Yeah spot on, it is indeed the 12k and 20k resistors!darcagn wrote:It should be the 12K and 20K resistors, why not just use a multimeter and test continuity from pins 1 and 2 on the CPU to be sure?
Thats a valid point!darcagn wrote:It doesn't matter from a technical standpoint but it's better to solder to the resistors because they are less likely to be damaged by heat and if they were, you could easily replace them compared to a CPU, and they are easier/cleaner to solder to anyway.
I was just watching GameTechUS video on the mod.....darcagn wrote:I am personally not a fan of doing the "stereo mod" to begin with, because that's not the way the system was meant to be heard and frankly I think it sounds bad. That having been said, why would you even use phono sockets on an AV Famicom? Just cut the traces on the board connecting the stock audio to the L-audio and R-audio pins, and then cut the trace connecting the L-audio and R-audio pins together, and then connect the outputs to the two pins so that you can get stereo audio out of the multiout connector. And then on top of that, the circuit you just described would mix the audio levels unevenly and doesn't account for expansion audio so FDS games and games that had extra audio chips would have portions of its soundtrack completely missing.
Hmm. If you will allow me to ignore whatever wikipedia says about all of this, I say 1/4" jacks = "phono", 1/8" jacks = "mini-phono", and RCA jacks = "RCA".lettuce wrote:he had a Top Loader, so that why i refereed to the phono sockets.
But the Top Loader and the AV Famicom are completely different in regards to audio so it's completely irrelevant. The Top Loader doesn't have a multiout, it just has RF output, so of course you have to add phono sockets. And their audio circuits are completely different.lettuce wrote:I was just watching GameTechUS video on the mod.....
https://www.youtube.com/watch?v=uG8387V ... e=youtu.be
he had a Top Loader, so that why i refereed to the phono sockets.
On what basis do you say this? You have it backwards.CkRtech wrote:Hmm. If you will allow me to ignore whatever wikipedia says about all of this, I say 1/4" jacks = "phono", 1/8" jacks = "mini-phono", and RCA jacks = "RCA".
Just my two cents.
Ok let's forget about the whole phono situation for the moment, of course you wouldn't need phono sockets where the AV Famicom is concerned, but you still need 2 audio output wires (fake left and right). What I was original asking is can the fake stereo mod be carried out of a system that has the NESRGB fitted and is using the NESRGB for the audio as your only have the one audio output wire coming from the NESRGB?darcagn wrote:But the Top Loader and the AV Famicom are completely different in regards to audio so it's completely irrelevant. The Top Loader doesn't have a multiout, it just has RF output, so of course you have to add phono sockets. And their audio circuits are completely different.lettuce wrote:I was just watching GameTechUS video on the mod.....
https://www.youtube.com/watch?v=uG8387V ... e=youtu.be
he had a Top Loader, so that why i refereed to the phono sockets.
I don't understand your logic here. When you do the stereo mod that you described, you are bypassing the NES mono circuit and creating your own, no? You are not "using" the NES's circuit in any way because it is a mono audio circuit. It is of no use to you. So what exactly are you trying to accomplish with the NESRGB mono circuit?lettuce wrote:Ok let's forget about the whole phono situation for the moment, of course you wouldn't need phono sockets where the AV Famicom is concerned, but you still need 2 audio output wires (fake left and right). What I was original asking is can the fake stereo mod be carried out of a system that has the NESRGB fitted and is using the NESRGB for the audio as your only have the one audio output wire coming from the NESRGB?
The Famicom series are built differently because they have to account for expansion audio. Your proposed stereo audio circuit doesn't account for expansion audio at all, so that is your concern. You have three sets of audio to worry about (CPU pin 1, CPU pin 2, and the cart pin). You can't just send one pin to the left and one pin to the right because you still have more audio. You'll need to design a different circuit to compensate for having another set of audio.lettuce wrote:Also in what way are the audio circuits different from the Top Loader to the AV Famicom please?
Guess its not so straight forward then.darcagn wrote:The Famicom series are built differently because they have to account for expansion audio. Your proposed stereo audio circuit doesn't account for expansion audio at all, so that is your concern. You have three sets of audio to worry about (CPU pin 1, CPU pin 2, and the cart pin). You can't just send one pin to the left and one pin to the right because you still have more audio. You'll need to design a different circuit to compensate for having another set of audio.
I'll cut the traces to Pins 45 and 46 then, as at the moment i haven't done that and only cut the 2 traces going to the audio pins on the multiout socket.ms06fz wrote:Famicom expansion audio isn't just an audio line coming off the cart. Game audio from the Fami goes into the cart on pin 45, it's mixed with the cart's internal audio signal (if any) and the mixed audio comes out pin 46. So potentially a cart could do things like filter the Famicom audio before it goes to the speakers - but in practice I don't think any carts actually did that. So usually when replacing the audio circuit people just sever the audio feed going into the cart and just use the audio feed coming off the cart. If you take pin 46 audio without severing pin 45 first, then the signal you're getting already has the 2A03 audio (unless you cut that signal off elsewhere) - you probably don't want that.
Personally, I have tried all of that. Even used shielded cable from the CPU to the NESRGB and then shielded cable directly from the NESRGB output to my receiver, just to bypass everything. Still buzzes. At this point I don't know whether it's a problem with the power circuit in the NES, or maybe the AC adapter, or maybe unclean electricity... or if it's normal to have some degree of buzz like this.cyborc wrote:I finally got around to installing my nesrgb to a front loading NES. Picture quality is stunning. I used to own a pc10 ppu rgb NES and this is in a totally different league.
There's some pretty bad audio buzzing though. I'm using the NESRGB's audio circuit. The audio output goes straight to the 3.5mm jack that was included in the kit. I'm also using the 3d printed snes multiav and it's only wired for RGB, ground, and sync. I'd hoped keeping the audio separated like this would minimize buzzing. I wonder if using shielded cable for the CPU pins to NESRGB board and also for the audio output would help?
That's unfortunate. Every front loader I've owned buzzed with the stock audio output. I was hoping the NESRGB's circuit would eliminate the buzz. I had the same problems with my everdrive as well. I ended up disconnecting the expansion audio because the noise when using the everdrive was awful.darcagn wrote:Personally, I have tried all of that. Even used shielded cable from the CPU to the NESRGB and then shielded cable directly from the NESRGB output to my receiver, just to bypass everything. Still buzzes. At this point I don't know whether it's a problem with the power circuit in the NES, or maybe the AC adapter, or maybe unclean electricity... or if it's normal to have some degree of buzz like this.cyborc wrote:I finally got around to installing my nesrgb to a front loading NES. Picture quality is stunning. I used to own a pc10 ppu rgb NES and this is in a totally different league.
There's some pretty bad audio buzzing though. I'm using the NESRGB's audio circuit. The audio output goes straight to the 3.5mm jack that was included in the kit. I'm also using the 3d printed snes multiav and it's only wired for RGB, ground, and sync. I'd hoped keeping the audio separated like this would minimize buzzing. I wonder if using shielded cable for the CPU pins to NESRGB board and also for the audio output would help?
One thing I did notice is that when using the Everdrive, the buzzing is much, much worse, and it was coming from the audio expansion pin. So I cut the trace for the expansion audio pin on the Everdrive itself and wired it up onto a switch on the cart to toggle it on/off.
Make sure you solder the resistor to the kit and not to the cartridge port pin/expansion port (depending on the model you are using). You want the resistor as close to the kit as you can get it. Doing so eliminated the buzz for me and I don't even run the audio separately.cyborc wrote:That's unfortunate. Every front loader I've owned buzzed with the stock audio output. I was hoping the NESRGB's circuit would eliminate the buzz. I had the same problems with my everdrive as well. I ended up disconnecting the expansion audio because the noise when using the everdrive was awful.darcagn wrote:Personally, I have tried all of that. Even used shielded cable from the CPU to the NESRGB and then shielded cable directly from the NESRGB output to my receiver, just to bypass everything. Still buzzes. At this point I don't know whether it's a problem with the power circuit in the NES, or maybe the AC adapter, or maybe unclean electricity... or if it's normal to have some degree of buzz like this.cyborc wrote:I finally got around to installing my nesrgb to a front loading NES. Picture quality is stunning. I used to own a pc10 ppu rgb NES and this is in a totally different league.
There's some pretty bad audio buzzing though. I'm using the NESRGB's audio circuit. The audio output goes straight to the 3.5mm jack that was included in the kit. I'm also using the 3d printed snes multiav and it's only wired for RGB, ground, and sync. I'd hoped keeping the audio separated like this would minimize buzzing. I wonder if using shielded cable for the CPU pins to NESRGB board and also for the audio output would help?
One thing I did notice is that when using the Everdrive, the buzzing is much, much worse, and it was coming from the audio expansion pin. So I cut the trace for the expansion audio pin on the Everdrive itself and wired it up onto a switch on the cart to toggle it on/off.
.Skips wrote: Make sure you solder the resistor to the kit and not to the cartridge port pin/expansion port (depending on the model you are using). You want the resistor as close to the kit as you can get it. Doing so eliminated the buzz for me and I don't even run the audio separately.
Did that too, the resistor leg is directly soldered to the 12K-20K mixing point on the NESRGB.Skips wrote:Make sure you solder the resistor to the kit and not to the cartridge port pin/expansion port (depending on the model you are using). You want the resistor as close to the kit as you can get it. Doing so eliminated the buzz for me and I don't even run the audio separately.
How loud do you turn up your audio? It isn't noticeable at lower volumes, but I Play It Loud.Einzelherz wrote:I've got my resistor soldered to the expansion port, and I'm running all my audio/video through a converted Naki Dreamcast SCART cable and I have no buzzing even with the expansion audio. At least none that I can notice.
If we're talking about buzz when the volume is ridiculously loud, I've never had any electronics that didn't exhibit this, particularly computers.Mikey wrote:I always found audio buzz in consoles generally, especially Megadrive and SNES, to be caused by audio signals being passed along the cable with the video or other signals. It helped to add separate audio ports to the Megadrive 2, so the closest the video and audio signals get is neighbouring pins inside the AV port.
As stated above, I took the audio directly from the CPU pins with a shielded cable and directly out of the NESRGB output pad to my receiver (with the case open and no connector used), and still had the same problem. I also have a Genesis model 2 that I installed a 3.5mm audio jack on and I still get the same buzz on that console (tested with the video cable unplugged just to test for video interference coming back up and through) as I did before as well.Mikey wrote:I always found audio buzz in consoles generally, especially Megadrive and SNES, to be caused by audio signals being passed along the cable with the video or other signals. It helped to add separate audio ports to the Megadrive 2, so the closest the video and audio signals get is neighbouring pins inside the AV port.
All game systems with analog audio are going through an XRGB-mini (which connects to the receiver via HDMI). I tested out my PlayStation 2 using a retro_console_accessories PSX sync-on-luma RGB SCART cable, no buzz. But I get a buzz using the same input on the XRGB-mini with the NES 1) using a retro_console_accessories RGB SCART multiout cable, 2) using the NES with a direct soldered connection to the NESRGB to my receiver, and with the Genesis 2 using a 1) retro_console_accessories RGB SCART Genesis 2 cable, and 2) using the installed 3.5mm jack on the Genesis 2 with a 3.5mm-to-RCA cable to use the XRGB-mini's RCA inputs instead (while leaving the SCART cable unplugged, so no video cable interference).Einzelherz wrote:Well you also have some other common denominators there too. Do you get that buzzing with other audio sources through the same set of jacks on your TV/sound system?
Would it be reasonable to expect this to be integrated into a future version of the NESRGB?viletim wrote:You'd be disappointed by the performance of that thing. Why do people still build crappy transistor based circuits when high speed opamps are readily available?leonk wrote:I was browsing around the net tonight when I stumbled across a neat web site and a cool idea for the NESRGB modding scene.
Imagine you have Nintendo multiAV port and an extra button/switch. The switch selects between RGB out and component out. This can be done using the tiny PCB that can be purchased here: http://www.tg16pcemods.com/.
Comments?
Better to wait for this one. Good performance, no adjustments. I've send them to a few people for testing already.
