New Effect: Payback

[ambulancevoice]

The Tone God's Domain

reminds me alot of the lofi loop junky
this pedal could be of great use to me

[The Tone God]

reminds me alot of the lofi loop junky

Well that was kind of the idea when Mr. Vex challenged me to fit the design into a 1590B. Payback v1.1 should be much easier to fit into a 1590B so I dare him to make that challenge again.

Andrew

[ambulancevoice]

that sounds like him...
how is the v.1.1 coming?

[The Tone God]

It was more of a rhetorical challenge then a direct one. I don't work often with 1590Bs and I had a stash of small pots that I wasn't using so what the hey.

I took a day off from working on Payback v1.1 to get a FX-X entry done. The circuit seems to be be tweaked properly but I have some testing to do. I can move forward with the article and start doing the images. Its coming.

Andrew

[Valoosj]

I stumbled into this thread today. This is exactly THE pedal I need in my band. Instead of me repeating one riff like 50 times I can use this pedal.
It would be sweet to have this built.

Is the schematic on your geocities website for the V1.1 finished? Because if so, we can all start making a PCB for this 

[The Tone God]

Is the schematic on your geocities website for the V1.1 finished? Because if so, we can all start making a PCB for this 

The Payback v1.1 schematic is finished. It has not been verified by anyone though. There is a thread about v1.1 here:

http://www.diystompboxes.com/smfforum/index.php?topic=61722.0

Andrew

[Valoosj]

which of the 2 versions is the best? I just need a nice loop, 20 seconds would be super. I don't need any vibrato and stuff. volume and record controls are enough.
As soon as I can I will post a vero layout, or if I get better a pcb

[The Tone God]

Its hard to say which is best. v1.0 is confirmed but the circuit is more complex and you have to find the IC which went out of production recently. You can still find the IC at some places...for now. v1.0 also can have more time if you want.

v1.1 is easier to build, cheaper, smaller, and uses current parts but comes in shorter times and it is as of this time unconfirmed. 20 secs is very do able with either.

Andrew

[Valoosj]

Ok Thanks Andrew. I'll stick with version 1.1

but I haven't found the IC for this one either in Europe 

[The Tone God]

but I haven't found the IC for this one either in Europe 

The ISB1600B family is fairly new so I wouldn't be surprised that most vendors are not carrying them yet. I got mine from Digikey.

Andrew

[Valoosj]

so, which one do I need?
http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=2556441;keywords=ISD1600

I clicked on 20 sec, SOIC (or should this be DIP?) and then I get to a new screen where they offer 6 possibilities 

[caress]

you probably want the DIP.  that's the standard size stompboxers use.
DIP - Dual Inline Package  -  http://en.wikipedia.org/wiki/Dual_in-line_package
SOIC - Small-Outline Integrated Circuit  -  http://en.wikipedia.org/wiki/Small-Outline_Integrated_Circuit

[soggybag]

Is there a layout for Payback 1.1?

[Valoosj]

ok, so this is the one I should, and can get?
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=ISD1620BPY-ND
the others only come in packages of 120 if I understood correctly.

[The Tone God]

Is there a layout for Payback 1.1?

I'm not aware of one yet.

ok, so this is the one I should, and can get?

Looks like they are out till near the end of the month. There is a section in the v1.1 article that discusses the different versions. There are some charts in the article to help you out as well. You could grab another length version and change the clock speed to get your desired time but at the loss of quality. In the article I was trying to emulate the old ISD1420 in time and quality which ended up being a ISD1616B with a 100K oscillator resistor.

So you can change to another IC length or wait until their shipment comes in. You could also change ICs later as all the IC behave the same.

Andrew

[Valoosj]

But if I get the ISD1620B in stead of the ISD1616B, won't I be able to have a longer recording at the same quality?
As I can read in your article, I would have 25sec at 6.4KHz. with the ISD1616B I would only have 20 seconds at 6.4 KHz.
(Does the KHz refer to the quality of the record?)
Forgive me this third degree, but I am new at this.

Digi-Key Part Number                              Minimum Quantity   Unit Price
               
ISD1616BPIY-ND       ISD1616BPIY                           120                       4.37500    
ISD1616BPY-ND       ISD1616BPY                            1                          5.34000
ISD1616BPY01-ND     ISD1616BPY01                        120                      3.81500
ISD1616BPYI-ND       ISD1616BPYI                           120

The second IC on the list I can buy per 1. The others only per 120. So that narrows the choice a bit

[The Tone God]

But if I get the ISD1620B in stead of the ISD1616B, won't I be able to have a longer recording at the same quality?
As I can read in your article, I would have 25sec at 6.4KHz. with the ISD1616B I would only have 20 seconds at 6.4 KHz.
(Does the KHz refer to the quality of the record?)

Correct.To get the longer time from the shorter ICs you will have to drop the sampling rate which is what the frequency rating is referring to.

I just checked and all the other DIP versions are availible in singles.

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=ISD1610BPY-ND
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=ISD1612BPY-ND
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=ISD1616BPY-ND

Andrew

[Valoosj]

So, If I want to get the longest delay time at 6.4KHz, then I should get the 1620.
Is 6.4KHz the best quality, or intermediate? You highlighted this in the scheme with the IC's, just wondering why

[The Tone God]

So, If I want to get the longest delay time at 6.4KHz, then I should get the 1620.

Yes. The only difference between the ICs is how much memory they put in. The rate sets how fast the IC goes through that memory so less memory means less time. You can slow down the clock so it doesn't go through the memory as fast hence longer time but at a lower quality since the clock is not sampling as often due to the slower clock.

Is 6.4KHz the best quality, or intermediate? You highlighted this in the scheme with the IC's, just wondering why

Oh no. You can get much better but then you run through the memory faster thus less time. The specs go up to 12khz but I would bet you can go even higher. All you need to adjust is the clock resistor.

The reason I highlighted that specific setup (ISD1616B with 100K) is because that is what the old ISD1420 performed at. Many people try to capture that old IC's characteristics because of it's "lo-fi"-ness. If you are looking for quality crank the rate up and go with a bigger IC.

Also think about how often you may end up using 20 seconds. I never found myself using that much but thats me.

Andrew

[Valoosj]

Ok, then I'll get the biggest IC, being the 1620.
The clock resistor, that's the record pot right?

I know I will not be using the 20 seconds that often, but I will use it from time to time.
So when I turn back the clock resistor (record?) then I have a high quality, but short record, which is good. and I can get really longs recordings that still sound good as well.
This might be useful to add a second guitar line underneath a solo or something.

Tomorrow I'll read through the article, now I just don't have the time.
And as soon as possible me and Ponq are going to work on a pcb layout