aion CHROMA Manual - Page 6

Browse online or download pdf Manual for Music Pedal aion CHROMA. aion CHROMA 11 pages. Based on boss sp-1 spectrum

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BUILD NOTES, CONT.

Setting the gain trimmer

According to the SP-1 service manual, the Gain trimmer should be set as follows:

Test signal: 5KHz +/- 10% sine, -20dBm, set SPECTRUM, BALANCE at max (FCW), adjust trimmer

pot 1K for 2.5dBm output at peaking freq. (5KHz +/-10%)

Follow the process if you want, but it's definitely overkill and an effect this simple does not need that

kind of precision. We couldn't hear much difference across the whole sweep of the trimmer, but it would

be most noticeable at full clockwise (wet) on the Balance control. You might be able to make its impact

more pronounced by raising the value of R7.

IC selection

The original SP-1 used the Raytheon RC3403A "ground-sensing" quad op-amp. Raytheon hasn't

manufactured analog components in several decades, and originals are scarce today—but fortunately

the New Japan Radio NJM3403A is an exact substitute and still in production.

CHROMA PARAMETRIC BOOST