Crystal Clear Audio Mod for Sega Mega Drive 2 & Genesis 2, version 1.0

[AlmostOriginal]

Could you take a picture of your pcb?

[MaxWar]

Could you take a picture of your pcb?

I am using Retrogamer343's CCAM board. For now I made an experimental setup so I can test many genesis boards quickly. I am getting FM and PSG right at the output of the ASIC and the regular circuit is completely disconnected ( cut trace for PSG and removed resistors for FML and FMR).

Seems from the VA7 plan on page 26 of the thread that R72, R73 should be removed and the spots bridged so i guess ill just try it. Also, the old RCA cable i used to solder on the console is not properly shielded as the ground wire does no wrap around. I will replace it with a better cable and try again.

[retrogamer343]

Not sure if you've seen my reference page but here is a link if it helps:

http://retrotimegames.com/ccam.html

there are diagrams for the va7 install.

Also I have a new board design if anyone is interested. I just placed the parts differently. This time the board is 100% single sided, the connections are placed closer to the solder spots so you don't have to cross so many wires and it's a couple of mm's smaller than my other board. I was also able to lower the price a bit because It takes me a little less time to make being only one sided. $25 shipped in the US and $30 outside. I will update my site soon and post some pics in a few hours.

[MaxWar]

@Retrogamer : Thanks, i had not looked at your page but I had seen the same schematics on the other page in this thread. Nice that you upgraded your manufacturing, Im liking the ccam board. Maybe ill get a second one.

Ok, I did a few things with my setup and now I think it is already much better.

1. I bridged R72 and R73 as per diagram. It did not really help with the interferences but it seems to have made the output louder, which is definitely a good thing. Initially I was appalled by how quiet the output was.

2. I replaced my wires going from the motherboard to the CCAM by good quality fully shielded ones and it definitely helped with the interferences. I'd say 15% reduction maybe.

3. I played with the position and orientation of the CCAM board, this is what made the most effect. By angling the CCAM board about 30 degree from the genesis mobo the interferences reduced drastically. around 50-75% reduction. And the high pitched buzz that was the most annoying thing almost completely disappeared. Tmee was definitely not exaggerating when he said that it was important to protect the circuit from interferences.

I am starting to like the CCAM now, It is still a little quiet for my taste but I tried running the ccam output through a mixer to amp it a bit before my sound system and its much better. Its like my sound system is not reacting well to a sub-line level signals, the sound kinds of miss some saturation to it and sounds more dull.


Ok, now time to try it on the VA7
And btw, anyone got this working on a VA2.3 ? I have one of those too.

[Drakon]

Yeah relocating the pcb makes a huge difference. In my va7 moving it to that gap that's above mostly just grounding plate made it sound good enough.

[retrogamer343]

Here is the new board if anyone is interested.



And compared to the original design:

[MaxWar]

Looks great Retrogamer!

In the meantime I tried the CCAM on my VA7. I think it comes off slightly differently. And the interferences are a bit different too. I am liking it, enjoying some TFIV on the big system right now.
Sounds great!!

I have 2 other model 2, I think one is a 2.3. Its a somewhat different ASIC, will the CCAM work on it too?

Will do comparative recordings in the end!

[AlmostOriginal]

retrogamer343: I like the new CCAM board! Very very nice.
MaxWar: I can barrely see the pcb.

[MaxWar]

MaxWar: I can barrely see the pcb.

What do you want to see exactly? My CCAM PCB? The VA1 motherboard? My soldering job on the motherboard?

[omp]

Not sure if the ccam works on the va2.3 (& va2.0) as it uses the different sound chip. The same as earlier model 1's, ym2612, whereas this is for the model/revisions that have the inbuilt soundchip.

I really should give this a go.

[MaxWar]

Not sure if the ccam works on the va2.3 (& va2.0) as it uses the different sound chip. The same as earlier model 1's, ym2612, whereas this is for the model/revisions that have the inbuilt soundchip.

I really should give this a go.

!!! Damn I had not realized that but you are right. Then I have a VA4 however also. Hmm apparently this one might be more readily compatible.

[Drakon]

What do you want to see exactly? My CCAM PCB? The VA1 motherboard? My soldering job on the motherboard?

Sticking the pcb on a piece of wood that's the same colour? Why did you glue it onto the wood though?

Anyway maxwar don't worry about using this circuit in a ym2612 machine. The machines that came with an asic 3438 have a better dac (digital to analog circuit) that outputs clearer quality audio than the 2612 models ever did. The only problem is all the asic 3438 machines came with a crappy amp which is what the ccam replaces. Tiido did make a ccam for the 2612 but it didn't sound as good as the one for the asic 3438 because that chip outputs cleaner audio. The better the dac is the less audio quality gets lost going from digital to analog. I did a digital audio mod in my snes and converted that back into analog using an ebay converter and that also produced slightly better quality sound.

[MaxWar]

Sticking the pcb on a piece of wood that's the same colour? Why did you glue it onto the wood though?

To make it modular, to test and compare the CCAM on several boards. Once I have made the connection on the motherboard, I can switch the CCAM to a different board in one minute

Anyway maxwar don't worry about using this circuit in a ym2612 machine. The machines that came with an asic 3438 have a better dac (digital to analog circuit) that outputs clearer quality audio than the 2612 models ever did. The only problem is all the asic 3438 machines came with a crappy amp which is what the ccam replaces. Tiido did make a ccam for the 2612 but it didn't sound as good as the one for the asic 3438 because that chip outputs cleaner audio. The better the dac is the less audio quality gets lost going from digital to analog. I did a digital audio mod in my snes and converted that back into analog using an ebay converter and that also produced slightly better quality sound.

Yeah I remember your improvised snes DAC, I thought that was quite interesting, but iirc there is not all that much to gain on the snes because the sampling rate of the original sound is not all that high to begin with.

About the 2612 vs 3438 I just thought Va2,Va2.3 was 3438 and the VA3,VA4 was 2612 but Omp's comment made me realize that I had inverted them. In other words I will see if I Can get the ccam to work on the VA4 since i have one of those too.

[Drakon]

I mean why did you glue it down instead of just leaving it on there loose? I put loose pcbs on plastic lids when testing but I don't glue them down to it.

Regarding the snes: The reason why my newer dac doesn't sound much better is because the dac in the snes is already pretty good. The dac in the ym2612 however leaves much to be desired.

[AlmostOriginal]

What do you want to see exactly? My CCAM PCB? The VA1 motherboard? My soldering job on the motherboard?

Soldering job on the motherboard please.