Which Analog to Digital converter

First of all the Puffin does a lot more than you can apparently fathom. It has always had a line input setting with no EQ. Add SPDIF out for a few $$ and you have ADC, DAC or both. Any analog in, digital out.

Vinyl records have been proven to have information well above 20khz unlike CD’s

Isn’t that special. Not news to me as you seem to think. I’d be amazed to see any proof that you can perceive that there info. LPs are NOT proven have any " useful info" above 48kHz.

For bare ones digitalization my JVC CD recorder does a fine job for Redbook. Write to RW and rip to files. Did many original cassettes when I had a cassette deck in the HiFi. Now it goes direct to the PC.

Too bad that you, me and we didn’t grab a Schitt Jil during their too short production run. Even with high quality digital you still need a USB interface to capture to files on an editing computer.
This is practically the only game in town, from Reverb or B&H. Or throw Bezos an extra $20, he needs it.

https://reverb.com/item/39928494-new-esi-audiotechnik-u24xl-24-bit-usb-audio-interface-for-pc-mac-wi...

I suspect better SQ converting to SPDIF first but the U24 XL does it all.

Another option is a standalone digital recorder that records to a memory card or USB stick. This method eliminates a lot of computer interfacing issues that audio interfaces can have.

nighthawk: Could you suggest a few? I've never seen such a thing

The Tascam DA-3000 is a example of a digital recorder that nighthawk is talking about.  It's roughly $899, which is cheaper than the RME.  However, most people that have compared them really like the RME ADI-2 Pro better for sound quality.  With the RME, you only need the $49 VinylStudio Pro software to do everything (and a USB port on the computer).  With the Tascam digital recorder you still need a memory card that is large enough to record the length of music you need and also a memory card reader for your computer (which also connects via USB).  I suppose it all depends on your budget threshold.  I would go for the RME.

That used RME on ebay is gone, but there are several "non pro" versions available, some under $1k.  The "RME ADI-2" which doesn't have that special small LCD screen on the front (it's a step down, but still good.

Additionally, I really don't think you will have the "computer interfacing" issues that nighthawk is talking about.

Another benefit of the RME is that many have rated this as a quite excellent DAC as well, so you will have a really nice DAC to playback anything on your computer to computer speakers or studio monitors of your choice.

As far as fuzztone's promoting the Muffin device.  It is a DSP based phono preamp which makes it very easy to do adjustments and special eq for turntables.  You can get it with S/PDIF output, but then you still need a pro audio interface that has a S/PDIF input so that you can record that music.