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Projects => Tech Help - Projects Page => Topic started by: sdb guitars on February 11, 2013, 11:25:39 PM

Title: Question about adding tone control to Sea Urchin
Post by: sdb guitars on February 11, 2013, 11:25:39 PM
I have an old Danelectro Dan-Echo that has what appears to be a tone control that affects only the wet signal...  turn it up to have echoes more like the original signal, roll it back to remove high frequencies from the repeats for a more analog/tape echo sound.

Is there any way to implement such a thing with the Sea urchin?  Replace a resistor with a pot, etc.? I would love to experiment with different values, provided I knew which resistor/capacitor sets were the ones applying the filtering to the wet signal.

Any input would be appreciated.

Thanks,

Shawn.
Title: Re: Question about adding tone control to Sea Urchin
Post by: madbean on February 12, 2013, 02:12:20 AM
Try this:

Replace R16 with a 5kB pot. Wire one pad to lug 3 and the other to lug 1. Solder a 220R resistor b/w lugs 3 and 2 on the pot.

When the pot is all the way down, you have approximately 220R of resistance with the 47n cap (c15) forming a low pass filter with a frequency of 15.4Khz. When the pot is all the way up, you have about 5k of resistance creating a corner frequency of 667Hz. So, it essentially "cuts" the highs.

This should give a very wide tonal range on the repeats.
Title: Re: Question about adding tone control to Sea Urchin
Post by: sdb guitars on February 12, 2013, 03:14:05 AM
Sweet... thanks, Brian!
Title: Re: Question about adding tone control to Sea Urchin
Post by: CK1 on May 20, 2013, 04:07:48 AM
Oooh, might try this, too.  Thanks, Brian!