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

[Drakon]

Lol at all those resistors.

[pinkwasa]

What a nice board

[infinateeff]

Hmm so since a VA7 won't overclock past 10mhz and I don't have any 10mhz oscillators (only 12mhz) I finally sat down and finished my CCAM. It's rather messy looking but overall the FM sounds good. I tapped the FM and PSG lines from my VA7 but I find one thing is missing. The Jumping sounds when Sonic/Tails jump in Sonic 2. Am I correct in assuming that the jumping sound comes in from the PSG?

BTW Retrogamer343, the SMD version looks awesome!

[retrogamer343]

Hmm so since a VA7 won't overclock past 10mhz and I don't have any 10mhz oscillators (only 12mhz) I finally sat down and finished my CCAM. It's rather messy looking but overall the FM sounds good. I tapped the FM and PSG lines from my VA7 but I find one thing is missing. The Jumping sounds when Sonic/Tails jump in Sonic 2. Am I correct in assuming that the jumping sound comes in from the PSG?

BTW Retrogamer343, the SMD version looks awesome!

Thank you for the compliment. And yes the jumping sounds in sonic is PSG.

[infinateeff]

I Fixed my PSG, forgot to connect the transistors and a ground point. So I have PSG now. It does sound rather quiet though. Also fixed a missed connection the FM Left which balanced the sound output, I hadn't noticed as I was sitting to the right of the TV. I find it amusing that the dreaded VA7 has become my favorite revision. I Also enjoy how I can tell a difference in the composition quality of different games. Some sounding better than others. It's much harder to tell a difference with muffled sound.

So with that working all I need is to wire in the power as I was using the lines from my S-video mod to power the CCAM, and the 32x/Sega CD lines. On a VA7 M1, will the CCAM work fine if I wire the Sega CD lines into the CCAM from the edge connector, or is there a more convenient point near the sound circuitry? And for the 32x (Don't have one yet but would like to wire it in anyway), where can I solder it in, or should I pull the sound off the cartridge connector?

[AlmostOriginal]

Okay TmEE, please explain this to me: I just rebuilt a new Audio Mod for the RetroN3 with the following tweaks:

-The 0.022uF capacitors were replaced with 0.1uF capacitors
-The 22Kohm resistors at the FM inputs were replaced with 100Kohm resistors as the FM would distort otherwise
-The 32X PWM and Sega CD PCM/CDDA inputs were omitted
-The 4558 op-amp was replaced with a TL072 op-amp
-The 1.5Kohm resistors were replaced with 3.3Kohm resistors
-The 3.3Kohm resistor to Ground at the PSG input was replaced with a 7.5Kohm resistor
-4.7Kohm resistors were added after the 100uF capacitors as the audio would become really garbled when trying to record it through my computer's audio input

And yet, I STILL get that noise in After Burner II as though the sound was produced by a YM2612 and not a YM3438(the GOAC in the RetroN3 uses a YM3438). WTF??? What am I doing wrong?

Still, the sound off the RetroN3 is near-perfect. I say near-perfect as it seems at least one of the square waves is too quiet on the TCT-6801 GOAC in the system.

I shall now record some samples from an Audio Modded RetroN3(Version 2, I should add).

EDIT: Well, isn't this F***ING NICE?! RIGHT IN THE MIDDLE OF RECORDING SAMPLES, THE CIRCUIT FAILS AND NOTHING I CHANGE MAKES IT WORK AGAIN!!! F***!!!!

EDIT 2: Got the circuit working again. For how long, I have no f***ing clue. Might have had problems with my VCC wire as I noticed when the circuit failed, the volume of the remaining audio was fluctuating quite a bit from loud and clear to quiet and distorted.

EDIT 3: I've got some audio samples recorded. Get them here: http://www.mediafire.com/?9bkh2gh92g5ekp7

I've recorded some samples from the following games:

-Thunder Force II MD
-Thunder Force III
-Thunder Force IV
-After Burner II
-G-LOC Air Battle
-Sonic the Hedgehog

Small note: the GOAC in the RetroN3 has HEAVY video noise in the audio output, so you'll hear a lot of background noise.

Now, someone tell me: is the PSG too quiet? Or are some sound channels on the GOAC's SN76489 too quiet compared to other channels?

Wow that´s amazing! I never thought a Retron3 could sound that good.

TmEE: How the h*ll did you figure the CCAM out?

[segasonicfan]

Got Retrogamers343 board and it works great in the old CDX! I had to trace out the mixing circuit and other stuff which wasnt easy, you can see the info on that over here:
http://nfggames.com/forum2/index.php?topic=3719.40

Sounds amazing though! And a very cool compact little board.

-Segasonicfan

[infinateeff]

Got Retrogamers343 board and it works great in the old CDX! I had to trace out the mixing circuit and other stuff which wasnt easy, you can see the info on that over here:
http://nfggames.com/forum2/index.php?topic=3719.40

Sounds amazing though! And a very cool compact little board.

-Segasonicfan

Nice! any audio samples?

I wish I could find a good deal on a CDX... I wanted one since I saw the adds back in the day...

[retrogamer343]

I Fixed my PSG, forgot to connect the transistors and a ground point. So I have PSG now. It does sound rather quiet though. Also fixed a missed connection the FM Left which balanced the sound output, I hadn't noticed as I was sitting to the right of the TV. I find it amusing that the dreaded VA7 has become my favorite revision. I Also enjoy how I can tell a difference in the composition quality of different games. Some sounding better than others. It's much harder to tell a difference with muffled sound.

So with that working all I need is to wire in the power as I was using the lines from my S-video mod to power the CCAM, and the 32x/Sega CD lines. On a VA7 M1, will the CCAM work fine if I wire the Sega CD lines into the CCAM from the edge connector, or is there a more convenient point near the sound circuitry? And for the 32x (Don't have one yet but would like to wire it in anyway), where can I solder it in, or should I pull the sound off the cartridge connector?

About the quiet PSG; I would check to make sure you cut the trace that seperrates the psg coming from the ASIC and the original circuit. If it is still connected to the original circuit it will be quieter than it should.

I will be making up a VA7 guide soon.

Got Retrogamers343 board and it works great in the old CDX! I had to trace out the mixing circuit and other stuff which wasnt easy, you can see the info on that over here:
http://nfggames.com/forum2/index.php?topic=3719.40

Sounds amazing though! And a very cool compact little board.

-Segasonicfan

I'm glad to here you have it working. Looks good. Please keep us updated with the progress and keep those great pics coming. I may attempt to do this to my CDX at some point.

[infinateeff]

About the quiet PSG; I would check to make sure you cut the trace that seperrates the psg coming from the ASIC and the original circuit. If it is still connected to the original circuit it will be quieter than it should.

I will be making up a VA7 guide soon.

Actually most of my issues where related to points I had forgotten to connect. As for the SCD and 32x Audio I ended up tracing the cart audio and SCD edge audio back to the caps in the audio circuit near the heat sink. So far it works pretty good. The audio in general is low, as Tiido's mentioned VA7's could benefit from a headphone amp. I plan on building one soon, as well I have been experimenting a tad with keeping the original circuit and allowing a switch between the circuit and CCAM. Needs more tweaking but it is doable. I'll eventually post a how two if the results are favorable. so far it's kind of mixed.

For the VA7 info I plan on doing a VA7 mod info thread sometime soon, seeing as for most mods OC/CCAM/LANG/HERTZ etc... you end up piecing most info for it from a mix of model 1/model 2 mods. Mainly I need some good pics of a VA7 board. I only have the one and it's got quite a bit of wiring coming off everything so not a good candidate for pics. But if you'd be interested in collaborating on it I'd appreciate the help.

Also one more quick question. Would you sell the SMD boards with all the components prior to soldering them? I'd like to build one to improve my SMD soldering skills, plus I want stereo out of my Model 3.

[retrogamer343]

For the VA7 info I plan on doing a VA7 mod info thread sometime soon, seeing as for most mods OC/CCAM/LANG/HERTZ etc... you end up piecing most info for it from a mix of model 1/model 2 mods. Mainly I need some good pics of a VA7 board. I only have the one and it's got quite a bit of wiring coming off everything so not a good candidate for pics. But if you'd be interested in collaborating on it I'd appreciate the help.

Also one more quick question. Would you sell the SMD boards with all the components prior to soldering them? I'd like to build one to improve my SMD soldering skills, plus I want stereo out of my Model 3.

Yes I can send you some pics of a va7 board. I have 4 or 5 of them. I can sell you the board and components if you would like. Are you in the US? Just so everyone is aware the USPS has raised there prices again so the cost to ship these boards outside the US has more than doubled. What cost me $3 last week to ship overseas cost me $6.55 yesterday to ship to the same place!

[infinateeff]

Sent you a PM with my e-mail for the pics. and parts, I think... It doesn't show any messages in my sent items box so let me know if you got my PM or not.

[Drakon]

The cdx need a ccam?

[TrekkiesUnite118]

Yeah, I always thought the general consensus was that the CDX sounded so good that it didn't need a CCAM.

[TmEE]

There is always room for "better" :P