EHX - Full Double Tracking Effect Schematic Re-Draw

[Scruffie]

Sorry aishabag23, I did see your PM on the other site but I was on holiday at the time.

It's just a filter resistor, 22-100R should be fine.

No idea if this layout works, as I said at the time, it was my first ever PCB layout and it certainly shows.

It is a bit confusing. Connects between 9V and pin 5 of the BBD. According to the schematic, pine 5 and R7 go to ground, but I'm not seeing this on the layout?

If you look at the symbol it's actually the 9V symbol,  not ground

[aishabag23]

Yeah, that's where I got confused, too.

[aishabag23]

Sorry aishabag23, I did see your PM on the other site but I was on holiday at the time.

It's just a filter resistor, 22-100R should be fine.

No idea if this layout works, as I said at the time, it was my first ever PCB layout and it certainly shows.

It is a bit confusing. Connects between 9V and pin 5 of the BBD. According to the schematic, pine 5 and R7 go to ground, but I'm not seeing this on the layout?

If you look at the symbol it's actually the 9V symbol,  not ground

Hey Scruffie, thanks for your reply. Your layout works perfectly, it sounds exactly like the vero version I built. I would love to make a clone of the original MN3005 version on an etched PCB. I think this thing would sound fantastic as an always-on thing for me if it could run cleaner, at 15v. You wouldn't happen to have done a PCB of the MN3005 version, have you? Thanks again for that resistor info!

[Scruffie]

I'm afraid I didn't do one for the MN3005 version no, sorry man!

[pinkjimiphoton]

Sorry aishabag23, I did see your PM on the other site but I was on holiday at the time.

It's just a filter resistor, 22-100R should be fine.

No idea if this layout works, as I said at the time, it was my first ever PCB layout and it certainly shows.

It is a bit confusing. Connects between 9V and pin 5 of the BBD. According to the schematic, pine 5 and R7 go to ground, but I'm not seeing this on the layout?

If you look at the symbol it's actually the 9V symbol,  not ground

Hey Scruffie, thanks for your reply. Your layout works perfectly, it sounds exactly like the vero version I built. I would love to make a clone of the original MN3005 version on an etched PCB. I think this thing would sound fantastic as an always-on thing for me if it could run cleaner, at 15v. You wouldn't happen to have done a PCB of the MN3005 version, have you? Thanks again for that resistor info!

hahaha, yeah, the original one wants to see 18v. don't worry aisha, i haven't forgotten you, life's just been.... life.
i will get it boxed up hopefully this week. i wanted to pull it out and make sure it was working etc.
you know the drill... hound me!!

i saw this thread and was like... wow, wonder if scruff needs an original to work from nope

[aishabag23]

Sorry aishabag23, I did see your PM on the other site but I was on holiday at the time.

It's just a filter resistor, 22-100R should be fine.

No idea if this layout works, as I said at the time, it was my first ever PCB layout and it certainly shows.

It is a bit confusing. Connects between 9V and pin 5 of the BBD. According to the schematic, pine 5 and R7 go to ground, but I'm not seeing this on the layout?

If you look at the symbol it's actually the 9V symbol,  not ground

Hey Scruffie, thanks for your reply. Your layout works perfectly, it sounds exactly like the vero version I built. I would love to make a clone of the original MN3005 version on an etched PCB. I think this thing would sound fantastic as an always-on thing for me if it could run cleaner, at 15v. You wouldn't happen to have done a PCB of the MN3005 version, have you? Thanks again for that resistor info!

hahaha, yeah, the original one wants to see 18v. don't worry aisha, i haven't forgotten you, life's just been.... life.
i will get it boxed up hopefully this week. i wanted to pull it out and make sure it was working etc.
you know the drill... hound me!!

i saw this thread and was like... wow, wonder if scruff needs an original to work from nope

Jimi, you're the best!

Btw, I built your Os Mutantes Fuzz vero layout for a friend and it rocked so hard, I had to make one for myself!

[bean]

I did up an MN3005 version but it's not a verified build so...
http://www.madbeanpedals.com/EP/index.html
Under the Delay section.

[pinkjimiphoton]

aisha, its yours once i can afford to ship it financially and time wise. i may still have a spare reticon chip for it too, if i can find it i'll stick it in with the FDTE

guys, this is a fairly crappy effect, why waste good chips on it?

seriously. tonally a 2399 sounds almost exactly the same, and would be a lot cheaper and easier to work with.
 i know, i know, no mojo there...

but damn little in the original. seriously. i got one. want a vid of it before i ship it off to aisha?

[aelling]

I know this is an old topic, but here goes anyways.

Are there any mods one can do to this circuit?
I know the Full Double Tracking Effect and the SlapBack Echo shares the name of a mode on the EchoFlanger/PolyChorus, and on those the Width, Tune and Feedback pots work in said modes, any chance you could add those pots to this effect?

The EchoFlanger schematic can be found here
https://experimentalistsanonymous.com/diy/index.php?dir=Schematics/Flangers

[aelling]

Since there wasn't much interest, I took it upon myself to look at other old ehx schematics to see if I could find some mods to do to this pedal.

First was easy, getting rid of the Blend pot, the way it well, blends between delayed effect and clean I didn't like, if you true bypass this it no longer reaches unity gain, and when you put a boost stage behind it, it just gets louder when turning the pot towards the clean signal. Remove the pot and the C2 22µF and the new effect out is the R13 & R14 section, add boost stage here if you want to true bypass it.

Second was the Delay switch, it doesn't do much with just 2 settings, so I got rid of the switch, R15/R16/R17 & C12 and then replaced D2 with a B100K pot wired in series with R18 between pin 2 and pin 3 of the 4047. This was taken from a Economy Memory Man found here: https://sites.google.com/a/davidmorrin.com/www/home/trouble/troubleeffects/electro-harmonix-memory-man/eh-1309a

Last was adding a feedback pot, what I found worked best was adding a B10K pot from the R13/R14 section and run it back to the Input (C1). This was taken from a different Economy Memory Man found here, but slightly wired differently as it didn't work like it was drawn. Adding a trimpot in series before the B10K pot will help controlling how much it will feedback.
https://sites.google.com/a/davidmorrin.com/www/home/trouble/troubleeffects/electro-harmonix-memory-man/eh-7810


Doing these mods did kinda what I was looking for, which was the Slab Back/Double Tracking mode on the EchoFlanger and PolyChorus pedals. Like I mentioned, on those pedals the Tune & Width pots still work and they kind of play off each other how the "delay" sounds, I wonder if I could add another pot that does the same thing to the FDTE.

[cymazic]

Hi ,sorry to necro an oldish thread . Im a  first time caller , a bit of a noob.

Just looking for a little clarification on the wiring of the delay switch from the original schematic re-draw at the start of this thread please.
  I have an EHX Full Double  doo dah to repair but the delay switch  ( original ) is a SPDT , whereas on the schematic it shows a SPST .  Is the solution simply to only connect 2 of the lugs of the original switch ?  And . if so , would anyone be so kind as to tell me which 2?  ( I presume , the centre lug and one of the outers ) . And to where?
   From the schematic it looks like a single pole single throw with one side connected to the 47k and the other side connected to power .  I'm thinking  centre pole of SPDT to the 47k  and one of the throws to power?  Which , if correct , begs my next noob query. Is the power at the top of the switch 18v or the 12.5v reference or what ?
   Thanks for your patience
       

[pinkjimiphoton]

hey man, welcome to the forum!

yeah, you can use an spdt. choose a side. center is common, only wire it up to one side of the two other poles, and you're good to go!
part two, ya already figured out.

keep us posted!
pink

[cymazic]

Thanks for the welcome Jimi ,
                       Just to clarify .On my SPDT I should connect centre to the 47k and one of the outer lugs to 18v , leaving the remaining outer lug unused ?
     Much appreciated man
I have quite a bit more to do to this pedal to get it back to life but for some reason this little thing with the switch/ schematic symbol discrepancy  got me questioning my sanity more than usual .
    P.S.   sorry to bug ya about the power thing again , but that would be 18v on one end of the switch , rather than the 12.5v reference?
  I look forward to reading this back in the future and being suitably embarrassed hehe
 Cheers

[pinkjimiphoton]

i'd need to see the schematic, bro, been years

just looked. power to center pole, outer pole to 47k

[cymazic]

Fantastic ! Many thanks again Jimi .
 Maz

[Ben N]

Never mind.