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Quick question about the ROG Tri-vibe

Started by diablochris6, March 19, 2017, 03:44:58 AM

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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

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 19, 2017, 04:15:56 AM
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?

midwayfair

Quote from: diablochris6 on March 19, 2017, 08:42:14 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.