News:

Forum may be experiencing issues.

Main Menu

02.01.13 - Zero Point Micro BOM change

Started by madbean, February 01, 2013, 10:52:51 PM

Previous topic - Next topic

madbean

While I was doing by final tweaking before boxing up, I realized that the straight through signal on the delay has too much of a boost to it. The input/output stages of the Micro are different than the other Zero Points (and most PT2399 delays). It's non-inverted, with an input buffer and an output mixer. I did it this way because it saved three parts on the PCB which was critical to fitting everything in.

It's not terribly noticeable at low volumes, but when you start cranking up your amp, there's too much of a jump...probably 5 or 6 db. So, these modified values will bring the input signal much closer to the bypass.

Change R3 to 100k and R4 to 4k7.

Two other notes: an external type DC jack will make this build much easier. I used one and fitting everything in was actually very easy. Remember to use enough length on your wired pots so that you can install them before fitting the PCB into the enclosure.

http://www.smallbearelec.com/servlet/Detail?no=666

Lastly, I set mine up with always on modulation and a Rate pot. I used 68k for R18 and 220k for R19. As I mention in the build doc, these two resistors should be experimented with and you will likely pick different values according to how you set up the modulation (fixed depth and/or rate, variable rate or depth, etc). Those are the values I though worked well when using a Rate pot.


madbean

I've also revised the PDF to include the text posted above.

My apologies on the last minute change. Lesson learned - test all builds and multiple volume levels, not just the one you are used to.