New Effect: Payback

[The Tone God]

Is the ISD1790PY that Futurlec sells the right one for v2?  It says "SPI Interface" - is this still DIP?

Yes that IC will work and it is a DIP pacakge. The "P" in the name means plastic DIP.

that actually sounds like it could pretty great, even if glitchy! sort of like a guitar-controlled mellotron.

I showed it to a few people and they got a kick out of it but it is really not that useful live so I never built a permanent version. Stilll good for the experience and laughs.

the diode is really sensitive 
sometimes it loops, sometimes it doesn't. sometimes it loops half a dozen times then stops, untill I wave my hand over the breadboard or something.

Yes it is very sensitive by it's nature. If you are using a 3PDT switch you can switch the audio and logic signals separately and use a pull up resistor of say 100K on the logic line. That makes things more stable. The diode option is for those with only DPDT switches.

Andrew

[Valoosj]

Well now, that would have come in handy when I had problems with the diode. Would using a 3PDT work on v1.1 in order to remove the diode?
Any hints on how to go about this process? Maybe I'll finally get some v1.1s working.

[The Tone God]

Well now, that would have come in handy when I had problems with the diode. Would using a 3PDT work on v1.1 in order to remove the diode?
Any hints on how to go about this process? Maybe I'll finally get some v1.1s working.

Sure. Wire up the switch audio lines as per the diagram. Disconnect the logic line that contains the diode on the output side of the switch. Connect this line to the middle lug of the third pole of the switch. Which ever side of the switch that puts the effect in bypass connect that side's lug to ground. So now when the effect is bypassed the logic line is connected to ground. Replace the diode with a resistor say 100K in value.

Wash hands, wipe on pants. Done.

Andrew

[cloudscapes]

Sure. Wire up the switch audio lines as per the diagram. Disconnect the logic line that contains the diode on the output side of the switch. Connect this line to the middle lug of the third pole of the switch. Which ever side of the switch that puts the effect in bypass connect that side's lug to ground. So now when the effect is bypassed the logic line is connected to ground. Replace the diode with a resistor say 100K in value.
Wash hands, wipe on pants. Done.
Andrew

this works pretty well, thanks! I can understand how many people will still want the diode trick to spare a 3PDT, but personally I'm more comfortable with basic switching.

[cloudscapes]

I'm getting a pause each time the loop starts again. the pause length varies depending on how fast I'm clocking the ISD chip, which leads me to believe it's a problem with that and not the 4093 logic (though I may be wrong))
http://www.youtube.com/watch?v=29QD7y1g7po
it does this diode or no diode, battery or adapter, and I've tried a few different chips. any ideas?

[The Tone God]

Ah I think I know whats going on. The clock that sets the sampling rate also sets the response time of the ISD. If you run the clock to slow the logic will run too fast for the ISD. The same thing can happen if you run the clock too fast, the logic won't keep up with the ISD. The values I gave were for 100K Rosc. Some tweaking maybe needed for different clock rates. Also when you run a lower clock rate it takes the ISD longer to re-power up itself, load the memory to the starting position, and start playing back so after certain clock rate the delay will just be impossible to overcome no matter the control logic. You test this by manually driving the play pin. The ISD will just respond slowly.

I ran into that with v2.0 and had to compensate when possible to get the loops tight. I just got through some initial jamming with v2.0. I think it is pretty close to being dial in.

Great video BTW.

Andrew

[cloudscapes]

cheers, thanks for the enlightenment
so if I understand correctly, the logic part was specifically calibrated/timed to work with the 100k on ROSC. I think for my application, I'll just need to live with the pause (for now), because I need manual speed control for what I intend to do.

there's still a pause if I manually hit PLAYL. you were right.

looking forward to seeing 2.0!

[The Tone God]

No prob. BTW great videos of your other builds.

Just got through playing with v2.0. I'm really enjoying it. The vibrato is great. I'm going to box it this week and post some samples for FX-X.

Andrew

[sebruzda]

Can somebody make an off board wiring diagram for this? thanks

[Baziiil]

I'll build it some time later. I prepared this for my payback maybe it will help you. But thats not verified..

http://img13.imageshack.us/img13/6783/123tfm.jpg

[station]

The only real trick with v2.0 is that it will have one specialized part but I am working on that too.

Still waiting on that mysterious part? I'm curious to see how this project turns out.

[kierc]

He told me it's a controller chip, and he's working on a way to get it readily available to builders 

I just can't wait to build this one!!! 

[pazuzu]

Hello everyone,

I posted a new effect called Payback at the site. It is a looping sampler with a host of features. There is article explaining it's operation and several modification suggestions.

Enjoy.

The Tone God's Domain

Oh and about that little challenge:









Happy Canada Day to all my fellow Canadians. Happy 4th of July to all my brothers and sisters to the south as well.

Your Tone God,

Andrew

this is cool. it won't make a good started project for me, but this stuff is starting to fall into place mentally for me, the schematic at least makes sense to me after spending a week looking around here and at beavis. i am officially adding this to my list of builds though. killer work.

[station]

I've got my ISD chip ready and awaiting orders

[cloudscapes]

Andrew, are you using AVRs to control the ISD chips via SPI? if so, any pointers? I'm sort of tentitavely experimenting with some ISD1700s and AVRs. The main interest is in defining where the loop start playign and hwere it ends in the full loop, in realtime.

[The Tone God]

Andrew, are you using AVRs to control the ISD chips via SPI? if so, any pointers? I'm sort of tentitavely experimenting with some ISD1700s and AVRs. The main interest is in defining where the loop start playign and hwere it ends in the full loop, in realtime.

Yes I am using a AVR to control the ISD via SPI. There seems to be a recent renewed interest in this project so I may get back to it. Its been awhile since I have played with it. I do remember that some commands didn't play well with others and some did not behave as expected. I need to reacquaint myself with the software and the driver to be able to give more info.

One thing I do remember is that you can set the start record address then when finished you can read the address that the recording stopped at.

Andrew

[Valoosj]

Andrew, how is v2.0 coming along? You said you were getting ready to release the schematic together with an article.

[The Tone God]

Andrew, how is v2.0 coming along? You said you were getting ready to release the schematic together with an article.

When I last left it there was just one minor software bug to deal with. I'll have to get back to the project and squash the last bug then I can get things moving with the article.

Andrew

[TheAttackman]

anymore news? im REAAAALLY interested in building this!!!!! 

[The Tone God]

anymore news? im REAAAALLY interested in building this!!!!! 

Holidays and biz gets in the way. It is coming but it will be a bit until things settle down around here.

Andrew