Rebote Delay Questions

[oldrocker]

I'm going to try and build the 2.5 version but I have a few questions.  Pin 12 from the PT is delay out.   Also I see a (delay in) at pin 15.  Are these test points along with (delay out) at those 12k's going to pin 13?
I assume there's no connections for pin 4 and the one side of the 50k pot.  Also on the 2399 diagram at Tonepad I see the + plus points have no connections also but the - negative side is pin 16 on delay in and pin 13 on delay out.  Am I right about this?  I know these sound like noobie questions but I just wanted to make sure.  Thanks.

[markm]

Don't know if this will help ya oldrocker but,
http://www.datasheetcatalog.com/datasheets_pdf/P/T/2/3/PT2399.shtml

[oldrocker]

Thanks Mark,  After looking at the datasheet  I'm more confused. LOL!  On the datasheet it shows pin 4 going to ground but the Rebote schem shows an NC next to it which I thought meant (no connection.) One thread here mentioned the symbol at pin 4 was a digital ground and was hooked to all the other grounds since they had the same potential.  When looking at the layout it seems this is true.  So does lug 3 of the 50K pot go to ground also?  It looks like it has to.  I'm answering my own questions now.  So maybe I'm OK here eh?
Since I'm perf boarding this project I sometimes forget to look at the PCB layout.

[markm]

It may be wiser to etch a board for the Rebote 2.5.
It's got a pretty high component count and you really want it to be quiet I would think.
That looks like it could be a tough one for perf but, I've seen guys do some amazing things on perf so, Go for it 

[$uperpuma]

soggybag has a perf layout for it that fits in a 1590b...amazing

[oldrocker]

Thanks again Mark, 
I perf all of my builds.  Surprisingly all my builds are pretty quiet.  My most recent builds are John Hollis effects - EasyVibe, Zombie Chorus and UltraFlanger.  All are equal to the Rebote for parts count and difficulty IMHO.  I'm actually lucky (knock on wood) on perf boarding all my builds so far.  I'm getting pretty good at it although I'm not as neat as soggybag and some others who have perfs that look as good as etched PCB's.  I know it's crazy but I love perfing circuits.  I have fun doing it and I get a good feeling when the effect comes to life especially since I do the layouts as I build it.  Of course this means they arn't as professional looking but since it's for me to use it doesn't bother me.
I did buy an etch kit and if I did do it I would like to etch my own PCB.  One of these days I'll do it.

[zpyder]

On the datasheet it shows pin 4 going to ground but the Rebote schem shows an NC next to it which I thought meant (no connection.)

Actually, pin 5 is NC.  Pin 4 is connected to pin 3 which is connected to ground.  Kinda hard to see...

One thread here mentioned the symbol at pin 4 was a digital ground and was hooked to all the other grounds since they had the same potential.

I believe this is true.  Probably good practice in general to isolate these grounds.  I don't believe it's so much the same potential that has them connected (though I could be wrong), but rather that you are effectively "star grounding" the two "digital"(non-audio?) grounds at one point (PT2399 pin 3), therefore eliminating the possibility of ground loops between the two potentials.

So does lug 3 of the 50K pot go to ground also?

Yes.  Through the same trace as pin 4.  The grey trace - which I believe is intended to show that it is a net which is star grounded to one point.

Since I'm perf boarding this project I sometimes forget to look at the PCB layout.

Heh... I put together a perf layout for the Rebote 2.5 just the other day.  I mostly based it off of the tonepad PCB.  I will gladly post it here when I get home tonight.  It is unverified at this point, so ONE of us is gonna have to verify it

soggybag has a perf layout for it that fits in a 1590b...amazing

Be forewarned - this is labeled rebote 2, NOT 2.5...

cheers,
zpyder

[oldrocker]

OK. thanks zpyder,
I didn't notice but you're right that NC is on pin 5 not pin 4.  Anyway you've cleared a lot of issues up for me.  I would be interested in any layouts you might have for the 2.5.  I'm glad you told me about the soggybag layout cause I was trying to find it so I could use it.   Well I can be the one to verify that for you.  I'm still waiting on some parts before I start building it.  There are some strange cap values for this one.  I read somewhere that you can use the 10 percent tolorence window and use more conventional cap values.
Thanks again.

[zpyder]

oldrocker-
I'm about to head home, and, unless I get sidetracked, will upload the layout for you.  I would say that the layout I put together is crammed into a pretty small space.  It's intended to go onto one of the 2.3" X 1.9" Perfboard pieces sold here by Aron.  So, there's a lot of crammage going on, but hopefully it will work, and that way it can fit into a smaller box!!

cheers,
zpyder

[oldrocker]

OK great.  Thanks that would be good so I can try and fit in a smaller enclosure then what I was going to.

[zpyder]

Alright.... well shite.  I just realized I made a super-f#*k up!!! arg... On accident I made the layout 24x18 instead of what Aron's perf actually is, which is 23x18.  Son of a!!!!  Well, since the entire bottom row is a Ground rail, this should be easy enough to do with some isulated wire below the board.  In any case, I hope it helps, as this is the most complex layout I've attempted to date (cramming sure helps with the complexity!).

UNVERIFIED:


Things to note:
1) There are 4 Insulated wires listed on the layout (not including the suggested GND rail at bottom due to sizing mishap).  I DID draw lines for them, so please check and double check that you aren't just connecting these as ordinary leads.
2) Lug 1 of each pot needs to go to ground.  You could either ground them directly to the chassis (directly to themselves) which can be noisy if the washers get loose, or star ground them in any fashion you desire.
3) Leg 2 of the Delay Pot (50k Lin) can be connected directly to lug 3 of the same pot
4) There will be some VERY close leads on the bottom, be careful

Here's the DIY Layout Creator source file:
http://www.mattrabe.com/circuits/Rebote%202.5.diy

looking at this thing, it's gonna be a challenge getting it all onto the board - good luck!
lemme know what you think!

cheers,
zpyder

[oldrocker]

Wow!!   That is one busy layout.  Nice job man.  I think this will be more difficult than I first thought.  But I'll do my best to make it happen.  Looks like you put a lot of work and effort putting that layout together.  Looks good though and I think it's going to be a big help when I start building it.  I keep you informed on  how it goes every step of the way.

[zpyder]

thanks man... yea, I did put some time into putting that thing together.   I just hope it's physically possible!!

I found that those box-style caps help quite a bit in fitting way too many things into a small space since they can be placed directly adjacent to eachother very nicely.

good luck and let me know how it goes!  I will re-do the layout sometime soon to omit that bottom row so it fits onto one of aron's perfs.

I will probably end up building at least two of these in the near future - one will be used for guitar, the other will be used for vocals with an accompanying balanced XLR to 1/4" switched loopbox.

cheers,
zpyder

[zpyder]

oldrocker-

hey man... I changed the layout to fit aron's perf.  I don't know what you're using... anyways, I reuploaded it to my gallery that I just created.  Pretty much just took the bottom row offboard and readjusted a couple of ground connections to make up for the lost row.

Check it out at http://aronnelson.com/gallery/zpyders-veb under Layouts (it's the only one right now...)

cheers
zpyder

[oldrocker]

Yes I went to your layouts and checked it out.  I will print it and work off that one when my parts arrive.  I may start building it sometime today so when my parts get here I'll be far enough along hopefully to finish it.  Thanks again for the layout.

[oldrocker]

Hey zpyder,
I'm done building the Rebote 2.5 using your layout.  I messed up with placement of the 16 pin socket.  (Not watching what I was doing.)  I didn't fix it since I was too far along and it would've been a hard.  But for the most part the layout is yours with only minor changes.  I'm unable to try it out because Futurlec is dragging their feet on getting a PT2399 and a 5 Volt regulator I ordered.  I will post a pic of the board too when they arrive. 
I have a question though.  Is pin 3 on the PT2399 supposed to be grounded also along with pin 4?  I assumed it is so I did but the layout doesn't show it.  Also on the 100k pot I noticed lug 1 wasn't going to anything so I grounded that also.
Anyway after I try it out I'll let you know how your layout worked. 
A note :  it seems that some components on the layout shared the same pin holes.  When looking at layouts on ROG they always show the separate holes for each component attachment.  Just an observation.

[oldrocker]

Well zpyder's layout works.  So it is now verified.  I will post some pics tomorrow.  The pedal sounds great.  It was everything I hoped it would be so i'm happy about that.  I had some soldering issues but once they were ironed out it fired up nice.  Thanks again zpyder for the layout.  I was able to slide the PCB into a slot in the enclosure I used.  It's not a small enclosure but I like being able to use the slots they provide so the board sits horizontal.  I just have to finish boxing it up tonight.

[oldrocker]

   Actaually I meant to say that I like using the slots built in to the enclosure so the board sits vertical leaving a lot of room inside the box to stuff in everything else.

[zpyder]

I have a question though.  Is pin 3 on the PT2399 supposed to be grounded also along with pin 4?  I assumed it is so I did but the layout doesn't show it.

Yes.  I put this board together over the weekend (haven't tested it yet...) and I noticed the same thing.  Actually, there IS a lead between pins 3 & 4 but it is nearly impossible to see because it is directly under the border of the PT2399.

Also on the 100k pot I noticed lug 1 wasn't going to anything so I grounded that also.

Yup, all pots should be grounded at pot 1.  I decided not to put any lead for them on the board to save space, since they can be grounded elsewhere.  I would recommend "star" grounding them all to one place on the chassis or alternately all to one place on the back of the perf.

A note :  it seems that some components on the layout shared the same pin holes.  When looking at layouts on ROG they always show the separate holes for each component attachment.  Just an observation.

Yea, I really crammed some of those in there.  This was the first layout I did for a somewhat-complicated circuit.  Definately a learning process.  When I put mine together over the weekend a few things occurred to me, which I was able to work around, and will change on the layout.

Well zpyder's layout works.  So it is now verified.

Woo hoooo!  Thanks for verifying!  Now I'm even more excited to finish mine!

cheers,
zpyder