Build and Sound Report: The Crank boost

[bipedal]

Just finished Mark Hammer's 'The Crank' circuit, using gaussmarkov's layout.  Point-to-point wiring (I haven't messed with etching yet), it worked right away, though I  mistakenly wired the dual-ganged pot in reverse -- easy to diagnose and fix.  Used 100k for the dual-gang pot, with 12k resistors soldered on to bring max resistance of the pot to about 10.7k.

I may be suffering from Builder's Bias (i.e. I built it, so of course it sounds cool as heck), but this pedal sounds cool as heck.  It has tons of output - noticeably more than what my TS-9-modded-to-808 puts out.

The grit added by turning up The Crank's Gain control ramps up very smoothly to my ears, and it's a full, "warm" grit throughout the range -- my Tube Screamer suddenly sounds quite nasal in comparison.  IMO the gain portion of The Crank's circuit creates plenty of gritty distortion as the control turns clockwise, though it's certainly not a metal or fuzz sort of saturation on its own.  Also, there seems to be minimal output change as the Gain control moves throughout its range; in other words, I can dial the Gain/grit up or down without having to adjust the Volume control significanly to retain the same perceived output level -- great! 

I had considered adding an SWTC into this circuit, but I wanted to preserve maximum output level, and after finishing the initial circuit I didn't really find a tone control necessary.  I play a Strat and Tele into an Ampeg 2x12 Reverberocket 50 watt, which is a fairly "loose" and mid-rangey amp, and the Crank adds a bit of pleasing crispness and definition to the upper ranges of the signal while retaining a full bottom end -- the result is a more lively tone through the amp's clean and dirty channels.  Any necessary tweaking of the high ranges is easily accomplished by rolling back my guitar's tone control a notch.

This one will definitely stick on my pedal board, probably to be left on at all times.  Thanks for a great circuit!

- Jay

[John Lyons]

Nice review there, thanks for taking the time to post it. I'd like to build this one as well.

John

[Mark Hammer]

Aw shucks.  Thanks for the thumbs up.

For me, the multiplicative-gain aspect is key to this baby.  In two ways: a) the retention of maximum bandwidth, and b) the smoothness of perceived gain change.  I'm wondering if the dual-stage/dual-pot strategy couldn't be productively applied to a discrete circuit like a pair of cascaded JFET stages.

[markm]

I had considered adding an SWTC into this circuit, but I wanted to preserve maximum output level, and after finishing the initial circuit I didn't really find a tone control necessary. 

I have a layout of this that incorporates the tone control into this circuit. Works really well and doesn't effect the gain.
Also, I made a "juiced" version on the Crank that is a real Hi-Gainer that may be appealing to the "harder" crowd here that
uses the same tone control as well......the tone control was Very Necessary in the high gain circuit!

[Ben N]

Very nice informative review, Jay. Thanks.
Ben