Death By Audio - Robot

Mrutg · Post by **Mrutg** » 24 May 2012, 17:14

IvIark wrote:I've done the layout but it was based around using the TGD, TGU, ROB, and VIB connections. This of course won't give you an exact robot but if I'm reading the datasheet right it should allow you access to all the sounds and more. But as I wasn't 100% sure whether this is an appropriate way to use the IC I thought I'd wait until I got chance to experiment.

I'm happy to post the layout if you fancy trying it out.

I still haven't finished the last layout. The Robot lays on my shelf half-assembled. Had some wiring problems. But hey! I wanna see your layout man!

IvIark · Post by **IvIark** » 24 May 2012, 18:41

Here's is where I am so far.

Beedoola · Post by **Beedoola** » 27 May 2012, 09:20

Mrutg wrote:Am i seeing things right on the layout? Are there 3 bridges under the IC's?
I don't see them on the schematic however I am not a good schematic reader.
Can somebody help me?

Is this layout verified? I'm gonna etch a pcb out of this one. Thanks

vintage man · Post by **vintage man** » 08 Jun 2012, 06:37

I´m as well interested in this project.

Can anyone confirm that the layout is verified?

Thanks, regard folks.

Glass_Hero · Post by **Glass_Hero** » 18 Aug 2012, 14:09

hey here is a sound clip of the three toggle switches to ground instead of the rotary switch..

night-butterfly · Post by **night-butterfly** » 20 Aug 2012, 06:29

You can get really cool sounds while rotating the control knob, it would be so cool to replace it with a switchable led/ldr combo for a constant sweep

Glass_Hero · Post by **Glass_Hero** » 29 Aug 2012, 13:24

the TGD & TGU functions work similar to the toggle switches but you have "scroll" thru all the pitch shifts.. they have a certain time in between shifts before you can get to the next pitch.. so if you constantly press the momentary button you will only get pitch shifts on certain momentary button presses.. so you have to slowly find the pitch you are looking for, instead of just flipping a few toggle switches and getting there faster..

you have to set the toggle switches on the other side so they are in arpeggio mode (not grounded, if not connected then they will be in Robot mode on start up, the arpeggio mode is the robot mode).. The TGU & TGD will then allow the user to scroll thru the shifts, and the ROB pin will let it go back into the arpeggio mode..

VIB is awesome and sets a really cool vibrato which works in all modes..

from datasheet:
The rate of vibrato effect can be changed by
adjusting the resistance of the external resistor between
the OSC2 and FVIB pins.

mountainsforclouds · Post by **mountainsforclouds** » 03 Oct 2012, 19:59

This pedal sounds great I etched a board and absolutely love it. The one thing is the gate seems to be really finicky. It has a hard time picking up some notes and others not so much. I was wondering if anyone would know how to maybe make it a little more sensitive. I don't know if that is possible. But it seems like you have to play pretty hard on your guitar to get it to really respond. Any thoughts?

vintage man · Post by **vintage man** » 03 Oct 2012, 22:10

I´ve etched a PCB, and the fx is working OK. Awesome!!!

But I´ve experiencing problems when using it with another stompboxes. It must be the power. That kind of ground between 0 and 9v is really weird. As the positive ground pedals, It can´t share the power supply with another boxes unless you have power supply with a special design for this affair.

I´m wondering wether could be possible to modify this ground line to make the box compatible with the others. The idea could be to attach in any way the ground to the negative pin of the power supply.

vintage man · Post by **vintage man** » 03 Oct 2012, 22:34

Ok, I´ve wired ground to negative, and I´ve take the schematic ground as another more wire, and it solved he problem.

Thanks for this wonderful fx.

Mountainsforclouds, I will test it for the sensitiveness issue that you mention.

biliousfrog · Post by **biliousfrog** » 04 Oct 2012, 14:32

IvIark wrote:Here's is where I am so far.

I'm a little confused by the momentary switches, does this mean that the octaves, for example, only work when the switch is held down?...or is there something clever happening with the circuit that registers the switch being engaged, in the IC perhaps? If so, it would be useful to have some indication of what effects are engaged, using LEDs for example.

IvIark · Post by **IvIark** » 04 Oct 2012, 17:33

Everytime you pulse the up or down it goes up or down one step and cycles. Pulsing the Robot turn it on or off alternately. Or at least that's how I interpreted it, although I don't know if anyone has built this yet.

biliousfrog · Post by **biliousfrog** » 04 Oct 2012, 20:35

Ah, right. Would it be possible to have standard toggle switches for on/off then?...like the rotary switch does but separating out the effects.

I apologise if it's a dumb question and thanks for the response.

biliousfrog · Post by **biliousfrog** » 04 Oct 2012, 21:20

Actually, now that I've read backwards a little more, I guess a more useful way of using the toggle switches would be in conjunction with the rotary so that you have the standard 'presets' which the rotary offers plus a 'manual-mode' which allows the toggle switches to become active.

I really like the idea of the switches to manually tweak the exact effect required but I can't see it being of much use outside of a studio/experimental environment unless the settings can be stored when the pedal is turned off. I'd mostly want to use the pedal in a live situation for just one or two sounds with the extra option of creating more custom sounds in a more relaxed environment - at home, in the studio, jamming etc.

My original thought, before reading more thoroughly, was that the switches just allowed you to turn on/off the four preset modes but they do much more than that...perhaps too much to be usable on a daily basis (for me)

Glass_Hero · Post by **Glass_Hero** » 02 Nov 2012, 16:48

here is how to adjust the control knob with out having to stop playing.. the drive and vol knobs are both outside the pedal, the toggle switches give instant access to what ever pitch you want, and the small black button turns on the VIB mode.. when using with a bass guitar in the pitch down modes with the VIB on you can get stupid gross "dubstep" style sounds..

I have built 3 of these, 2 of which are in wah cases..

cortezthekiller · Post by **cortezthekiller** » 21 Nov 2012, 04:11

I'm just finishing up a version of the DBA Robot. I've used the 3 separate toggles instead of the 4 position rotary. I also added a VU input level meter by finding the right series resistor value (in my case 2k7) and connecting it to the LED out and power connections on the Pitch Shifter chip. Also, borrowing from the DH Pitch Shifter on GGG, I've included a blend control, which in this case is part of the joystick control along with the Pitch Shifted signal volume. So there is an X-Y axis blend of both. Although the "clean" signal is more overdriven, it retains only the fundamental input signal pitch so can add more layers to the pitch shift tone when mixed properly.

I used a 220k resistor in series with the pitch shifted signal and a 470k with the dry to meet at the input of the last opamp stage. This gave me the best mix of volume levels for both and not having either as insanely loud as they were originally. For the dry level control I used a 150k since that was what the joystick had built in. The pedal sounds like a nightmare so I think it works!

CABrook · Post by **CABrook** » 26 Nov 2012, 16:39

Glass_Hero wrote:here is how to adjust the control knob with out having to stop playing.. the drive and vol knobs are both outside the pedal, the toggle switches give instant access to what ever pitch you want, and the small black button turns on the VIB mode.. when using with a bass guitar in the pitch down modes with the VIB on you can get stupid gross "dubstep" style sounds..

I have built 3 of these, 2 of which are in wah cases..

Nice work! I've been wanting to do exactly this type of thing ever since I found this thread. May I ask, what did you use for the expression pot? I've never worked with expression pedals before, but I've read that finding expression pots of the appropriate values can be quite the challenge.

Glass_Hero · Post by **Glass_Hero** » 27 Nov 2012, 16:56

CABrook wrote:
Glass_Hero wrote:here is how to adjust the control knob with out having to stop playing.. the drive and vol knobs are both outside the pedal, the toggle switches give instant access to what ever pitch you want, and the small black button turns on the VIB mode.. when using with a bass guitar in the pitch down modes with the VIB on you can get stupid gross "dubstep" style sounds..

I have built 3 of these, 2 of which are in wah cases..
Nice work! I've been wanting to do exactly this type of thing ever since I found this thread. May I ask, what did you use for the expression pot? I've never worked with expression pedals before, but I've read that finding expression pots of the appropriate values can be quite the challenge.

470k wah pot.. it close enough to 500k.. the wah pot has a taper but its not too bad since you can use your foot to get the right amount of control.. i made one for my buddy and we put in an exp jack that disconnects the "conrtol" pot and allows for photo cells.. We found the value of 1meg or more will cause the whole thing to shut off during some oscillations and be very destructive to the signal..

Cube · Post by **Cube** » 07 Feb 2014, 05:53

Hello fellows!
I finished robot pedal - everything goes good, until I press SW2....And all effect changed( robot doesn't work anymore....i tryed to get normal mode by presseng sw2-sw0...and i can't get the normal work (as before).
Can anyone help me?
Thanks in advance!

commathe · Post by **commathe** » 21 Feb 2014, 08:11

A question for people who built this: how did you ground the jacks if you used a power-supply?

I'm looking at the schematics and I see a virtual ground between +/-3.6V. I surely can't ground my jacks to that? I feel like that will create a ground loop. Am I right in assuming I have to ground my jacks to the power-supply ground? Also, since I am using a volume pot after the second op-amp, surely I have to ground that to the power-supply ground too?

Death By Audio - Robot [traced]