Component identification from SansAmp Bass Driver DI

[MRiddickW]

Hi all,

Does anyone have any idea what this component might be? It's from a Tech21 SansAmp Bass Driver D.I. (gen 1). No markings other than "CH34-4" and pin 1 indicator. Same on the other side. SIP-8 package.  My first thought was a SIP resistor array, but that makes no sense once I think about it more. That said, here's the resistances referenced to pin 1.
Pin 2: 15.2 MOhm
Pin 3: OL
Pin 4: 217 kOhm
Pin 5: 310 kOhm
Pin 6: 440 kOhm
Pin 7: 660 kOhm
Pin 8: OL

I measured these before I realized how ridiculous it would be for it to be a resistor array; why not make the resistors surface mount like all the others? Also that would be about 6 times the size of any other resistor array I’ve seen.

I've sketched out a few of the connections. I'm making it into a readable schematic that I'll add when I'm done, but I figured I'd get this out now in case someone immediately recognizes it.

Thanks!

[amyk]

The summary is that it's just the manufacturer trying to hide parts of the circuitry from reverse-engineering... which didn't work, because I found some very useful information in here: https://www.freestompboxes.org/viewtopic.php?f=1&t=6571&start=80
Whole thread is interesting too. Sadly a lot of the links and pictures are dead, and the archive.org does not have them either, but you can get most of the info from there.

[MRiddickW]

22 pages! Well I guess I have my reading cut out for me; thanks!

There are a lot of things more depressing than old, broken forum threads, but it's definitely a unique feeling of hopelessness.

[MRiddickW]

So I don't turn into the thing I hate the most, here's an update: Thanks to you and the thread you linked, I managed to find a few schematics that use the module. Attached is a screenshot of the module portion of the schematic.