What's new
Agreed, I'll need to find someone willing to test this who has a large collection of cabinets with different monitors.
I have SCART cables for Saturn, PS1, PS2, Dreamcast and a ton of monitors (Sanwa PFX, Nanao MS8, Nanao MS9, WG K7000, WG K7400, WG K4900, and more).

Like I said, I'd be up for tinkering with this PCB once you are ready.
 
Prototypes are in!
lok0YtF.jpg


This is not the most current version of the layout, but electrically this is exactly the same as my most up to date design. I am currently trying to make arrangements with those who have reached out about testing and will hopefully have these in their hands soon. As far as my own testing these have worked beautifully on my New Net City via Jammafier. I'll try to do a youtube video demonstrating one of these in action tomorrow.
 
That looks beautiful.

Happy to test if needed, but if you already have enough testers lined up no sweat.

I have an Astro City to test on and pretty much every RGB console imaginable.
 
Slick proto!

Just curious, how often are people going adjust the RGB impedance?
I was thinking if every console needed different adjustments, removing P1’s controller pcb every time you switched consoles would be an extra step. Not a big deal I guess, it just makes swapping consoles a bit more work.
but if you just need to adjust it in rare circumstances, then that extra step isn’t too bad.

Btw what’s that jumper wire for near the SCART Connector, powering the RGB caps?

I can help with testing too, but my set-up is similar to Franks. NAC and all consoles. I do have your equally slick EZ Cthulhu’s I can install, and all the RJ45 cables for my systems...
 
Dude that looks pretty sick! If you don't have enough testers, I'd be happy to help!
 
This is great I'm on board if you need more testers I have blast city and quite a few retro consoles
 
...Yup, put me in the tester line too! :P

I'm sure you've got plenty enough already; count this as my eventual "I'm interested" pre-order too lol
 
Slick proto!

Just curious, how often are people going adjust the RGB impedance?
I was thinking if every console needed different adjustments, removing P1’s controller pcb every time you switched consoles would be an extra step. Not a big deal I guess, it just makes swapping consoles a bit more work.
but if you just need to adjust it in rare circumstances, then that extra step isn’t too bad.

Btw what’s that jumper wire for near the SCART Connector, powering the RGB caps?

I can help with testing too, but my set-up is similar to Franks. NAC and all consoles. I do have your equally slick EZ Cthulhu’s I can install, and all the RJ45 cables for my systems...
Impedance adjustment should only be necessary when first connecting it to a new monitor. It may not be necessary at all if the image looks good on your monitor on default settings. I have already moved the pots down to the bottom of the board just above the JAMMA edge on the current design file so they will no longer be under either of the controller PCBs.

The jumper wire is a bodge wire that adds AC bias resistors that were not originally on this version of the board. They are now on the current revision of the board so I added them for the testers so I can get an accurate idea of how they will perform with a variety of monitors.

As for testing, thanks everyone for your offers, but all of my current prototypes are spoken for. Assuming that testing goes well I should be able to make moves toward going into production so anyone who is interested in the finished product should keep their eyes peeled.
 
Definitely down for purchasing one when they’re produced! :thumbsup:
 
If all scart outputs are at correct voltage levels it really should be set once and forget...Nice work!

Any other (think EU) sources on MC Cthulhu upgrade sets?
 
Prototypes in action!

And for good measure here is a shot of the board in what I expect to be it's final form.
d1a8615d4e88a8e55f0e5e0ae1ea97d1.png


And here is the current VGA hat.

a0376333bf3eb0f6976e72474e346e80.png


New features:
  1. Added pads for AC bias resistors.
  2. Added a trimpot for gain control on the LM386.
  3. Added the necessary traces and vias to the board to make a future NEO-GEO Stereo over JAMMA compatible version possible. This will require a separate stereo amp card.
  4. Switched the EXT port from a 3 row 9 pin header to a cheaper and more available 2 row 8 pin header.
  5. Added an optional simple sync combiner to the VGA hat.
  6. Adjusted the dimensions of the scart plug pattern to give a tighter fit.
 
Last edited:
Ha! We must be kindred spirits of some kind @Arthrimus. My NNC is decked out with gun-metal buttons on the left and chrome buttons on the right too!

Can't wait to test this out. Queing up my Egret 2 first for the job (Nanao MS9). I think it is CHAMMA wired?
 
That's the way to do it, simple and elegant no fuss design. I really like it. Well done!
 
Regarding the potential brightness fluctuation issue from the THS-series amp use, I feel that the SCART cables might have some hand in adding weight to that too. Doubtful, anyone is going to want to dissect their consoles to remove the coupling capacitors (if any and depending on the console). For the PS1/2/3 (and maybe the Dreamcast?), I have two SCART cables each. One where I left the coupling capacitors intact and one where I removed those capacitors. I'll test them both out and see what the results shall be.

Also for MAME application, I will rig something up. Want to demonstrate the inferior contrast that is produced by the J-Pac's amp (MAX4386EMAX4386E). I really feel the THS-series amps do a better job of amping RGB than the IC that the J-Pac uses.

Question on how you came to derive the measurements for both the MC Cthulu PCB and JAMMAizer: Did you just put in the sweat equity with digital calipers to get the measurements? Or did you get your hands on the schematics somehow? Seems so precise.
 
Regarding the potential brightness fluctuation issue from the THS-series amp use, I feel that the SCART cables might have some hand in adding weight to that too. Doubtful, anyone is going to want to dissect their consoles to remove the coupling capacitors (if any and depending on the console). For the PS1/2/3 (and maybe the Dreamcast?), I have two SCART cables each. One where I left the coupling capacitors intact and one where I removed those capacitors. I'll test them both out and see what the results shall be.

Also for MAME application, I will rig something up. Want to demonstrate the inferior contrast that is produced by the J-Pac's amp (MAX4386EMAX4386E). I really feel the THS-series amps do a better job of amping RGB than the IC that the J-Pac uses.

Question on how you came to derive the measurements for both the MC Cthulu PCB and JAMMAizer: Did you just put in the sweat equity with digital calipers to get the measurements? Or did you get your hands on the schematics somehow? Seems so precise.
The capacitors in the cables are what makes the video signal from the consoles AC coupled. They are there to strip the DC reference out of the video signal. If you remove the capacitors from the cable then you should get DC coupled video from the console. I'm not sure how this might affect the image through the current JAMMAizer amp design.

As far as the measurements for the boards. That was all done with calipers using a Brook Retro Board as reference.
 
Potential users for the JAMMAizer may want to use their SCART cables as is and may even switch back and forth for whatever existing uses they have with them already (PVM's, OSSC->Modern HD displays, or whatever). Probably don't want them to reinvest in a 2nd set of SCART cables.

So I'll test them out with and without the caps in the SCART hood and report back the results.
 
Potential users for the JAMMAizer may want to use their SCART cables as is and may even switch back and forth for whatever existing uses they have with them already (PVM's, OSSC->Modern HD displays, or whatever). Probably don't want them to reinvest in a 2nd set of SCART cables.

So I'll test them out with and without the caps in the SCART hood and report back the results.
I want to clarify so there is no misunderstanding on this issue. The JAMMAizer's amp design has, to the best of my understanding, a properly implemented DC restoration circuit. Therefore standard SCART cables with capacitors are what I intend to be used with the JAMMAizer. There should be no need for the user to modify their existing SCART cables in any way.
 
Back
Top