Boss 14-Pin OD-1 Clone
The Boss OD-1 clone shown below was made purely to satisfy my own curiosity. There is a lot of mystique surrounding the early 14-pin version, and I wanted to hear one again for myself (I bought one new from the ‘Sound Centre’ in Cardiff when they first came out in the late seventies, so there is a certain sepia-tinted nostalgia involved here).
I distinctly remember handing over £42 at the time, which is about £165 at today’s prices. How times have changed – the OD-1 has long been absent from the Boss catalogue, but one can still purchase a modern SD-1 for £42, or maybe even less. It has to be said that the new product lacks the rough-finished charm of the early units, though.
Originals are now collector’s items, and tend to be even more expensive than when new, so I had a go at building one. It’s accurate even to the extent of having the momentary-action LED and ACA adaptor setup, which some might say is just a little too accurate!
Open up and say ‘Ah!’
There seems to be a great deal of misinformation posted on the internet regarding the 14-pin OD-1, and the best way to modify a later version OD-1 to sound just like it. Contrary to popular wisdom, it is not sufficient to just replace certain capacitor values in the eight pin version to convert it to 14-pin specs, since most of the capacitors to be replaced form High Pass Filters, along with their corresponding resistors. In order to preserve the correct frequency response, both the caps and resistors must be replaced with the correct values. The net effect of this is a unit with a similar frequency response, but lower impedances at various points in the circuit, including at the input (220k as opposed to 470k).
The enclosure I used for this project started life as an SD-1 Super Overdrive. The tone control was removed, the resulting hole filled with car body filler and the enclosure re-painted to resemble the OD-1 (I never did care for that insipid lemon-colour paint Boss chose for the SD-1). A new ‘B’ version PCB was etched and a modern Texas Instruments MC3403N quad op-amp fitted. The original potentiometers, sockets, wiring, and LED were kept. For the sake of accuracy I used NOS Hitachi 1S1588 diodes for the clipping circuit, although I’m not sure I can hear a difference compared to ordinary 1N4148′s or 1N914′s (Edit: To be honest, I am pretty sure I can’t hear a difference!).
The pedal sounds great, and is quite a bit less noisy than my real 1980 8-pin OD-1. The two pedals sound much more similar to one another than some would have you believe – especially those attempting to sell the earlier version on Ebay for vastly inflated prices!
Steve Giles, March 2012
The other pedals featured on this page are a Rangemaster clone built with many NOS parts for a collector in the USA, and a re-issue Fender Blender with added LED indicators.
OC71 Rangemaster
Fender Blender with status indicator LED’s added