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

[TmEE]

-V is GND

All stuff is AC coupled and VREF is at 2.5V.

[shymog]

-V is GND

All stuff is AC coupled and VREF is at 2.5V.

Not trying to hijack your thread or go off-topic, but I can't post a new thread in this area (and I don't know how else to get in touch with you), and with you being the ASIC Genesis audio master, I was wondering if you could possibly offer some advice on my issue here: http://www.sega-16.com/forum/showthr...l=1#post489167

Great work with the CCAM, I'm going to be working on that with my Genesis 2 as soon as I finish up a few other projects I'm working on. I really love the sound from the Genesis, and that's honestly the best possible audio I've ever heard from a Genesis from the samples I've listened to.

[Mamejay]

I am writing this on behalf of someone who has been trying to join this site and has not been authorised.
From Roxbury
I have made a diagram based on MEGADRIVE Jerois proto board layout of TmEEs CCAM circuit. I did this to help my planning of building the circuit, but wanted to share in case it helped anyone.

I have included the values of the components in the diagram. I have included 2 pictures – one of the components with traces underneath, and another in which you have a clearer view of the traces. Also the original file for use with the DIYLC program http://code.google.com/p/diy-layout-creator/





http://tehkella.net/damian/MegadriveCCAM/CCAMDraft1.diy

Please give me any feedback if I have any of the components or traces incorrectly placed or missing.

PS I have had to request somebody post this on behalf of me on Sega-16. I have run through the process of registration, and emailed the admin address to ask for help, with no luck. I think my account is awaiting activation? Can anybody help?

Thank you, Roxbury

[TmEE]

Nice layout !

At first glance it looks ok to me

[raylyd]

nice one thats looks much nicer board i would love to have a few made with smd parts to make it as small as possable.

I am writing this on behalf of someone who has been trying to join this site and has not been authorised.
From Roxbury
I have made a diagram based on MEGADRIVE Jerois proto board layout of TmEEs CCAM circuit. I did this to help my planning of building the circuit, but wanted to share in case it helped anyone.

I have included the values of the components in the diagram. I have included 2 pictures – one of the components with traces underneath, and another in which you have a clearer view of the traces. Also the original file for use with the DIYLC program http://code.google.com/p/diy-layout-creator/





http://tehkella.net/damian/MegadriveCCAM/CCAMDraft1.diy

Please give me any feedback if I have any of the components or traces incorrectly placed or missing.

PS I have had to request somebody post this on behalf of me on Sega-16. I have run through the process of registration, and emailed the admin address to ask for help, with no luck. I think my account is awaiting activation? Can anybody help?

Thank you, Roxbury

[raylyd]

Nice sound from that youtube footage i must try this mod one i am done with a load new dreamcast usb coders cables i am building.

Board looks like a lot of part's whats the total cost of bits to make these boards i would like to get some boards printed or made and then i can buy the parts and make a few of m mega drives and genesis 2 work cool.

What about a va4 pal board how is that wired to that board if anyone knows.

i have a collectiors not a mark on the console a audio mod would be cool what about a model 1 clear audio mod for the interference in the headphone socket.

[pinkwasa]

If someone build a smd-version of this board - i would totally buy it instantly

[Drakon]

Looks a lot better than hand building it for sure.

[villahed94]

Tiido, got a slight problem when building the circuit using the board layout posted above. Only left channel works, with PSG. However, both channels power up well, as indicated by the typical pop when turned on.
Will a board scan and a sound clip be enough to diagnose what's wrong? Thanks in advance..

PS: The uppermost and the 4th transistors output at about 2.16V, whilst the middle transistors only reach 0.5-0.6 V.

[TmEE]

Misconnection or short is somewhere, or perhaps a broken component (which has happened to me before). Both sides are symmetrical so it makes checking for problems easy, when one of the sides works.

[villahed94]

OK, I'll check for that. Thanks for the reply.

[villahed94]

Checked everything and apparently it might be a dead component.

Here are the pics of the solder side and the component side.



The Solder side has been mirrored to have the same orientation as the component side, thus making it easier to trace lines. (Even though I have already triple checked).

[BlockABoots]

Will ayone be making these custom circuits to order??, how many wires are needed to solder to the console from the circuit?

Also is the sound chip from a VA1-4 mega drive (headphone socket) just as good as this mod, as in did sega cheap out on the soundchip on the 2nd console?

[Ace]

Sega cheapened out on the audio amp, not the chip. However, they did have to switch to the YM3438 due to a manufacturing process mismatch between the YM2612 and the custom ASICs on those later motherboards. The YM2612 is an NMOS chip while the YM3438 and Sega's ASICs are CMOS, so Sega switched over to the YM3438 because of this.

In general, though, a console with a YM3438 will NEVER sound like one with a YM2612 due to the YM3438 having a different DAC than the YM2612, which in some games, particularly After Burner II, the music will sound MUCH different on a YM3438 than on a YM2612. TmEE's Audio Mod as-is offers clearer sound than any console with a YM2612 as it doesn't have as much low-pass filtering as the audio amps in those other consoles. You could vary the amount of filtering to get overall audio quality very close to the VA0 to VA6.8 Genesis Model 1, but it will still not sound the same due to the presence of a YM3438 (it's integrated within the main Sega ASIC on the motherboard, so you won't be able to see it).

[BlockABoots]

So this mod for the Genesis/Megadrive 2 is just so the audio sound as good as that of an early Genesis/megadrive 1 console, or does this mod sound even better than a megadrive 1 console (if using the the headphone socket)?