New Effect: Payback

[The Tone God]

The clock resistor, that's the record pot right?

No. It is the Rosc resistor (R2 on schematic stated as 100K) off of pin 14 on the ISD1600B. You can put a pot on this pin to adjust it if you wish. Adjusting the value will change the pitch of the current recording which is why I use it for the vibrato function.

Andrew

[Valoosj]

ah ok. Thanks for the replies. I'll stop asking until I read through the article

[Michael Allen]

On the 4093, pin 14 goes to power? Is there a cap to ground too? just to filter the power supply or what? And then pin 7 to ground right?

[Michael Allen]

Just finished a layout for version 1.1 that's 2.1 x 1.6 inches. It's pretty small, i just have to finish drawing up the layout and then i'll post it.

[The Tone God]

On the 4093, pin 14 goes to power? Is there a cap to ground too? just to filter the power supply or what? And then pin 7 to ground right?

Yes pin 14 of the 4093 goes to the 5v supply. The cap goes from pin 14 of the 4039 to pin 7 which is ground of the 4093. The cap should be as physically close to the 4093 as possible. It is a decoupling capacitor.

Andrew

[Michael Allen]

The schem shows two sets of .1 and 10uF caps off of ISD pin 10. One sets grounds off pin 5 of 4093 and the other off of pin 9 of ISD. Is this necessary to connect them to ground with the respective pins or just how it appears on the schem?

[Michael Allen]

Here it is, layout for Payback 1.1. 54mm x 41mm.




There is a square pad by the 1N4148 diode, jumper it to the other square pad on pin 8 of the TL072. The circle pad on the other end of the 1N4148 goes to the bypass switch as per schematic. Also, I couldn't remember how to ground the unused portion of the CD4093 but it should be easy to do. I went through it so it should all be correct, but it has not been confirmed.

[Valoosj]

damn you're fast. 

once this is confirmed, and the grounding and whatever else might not be fully there, I'm etching!

[Michael Allen]

yeah just tie pin 12 and 13 on the CD4093 together to ground. you can add it in in paint or just draw it on the copper with a sharpie.

[Valoosj]

maybe I'm seeing this wrong, but did you not forget about pin 15?

[Michael Allen]

Good call, i had a pad on there to jumper pin 15 to the 5V rail but I took it off by mistake. I''ll fix it soon.

[Valoosj]

no problem   
Only thing left that I don't understand is how to wire all the pots and switches. Each pot only has one lug attached to your pcb :s
Could you possibly add the offboard wiring? I know how to do it with other effects, but this one does things a bit different as I read in the schematic

[Michael Allen]

[Valoosj]

Thanks, that makes it a lot clearer, but weren't there 2 switches? 

[Valoosj]

one for recording, and one to start the playback? and the safe switch, is a 1pdt nog enough? I don't see the reason why to use a 2 pdt

[Valoosj]

ok, I looked at the schematic, and tried to help out a bit
This should be correct


the only thing that is not clear to me is how the 2 leds funtion. referring to the article where it said something about blinking when recording etc. that part was not too clear to me

[The Tone God]

the only thing that is not clear to me is how the 2 leds funtion. referring to the article where it said something about blinking when recording etc. that part was not too clear to me

I guess I didn't make the LED situation very clear. The LED off the speaker output gate (D2) is being used to limit the signal going into the filter network. It is not meant to be visible to the user, it is just the diode type I choose happens to give off light.

The LED indicator (D1) is controlled by the ISD and will blink the LED during playback automatically without any work on the builder's part.

Andrew

[Valoosj]

would it not be easier with 2 leds? one that is on or off when play button is pressed. and the other that blinks during recording, and when using the playback that it blinks once when the recorded session repeats. kinda like the lofi loop junky.

I would like to build this with 2 buttons, like version 1.0 , and I was thinking it would have 2 leds. If you have one led, that comes from the ISD, doesn't it always blink when not recording? since the playback is controlled with another switch.

Is that possible?

(and is my offboard wiring from my previous post right?)

[The Tone God]

I haven't gone through the whole board to be sure everything is correct. What I am pointing out is that D2 was never meant to be external or visible for the user. It does not give any useful information to the user that is not given by the LED indicator. It is just a diode on the board so the PCB should be corrected by removing the external D2 access and just treating the LED like a normal diode.

In v1.0 the play/rec LED indicator was just a coincident that it operated similar to the Lo-Fi Loop Junky. In v1.1 the LED indicator operation off the ISD is determined by the ISD and not the external logic. It is fixed and cannot be changed. The operation of the LED is off when powered down, on solid when recording, and blinking when playing back. To be honest I think this is better the the v1.0 setup as you would only know if playback is happening when you saw that very quick blip at the end. With this setup you know when it is playing back when the LED is blinking.

If you want a different operation you will need some more logic. Just thinking off the top of my head if you are not using the spare gate to disable the vibrato during playback you could reuse it for a v1.0 style LED indicator attaching the one input of the gate off the PLAYL input and the other input off of the record switch. Thats just a guess though.

Andrew

[Valoosj]

too bad that I don't know much about it :s

Maybe I should just make the play switch a 3pdt instead of a 2pdt, and add a led there. that way that will be solid, and one blinking when playing back.
The only thing that would make it better then is when the blink would only be there when the record starts over