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Curious how your USB AMP turns out @rewrite, if I can find another vga cable that fits through the rear power hole in my Astro, I can keep the PC outside the cab (which I'd prefer) for easy access as I don't keep it connected to the Interwebz.
Get a male VGA breakout terminal to connecto to the PC. Then get a female VGA breakout terminal to connect to the J-Pac (I believe that you are using the J-Pac, right?). Then connect 22AWG between the two terminals for:
  • Red - Pin 1
  • Green - Pin 2
  • Blue - Pin 3
  • VGnd - Pin 5
  • H-Sync - Pin 13
  • V-Sync - Pin 14
with the male terminal connecting to your PC and the female terminal connecting to your J-Pac. Also, make sure the J-Pac does indeed need a male connection. I believe it does. Just been a while since I've used one. Just remember that H-Sync and V-Sync must have separate wiring. The J-Pac combines H-Sync and V-Sync into C-Sync.

You should be able to fit 6 strands of 22AWG wire through the hole on your Astro easily.
BTW - @acblunden2 thanks for the motivation regarding ATOM-15, I backed up the BIOS and went after it again tonight, it works great. I think the first time I did it I must've accidentally checked 'composite sync' or just had a few too many barley sodas.
I've fiddled around with 'enable C-Sync' in VMMaker and ATOM-15. Never got it to work with Candy cab monitors (Nanao, Sanwa, PFX). Now I just stick to the tried and true method of twisting/jumper pins 13 & 14 together. Never fails.
 
Flash your Radeon card with ATOM-15. Works great. Save your OG BIOS and you can flash it back anytime you like. I use WinFlash and it works fine in Windows. Never had a problem. (EDIT: Interestingly enough, all the issues I've had with ATOM-15 was when I used the DOS version of ATIFlash. WinFlash seems to be much more stable for me. Perhaps the key is a clean install of Windows is needed). All the Radeon cards I've ever flashed are HD7000 series or lower. No need to go higher for MAME since MAME doesn't offlload processing routines to the CPU. All my MAME builds are all fresh installs of Windows. I don't take a PC that has been used for Desktop applications and just decide to use it for MAME. I wipe it clean and only install updates needed to run MAME. Here is a great tip for ppl wanting to setup MAME:
  • Create a Restore point for every step you go through when setting up MAME
    • Restore Point 1: Base Windows and driver Install
    • Restore Point 2: MAME roms and front end copied over
    • Restore Point 3: Windows Updates Applied and base programs installed
    • Restore Point 4: CRT Emu Installed
    • Restore Point 5: MAME and front end configured
    • Restore Point 6: Hide Windows Complete
    • Restore Point 7: CRT Emu installed/Modes Installed/Front End shelled
    • Restore Point 8: EIDID Enabled in CRT Emu
  • If your PC takes a dive anywhere along the process, you can restore it and be back in business
In answer to your question, J-Pac takes the 31khz signal and divides the frequency to 15khz so it can be displayed on a 15khz monitor without damaging circuitry. You get a horizontally split screen. J-Pac sucks in general if you ask me, so I skip it. I always use ATOM-15 because the safeguards in J-Pac while functional, are not practical. There are times when I need to see the BIOS screen on my arcade monitor. Plus aesthetically, seeing the BIOS image is more pleasing than a blurry horizontally split screen on my arcade monitor.
Which preset do you use in VMMaker? I've been using Arcade 15Khz, I have a MS9 chassis, is this preset still valid?

// Nanao MS9-29
ms929

crt_range0 15450-16050, 50-65, 3.910, 4.700, 6.850, 0.190, 0.191, 1.018, 0, 0, 192, 288, 448, 576
crt_range1 23900-24900, 50-65, 2.910, 3.000, 4.440, 0.451, 0.164, 1.048, 0, 0, 384, 400, 0, 0

http://forum.arcadecontrols.com/index.php/topic,116023.0.html
 
USB order is still MIA, but the two amps I ordered per @acblunden2 's recommendation have arrived!

Just need to find the time to wire them up. hopefully it's pretty straight-forward how it ties in with the J-Pac? (I do think moving forward I'll use the Zero Delay PCB's).
 
I hooked up my sound to an amp that has two channel output but JPAC only takes Inputs for 1 channel. How can I get stereo audio out of my cab through jamma if JPAC only takes a single + and - wire for one channel of my audio?
 
I hooked up my sound to an amp that has two channel output but JPAC only takes Inputs for 1 channel. How can I get stereo audio out of my cab through jamma if JPAC only takes a single + and - wire for one channel of my audio?
Jamma standard is mono. So you wouldn't be able to get stereo off of the Jamma harness anyway.

If the particular game had stereo it would have had a separate connector on it you'd hook things up to.
 
@acblunden2 - You have a point. From what I read in the Amazon reviews, some amps arrived with loose parts and needed to be soldered.

I guess it's to be expected from a cheap $10 amp. If you guys check the connections, everything is solid, and were still getting noise, maybe adding a ground loop isolator would work.

You know what would be really awesome? Finding a way to turn one of these cheap amps into a Qsound amp.
 
Sorry i'm late to chime in on this. Most of my MAME builds I just decided to go with the Sega amps that come with a transformer. They always seem to be laying around and the one out of the driving cabs with the bass and the quad speakers actually is not half bad. I am not an audiophile so I am not that picky. They are rock solid and you can pretty much mount the volume pot anywhere you want.

sega-naomi-stereo-sound-audio_1_acb62554dd4be96b23531b43ae0b2ebf.jpg
 
I have an RCA cable coming out of the cab. I’m not sure where it’s going into. I was plugging it into the cps2 board. The red and white inputs. I tried to connect my audio out of my amp straight into that connector but it didn’t seem to work. I got no sound coming through.

I will take pictures of it when I get home.

Okay so I found this guy's article. This might be what I need to do. I'm not sure if Blast City has the same connectors as an Astro City. I'll have to see.
https://segamadebaddecisions.wordpress.com/tag/astro-city/

I kind of want to even upgrade the speakers on the machine as well as I don't think they're all that great. Any advice on that?
 
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Omg I think I got it. I just had to switch connectors. After digging through the wiring specs. I finally traced all the wires.
 
Well, I have a few MAME builds to ship out. Bought a handful of these amps to go with them. If there is no ground loop/buzzing issues and the volume is high enough, time to abandon the TDA7972 amps. 5v power vs. 12v power, so I am skeptical.

Will find out in a month when they arrive from China. Report back then.
 
Any variant of the TDA7297 variant works plenty well. The hard part is powering it cleanly.
So I finally got around to this and neither one that I ordered works. Or the J-Pac doesn't.

Powered by 12v off of one of the molex connections on the PC PSU.

Known working audio out of the PC (verified with headphones) and into the amp.

Amp speaker lines into the J-Pac speaker lines.

Cab volume maxed, windows volume maxed, no sound whether the amps are at 0 or 100.

http://imgur.com/a/GX17qeC
 
Has anyone replaced their speakers on the blast city, I keep reading they don’t make them in that size anymore. My speakers kind of buzz and it’s kind of bothering me.
 
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