Olmsted Quad Direct Input Amplifier (Quad DI)

Download the specs/user-guide for the Olmsted Quad DI:

DOWNLOAD: Olmsted Quad Direct Inject

Let’s say that you have many vintage keyboards with weak output levels and often with high (10k ohm or above) output impedance.  You’d want to bring them up to modern operating levels and a low source impedance, and maybe to be able to color the sound with some grit.  Based on these parameters, here is what I developed.

The Quad DI provides up to 40db of all-tube gain with a 10db output pad to allow for either clean reproduction or heavy distortion.  The distortion is thick and smooth and has potential application for everything from electric bass to Rhodes piano to synth leads and even mix stems.  The cathode-follower output and hefty output transformers provide very solid bass; at +10 output levels bass response is absolutely flat down to 20hz. This is an all-tube unit, all the way back to the rectifier tube.  The only silicon devices are a handful of diodes in the input-stage heater-supply.  The power supply also features dual chokes, a feature of some very high-end hifi equipment which rarely (if ever?) makes it into pro audio gear.

The unit has 1/4″ TS inputs on the rear panel along with XLR outputs; the inputs are reproduced on the front panel with priority jacks:  I.E, you can keep the rear inputs permanently connected to a patchbay or a synth collection, and the front panel inputs will automatically disable the corresponding rear panel input if, say, you plug in a bass guitar to do a quick overdub.

I found this to be a very interesting piece to develop because it seems to synthesize several notable trends in modern music in one device.  First of all, the desire to be able to add grit/fuzz/overdrive to the sort of instruments that were considered best left ‘clean’ for many decades.  Sure, guitar amps have boasted of ‘overdrive channels’ since the mid seventies; but keyboard amps?  Not until recently.  Second, the prevalence of keyboards/synths in rock music in general:  not done some much in the Grunge era, back in a big way now, especially since bands like Animal Collective became the  standard-bearers of Indie.  Next, the console-less pro studio!  Not a big surprise there.  You can’t give consoles away anymore.  And, finally, lest-i-get-too-meta, the current widespread cultural appreciation of all things handmade + crafted, especially those that function through obsolete or antique technologies.  Could a similarly-functioning apparatus be strung together for the same price out of a pile of Chinese-made prosumer audio gear?  Probably.  But it probably wouldn’t sound this good or function this ergonomically.  And definitely not at 375 volts.