Aion Electronics Andromeda Nobels ODR-1 Natural Overdrive Manual

Andromeda
Nobels ODR-1 Natural Overdrive
Overview
Controls & Usage
• Gain controls the amount of gain from the op amp that is fed through the feedback clipping diodes.
• Level is the output level of the effect.
• Bass allows you to adjust the bass response of the circuit. The stock ODR-1 circuit is the equivalent of
having the Bass knob turned all the way up.
• Spectrum is a very non-standard tone control of sorts. You can pan between a 700 Hz lowpass filter and
a 5 KHz high-pass filter, which is mixed with a fixed 2.1 MHz frequency boost (upper mids). This control
is much more complex than your standard hi-cut or Tube Screamer style tone control.
Modifications
This is a tight layout, so you won't find any of the "standard" Aion modifications such as a
clipping diode switch. However, there are extra pads for the hard clipping diodes (D4 and D5)
in case you want to stack two diodes in series—for instance, two 1N914s or one 1N914 and
one BAT41 on each side. This will reduce the hard clipping of the circuit and result in a less
compressed sound and more output volume.
Note that D4 and D5 are not labeled on the PCB due to the extra pads. They are located
below D2 and D3 and are oriented as shown to the right.
The Bass knob is an addition to this circuit, and while you can omit this control and use the alternate Spectrum
orientation for a symmetrical control layout, I don't recommend it—as mentioned earlier, the main criticism of
this circuit is that it has too much bass.
Any other standard-pinout dual op-amps will work in this circuit as well. Try a TL072 or OPA2104.
Like a Tube Screamer, you can adjust R7 + C4 and R8 + C5 to change the gain structure and the low-end
rolloff frequency.
NOBELS ODR-1 OVERDRIVE / ANDROMEDA OVERDRIVE
The Andromeda Overdrive is a clone of the Nobels ODR-1, a
somewhat obscure pedal from Germany that nonetheless is
considered a "secret weapon" among Nashville studio musicians.
The primary complaint of the ODR-1 is that it has way too much
bass with no way to dial it out. To that end, this PCB project
incorporates a variable bass control inspired by the Timmy and
Zen Drive. The stock tones are still there with the knob all the
way up, but now you have the option to turn it down.
Looking at the schematic, you can see a stark difference with
Japanese-designed pedals (i.e. most Ibanez & Boss circuits).
This is German engineering at its finest—tons of odd-value
resistors and capacitors forming very precise filters and signal
shaping. This is not a particularly simple build, but it's very
rewarding and well worth the effort.
Andromeda Project Link
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