New Effect: Payback

[The Tone God]

Very nice 

The switching looks much better than the design I came up with. I'll see if I can come up with a vero layout 

Thanks and good luck While I breadboarded one and perf'd a second with both working I would actually feel better if someone would breadboard it to make sure the circuit works, the timings are appropriate for their 25xx, and the sound is acceptable as I tunned mine somewhat to my tastes which may not be the same as others before a bunch of layouts came out which could contain errors. Thats just me as I am kind of particular about those things.

incredible work indeed, especially fitting all that in such a small box!
Do you plan on posting the pcb layout that you used to make it so tight?
That would be great!

I think I have a chance at the "most stuff in a 1590B" crown.

I didn't use a PCB. It is perf board. I decided awhile back that I will not be doing PCB layouts for anything for now on. To do "proper" PCB for that size enclosure I would need a double sided board anyways IMHO. Those gray wires you see near the top of the case on the board are the jumpers not the main collection of connections which essentially makes it a double sided board. I also used various tricks to get everything in there. All the parts with exception of the two LED resistors are on the face of the board. There are no jumpers on the face of the board.

Andrew

[Big Red]

wow I'd love to build this!
if anyone makes a layout, pcb, perf or otherwise, could they please hook me up with a copy of it?


happy (belated) Canada day to my fellow canucks and happy (early) July 4th to our brothers to the south.

[RaceDriver205]

I tell you what though, im liking the look of the ISD4xxx series, futurlec sells an 8Khz resolution 4minute chip.
Needs serial comm. though. But 4 minutes! I could record a whole backing for a song with that!
Shame they dont sell the 8minute 8Khz 4xxx model.
Something else to add to the list (groan).

[Michael Allen]

Heres's my first draft layout!  It's about 2.1 in by 2.8 in.... It should fit in a 1590B if I plan the box right... we'll see i've always just flown by the seat of my pants in that area and it never really works out!

Andrew, and others, do you think that all the parallel traces might pose noise issues? I put a little grid plane between the logic IC (left) and the audio portion (right) because I've seen this in several other pcbs to help reduce crosstalk, does it serve a purpose or can I get rid of it? There is a filter cap and resistor at the +V input as per the vanishing point article, and the logic and audio both have separate ground loops. The only place the power loops connect is through the 1N4148 leaky diode (top center), and through the 5v regulator (bottom next to ISD chip.)

I want to make sure this looks alright as far as inital physical layout before I do all the image editing and such...



http://img.photobucket.com/albums/v368/soma_hero/payback_lay_one.gif

[robbiemcm]

Good to see someone is making a PCB layout for it, I think I'd struggle with this one Hopefully I'll be able to build this one in a week or two, I've been looking at the ISD2560P from Futurlec.. I suspect it'll work?

[The Tone God]

I don't have much time right now so I can't to go through the whole layout but the first thing that throws me off are the traces between the IC pads. I don't think most people with common PCB making means (i.e. PNP and the like) have the resolution to do something like that. Someone else can go through to confirm the connections.

I let you in one little trick I used for the Payback in the initial post. I used open frame sockets, you could also use SIP sockets, for all my ICs. While this makes replacing IC easier it also serves as a spacer of the IC from the board allowing me to place parts under the ICs. The vast majority of parts in my Payback are under the ICs. By using parts like lower voltage ceramic caps, minature electrolytic caps some times on their side, and 1/8 watt resistors (I actually used 1/6 watt if you want to be specific) that one can fit under the IC when placed in the socket the board can be made MUCH smaller. If you are will to space the IC high enough you maybe able to fit standard 1/4 resistors.

Good to see someone is making a PCB layout for it, I think I'd struggle with this one Hopefully I'll be able to build this one in a week or two, I've been looking at the ISD2560P from Futurlec.. I suspect it'll work?

Any ISD25xx will work so yes the 2560 will work in it.

Andrew

[Michael Allen]

ah...open frame.... I put connections through the pads beacuse I've been able to get them to come out before and I didn't want a lot of jumpers. I suppose it would be easier to use jumpers than not get the traces to come out....

As far as the physical layout goes, is there enough separation between the audio and logic to keep out noise? I suppose i'll only be able to tell when I make it....

Alright, round two coming up...

[calculating_infinity]

looks great andrew.  one day when my skills are up to par I will attempt this build.  great work!  i like the mod suggestions. 

[zachary vex]

excellent, Andrew.  it's amazing how much you can stick on a perfboard if you hand-wire... you'd likely have to use a 3 or 4-layer board to wire something so complex with so many chips.

...I think I have a chance at the "most stuff in a 1590B" crown. ...

err... this one has 10 pots, 8 chips and 3 circuit boards.  ringtone prototype.

[nelson]

the first thing that throws me off are the traces between the IC pads. I don't think most people with common PCB making means (i.e. PNP and the like) have the resolution to do something like that. Someone else can go through to confirm the connections.

Andrew

I have managed 3 traces under an IC with PNP many times. Its possible to get impressive resolution.

[Torchy]

err... this one has 10 pots, 8 chips and 3 circuit boards.  ringtone prototype.

Show-off 

[The Tone God]

ah...open frame.... I put connections through the pads beacuse I've been able to get them to come out before and I didn't want a lot of jumpers. I suppose it would be easier to use jumpers than not get the traces to come out....

I would use jumpers as annoying as they can be. I usually jump power supply runs before anything else. Then digital logic control signals. Audio gets priority. To get an idea about the parts under IC trick heres a pic:



It is not my greatest work to say the least.

As far as the physical layout goes, is there enough separation between the audio and logic to keep out noise? I suppose i'll only be able to tell when I make it....

I haven't had any time lately to trace your layout and compare to the schematic but I think you should be okay. I the above picture I put all the logic on the left of the 2575 and all the audio on the right. Running control lines/wires is going to be important to noise as well.

looks great andrew.  one day when my skills are up to par I will attempt this build.  great work!  i like the mod suggestions.

Thanks. After doing a few articles I realized that its a good idea to try to cover those things in the article to help reduce posts and emails asking about such things. Good luck when you give it a shot.

excellent, Andrew.  it's amazing how much you can stick on a perfboard if you hand-wire... you'd likely have to use a 3 or 4-layer board to wire something so complex with so many chips.

Thank you! I agree. This was a fun build I must say and I enjoyed it. It even worked on the first try which was scary enough.

err... this one has 10 pots, 8 chips and 3 circuit boards.  ringtone prototype.

Bravo. Nice work but if thats they way its going to be then it is as the kids these days say "on". I'll come up with something from scratch and challenge that. Oh its on.

I have managed 3 traces under an IC with PNP many times. Its possible to get impressive resolution.

I have actually gotten four 10mil connections under an IC but it is the runs between the pads that bother me. Granted they are the long style pads but it is one of the things that can be on the edge for some. It would be safer to do other things, even jumpers, to keep the project as accessible to others as possible.

Andrew

[moody07747]

I'm just shocked on how that huge wiring sheet circuit can fit into such a tiny stomp box, i don't know enough about electronics to make this unit so I'm stuck spending money on one i guess 

BTW, great job

[nelson]

I have managed 3 traces under an IC with PNP many times. Its possible to get impressive resolution.

I have actually gotten four 10mil connections under an IC but it is the runs between the pads that bother me. Granted they are the long style pads but it is one of the things that can be on the edge for some. It would be safer to do other things, even jumpers, to keep the project as accessible to others as possible.

Andrew

Ah, I never noticed the traces in between the pads.



On a side note I just finished designing a layout for the Vanishing point v2.1 with the manual mod thats fits in a 1590b.

Just moving on to the fun part of designing little add on PCB's for the audio effects.

[Michael Allen]

Ok here's the latest version. This one will be tight, so you have to use miniature caps and smaller wattage resistors. I printed it out and fit parts and it works with mini caps and can be done with 1/4w resistors (tight!).... should be able to fit in a 1590B.

70mm by 43mm

I'll most likely make another one or finish the old one so regular size parts can be used...

http://img.photobucket.com/albums/v368/soma_hero/payback_lay.png
http://img.photobucket.com/albums/v368/soma_hero/payback_PCB.png

[j.frad]

looking great man! hope it works!

[The Tone God]

I'm just shocked on how that huge wiring sheet circuit can fit into such a tiny stomp box, i don't know enough about electronics to make this unit so I'm stuck spending money on one i guess 

Schematics tend to look complex due to the need to show everything clearly. Often when you go to build the actual circuit you can shrink things quite a bit. I've been doing this for awhile and have learned some tricks along the way but as Mr. Vex pointed out with perf (and even vero) you can easily produce a board that would take three or four layers on a PCB. It is one of the reasons I like to use perf for one offs.

Ok here's the latest version. This one will be tight, so you have to use miniature caps and smaller wattage resistors. I printed it out and fit parts and it works with mini caps and can be done with 1/4w resistors (tight!).... should be able to fit in a 1590B.

70mm by 43mm

MUCH better! I'll take a closer look later at the layouts and give some feedback. Nice work.

Andrew

[Big Red]

Thanks for the layouts!!!
I think this will be my next project once I get my easy-vibe started/finished 

[The Tone God]

I took a quick look through and found a few minor things.

1. Label the "Playback Level 1" pin.

2. Label the bypass control input.

3. See if you can get the 0.1uF decoupling caps closer to the ICs. Not a big deal but of you can work it out that would be good.

4. Flip the 1N4148/bypass diode. Cathode goes to 9v.

As for the noise issue I didn't have much as almost all the logic switching happens only occasionally. The only real noise to be concerned with is the clock gate and that only bled through when I did some bad wiring on the bread board.

Good work.

Andrew

[RaceDriver205]

Dont suppose you could record a short sound sample? Just of a backing guitar and solo guitar using the looper for the backing.
That'd be awesome.