Putting out some feelers to see if anyone is interested. I am planning to manufacture some affordable modification kits for adding AC3 output to Laserdisc players (and other devices). The boards will come assembled and all you need to do is wire them up. Unless I missed something, I can’t find anything like this readily available in the US. The circuit is just the tried-and-true design from LA Audiophile
UPDATE 10/11/22: interest seems to be good enough that I will be ordering prototypes! I have some "beta testers" lined up who will be testing the boards in various players. I plan to order a prototype run at the end of this week (around October 14th) and should have them in the hands of testers by the end of October / start of November.
If the board is successfully approved and people are interested, I’ll put up a page for pre-orders and make up the kits on a per order basis. I would probably leave the pre-order page up for a month and then should be able to get them all made and shipped out 2-4 weeks after closing the preorder. They should be around $25 USD (or possibly $20) plus shipping.
The kit would include:
— AC3 modification PCB, fully populated with all components
—
(edit) PCB mounted 75 ohm BNC jack OR RCA jack, there will be an option to choose either or
— 2 feet of Canare coax wire for running to the jack
— 2 feet of hookup wire (PTFE mil-spec high-temp)
— bolt with solder lug / ring terminal for chassis ground and nut
— adhesive mounting squares
— total dimensions are 37.5mm x 20.35mm before cutting the jack daughterboard off
Obviously it would be up to you to figure out how and where to wire and place the PCB based on your model player.
Attachment:
File comment: Mockup
2022-10-10---PCB-mockup2.jpg [ 174.63 KiB | Viewed 1740 times ]
Boring Details:
I would also include coaxial wire with the kit for running from the main PCB to the jack. 1% resistors, C0G/NP0 capacitors, and the correct transistors.
**EDIT** after much feedback, I plan to include an option for either a BNC or an RCA jack. As you can see on the mock-up, the board can be installed in the back of the player as one (jump the JACK+ and JACK- pads with a small piece of coax) or cut/snap the PCB across the perforation and run wire from the main PCB to the jack. I plan to use a plastic threaded jack (TE Connectivity part # 1-1634622-0 for the BNC one, RCA jack will be a different part that I will have to source from overseas) so the sleeve will be fully isolated from the chassis ground, with a 100nf MLCC between the sleeve and the chassis ground (it is important to have this as close to the jack as possible), so you’d have to drill an additional hole for a chassis ground bolt next to wherever you place the jack. The PCB also has a hole for an M3 mounting bolt depending on where you want to put it.
However, you could use a standard chassis mount jack (BNC or RCA) and not the included PCB solder pin one.
You can omit the mute circuit if you want by carefully removing Q2 and then jumping the correct pads. Figured better to include the mute portion than not.
Here are the sources of the schematic.
Attachment:
File comment: Mockup with more details
2022-10-10---PCB-mockup.jpg [ 231.74 KiB | Viewed 1740 times ]
Here are the sources of the schematic. This scheme has been around for ages (and I'm pretty sure is based on Pioneer's original one??) so I cannot take credit for it:
http://www.laserdiscarchive.co.uk/laser ... pgrade.htm and
http://www.laaudiofile.com/ac3mod.htmlAttachment:
File comment: Source schematic from LA Audiophile
schematic.gif [ 7.14 KiB | Viewed 1740 times ]