mobius trip looper mods

[El Heisenberg]

Hey, I'm takin on the mobius trip looper. Seems simple enough.

The Lo-Fi loop junkie has a tone control for the playback and no "dry" control. The signal is just uneffected.

I'd like to add a tone control to the playback chunk or block and cut out the dry control.

http://www.generalguitargadgets.com/pdf/ggg_mobius_trip_analog.pdf






Will this wiring get the mobius trip to function just like the lo-fi loop junkie does?:






and how does z vex get the light to blink when the loop starts?? Something on the recorder chip?

[Taylor]

http://tech.thetonegod.com/payback/payback.html
http://tech.thetonegod.com/payback_v11/payback_v11.html

Logic is needed to do the things like flashing the LEDs to show status, etc. The Tone God has done all this logic, added mixing, separate volumes, tone control, and vibrato. The chip is more expensive than the one used in the Mobius, but if you want all those extra features and you don't want to have to figure out all the NAND gates yourself, I'd go for one of the Payback designs. In fact, I did.

[El Heisenberg]

I saw that design right after I ordered the parts for the mobius trip.

I don't know where I'd find that chip either. And I still haven't even thought about trying to etch my own PCBs. I might burn my hand off with acid or something.

[Taylor]

You could perf it.

I have a layout I did for it, I can post it here if you want to use it. There are a bunch of people here who etch boards - bluesdevil, aziltz. The chip for the original payback can be found on ebay.

[El Heisenberg]

Do you mean people will etch boards for me?

I want to learn, but then I think of all the work that goes into drilling the holes after the etching! Isn't it easier to just use perf board? Especially for small projects.


Anyway, I don't have the money for the chip right now anyway, and I already have the parts for mobius trip comming. I'm sure I'll prolly move onto the payback after I get the mobius up and running.

[El Heisenberg]

But adding at least a tone control to the mobius trip shouldn't be that hard

[El Heisenberg]

There aren't any sound clips of the mobius trip or the payback??

[Taylor]

I don't know, but they sound the same as the Zvex one, as the answering machine chips are the only factor which contribute to the sound of the effect.

True, adding a tone control is super simple. It's just a standard RC lowpass filter. But, I don't see too much use for the tone control unless you also add a sample rate knob:

Use a 1k or 2k linear pot between the +V and the + supply pin of the recording chip. This lets you lower sample rate. If you lower it before recording and keep it there, it just gives you longer recording times (at lower fidelity). Having the tone control here helps to cut some of the aliasing noise.

You can also use this to repitch your loops. Record at high rate, then lower it to drop the pitch and speed of your loops. Record with sample rate low and turn it up for chipmunk sounds.

[El Heisenberg]

Use a 1k or 2k linear pot between the +V and the + supply pin of the recording chip. This lets you lower sample rate. If you lower it before recording and keep it there, it just gives you longer recording times (at lower fidelity). Having the tone control here helps to cut some of the aliasing noise.

You can also use this to repitch your loops. Record at high rate, then lower it to drop the pitch and speed of your loops. Record with sample rate low and turn it up for chipmunk sounds.

HAhah!~ Awesome!!

ARRGh! I know SmallBears package wont arrive until Monday or Tuesday!! I HATE getting all amped up for a circuit and having to wait for the parts!!


The more I look at Payback the more it scares me. I think that's why I first poo pooed the idea of doing it on perf. Mobius Trip is definetly simple enough. DIY loopers! HAH! It seems too good and too simple to be true!!

I'll definetly be on the look out for old answering machines and voice recorders. I'm gunna look around the house right now...

[Taylor]

The only thing to watch out for is that it's possible to lower the voltage enough that the chip turns off. It doesn't damage anything or erase your loop, but if you lower it too far you can't record, and lowering it too far during playback will stop playback.

[El Heisenberg]

Small bear is taking unusually long to deliver. I decided to try to find an ISB16* chip on ebay and can't.

[Colonel Angus]

Sorry for the cobwebs... What was the verdict on these mods? I'm looking to build a lo-fi looper and this looks like the best option. Or would you recommend the madbeans loophole instead?

[Taylor]

The loophole looks pretty good, and I'm partial to anything with a nice fabricated board, so I would go with that (that project didn't exist back when I built The Tone God's Payback). The only thing it's missing is the vibrato, so decide whether that's a big enough downside for your needs to go with something else.

[Colonel Angus]

*singing* tuh tuh tuh Taylor to the rescue , helping that obnoxious dude
Answers question that they ask you, doesn't matter If you wanted to!

Srsly thanks a lot. With some luck this looper build will go to one of the gents from negativland!

[the3secondrule]

if you are going to build either the mobius or loophole, I'd suggest using the isd25** series of chips - you can pick them up on ebay for about the same price as the isd1020.

I used the isd2590 for 90 seconds of looping - and its much better quality than the isd1020.

just note, if using the isd25**:
"Yes you can use any chip in the ISD25xx(x) line. If you look at the data sheets (which you have posted) you need to connect pins 7 and 8 to ground."

J