IR 3109 filter board

Does anybody have the component layout for the IR3109 filter board ?.
I have finished mine and have found that the output is muffled. This filter works but there’s no top end.
I’m going to start checking that I’ve got the components in the right places but I don’t have the layout.
Can anybody help ?.

WayBackMachine is your friend:

Thanks eelco, the archive is there but the layout is not.
Many thanks anyway.

I’ve also looked for that schematic for my archives (especially since my SDE modlist now includes an IR3109 tweak), but haven’t been able to track it down anywhere.

I’ve got all the other circuit diagrams in PDF format, but not that one - sorry!

Perhaps Olivier will take pity on the two of us for archive purposes only :wink:


The schem has been papershredded.


“Thanks eelco, the archive is there but the layout is not.”

The (large) picture does not help ? You wanted to know whether your components are in the right place … the picture should help.

Ah … Pete has the actual Eagle files …

@qp: Thanks - just what I needed - my circuit diagram collection is complete


Short question: which b0ss ph2 pedal to look for (for the IR31O9)? Can it be with the blue knobs, or only the one with the green/yellow knobs? Thank you.

PS: I would like to have the layout, or, schematics for the shruthi IR pcb too :slight_smile:

Boss PH-2… Please don’t cannibalize… You’d be better off just buying a chip on eBay… Or just using the SMR4 filter which sounds pretty damn close.

I didn’t mind hacking up a PH2. It’s not a stellar pedal… And it has 2 useful IR3109’s in there along with some other parts. Still, each to their own :slight_smile:
Im pretty sure a PH2 is a PH2 though. So even if the outside appearance may vary some, the innards should be the same. Obviously a PH1 or 3 wouldn’t do however…
Still, if you only need 1, then it probably is just easier to grab one from here
I’ve had 2 or 3 from there and they have all worked fine.

It would be only one I´ll need, since I need badly the blue and green knobs too for my other Rolaundry gear where the knobs are missing
If no one comes with a clear answer I´ll have to buy two PH-2 to be sure (I have to buy them in US and then have them to be shipped to me) to get what I “need”.
Since one has two IR´s in them, there will be one left for anyone who feels like I do since long time.
I wont buy any JuptaB, they sold for under $1k in the 90´s and now … I won´t encourage anyone and even bid on one, people need to get real, this old stuff isn´t going to last another 30 years, there are physical limits to any component.
Yes I could buy only a chip off bay, but then I remember what happened to Olivier with some IR´s…
I like to be on the “safe” side.

Edit: Thank you Luap, I´ll have a look at the synthparts site (if available).

Boss PH-2 I got from ebay in 2011 for $50 had all green knobs… and enough good stuff on board (including two IR3109’s, one of which went into a Shruthi-1 another into AMSynth’s AM8109 JP8 VCF clone) to justify its death as a donor.

In the old days I thought nothing of sacrificing old Ensoniq ESQ-1s and SQ80s with problems, then I discovered that those machines have great personalities and sound nice. One man’s trash is another man’s treasure.

I wouldn’t be upset about an old Boss phaser getting useful again. If people started slaughtering old Prophets VS or EH Pedals for parts I’d be pissed off.

Anyone who slaughters a VS for Chips has agreed to donate his Liver as well…