Some help (Lofi Looper) -Changing some things, eh? S.O.S.!

[geir_helgi]

Hi!

My name is Geir Helgi and I'm a total rookie (I'm getting there!)

Ok so I wanted to build the Lofi Loop Junky kind of pedal (Payback, Mobius, etc.)
I bought a looper kit locally (YES! I actually found one in an electronics store, PCB, components+ISD 1600 and everything!!)
It was the first thing I've ever soldered and I did a pretty good job, I'm so proud!

Only thing is it has a "spot" for a tiny microphone (to sit into) and also a "speaker out" (and a line out too)
So I was thinking, how do I rig some inputs onto it instead of the microphone slot?
Can I just solder some wires in there instead?

Another thing is: How should I change the battery plug to accept a wallwart?
It only needs 4,5V (Does the microphone need some voltages? Would it kill it if I skip the mic and then apply 4,5V? -isn't the mic "calculated" into the sum of 4,5V?)

This is how it looks:



Also, one more thing actually, you can see on the picture that it uses some tiny, tiny buttons (they have four "legs")
Can I put other switches onto the box instead? How would I do that?
Or should I use one of those "extending" buttons that only press the tiny button on the PCB, but from the face of the pedal?

I just don't want to fry the little thing and I want to get it over so I can try it

Thanks,

-Geir Helgi

ps. the vibrato, is that hard to implement onto this premade PCB?

[aziltz]

Hi!

My name is Geir Helgi and I'm a total rookie (I'm getting there!)

Ok so I wanted to build the Lofi Loop Junky kind of pedal (Payback, Mobius, etc.)
I bought a looper kit locally (YES! I actually found one in an electronics store, PCB, components+ISD 1600 and everything!!)
It was the first thing I've ever soldered and I did a pretty good job, I'm so proud!

Only thing is it has a "spot" for a tiny microphone (to sit into) and also a "speaker out" (and a line out too)
So I was thinking, how do I rig some inputs onto it instead of the microphone slot?
Can I just solder some wires in there instead?

Another thing is: How should I change the battery plug to accept a wallwart?
It only needs 4,5V (Does the microphone need some voltages? Would it kill it if I skip the mic and then apply 4,5V? -isn't the mic "calculated" into the sum of 4,5V?)

This is how it looks:



Also, one more thing actually, you can see on the picture that it uses some tiny, tiny buttons (they have four "legs")
Can I put other switches onto the box instead? How would I do that?
Or should I use one of those "extending" buttons that only press the tiny button on the PCB, but from the face of the pedal?

I just don't want to fry the little thing and I want to get it over so I can try it

Thanks,

-Geir Helgi

ps. the vibrato, is that hard to implement onto this premade PCB?

read the payback articles here. http://geocities.com/thetonegod/ and you'll probably have to make a separate small board to adapt the signals and switches to use that thing.

[geir_helgi]

Hi!

My name is Geir Helgi and I'm a total rookie (I'm getting there!)

Ok so I wanted to build the Lofi Loop Junky kind of pedal (Payback, Mobius, etc.)
I bought a looper kit locally (YES! I actually found one in an electronics store, PCB, components+ISD 1600 and everything!!)
It was the first thing I've ever soldered and I did a pretty good job, I'm so proud!

Only thing is it has a "spot" for a tiny microphone (to sit into) and also a "speaker out" (and a line out too)
So I was thinking, how do I rig some inputs onto it instead of the microphone slot?
Can I just solder some wires in there instead?

Another thing is: How should I change the battery plug to accept a wallwart?
It only needs 4,5V (Does the microphone need some voltages? Would it kill it if I skip the mic and then apply 4,5V? -isn't the mic "calculated" into the sum of 4,5V?)

This is how it looks:



Also, one more thing actually, you can see on the picture that it uses some tiny, tiny buttons (they have four "legs")
Can I put other switches onto the box instead? How would I do that?
Or should I use one of those "extending" buttons that only press the tiny button on the PCB, but from the face of the pedal?

I just don't want to fry the little thing and I want to get it over so I can try it

Thanks,

-Geir Helgi

ps. the vibrato, is that hard to implement onto this premade PCB?

read the payback articles here. http://geocities.com/thetonegod/ and you'll probably have to make a separate small board to adapt the signals and switches to use that thing.

That thing
It is.. hehe

Anyways, thanks, I'm reading it right now!

[cloudscapes]

interesting, does it loop? I see no logic on there aside from the main chip!

[geir_helgi]

interesting, does it loop? I see no logic on there aside from the main chip!

no it doesn't loop, but there's an easy fix to that:

From tonegod:

Looping Playback

Up until now the control logic was smooth sailing but you should know by now that when things seem to be too good to be true you will get hit with something big. Here it is.

The ISD1600B has no facilities for looping the playback. There are no internal modes to perform this function. There are no logic outputs that signal the end of playback. The only logic output available is the LED output but unlike previous ICs during playback the LED consistently blinks giving no clear indication when the sample ends so it is not very useful for knowing when the playback has ended.

The only other outputs on IC are the audio outputs. If there was some way to monitor the audio output we could find out when the loop ends but the audio output is not logic based. Time to pull out one of my dirty tricks.

Reading through the datasheet tells us that when playback ends the IC goes into shutdown putting the AUD and SP+/- outputs into tri-state which basically means the pins are left floating. If we set the output to a known state that is opposite to when it is active we will know when the output is active playing back a sample or if the playback operation has stopped. We are already using the AUD pin for our audio output so it might be better to use one of the speaker outputs, SP+ (pin 11) and SP- (pin , to prevent interfering with the AUD output. I choose to use the SP- speaker output.

There is an added advantage to using a speaker output. Remember the speaker amplifier is now class D which uses PWM. For our purposes the important thing to know about PWM is that it switches between full high and low states very fast. The amplifier uses the same voltage supply as the logic so the high amplifier state is the same voltage as the high logic state. The high output can override a pull down resistor, say 1K, serving as a dummy load on the output thus giving us a high signal when a playback is happening. When inactive the pull down resistor can set the output low. The speaker output then can now be fed into a logic gate to indicate activity.

There is still a problem. The PWM output switches between high and low states quickly causing the gate to switch between states quickly as well. This is not giving us the clean high or low states indicating if playback is in progress or not that we need. This problem can be solved easily enough. Using the speaker logic gate as a buffer the output can be put through a RC filter network to smoothen out the output giving us nice clean high and low outputs indicating operation. There is an LED used on the speaker gate output to limit the signal. The LED can be just about any type.

This clean output from the playback gate can now be fed into a pulse detector creating a trigger gate to retrigger the PLAYL input thus restarting the playback (Figure 6). We now have a looping sampler.

I'm just waiting for my friend to help me out with it
I don't fully understand Tonegod's procedure..

[The Tone God]

I'm just waiting for my friend to help me out with it
I don't fully understand Tonegod's procedure..

There going to be alot of hacking to make that thing work. Atleast its comes with a 1600B in DIP format in a socket. Some people may want to know where to get that if they need the 1600B so where did you find this ?

If you have any questions about the operation of v1.1 feel free to ask. I'll try to explain better if there is trouble.

Andrew

[geir_helgi]

I'm just waiting for my friend to help me out with it
I don't fully understand Tonegod's procedure..

There going to be alot of hacking to make that thing work. Atleast its comes with a 1600B in DIP format in a socket. Some people may want to know where to get that if they need the 1600B so where did you find this ?

If you have any questions about the operation of v1.1 feel free to ask. I'll try to explain better if there is trouble.

Andrew

Hey Andrew,

thanks, yeah, I'll get back at you later..
I found it at a local electronics store here in Iceland, it's a mini-kit manufactured by some german company..
I got the last pack, I'm gonna ask him to order some more (I was planning on having three loopers together in a single box)

It's called a Single Message Recorder (and it even has a Frequency/Speed pot/trimmer to adjust the length of the sample, to quote from the manual: "using the speed adjust a " funny voice" can be created" hahaha )

[puretube]

It`s Belgian... (or Dutch?) "Velleman Kits"

[edit]: schemo for nuffin`

[The Tone God]

http://www.kitsusa.net/phpstore/html/Velleman-K8030-ELECTRONIC-RECORDPLAYBACK-MODULE-66.html

http://www.apogeekits.com/voice_recorder.htm

http://www.arcade-electronics.com/detail.aspx?ID=25943

http://www.quasarelectronics.com/velleman/mk174-electronic-record-playback-kit.htm

[geir_helgi]

I'm just waiting for my friend to help me out with it
I don't fully understand Tonegod's procedure..

There going to be alot of hacking to make that thing work. Atleast its comes with a 1600B in DIP format in a socket. Some people may want to know where to get that if they need the 1600B so where did you find this ?

If you have any questions about the operation of v1.1 feel free to ask. I'll try to explain better if there is trouble.

Andrew

Hey hey,
a little late chiming in now, but I finished soldering most of the kit (left out a few things that I thought would prevent me to "hack" it so it loops)..

It's been in the drawer for way too long and I want to finish it, any tips?
How do I ghetto-rig this kit so it loops?

Wire the speaker (-) output to the PLAYE or PLAYL?
How would I stop it then?

Also, the kit has a tiny built-in microphone, what should I do to change it to a jack-input?

thanks!

[geir_helgi]

bump for the last question?

[The Tone God]

Wire the speaker (-) output to the PLAYE or PLAYL?
How would I stop it then?

Also, the kit has a tiny built-in microphone, what should I do to change it to a jack-input?

You can rewire the microphone as per the schematic of Payback v1.1 which is simple enough.

As for the PLAY pin its not as simple as connecting the speaker output to the PLAY pin. If you read through the Payback v1.1 article you will know why.

Andrew

[deb]

Hi. Has anybody made a looper out of mk174? I can't open http://geocities.com/thetonegod/
so it would be nice, if somebody would share his experience with me, or show me a useful link.

[esnabez]

The articles have moved here: http://www.thetonegod.com/tech/