Yikes, some of those adapters are going for $350 on eBay. While we're at is that the only solution for connecting a Zip drive to a current Mac?
That's what I do. I have a SCSI Zip drive that I use with my various Mac II (II, IIcx, IIvx) models. I use it to transfer various data to my G4.
Just note that with the SCSI Zip drive. You need to install drivers for your Quadra to be able to use it. This requires a properly formatted floppy disk. I used my G4 mainly because I needed OS 9 to create floppies from Stuffit images. Although I can't recall if the IOMEGA Zip installer was packed that way or if I was able to drag and drop the installer onto the floppy.
WARNING: The SCSI interface on the Zip drive looks like the Parallel Printer model interface. These are not compatible and may cause damage. Sellers often mix these up (probably because the SCSI model is worth more). Be very careful and look at the pictures for model identifiers before buying.
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I think the easiest route is going to be networking with an AAUI to Ethernet adapter. Although I can't say for certain if there is a way to directly network to a modern Mac.
Be aware, as I recall Apple changed their file sharing protocol quite a while ago. On a modern Mac or PC, you might be able to still network directly by using an emulator (Basilisk II, mini vMac, SheepShaver, Qemu) running a classic Mac OS or Early Mac OS X. I've never tried this as my Mac II models don't have Ethernet or AAUI and I just fooled around some having them talk to each other over Localtalk.
Anyways, the AAUI to Ethernet option is cheaper. It also can use the built in Ethernet drivers and file sharing. According to Lowendmac.com.
https://lowendmac.com/2001/what-is-aaui/
If the emulator does allow directly talking via Appletalk. Which I'm not sure why it wouldn't. You'll need to get an interim Mac. Such as a G4 running Mac OS 9/Early X. To talk over Appletalk. Which you would need with the Zip drive solution anyways. But you may not need to buy one. Assuming the emulator works for Appletalk.
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I just realized another possible option. Buying a Beige G3. I think those are the only models with both IDE and SCSI (50 PIN). Plus you can install stuff like a USB card for a flash drive or SATA card. That or connect via SMB to any computer with Mac OS X. To transfer files directly to the hard drive.