EHX - Y-Triggered Filter Schematic Re-Draw

[Scruffie]

Here is a Preliminary Schematic Re-Draw for the EHX Y-Triggered Filter from the Schematic Here - http://sites.google.com/site/electroconducive/EHXY-TriggeredFilter-Factory.gif (Thanks to Nelson Again for Hosting These)


I've only filled in the values I could definitley read for now and realise a few bits needs changing but it should be close enough to the original to get started on completeing the schematic.

Here are two Gut Shots provided by Mark Hammer which should help in deciphering the rest of the schematic :-
http://img.photobucket.com/albums/v474/mhammer/ytf_co1.jpg
http://img.photobucket.com/albums/v474/mhammer/YTF-labelledmirror-imagecopperside.jpg



Anyone that can add values would be helping greatly to help me confirm what I add as I go along.

[Scruffie]

Okay... Going from Marks Unit I'm now at this stage... a Few Values I haven't worked out yet and my eyes have gotten too tired for one night, if someone could check it over it'd be appreciated.

[Mark Hammer]

Thanks!!  Much better.  Still can't figure out what the hell does what, but at least I can read it, and that's a good start.  A few missing resistor values but we can figure those out.

I gather the switch does two things at once.  Could someone who understand OTA-based filters better than I do explain to me what those two things are?  I can see one set of contacts changes one series resistance from 345R to 75R, while the other changes a different series resistance from 147k to 47k.  I just don't know what those changes "do".




And, um, just how much coffee do you drink?

[Scruffie]

And, um, just how much coffee do you drink?

I'm not quite sure what that was aimed at, the lateness of my posting in general, the staring at schematics untill late at night part...

But only about one cup, sometimes two, sometimes none a day 

I'm gunna try and finish this up later... if anyone else has some more gut shots, due to Electro Harmonix insistance on never quite using all the right parts and changing designs alot, it'd be helpful... I can't see the 4th transistor in Marks shots for instance (unless I just missed it or it's hidden under another part).

[Mark Hammer]

Stephen Giles found a better scan of the original YTF factory schem, where the component values are clearly visible, including the mystery resistors.  I'll try and post it later tonight, if he doesn't beat me to it.

The "coffee comment" was simply a tongue-in-cheek remark about this burst of productivity on your part.

[Scruffie]

Stephen Giles found a better scan of the original YTF factory schem, where the component values are clearly visible, including the mystery resistors.  I'll try and post it later tonight, if he doesn't beat me to it.

The "coffee comment" was simply a tongue-in-cheek remark about this burst of productivity on your part.

Indeed he has, he's just sent me the copy (Thanks Stephen) and i'm just updating my schematic now and touching it up a bit with the new information.

Ahh  that would be due to being stuck in the middle of nowhere for the week with nothing better to do, so i've dedicated it to EHX.

[StephenGiles]

Just mailed you an idea for repositioning TR1 Scruffie - just to take a rest from preparing accounts for a chain of Fish & Chip Shops which is an even bigger muddle!

[Scruffie]

Just mailed you an idea for repositioning TR1 Scruffie - just to take a rest from preparing accounts for a chain of Fish & Chip Shops which is an even bigger muddle!

Dear God... What have they done!?

Anyway, here it is, think everything is right now and labeled with the correct part numbers, Thanks to Stephen & Mark for the help -



I Just got your E-mail aswell Stephen so I'll Draw up your Repositioned Version in a little bit too... then we can sort out testing it and converting it to a more available OTA.

[Mark Hammer]

Re: "productivity"

Ahh  that would be due to being stuck in the middle of nowhere for the week with nothing better to do, so i've dedicated it to EHX.

Forum member Rick Lawrence has always impressed me with his productivity.  But then, as he explained it to me, because of his job as travelling inspector, he spends a lot of time cloistered on ferries and stuck in small-town motel rooms with nothing else to do, so he always brings his building kit with him.  Probably helps to have a fully-outfitted top-notch machine shop at your work too.

Some guys have all the luck.....and time.

[Scruffie]

Re: "productivity"

Ahh  that would be due to being stuck in the middle of nowhere for the week with nothing better to do, so i've dedicated it to EHX.

Forum member Rick Lawrence has always impressed me with his productivity.  But then, as he explained it to me, because of his job as travelling inspector, he spends a lot of time cloistered on ferries and stuck in small-town motel rooms with nothing else to do, so he always brings his building kit with him.  Probably helps to have a fully-outfitted top-notch machine shop at your work too.

Some guys have all the luck.....and time.

Ahh, All my building kits stuck in storage, just got the ol' laptop. This situation didn't arise from luck exactly, I was supposed to be living in my new place by now but the builders and decorators decided they liked not finishing for an extra 2-3 weeks so the last place I could get to stay with flooring and plumbing within reasonable driving distance of my last home and bring my dog with me was here in the middle of the countryside, I can't complain about the surroundings but for activities, other than 'The Local Pub for Local People' and the occasional young country wench, I'm rather limited.

So rather i'm a comfortable homeless person with electricity, internet and too much time on his hands.

[StephenGiles]

U2 could be redrawn like this:



It makes it slightly more normal looking - presumably it's some kind of filter for the CV. I don't understand what R21 is all about.

[RickL]

Nice to know I made an impression 

As I type I'm sitting in a hotel room in Campbell River contemplating finishing a flanger that I've worked on for the last two nights. I love free wireless internet!

My favorite ferry story is the time that I was soldering in a study station on the way to Vancouver when I heard "he's making a bomb, no, look, he's making a bomb" from a group of young people sitting a few seats away. A few minutes later a woman in a BC Ferries uniform came up and said "we've had some concern expressed about what you're doing here". When I explained what I was doing there was no problem but I did imagine the captain preparing to call in a SWAT team.

Sorry 'bout the sidetrack, when I saw my name I had to respond.

Rick

[rankot]

Just mailed you an idea for repositioning TR1 Scruffie - just to take a rest from preparing accounts for a chain of Fish & Chip Shops which is an even bigger muddle!

Dear God... What have they done!?

Anyway, here it is, think everything is right now and labeled with the correct part numbers, Thanks to Stephen & Mark for the help -



I Just got your E-mail aswell Stephen so I'll Draw up your Repositioned Version in a little bit too... then we can sort out testing it and converting it to a more available OTA.

I would like to build this one, but I see an error - V/2 is connected to ground at the bottom of a schematic. So the question is: shall I connect R34, C17 and C16 to GND or V/2? Also, why are Q2 emitter and collector shorted?

[rankot]

I think that it shall look like this, according to PCB photos provided, but I am still not sure where does C16 go, to V/2 or to ground.