New Looper Design

[domenico]

I've tried this too...sorry it pops the same...listen to me , use a 4070 ic based circuit to control the isd25xx play/rec/stop/start/

this one will work : http://humano.ya.com/guruzeta/Guitarra/dirtysam/digital.html

domenico

[robbiemcm]

You seem to have it very well sussed out Jaicen, do you think you will be able to make us some audio clips of it when you have finished making it? Or do you not have the setup at home to be able to do that?

[slacker]

I guess the only way to find if it pops is to build it
If the pop is casused by a DC offset on the inputs as the chip powers up like one of the links domenico posted suggests then you may be able to cure it by biasing the ana in pin to half the chips supply voltage.
If you do end up having to use logic to control it then at least you might be able to use the other 5 invertors from the 40106 on your wobbly power supply.

[Jaicen_solo]

I'm a sound engineer by trade, so I imagine I could knock up some decent enough recordings

The whole point of the ISD25xx series was to simplify control by allowing push button or edge control. I find it strange that they would deliberately design an IC for this that is unsuitable for it's purpose! How exactly does using a mechanical switch cause popping, excepting self noise?  I don't see where it would come from, since the control circuit is seperate from the analogue signal.
I plan to get all the components to build mine this week, so I'll probably build it on sunday/monday. If I do have problem's I can't fix, I may consider inverter control, but in that case, I may as well build the dirtysam! The point of this was to build a looper with the simplest possible configuration.

[slacker]

Any news on this yet?

[Jaicen_solo]

As of yet, i've not had time to work on anything stompbox related at all. I work in a shop and we're getting the christmas rush, so it's all hands on deck at the minute. I'll let you know as soon as any progress is made.

[nelson]

Got my chip all ready too build this. I hope it works and I dont have to start trawling through datasheets and design one myself.

If you want this all wrapped up nicely in a PDF project file jaicen send the stuff to me once its verified and I will tie it all together.

[robbiemcm]

Good work Nelson make sure you give us all a detailed summary of how it went when you're done. Out of interest, do you think you'll be done in the next few days or will it take you a while? I'm off to England in 3 days, but I suppose I will be able to check back here at my cousin's house.

[Zak Mc Kraken]

Hi,
I ve just read the datasheet, and to avoid popping, the ISD must be in push button mode. But in this mode, it is said that the chip powers down after each playback. So you don t have the loop function.
Is it right ?

[Jaicen_solo]

You can loop whilst in OP mode if you keep address pin 4 high.
Whilst in OPmode, the chip can be level or edge activated, so you can either use latching or momentary switches for operation.
This layout should in theory allow either to be used. I still haven't had time to build mine, i've been working late shifts all week, sucks big time! 

[kissack101]

hey,

at the risk of sounding like a kid on holiday... any news on if this works or not? I was watching this thread unfold back in October with some amount of anticipation of a cool lo-fi looper and then it all went a little quiet...

Adam.

[Jaicen_solo]

Once again, I must apologise. I guess since this is my baby I should be the first to build it 
I've just not had a lot of time with this being the holiday period (I've got a temp job in a shop, sucks). As soon as I build anything, you guys will be the first to know!!

[robbiemcm]

Just keeping this topic alive to see how the building is going, Nelson seemed to state that he had the bits ready to go.. so I was wondering whether he ever got round to it?

[Jaicen_solo]

Just a quick note to let all those that are following this thread know that I haven't forgotten them ;-)
Having been sacked from my temp christmas job I have a little extra time on my hands so hopefully I should have some results for you all pretty soon.
If all goes to plan, at least one looper will be finished (and hopefully working) by the end of the week.

[galad]

hi, just registered but i've been reading this and the other posts on loopers
and i would like to try to build one too

i only know a few things about electronics, although i did build a fuzz pedal

i've got an answering machine i've been messing around with, although i don't think it has an isd25xx

it'd be great if you could post some really basic looking schematics when you're done

[nelson]

Waiting for the verification that this thing doesnt pop, then the board will be etched populated and enclosed before you can say polly want a cracker.

[robbiemcm]

Mmmm, on my holiday in England I've been thinking about just how much I want to build this project, I can't wait! This will be the first project I build when I get back, providing I think I can cope with it. Make sure you take some photos while your building it to give us a nice look

[kissack101]

...any word yet? I got paid more than I was expecting today and this cool piece of kit has been on my agenda for a while. Unfortunatly, my limited abilities means i'm probably not the pioneer required to see if the thing works. Just keeping the thread alive, many thanks to all those doing the leg-work...

[robbiemcm]

Yeah, I'm not really up to the task of building this thing to tell you guys whether it works or not. The chances I will do something that makes it not work that is no fault of the circuit is about 90% so chances are I would come back saying it doesn't work even if the circuit is perfect 

[robbiemcm]

Galad, here's the schematics and all for the looper:

MOBIUS LITE:


MOBIUS LITE PCB:


LAZARUS LAYOUT:


LAZARUS PCB:


LAZARUS SCHEMATIC:


DIGITAL SCHEM: