Reddit reviews Nine to Nine 3.5mm Stereo Jack Panel Mount Connector Pack of 10

Here are the main parts:

Bluetooth receiver - https://www.amazon.com/gp/product/B008AGQMQC/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

3.5 jack - https://www.amazon.com/gp/product/B01C3RFHDC/ref=oh_aui_detailpage_o06_s01?ie=UTF8&psc=1

side button - https://www.amazon.com/gp/product/B01LYZSEVB/ref=oh_aui_detailpage_o06_s01?ie=UTF8&psc=1

You could probably find cheaper options. I just bought a lot because there wasn't really any tutorials out there on doing this. Other stuff you would need are a soldering iron, a dremel, and some wires, Also, please get better earcups if you haven't already - https://www.amazon.com/gp/product/B00MFDT894/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1

Here are the internals: https://imgur.com/gallery/N91espA

The radio is not AM/FM, it is AM "Standard Broadcast" and shortwave, formerly used for international broadcasts. You may want to check to see if the loop antenna (the square-ish symbol at the left center) is connected. You could also try attaching a 5- or 10-ft piece of any kind of wire to the "A" (antenna) terminal to see if you can get some AM stations. This radio has only one IF (intermediate frequency) stage and so will not be a good performer for long-distance AM or shortwave, but could get local stations.

It does not contain a phono preamp as such, but was designed for a crystal or ceramic phono cartridge. The phono input contains a shunt capacitor (C28) for approximate equalization, but not an equalized preamp that would be required for a magnetic phono cartridge. If you just remove C28, the .005 uf capacitor, the response should be fairly normal for a "line" input from a phone or iPod.

If you want a stereo input to this radio, you can replace the RCA-type phono "socket" with a 3.5 mm stereo jack like this. You should connect the "sleeve" terminal of the jack to chassis ground, as the original RCA jack had. You can probably do that mechanically with a thin washer. To combine the two stereo channels, use a separate 10K ohm 1/4-watt resistor from the "tip" and "sleeve" connections on the jack and connect the other end of both to the the point "P" on the radio-phono switch. Using the resistors will correctly sum the two stereo channels from the incoming signal.

Interestingly, the schematic shows resistor values in an unusual way. The "M" means thousands of ohms, normally specified as "K" for kilohms. The "MEG" means megohms, millions of ohms.

Hope this helps!

I went with the below jacks. Pm me your address and it just send you one via snail mail.

Nine to Nine 3.5mm Stereo Jack Panel Mount Connector Pack of 10 https://www.amazon.com/dp/B01C3RFHDC/ref=cm_sw_r_cp_api_i_JXjzDbAGJ3472

I'd be happy to.
Here are the parts I ordered from Amazon.
Trim Pot
Stereo Jacks
I bought extra jacks and a kit of trim pots so I could try different values, but I ended up using just the 1K. I put the Trim Pot in series with the left speaker for my wife.

Just wanted to drop a note and say that the issue with your MSR7 is likely the barrel contact tab at the jack. If you or someone you know is comfortable with a soldering gun, it's a fairly simple fix with a replacement panel jack.

Hey it's me again :) Since you've decided you're actually gonna do the mod, I would go ahead and lookup a ton of material on soldering, things like how to tin small wires, and making a clean connection. The stock pads on the 770s are probably your best bet, they're so freakin comfortable and they compliment the bass on the 770s very well. Use these connectors from amazon, and yes I would get the 10 pack because I screwed up at least 3 of them before getting it right haha. Here are some more shots of mine if you want more inspiration. There's cotton in there still, I really need to get around to using glue lol