Supergun RGB Attenuation in 2023

[brandon.arnold]

I have one of these superguns with RGBS on the JAMMA edge wired directly to a DIN8 port (and by convention, the associated SCART pins). This includes the Boardmaster, PANA Twin, COMBO AV EX++, and others. There are several threads on the topic, but they are a little out of date.

RGB pots on a JAMMA extension work okay, and I already have that. What I would love is Tim Worthington’s Supergun Attenuator (SUPATT) or AV-Driver products, but he doesn’t seem to be stocking them now (though I’ve emailed him for an update on that). These are active amplifier-based components without any impedance-mismatch compromises on the output.

Can anyone share a perhaps lesser-known packaged option that may serve my purpose today? I am open to wiring a board in between the JAMMA and DIN8 for this purpose.

 

[alamone]

DIY option, but this is the same 4-gang pot that is used in the NAC Splitfire:

https://www.mouser.com/ProductDetail/652-PTD904-1020KA103
https://www.digikey.com/en/products/detail/bourns-inc/PTD904-1020K-A103/3534253

4-gang because 3-gang aren't easily available, just ignore the 4th gang.

You could easily wire a RGB amplifier and add the above pot to get a similar functionality as those RGB driver boards you mentioned above.

 

[brandon.arnold]

DIY option, but this is the same 4-gang pot that is used in the NAC Splitfire:

https://www.mouser.com/ProductDetail/652-PTD904-1020KA103
https://www.digikey.com/en/products/detail/bourns-inc/PTD904-1020K-A103/3534253

4-gang because 3-gang aren't easily available, just ignore the 4th gang.

Nice option, thanks! I do have some 6-gangs in the garage that may work. I especially didn't know about the NAC Splitfire, which is actually quite a nice JAMMA-inline design for a basic passive attenuator.

You could easily wire a RGB amplifier and add the above pot to get a similar functionality as those RGB driver boards you mentioned above.

Good point, I suppose I'm also curious any in-between options on the component level, without going all the way down to building one with fundamental op-amps and stuff. I see a discontinued DIP IC, LM1203. There are extracted ones available on eBay.

Edit: Maybe this isn't that hard to find. There is the THS7374 RGBS amplifier (probably best) and Mouser has a number of options from Analog Devices.

 

[brandon.arnold]

Interesting. I just noticed Axunworks offers the Arcade JAMMA adjustment conversion board, which may be the only package option that is currently in production (well, made to order, with the several-months lead time that is typical of Axunworks). It seems to be more flexible than just this application, but the main thing is it has a THS7374 active amp, along with switches and an adjustment pot to attenuate the JAMMA to 75-ohm RGBS output.