New at runoffgroove.com: Tri-Vibe

[El Heisenberg]

this is cool. Ive found my next build.

[Fuzz Aldryn]

this is cool. Ive found my next build.

... me too. Still waiting for the layout as I'm too lazy to do my own and the previous posted one looks pretty good.

[El Heisenberg]

Ugh i cant do pcb so i always do pad per hole. Sometimes i follow ROGs PPH layouts. This is a big circuit so id prolly have to. I plan on using two dual op amps instead of a quad so that might be trouble. I wanna put this in an amp. Not too interested in the swirl effect. Maybe a little.

[MikeH]

Totally awesome as always!

[El Heisenberg]

ugh I want this right now!!!

what about putting this in an amp? does vibrato in fenders go after or before tonestack?

[Ben N]

ugh I want this right now!!!

what about putting this in an amp? does vibrato in fenders go after or before tonestack?

After, between the preamp and the phase inverter (in black/silver-face Fenders, anyway).

BUT, the "vibrato" in Fender amps is really a tremolo (modulates the volume following an LFO), and the "tremolo" on Fender guitars is really a vibrato (modulates the pitch). So don't expect this to sound like a Fender amp "vibrato," because it is an entirely different effect.

BTW, is anyone doing an RTS board for this one?

[El Heisenberg]

.

[El Heisenberg]

ugh I want this right now!!!

what about putting this in an amp? does vibrato in fenders go after or before tonestack?

After, between the preamp and the phase inverter (in black/silver-face Fenders, anyway).

BUT, the "vibrato" in Fender amps is really a tremolo (modulates the volume following an LFO), and the "tremolo" on Fender guitars is really a vibrato (modulates the pitch). So don't expect this to sound like a Fender amp "vibrato," because it is an entirely different effect.

BTW, is anyone doing an RTS board for this one?

WTF? why would fender do that? Anyway the sound I want is like this guy who uses two fender amps at the same time. One has tremolo and one has vibrato. So I dunno what to do.

[aziltz]

No Fender amp has pitch vibrato though.  I think he's just using two Fender amps, one calls it Tremolo, one calls it Vibrato.  Same Volume-WaVeRiNg effect.

[Andre]

Here's my PCB design and partslayout for the runoffgroove Tri-Vibe:

[soggybag]

That 820K resistor looks odd to me. Seems if the pot is at one extreme you have 310K at the other the 820K does nothing. Since the pot is already reverse log we're getting some strange resistance curve with the 820K across the two lugs. Is the intent here?

[Paul Marossy]

Nice work from the ROG team! Sounds really nice man. 

[Morocotopo]

Very nice! i like the sound samples, sounds really cool.
Of course, I´m already thinking about mods and hot rodding the thing... for example, the 47 and 100K resistors switched by the SPDT could be replaced with a 100K pot with a SPST to get all the variable sounds between "whirl and swirl", besides the vibrato. What do you think? Or, letting my mind fly freely, two of them fed by a low pass and a high pass filter respectively and recombined at the output, "leslie in a box"...

[stm]

That 820K resistor looks odd to me. Seems if the pot is at one extreme you have 310K at the other the 820K does nothing. Since the pot is already reverse log we're getting some strange resistance curve with the 820K across the two lugs. Is the intent here?

Yes, the 820k resistor is there on purpose to limit the minimum RATE and tame a bit the logarithmic nature of the pot.

[stm]

Very nice! i like the sound samples, sounds really cool.
Of course, I´m already thinking about mods and hot rodding the thing... for example, the 47 and 100K resistors switched by the SPDT could be replaced with a 100K pot with a SPST to get all the variable sounds between "whirl and swirl", besides the vibrato. What do you think?

Yes, I already thought about a third pot during development, but we opted for the simplicity of a switch as this produces well defined and reproducible sounds.  Nevertheless, for what you want the way to go is as follows:

1) Currently the resistance is varied from 47k to 100k to infinity (switch at center).
2) Consider removing the 100k resistor, and replacing the switch with a 500K log or audio pot (A-taper).  At minimum, you have just 47k--same as before.  At center, you have 47k+50k which is essentially 100k--same as before again.  At max rotation you have 47k+500k, which for practical purposes is almost identical to the vibrato mode.  There you have same three modes, continuously variable with a single pot.

Or, letting my mind fly freely, two of them fed by a low pass and a high pass filter respectively and recombined at the output, "leslie in a box"...

Yes, two tri-vibe boards could be used as building blocks for a more accurate leslie simulation.  You will need an additional daughterboard with four opamps as follows:
1) Input buffer or TS-style stage set for low gain and soft clipping
2) 800 Hz 2nd order lowpass filter (negative gain implementation)
3) 800 Hz 2nd order hipass filter (positive gain implementation)
4) Two input adder

The two crossover filters need to have opposite polarities so when they are added phase relationships do not cancel the midrange frequencies (this is from crossover theory).  Another possibility is to implement the 4th opamp as a differential opamp to do the subtraction.

The hipass filter feeds a tri-vibe set for whirl mode (rotating tweeters do have some amplitude variation as well).  The lowpass filter feeds the second tri-vibe set for vibrato mode (the low frequency rotor produces almost no amplitude modulation).  Both LFOs are adjusted close to each other but not identical.

Now the cherry for the cake would be controlling the LFOs to ramp up and down.

[Brymus]

This Leslie in a box sounds really really cool !!!!!
I have a VSTi that does a good Leslie sim but a pedal would allow for "live" use.
What about an option that would allow it to be sent to two amps instead of being re-combined?
Now that would be SIC in a club situation.

Thnx for the cool design ROG

[Slade]

Thanks for another fantastic proyect, guys, I'm really impressed with this one.

Gracias por la ayuda con las modificaciones, compatriota

[Andre]

1) Currently the resistance is varied from 47k to 100k to infinity (switch at center).
2) Consider removing the 100k resistor, and replacing the switch with a 500K log or audio pot (A-taper).  At minimum, you have just 47k--same as before.  At center, you have 47k+50k which is essentially 100k--same as before again.  At max rotation you have 47k+500k, which for practical purposes is almost identical to the vibrato mode.  There you have same three modes, continuously variable with a single pot.

I did that and it works OK although there's not much "action" in the range from twirl" to "Vibe".

Here's a picture of my PCB in a 1590B:
The extra wire on the PCB is not necessary in the final version of the PCB

[El Heisenberg]

i wish i could work with PCB

[stm]

1) Currently the resistance is varied from 47k to 100k to infinity (switch at center).
2) Consider removing the 100k resistor, and replacing the switch with a 500K log or audio pot (A-taper).  At minimum, you have just 47k--same as before.  At center, you have 47k+50k which is essentially 100k--same as before again.  At max rotation you have 47k+500k, which for practical purposes is almost identical to the vibrato mode.  There you have same three modes, continuously variable with a single pot.

I did that and it works OK although there's not much "action" in the range from twirl" to "Vibe".

That could happen if you are using a LIN pot instead of a LOG pot, or if you have the LOG pot wired backwards.  If you want to further check this, you should make sure that with the pot at the center the total resistance (47k + pot resistance) is close to 100k.

By the way, your build looks really nice, especially considering the compactness of the the PCB to fit a 1590B box.  I guess the size of this circuit is as much as you can pack in such space without going to surface mount devices.