering prowess is yours for just £199 and equivalent - which is a very fair price for such a precision engineered device. Every part of this overdrive pedal has superior levels of attention to detail. And in a sea of mostly cloned overdrives this is distinct and out there on its own merits. Available right now from the Muir Audio Design Webstore.
However good the early demos are, I'm not sure they do full justice to the glorious core tonality and character of this pedal - I'd really want to see what Alberto Barrero, Bjørn Riis or even the great man himself - Carlos Santana could do with this pedal - were we able to prise him away from his Las Vegas House of Blues residency for just a moment or two.
This is a rare one more overdrive that is definitely worth checking out - particularly if you're a fan of smooth sustaining saturated overdrive tones and any of the artists mentioned here!
Demos
