Mad Bean Pedals Aquababy, Manual

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Aquababy
FX TYPE: Delay
Based on the Boss® Dm-2™
The Aquababy is nearly identical to the Aquaboy project, but shrunk down to fit in a 1590B enclosure. This is a good proj -
ect if you want an analog delay in the smallest enclosure possible, or if you just want a new challenge. This project does
compromise from its counterpart in that it requires 1/8W resistors and wired pots.
It is possible to include modulation on the Aquababy...if you are a total DIY masochist!
Controls
MIX – The ratio of delay vs. clean signal.
FDBK – The number of delay repeats. Maximum FDBK setting will induce self-oscillation.
Delay – Delay time from slap-back to about 300ms.
Bias – Used to set the proper bias on the input of the MN3005 for it to produce clean delay.
Cancel
– Sets the mix of the two delay outputs on the MN3005.
Clock – Sets the correct clock frequency range produced by the MN3101 to drive the BBD delay lines in the MN3005
Calibration
Make the following adjustments before beginning:
Mix control at center.
Delay at max position.
FDBK at about 1/3 up.
BIAS and Cancel trimpots to their center position.
If you have frequency measurement on your DMM, adjust the Clock trimmer to about 6.5kHz while probing either pin2 or pin4 of IC5. If you don’t have
this feature set the Clock trim half-way up (note: this is when using a 9v supply).
Audio probe pin3 of IC3 while either strumming the guitar or send some audio through the input of the circuit. Adjust the
BIAS trimmer until you get delay passing. The range over which the trimmer will result in delay is usually about 1/4 to 1/6
of its entire rotation. Continue refining the position of BIAS until you get the smallest amount of distortion on the delay
signal. Now probe pin4 of IC3 to confirm it is also passing delay. If it does not, make sure that you have clock frequency
on both pins 2 and 6.
Now finely adjust the CLOCK trimmer until just before you hear any high pitch whine in the audio path. This is the maxi -
mum delay setting. The clock frequency should land somewhere between 6 and 7 kHz.
Unless you are using an oscilloscope to calibrate the delay, leave the Cancel trim in the center position.
Terms of Use: You are free to use purchased Aquababy circuit boards for both DIY and small commercial operations. You may not
offer
Aquababy
PCBs for resale or as part of a “kit” in a commercial fashion. Peer to peer re-sale is fine, though.