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Quick question about the ROG Tri-vibe

Started by diablochris6, March 18, 2017, 08:44:58 PM

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diablochris6

I was wondering about the "whirl" setting on the Tri-vibe. It has that neat, for lack of a better term, Leslie sound. Is it simply because the 100k allows for more dry signal to mix in with the vibe sound? Could a similar setting be placed in any vibe-style pedal?
http://www.runoffgroove.com/tri-vibe.html
Build guides of my original designs and modifications here

midwayfair

Whirl mode has HALF the gain of the Swirl mode and the phase signal (which may have more of its own gain, so it's not necessarily 1:1) for the dry signal. (Remember that the gain voltage divider is R_feedback:R_input.)

The univibe's chorus setting mixes in the dry setting, and there have been many instances of people adjusting the R network to produce different sounds. As far as actually duplicating the settings on the trivibe ... maybe you can figure out a way to do it, but the 3V will still sound different.

Incidentally, some phasers take a slightly different approach and make the dry blend and feedback frequency-specific. You might experiment with that as well.

diablochris6

Quote from: midwayfair on March 18, 2017, 09:15:56 PM
Remember that the gain voltage divider is R_feedback:R_input.)

Thank you. I had the formula upside down when I was thinking about it (it was late, and I was too busy enjoying a Bells Two Hearted to look it up).

What do you think makes the 3V unique compared to a LDR or JFET style of vibe/phaser? Is it the sine wave LFO or the OTA circuitry response? A mix of the two?
Build guides of my original designs and modifications here

midwayfair

Quote from: diablochris6 on March 19, 2017, 01:42:14 PM
What do you think makes the 3V unique compared to a LDR or JFET style of vibe/phaser? Is it the sine wave LFO or the OTA circuitry response? A mix of the two?

Probably a combination of several things. OTAs have some headroom issues (though granted you get this even in the Univibe running on 15V), the waveform is not actually a sine wave (like in the Univibe) or a triangle (like in many phasers and choruses) but an exponentiated sine, and the frequency response is very slightly bright in some settings. It really is one of their best designs.