Does anyone know what pins on the famicom cart are usend for the extra sound channels?
I have an HES unidapter and a friend of mine is trying to get the extra famicom/FDS sound channels to work with it
Go to
the main site and click
Family Computer schematic. Then look at pins 45 and 46.
I want to get the extra channels of sound from a famicom/fds game working on a usa NES through the converter.
I would think it is possible to get a famicom/fds games with extra audio
to work on a usa nes?
seems like the powerpak mod would be part of the solution?
with pins 3 and 9 tied together with a 47k resistor on the expansion port.
if pins 45 and 46 on a famicom/fds game get routed to the right expansion ports pins in the nes it should work?
are there any proper mods out right now to get the extra famicom sounds to be heard on a usa nes?
what are the technical details on the powerpak mod?
from what i see pin 54(51 on some other pinout I found I think this is wrong?) on a usa cart runs to exp pin 9.
then exp pin 9 is jumpered to exp pin3 with a 47k resistor.
when i look at a famicom cart pin out it uses pin 45 for sound I and 46 for sound O.
how does that relate to the power paks pin 54? is that sound O ?
do I need to worry about sound I? what would sound input be used for? the mic on the famicom controller?
So I guess I would need to tie pin 46 sound out on the famicom cart/FDS unit to pin 54 on the USA NES side a famicom to NES adapter?
I've made my Just Breed cart work with extra sound back when I still had a 60 -> 72 converted. I had to add one wire in the converted itself (cause the sound pins were just left unconeected) and a Resistor and a Capacitor inside the NES (I guess only a resistor on the expansion port would work as well ?)
Well, the PowerPak mod requires a 47k ohm resistor. But I think that you need closer to 100k ohms in order for physical carts with external audio to mix properly with the NES output. If you already did the PowerPak audio mod, just bridge the relevant pins on the adapter with ~50k ohm resistor and it should sound fine if the total resistance adds up to around 100k ohm. Did somebody figure out an exact number for optimum mixing, or is it just 100k ohm?
You can't just mix in expansion audio and expect the proper levels, obviously for that 2A03 audio needs to be mixed within the carts. If you plan to still use NES carts, you can't have it both ways without an active circuit or switch, just a passive or two won't be right.
acem77 wrote:
how does that relate to the power paks pin 54? is that sound O ?
do I need to worry about sound I? what would sound input be used for? the mic on the famicom controller?
In case that wasn't clarified fully, the audio input is so the cartridge can receive the Famicom audio, mix it with any expansion chips, then return it to the Famicom through the audio output (or the other way around, depending if naming perspective is from console or cart edge). I'm guessing on a "normal" cart then that these 2 signals are simply bridged together? I don't really have any Famicom carts (except a pirate one hidden away somewhere).
Quote:
I'm guessing on a "normal" cart then that these 2 signals are simply bridged together?
Yes this is very visible on PCB pictures on Bootgod's database, you see 2 adjacent pins tied together with a large track, it's for the audio (if there is 2 times this, one is for the audio and the other routes the internal CHRRAM /CE to PPU /A13 to enable internal RAM when acessing nametables which is also present on the vast majority of 72-pins NES carts).
And yes the resistor I used was 100kohm, I originally messed up and put a 100 ohm here it worked but extra sound was ridiculously loud.
Iirc some famicom carts use a resistor......but bridging it works fine.
Ok
I do not need to jumper anything on famicom side of the adapter? As pins 45 and 46 are jumpered already in the famicom carts and the FDS?
Since the nes is modded with a 47k resistor I just need to add another 50k resistor in series from
pin 46 on the famicom side of the adapter to pin 54 on NES side?
Do I really need to bring the audio out from the nes to the famicom adapter?
No, just mix the audio out with the NES output and leave audio in unconnected. The mixing is done with the resisitor you add instad as in the cartridge as it's done on a FC, but it doesn't really make a difference I guess (maybe signal quality will even be higer ?).
