EHX - Full Double Tracking Effect Schematic Re-Draw

[Scruffie]

Here's a Redraw of the Factory Schematic of the EHX - Full Double Tracking Effect for those of you with poorer eyesight, I think the Redraw is True to its source, I can't recall where I got the original Factory one from and nor can I confirm its Authenticity so if someone knows the link to that or if it's correct, that'd be handy.



I might see about converting it to 9V & V3205s as it's quite a nice simple looking Delay Project.

The EH Mans Article on the Pedal and its Predecessors - http://electroharmonix.vintageusaguitars.com/index.php?option=com_content&view=article&id=31:ehs-other-delays-part-1-batteries-not-included&catid=13:electro-harmonix-articles&Itemid=45

[Scruffie]

Converting this to V3205... could I forego the Power Supply section and just give the whole thing 9V straight from a battery, swap the pin connections on the V3205 as usual and then just use a 5V Zener to give it its bias voltage? (As it's only rated up to 8V and runs best at around 5V).

Or is that a little bit too simple...?

[Scruffie]

Crap, Realised I missed a Ground Connection off the MN3005 -


(How do you go about replacing images on photobucket without having to change the link and repost them? Any way?)

Found where I got the original too - http://sites.google.com/site/electroconducive/EHXFullDoubleTrackingEffect.pdf (Cheers Nelson if you're still around)

Can someone explain why Vdd & Gnd are linked on the 3005... is that right?

[dmc777]

I've been interested in building one of these pedals for a while now. Seems like it would be a pretty "first delay" project. Hope you work it out.

[Scruffie]

I've been interested in building one of these pedals for a while now. Seems like it would be a pretty "first delay" project. Hope you work it out.

I think i've basically worked out the best way to do the conversion now (With a helping hand) It just needs Breadboarding to Verify it, i'll post the schematic here afterwards (might be a bit off though as no chance to get to the breadboard)

[Scruffie]

Right... this has now been verified with a 3205 chip and it works well, ableit needing a few refinements to bring the pedal into the modern age.

What I was thinking though, was if there'd be interest in a fabbed, double sided, silk screened PCB to fit a 1590B enclosure with battery using the 8 - Pin DIP Version of the 3208 Chip available at smallbear (assuming that works upon testing rather than the 3205, don't see why it wont as the full delay of the 3205 isn't utilised) laid out like the EHX Nano Stone/Clone (Pot to the right, switch to the left side) with onboard pot.

I think it'd make a good sorta, babies first BBD Delay project, from the clips i've heard (I couldn't breadboard this myself as I don't have access to my electronics so this was performed for me) it sounded very nice as a slap back delay and I think for a 1590B project, it'd be pretty nice to have and also give a very simple insight into how BBD based effects work for people interested in learning (Doesn't get simpler than the Clock, BBD & Single OpAmp set up) at speculation say the boards were... $7 each? What would everyone think of that? So I know if it's worth looking in to.

[chi_boy]

I'd buy a board.  Woundn't hesitate. :-)

[Scruffie]

Okay... here's my first ever attempt at a PCB layout for a pedal so go easy on it... it's not the greatest and I haven't checked it but it's a proof of concept atleast to get this into a 1590B with a Board Mounted Pot (Pot Mounted on Back) and hopefully battery too.

Here's the verified schematic for the 3205 version I dropped the 0.1uF Cap and 1N4001 from the power supply section as there just wasn't room.








Board measures 53.34 x 53.34

Do any of the PCB gurus have any tips from what i've done? If I used stand up resistors or upped the enclsoure to a 125B I could probably get it in but i'd much prefer not to, I know it's kinda ugly in places but I quickly lost room, hence the generally squished areas and one large jumper aswell as 6 smaller ones.

Any feedback however harsh will be appreciated  

[Scruffie]

Corrected missing ground trace -



No love for this effect? 

[Hides-His-Eyes]

No love for BBDs scruff!

[Scruffie]

No love for BBDs scruff!

Damn you PT2399 *Shakes Fist at Sky*

[El Heisenberg]

heh heh maybe i'm tired or maybe it's what i just inhaled but that was funnay and i wanna say so

[chi_boy]

No love for this effect? 

Did you build this thing?  If so, and samples?

I like the double track sound and it looks like you can do the same thing with a regular delay, but my PT-80 just sounds like a reverb when I try.

[Scruffie]

No love for this effect? 

Did you build this thing?  If so, and samples?

I like the double track sound and it looks like you can do the same thing with a regular delay, but my PT-80 just sounds like a reverb when I try.

I haven't yet as i'm still waiting on a PCB I ordered from someone a month or so ago however I have heard samples (I was asked not to post them) and it sounded pretty damn good to me.

[azrael]

Could they be PMed? I've never heard of this effect, but it seems interesting enough, if I could hear what it sounds like.

[Scruffie]

Could they be PMed? I've never heard of this effect, but it seems interesting enough, if I could hear what it sounds like.

Urmm, i'll ask him.

It sounds like a short slap back delay or a reverby delay though depending where you set the switch, it was nice even on a camera phone recording.

[chi_boy]

Is he shy about his playing?  No need to be, if it is.  It's about the effect, not a talent show.

[Scruffie]

Is he shy about his playing?  No need to be, if it is.  It's about the effect, not a talent show.

No idea, he just asked me not to post them when he gave them to me, probably due to the poor audio being a camera phone recording and all.

[aishabag23]

Okay... here's my first ever attempt at a PCB layout for a pedal so go easy on it... it's not the greatest and I haven't checked it but it's a proof of concept atleast to get this into a 1590B with a Board Mounted Pot (Pot Mounted on Back) and hopefully battery too.

Here's the verified schematic for the 3205 version I dropped the 0.1uF Cap and 1N4001 from the power supply section as there just wasn't room.








Board measures 53.34 x 53.34

Do any of the PCB gurus have any tips from what i've done? If I used stand up resistors or upped the enclsoure to a 125B I could probably get it in but i'd much prefer not to, I know it's kinda ugly in places but I quickly lost room, hence the generally squished areas and one large jumper as well as 6 smaller ones.

Any feedback however harsh will be appreciated 

This is an old thread, but I figured I would give it a try... I've etched and built Scruffie's PCB layout and I've got it all finished except for R19. I can't see to find it on the schematic. Am I blind? It's driving me crazy! If anyone can help I would be grateful.

[mth5044]

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?