EHX - Attack Decay (I Need your Help!)

[Scruffie]

Does anyone have the Redrawn/Corrected schematic for this effect that was available a few years back, i've looked and the only link I found, was a geocities link and the 'Way Back Machine' Couldn't find it.

If you have it saved somewhere, it'd be very helpful! Also, if you happen to own the pedal or know someone that does, some good gut shots of it would also be be very helpful.

Many Thanks!

[emstin1]

I found this http://www.freeinfosociety.com/media/pdf/4118.pdf, but I have the feeling this is the uncorrected version. 

[Scruffie]

Yup, that'd be the factory one I already have 

But thanks for checking for me Anyway! 

[newperson]

http://www.diystompboxes.com/pedals/attackdecay.jpg

[Processaurus]

Just a random thought on building a workalike of the EH Attack Decay, while the note trigger detection works things out, to  make sure it doesn't false trigger, it takes a couple cycles of the signal, but so it doesn't let the first couple cycles of the note *blip* through the VCA, it has an analog delay built in to delay the sound a bit, much like plugins that have a lookahead option.

It doesn't have to be a BBD to do the delay, it could be a PT2396 in "Easy Mode", a low parts count (a 5v regulator, the IC, and a couple support R's and C's)way to get a high quality 10ms digital delay.

[StephenGiles]

What was changed? I'm working at home today due to the snow (as you can see!!) so I can dig out the circuits I have.

[nelson]

There is a redraw kicking about with some corrections. I remember someone sending it to me. I'll have a dig about in old correspondance and see if I can find it.

[Mark Hammer]

Just a random thought on building a workalike of the EH Attack Decay, while the note trigger detection works things out, to  make sure it doesn't false trigger, it takes a couple cycles of the signal, but so it doesn't let the first couple cycles of the note *blip* through the VCA, it has an analog delay built in to delay the sound a bit, much like plugins that have a lookahead option.

It doesn't have to be a BBD to do the delay, it could be a PT2396 in "Easy Mode", a low parts count (a 5v regulator, the IC, and a couple support R's and C's)way to get a high quality 10ms digital delay.

Although it might be easier and cheaper to go with a Coolaudio MN3207 workalike and just make the appropriate connections for the change in polarity.

[Scruffie]

What was changed? I'm working at home today due to the snow (as you can see!!) so I can dig out the circuits I have.

Not even a flake where I am staying at the moment, i'm quite dissapointed!

As Nelson said, there's apparently a redraw with some corrected values which is what i'm after (Thanks newperson, but that's the same as the pdf above as far as I can make out  )

Just a random thought on building a workalike of the EH Attack Decay, while the note trigger detection works things out, to  make sure it doesn't false trigger, it takes a couple cycles of the signal, but so it doesn't let the first couple cycles of the note *blip* through the VCA, it has an analog delay built in to delay the sound a bit, much like plugins that have a lookahead option.

It doesn't have to be a BBD to do the delay, it could be a PT2396 in "Easy Mode", a low parts count (a 5v regulator, the IC, and a couple support R's and C's)way to get a high quality 10ms digital delay.

Although it might be easier and cheaper to go with a Coolaudio MN3207 workalike and just make the appropriate connections for the change in polarity.

That's basically what i'm gunna do, convert this over to the 3207 and a LM13X00 instead of the 2 CA3080s, I can redraw the schematic we have here but doesn't seem a lot of point when It's known to have errors and of course, this isn't just about having a workalike, wouldn't be in keeping with the rest of what i'm doing!

This is what sparked it - http://www.youtube.com/watch?v=ihsqM0MLRLg

[nelson]

That video is pretty awesome.

I've had a look through some correspondance. I can't seem to find the schematic anywhere.

Last ditch attempt is looking into old hard drives. But, they're in the garage. I don't have a way to access The old 2.5" IDE drives that they're probably on.

[StephenGiles]

I can't find the other factory schematic that I got from EH UK, it could be anywhere now unfortunately. I have always tried to keep my EH collection in one folder but a small number do seem to have gone astray. It was a bad copy but would have come from EH USA before any alterations appeared!!!

Any snow yet Scruffie? We are completely snowed in now with 12-18 inches. No cars will be moving in our road for a while, just a narrow footpath in the middle!! My boss had to stay in London last night as there were no trains out of Victoria due to the Arctic conditions!!

[Scruffie]

I can't find the other factory schematic that I got from EH UK, it could be anywhere now unfortunately. I have always tried to keep my EH collection in one folder but a small number do seem to have gone astray. It was a bad copy but would have come from EH USA before any alterations appeared!!!

Any snow yet Scruffie? We are completely snowed in now with 12-18 inches. No cars will be moving in our road for a while, just a narrow footpath in the middle!! My boss had to stay in London last night as there were no trains out of Victoria due to the Arctic conditions!!

Drats, this seems like it might be the project that got away... Which at $700ish an original, is a bit of a shame, let me know if you do manage to break into any of those old Drives Nelson.

Nope! None at all, i'm down near Teignmouth/Torquay waiting to move into my new House (Which with solicitors and estate agents being snowed in, is increasingly more doubtful before christmas) hasn't been any that i've seen, just bloody freezing outside. I only have last years snow to go on (I missed out on the big 87 was it one?) but this sounds like it's been even worse! Kinda a shame to miss all of it though.

[nelson]

I can't find the other factory schematic that I got from EH UK, it could be anywhere now unfortunately. I have always tried to keep my EH collection in one folder but a small number do seem to have gone astray. It was a bad copy but would have come from EH USA before any alterations appeared!!!

Any snow yet Scruffie? We are completely snowed in now with 12-18 inches. No cars will be moving in our road for a while, just a narrow footpath in the middle!! My boss had to stay in London last night as there were no trains out of Victoria due to the Arctic conditions!!

Drats, this seems like it might be the project that got away... Which at $700ish an original, is a bit of a shame, let me know if you do manage to break into any of those old Drives Nelson.

Nope! None at all, i'm down near Teignmouth/Torquay waiting to move into my new House (Which with solicitors and estate agents being snowed in, is increasingly more doubtful before christmas) hasn't been any that i've seen, just bloody freezing outside. I only have last years snow to go on (I missed out on the big 87 was it one?) but this sounds like it's been even worse! Kinda a shame to miss all of it though.

Don't give up so easily. I'd be willing to lend my skills to this one. If you can find good gut shots, we can rev engineer it. I'd be happy to do the PCB and convert to LM13X00 for this one.

[Scruffie]

I can't find the other factory schematic that I got from EH UK, it could be anywhere now unfortunately. I have always tried to keep my EH collection in one folder but a small number do seem to have gone astray. It was a bad copy but would have come from EH USA before any alterations appeared!!!

Any snow yet Scruffie? We are completely snowed in now with 12-18 inches. No cars will be moving in our road for a while, just a narrow footpath in the middle!! My boss had to stay in London last night as there were no trains out of Victoria due to the Arctic conditions!!

Drats, this seems like it might be the project that got away... Which at $700ish an original, is a bit of a shame, let me know if you do manage to break into any of those old Drives Nelson.

Nope! None at all, i'm down near Teignmouth/Torquay waiting to move into my new House (Which with solicitors and estate agents being snowed in, is increasingly more doubtful before christmas) hasn't been any that i've seen, just bloody freezing outside. I only have last years snow to go on (I missed out on the big 87 was it one?) but this sounds like it's been even worse! Kinda a shame to miss all of it though.

Don't give up so easily. I'd be willing to lend my skills to this one. If you can find good gut shots, we can rev engineer it. I'd be happy to do the PCB and convert to LM13X00 for this one.

I wasn't exactly giving in, just didn't think it was going to happen any time soon as i'd contacted several people that used to own the pedal and received no reply...

However! A Collector Contacted me yesterday and is hopefully going to provide some gut shots to me of his EHX collection (whether or not that includes an Attack Decay remains to be seen, but still, that should be helpful for some of the other pedals on the go) and also an extremley kind Mr.Giles has found me a copy of the correct schematic so a Redraw will be on its way shortly 

If you think you can help on the Conversion Nelson, that'd be great, I think this one is definitley on the cards for a PCB run if it works out.

[Scruffie]

Here we Go!

There's a few bits I can't make out... Like what the hell connections are going on inside the 4066, I did my best to mark out what I thought I saw, however my guess is that  3,4 & 5 connect and so do 6, 8 & 9, even though I haven't drawn it like that. There's also a note on the Top Right of the Original... probably not too important...

C17 is questionable, it looks like it says 2.2uF but it also looks like it says 1uF so I went with 1uF for now, not sure why C13 is crossed out in the factory schematic, assume it was of negligible importance at only 15pF. Finally there's a 1 by the Output of the 741 but the output should be Pin 6... maybe it's just a mark on the schematic that looks like a 1.

Think that's everything and with those notes, the Schematic Redraw:-

[StephenGiles]

It is a mark near the output of the 741, I can just about see a very faded 6 by the output pin. I think C17 is 2.2uf crossed out with 1uf underneath. I've looked at the 4066 with a magnifying glass and can't make head nor tail of it.

[EATyourGuitar]

so I guess all we're waiting for is the mn3007 to cool audio 3207 conversion. then a breadboard test. then PCB's

WOOT!

[Scruffie]

It is a mark near the output of the 741, I can just about see a very faded 6 by the output pin. I think C17 is 2.2uf crossed out with 1uf underneath. I've looked at the 4066 with a magnifying glass and can't make head nor tail of it.

I'm glad i'm not the only one that couldn't tell what was going on in there! I don't really know the 4066 all that well so i'll have to look into it... that or just trial and error breadboarding.

Looking at the incorrect schematic however... the 4066 doesn't have those dotted connections and just has 3&4, 8&9 and 11&12 connected internally, seeing as those are the clear connections on the schematic, maybe they're correct and those dotted lines that appear to be inside the original are just scribbles.

Yeah I saw the faded 6 but it really looked like a 1 there, i'll take that off now though. Can you make out what any of the information on the top right by the MN3007 is about? I think it might just be information about resistor wattage but I really can't tell.

so I guess all we're waiting for is the mn3007 to cool audio 3207 conversion. then a breadboard test. then PCB's

WOOT!

It's a bit further than that away... gotta get it running with the MN3007s first, there's no Guarantee this works in its current state so it'll be breadboard this to verify (along with hopefully finding some gut shots to check final values) then conversion to V3207s & LM13700s in place of the 3080s and then if that works, on to PCBs if there's enough interest for a run.

[StephenGiles]

It looks like 500mv pk so it could mean 500mv peak to peak.

[Scruffie]

It looks like 500mv pk so it could mean 500mv peak to peak.

Ah yes, that's what that'll be, but above the 3007, there's an arrow going down to Pin 5 of the 3007, the note looks like it says '5' something.