New Looper Design

[The Tone God]

As per request I am posting a link to the thread introducing my looper that I call Payback. Also in that thread is my answer to the challenge mentioned earlier in this thread.

http://www.diystompboxes.com/smfforum/index.php?topic=46680

Enjoy.

Andrew

[Triple Pole]

Hi all
Sorry to be an annoyance but has anyone got a layout for the latest version of the Mobius Lite? I'm really interested in building a straight forward, plays-what-you-just-played looper,  If anyone can help me on my way to this goal, that would be fab does anyone have a layout with parts labelled? Is this thing do-able on perf board or am I going to get etching?

One other thing is, Im quite new to the whole DIY stompboxing, Ive done electronics in school beofre so I basically understand schematics and such but Im a little hazy about attaching switches. How do the lugs of the switches correspond to the labels ABC 123 etc on the the schem?

Thanks
You guys are soooo much smarter than me! lol!

[RaceDriver205]

Welcome to the site.
You can find the 'mobius trip looper' at www.generalguitargadjets.com, it uses a ISD1xxx (1000 and something), which is available from www.smallbear.com. Not as good as 'the tone god's new design, but it is indeed simple. I believe it records a loop of up to 20seconds.

[Triple Pole]

Thanks for the link, that does look simple indeed. I think ill do that

Do you know if there are any fixes so that It will use a newer chip with better record times? For two reasons, I dont think ill be able to get that NOS chip in the UK, and also I dont think 20 seconds is enough for say a 12 bar blues progression.

Thanks again

[nelson]

Thanks for the link, that does look simple indeed. I think ill do that

Do you know if there are any fixes so that It will use a newer chip with better record times? For two reasons, I dont think ill be able to get that NOS chip in the UK, and also I dont think 20 seconds is enough for say a 12 bar blues progression.

Thanks again

http://www.geocities.com/thetonegod/payback/payback.html


you can get the chips in the UK or they are exceptionally cheap at www.futurlec.com

[Triple Pole]

Hey guys, talk about bringing threads back from the dead!
I've been spurned into action today by the recent 4x15s looper project which was just posted. I've now got what I consider to be the definitive Lazarus Looper project ready to go, though I'd appreciate it getting the once over by those in the know (Slacker, i'm talking to you!).
The layout now includes the Schmitt switching system designed by slacker, as well as the LFO vibrato system i'd devised (read, copied from Tim's PWM design Thanks Tim ). I decided not to use the buffered effects loop, as it was taking up too much space for how useful it was. I figure anyone building this will have the skills to make an input/output buffer on a bit of perf or something. I think a round of applause is well deserved for the switching scheme, which is very elegantly done. I'm sure I would have come up with something far more complicated and less good. Big thanks also to Bill Bergman for the nice analogue design.

Anyway, as ever thoughts and opinions welcomed.

Oh, and the PCB artwork should print out at 4.4x2.7" @ 300dpi. (It's reversed ready for PnP).

Looking back in the thread ive spotted this. Is this a working layout? This has no vibe or anything right? If this is working, I could make this right?

[piggyfinger]

hey guys, sorry to dig up an old post...
fantastic work on this looper!   i love the sound of the 'lo-fi junky', which i think this would be similar to.
but for MY tastes... a looper isn't really a looper unless you can overdub.
i know this chip can't do overdubbing, but i was wondering if it would be possible with two chips?

now i'm a total noob, and i'm sure this might have alot of problems associated with it...
but here's how i see it:

you have two isd1xxx chips: A and B

1. initial loop gets recorded in chip A, playback starts from chip A after memory is exhausted or person ends loop.
2. Overdub mode would consist of chip A's playback mixed with the live signal, and recorded in chip B.
3. The next overdub layer would be chip B's playback mixed with the live signal and recorded in chip A, and so on.

this would even allow for one level of "Undo" since you could toggle back to the previous chip if needed.
of course the sound is gonna get really muddy really fast, do to making so many analog copies... but it might be cool.

just curious to see what y'all thought of this... again great work on this one!

[The Tone God]

hey guys, sorry to dig up an old post...
fantastic work on this looper!   i love the sound of the 'lo-fi junky', which i think this would be similar to.
but for MY tastes... a looper isn't really a looper unless you can overdub.
i know this chip can't do overdubbing, but i was wondering if it would be possible with two chips?

This is really a topic that could be a thread unto itself. To answer yes I have done an overdubbing looper using a pair ICs. I could see it being done with logic ICs but that would take alot of work.

Andrew

[abakuzam]

Yeah, you can use the play pot for a master volume control, but you might find that the signal coming out of your effects varies in strength, so I added the option of decreasing the gain somewhat at both the send and return. That way i've covered all the bases so to speak.
Usually with volume controls, you want the cap on the wiper, that is going back into the circuit. That will protect the output from any scratchy DC which might be getting onto the pot. I'm not sure how much difference it makes putting it before the pot, but that's the way I try to do things.

Anyway, here are the layouts and PCB's for both versions of my Looper. The schem is also shown, which is the same for both versions, except for the effects loop.
I'm going to say they're complete for now, unless anybody spots any errors, I'd appreciate them being checked.

MOBIUS LITE:


MOBIUS LITE PCB:


LAZARUS LAYOUT:


LAZARUS PCB:


LAZARUS SCHEMATIC:


DIGITAL SCHEM:

is this verified? i want to buil this very much!

[Jaicen_solo]

The design is unverified. I haven't looked at it for a long time, though I think it should work.
To be honest, you're probably better off building the Tonegods payback. I built one on vero, and it worked quite well, though i'm still having a couple of switching issues leaking some digital noise. Probably my vero layout.

[abakuzam]

The design is unverified. I haven't looked at it for a long time, though I think it should work.
To be honest, you're probably better off building the Tonegods payback. I built one on vero, and it worked quite well, though i'm still having a couple of switching issues leaking some digital noise. Probably my vero layout.

thanks for information.But i have a question about tonegod's payback v1; how can i disable the multiple recordinf , i want to record 60 sec only  . is it  possbile?