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DIY Stompboxes => Digital & DSP => Topic started by: runmikeyrun on October 14, 2018, 10:51:45 PM

Title: High pitched whine from my TC Hall of Fame mini
Post by: runmikeyrun on October 14, 2018, 10:51:45 PM
Hi all,

I picked up a TC Electronics Hall of Fame mini reverb and it has a high pitched whine.  In the past (with analog pedals) ive changed the power filter cap and the whine is fixed.  No such luck this time.

I connected it to the computer and downloaded a new patch and no issues.  You can hear the effect, there's just a whine along with it. 

Any thoughts?  Can I do a hard reset or something on this pedal?
Title: Re: High pitched whine from my TC Hall of Fame mini
Post by: SonaMagna on October 17, 2018, 01:50:54 PM
Hi,

Whine is sometimes generated by the digital electronics in an effect pedal.  The PedalSnake website has some good info about how to remedy whine using isolated power supplies.  See https://www.pedalsnake.com/blog/2016/09/dealing-digital-whine/

The prototypes of a pedal I designed (9 in 1 Drive - analog audio with digital control -  see https://reverb.com/item/10910777-sonamagna-9-in-1-analog-drive-overdrive-distortion-fuzz-metal-eq-boost-midi ) had a whine issue which I fixed by adding an extra 100uF filter capacitor to the input of the 3.3V regulator which powers the digital ICs (see image).  The latest design uses a surface mount cap (no cut-and-wires).

If you can post a schematic of the pedal, or some high res images of the circuit board(s), I may be able to help you identify the regulator(s).

Best Regards,
Rich
SonaMagna
   



(https://i.postimg.cc/4nrwPpVW/whine-eliminator-filter-cap-mod-sm.jpg) (https://postimg.cc/4nrwPpVW)