Introducing the Mega Amp - The universal Genesis audio circuit

[Ace]

If you like the idea of sticking to the original Genesis Model 1 sound, power down the YM3438 and install a YM2612 in its place. It's possible to do so, that's how Villahed got a YM2612 to work on his VA3 Genesis Model 2. Then, you would install a filtered Mega Amp on that.

Now, I'm in the process of designing a PCB for a through-hole Mega Amp board, though I need to work my way around Eagle. You'll get a TL074 with a socket so if the op-amp craps out, you can remove it and replace it with another one.

[villahed94]

I might post a tutorial in a few days on how to perform the YM2612 mod on any systems up to the VA3 Model 2(this includes Nomad!).

[makaighost]

I might post a tutorial in a few days on how to perform the YM2612 mod on any systems up to the VA3 Model 2(this includes Nomad!).

This! Do want Please! Us beginners would love you forever!

[BlockABoots]

So is this like the CCAM??

[makaighost]

Ill be placing an order for.parts soon. I decided I'd like to do this on my va2.3 . Would you (Ace, villahed, misc. willing participant) be able to give me a shopping list for an unfiltered mod for straight stereo; excluding the 32x, sega cd mono and headphone? Much appreciated and happy gaming gentlemen

[Ace]

For the most basic unfiltered Mega Amp setup with the omissions you stated, you need the following:

-TL074 (1 - although you can use a TL072, I advise to stick to a TL074 in case you want to add in Mono sound later)
-10uF electrolytic capacitors (2)
-1uF electrolytic capacitors (2)
-100uF electrolytic capacitor (1)
-220uF electrolytic capacitors (2)
-47pF ceramic capacitors (2)
-1.3Kohm resistor (1)
-6.2Kohm resistor (1)
-100Kohm resistors (2)
-510ohm resistor (1)
-750ohm resistor (1)
-160Kohm resistors (2)

Then follow the unfiltered YM2612 Mega Amp schematics and the VA2.3 Genesis Model 2 installation diagram.

I'm actually a bit surprised you're going for such a bare-bones setup, that is FAR from the point of the Mega Amp, but hey, to each their own.

So is this like the CCAM??

Oh no, this isn't JUST like the CCAM. It's more than that. The Mega Amp is a complete replacement circuit that can give you three different types of sound out of any Genesis ever made:

-Filtered like a VA0 to VA2 Genesis Model 1 without their excessive gain that causes nasty distortion
-Unfiltered (well, not exactly because there are too many high frequencies above the audible range of the human ear) for the full spectrum of the Genesis' audio hardware (even less filtered than the CCAM's 15KHz filter, this Mega Amp's filter is set at 21KHz)
-System C-2, made to match the Sega System C-2 arcade board, most known for being the board Thunder Force AC was released on (sounds a lot different than your typical Genesis audio setup due to different filters for different audio sources)

The Mega Amp works with the YM2612 and all variants of the YM3438 whereas the CCAM is YM3438 only. The Mega Amp also offers both Stereo and Mono outputs plus two extra transistor circuits to allow the Mega Amp to drive headphones.

[villahed94]

So is this like the CCAM??

Also by not needing any transistors like the CCAM the power consumption is much lower, allowing to be installed in systems where power is a real constraint (like the Nomad)

[makaighost]

For the most basic unfiltered Mega Amp setup with the omissions you stated, you need the following:

-TL074 (1 - although you can use a TL072, I advise to stick to a TL074 in case you want to add in Mono sound later)
-10uF electrolytic capacitors (2)
-1uF electrolytic capacitors (2)
-100uF electrolytic capacitor (1)
-220uF electrolytic capacitors (2)
-47pF ceramic capacitors (2)
-1.3Kohm resistor (1)
-6.2Kohm resistor (1)
-100Kohm resistors (2)
-510ohm resistor (1)
-750ohm resistor (1)
-160Kohm resistors (2)

Then follow the unfiltered YM2612 Mega Amp schematics and the VA2.3 Genesis Model 2 installation diagram.

I'm actually a bit surprised you're going for such a bare-bones setup, that is FAR from the point of the Mega Amp, but hey, to each thier own.

Much appreciated Ace! To be honest I'm going so basic with it because I'm still a beginner with a soldering iron and don't want to ruin the only thing I have left from growing up. I guess I lucked out with the model 2 and at one point had two (go mom!) Plus I don't intend on owning another Sega CD for some time and I had a 32x growing up but didn't care for it. Thank again, the hard work of everyone here has given me a whole new appreciation for games I already loved.

[goodtofufriday]

So has a pre-made board or guide or even detailed pictures come out yet? I'm rather rubbish at following schematics.

[villahed94]

So has a pre-made board or guide or even detailed pictures come out yet? I'm rather rubbish at following schematics.

Not yet, we're working about that. Personally I haven't really had time to dedicate to the MegaAmp (differential equations are fun).

[Helder]

So has a pre-made board or guide or even detailed pictures come out yet? I'm rather rubbish at following schematics.

Tofu you're on here too? Anyways good news to a select few, the boards will be here this week perhaps Friday or even Thursday! Then we can get kits made to sell once the prototypes have been thoroughly tested.

[Helder]

Ace you need to clear some PM space, trying to send you a link to the board images.

Anyways here are images of the prototypes to tease a little:

http://postimg.org/gallery/3d8rkrcc/

Edit: Just tested out the board and it works awesomely! Very loud in comparison to the CCAM and sound was crisp.

[fluxcore]

Ace you need to clear some PM space, trying to send you a link to the board images.

Anyways here are images of the prototypes to tease a little:

http://postimg.org/gallery/3d8rkrcc/

Edit: Just tested out the board and it works awesomely! Very loud in comparison to the CCAM and sound was crisp.

I'm guessing this is a little bigger than say, RetroGamer343's CCAM pcb? I know it has more utility. I guess I'd just prefer a smaller, more specific board for a MD2 mod (since there's not really good places to mount such a PCB in them). Nice work anyway though!

[villahed94]

I'm guessing this is a little bigger than say, RetroGamer343's CCAM pcb? I know it has more utility. I guess I'd just prefer a smaller, more specific board for a MD2 mod (since there's not really good places to mount such a PCB in them). Nice work anyway though!

Actually that board is big because it's a test prototype. Helder suggested the use of ceramic caps, and I'm really looking forward to that since ceramic caps would make the boards even smaller and also provide a much longer service life (about 30-40 years at least!).

[AlmostOriginal]

How much are they going to be? Do you have a unassembled board for sale?

Edit: Just tested out the board and it works awesomely! Very loud in comparison to the CCAM and sound was crisp.

In what system did you fit it in?