INFANEM the driving notion clone

[crochambeau]

All this talk has piqued my interest, so I went to the EYG website to maybe buy a PCB and have a run at it myself, but it's a placeholder now. Are these available elsewhere?

[imJonWain]

Not that I know of, EYG actually comes up as forsale to me lol.

Per the notes in the thread I find even with the changes listed (adding a bias ref to GND and change another bias R) it's more a splattery glitch fuzz. I'll keep playing with it tonight/tomorrow and see what can be dids.

[BetterOffShred]

Yeah mine is splattery and glitchy as stated

[BetterOffShred]

I've got insane oscillation issues so who knows. I don't want to give up on this yet. I wish we could get some photos of one of the through hole boards.

You want pics of my board?

[imJonWain]

I meant photos of an original through hole version.

[goroth]

Yeah mine is splattery and glitchy as stated

Yep. This was afaik Schlatte’s impression too. Put a booster In front and it’s noisy but pretty sick.

Curtis, I can send you a board or two that schlatte made me, but it’s clearly not correct.

[Schlatte]

Just to chime in, during my go at this I made the following adaptations, to get the oscillations and sputtery madness down:

All the troubles I found were in the "Hi EQ" Path or Treble path or whatever you wanna call it. The schematic on EYGs website seems to be offline, so I can't show all the mods, but basically I did all this:

-) Added a 10M Resistor to +9V from the J201 Gate (causes a slight bias shift)
-) changed the strange 170k/17k biasing on the "Hi" BJT to 220k/22k
-) added the 47k Resistor to GND on the BJT after the 7n5 cap (as previously discussed in this thread)
-) changed the collector resistor on that BJT from 100k to 10k -> AC Gain is anyway given by the 10u Emittor Resistor bypass cap, reducing the DC Gain helps to reduce the sputterness
-) changed the biasing resistors on the next BJT stage to 470k/47k
-) also reduced the Collector Resistor to 10k on that one
-) reduced the 100n cap in series with the soft clipping diode to 10n
-) to get some gain symmetry, I also reduced the 47k Collector resistor on the BJT Stage in the "Bass" or "Low" Path to 10k, but that isn't strictly necessary I think.

As mentioned by goroth, it doesn't sound true to the original with those mods, but thats how I got it to work.

[imJonWain]

I'm really curious what things I may have missed or messed up in the trace or if it's mostly component values (off by a decade or something). I guess also we can't be 100% on the transistor IDs.

I'll try some of those mods out!

[goroth]

Recall that I'm not being bashful when I say that I know awfully little about electronics - I know enough to get into trouble.
But... from what I recall of playing a DN I got that kinda Devi reversed transistor vibe about it, tonewise. Is the orientation on the transistors correct?
I also recall the DN being quite smooth, even though it was clangy.

For reference - DD's demo is perfect tonewise and gives you a good view of how the knobs affect the sound. My rig is veeeery different to DD's but this is how it sounded to me as well. So I think it's very representative for how the pedal should sound
[youtube]http://www.youtube.com/watch?v=yPDiuxBdvrU[/youtube]

[ibarakishi]

the feeling when you have not played guitar almost at all in 2020, literally have been waiting a year for your favorite pedal ever to come back into your life, are told that its traced and done, and then are told upon further inspection by others that the saga is not yet complete




side note: the pedal is very much as goroth says above. and that demo is by far the best representation of how it sounds pretty much across the board in my own experiences too. i have alumitones though, so my sound was always more crisp and hi fi sounding obviously, and way less forgiving in the high register. this thread is bumming me out big time

[imJonWain]

orientation may, or possibly may not, be right since I had no way of telling besides assuming package pinouts based on the smt 2n2222 and some deduction. Not sure how much EYG dug into it. I basically traced up to the transistors, drew out what I saw, and based off the common 2n2222 package said "this makes since" with what the part is. I didn't have it in hand so It's possible I made a mistake in the routing but I spent a lot of time on it.

I'll look over the images and tracing today when my head stops hurting.

The 2011 thread on here says "Gain and distortion are via transistors, a jfet, and a germanium diode." The image shows Clearly 5x 2n2222s (Metal can through holes) and 3x "others", 1 being the J201, the other two would "some other" transistor which matches up with ibarakishi's pedal. So the only "maybe" there is the last two transistors. I assume EYG measured the HFE of them and from that guess on the 2n5089s.

We will get it done! Let me see if I can track down some other infanem or devi schematics and see what they are doing.

[crochambeau]

Curtis, I can send you a board or two that schlatte made me, but it’s clearly not correct.

No, thank you. I do better with as clean a slate as possible at start and this was already sounding like a challenging exercise.

That demo though, delectable. I understand the excitement...

this thread is bumming me out big time

Well now, we can't have that.

I guess I'll have to take a stab at a strip version and see if I can contribute anything to our knowledge pool here (I expect it'll just be more of what not to do, hahaha).

[imJonWain]

Looking over the pictures now I believe at least part of the issue is in the trace, related to the Q6 and Q7 diode/negative feedback. I'm making more coffee.


Nevermind, it appears correct all correct including Q6 being biased by a solo 470k resistor. The 170k/17k pair does look to be 470k/47k pair though but it's hard to tell. The only thing I can think of is if there is a weird connection under Q6 or Q7 I can't see. Q6 and Q7 could be some other transistor though, the pinouts don't match a standard sot23-3 2n3904/2n5088/etc even upside down.

If anyone else wants to take a look I can send you the photos I have.

[imJonWain]

If anyone has an idea for what Q6 or Q7 could be or another possible orientation...

[crochambeau]

I'm still digesting this thread a bit, so forgive me if I'm hitting something that has been addressed already.

The hand drawn Q6 & Q7 are BJT, while those positions in the pdf are depicted as a FET type (granted, I'm not taking the pdf as a proofed document based on the C2 value). With respect to Q6 & Q7 orientation, short of swapping the collector and emitter and changing Q type to PNP and stage configuration to common collector I am not groking any alternate types. The common emitter as drawn does make the most historical sense. I suppose a common base configuration might be nifty if you're hitting it hard enough, but we're veering into weirdo waters here and that's not the vibe I'm getting from this thing.

I did find the PCB listed for sale at EYG's shop, but I'm a bit reluctant to cough up $16 plus shipping with nary a single successful completed PCB (that is the current score at the moment, correct?). Anyway, those are still listed here: https://eatyourguitar.myshopify.com/col ... ing-notion.