nesdev.org

Bregalad wrote:$200 for a 20 year old console based on a 30 year old architecture is definitely a steal.

Oh the joys of English language, "a steal" actually means "bargain", i.e. opposite of what you most likely meant.

For "way too expensive", did you mean "highway robbery"?

Official Nintendo-branded Famicom AC adapter has the following on it:

Input: AC100V (50/60Hz)
Max: 18VA
Output: DC10V, 850mA
Polarity: Diagram on the adapter matches the one labelled "Negative polarity" in this picture: http://upload.wikimedia.org/wikipedia/c ... larity.png

Here's a reference if you need one too (and how the clone units often differ in their power requirements): http://famicomworld.com/workshop/tech/f ... r-adaptor/

Dwedit wrote:When you said "Gray RF box" I thought you were talking about the internal part, not that thingy that hooks it up to coax.
Nintendo always referred to the gray thing as the RF Switch, so calling it by another name got me confused.

Oh I see, you thought I was talking about the RF circuitry contained within that silver/metal box within the console itself. :-) Sorry, I should have been more clear, my apologies.

I didn't call it an "RF Switch" because despite the name, the actual "switch" itself (on the NES: channel selection only; for the Famicom: both TV/Game and channel selection) is located on the back of the console, not on the little box.

In "my day" we used to refer to the box that hooked up to the TV as a Game/TV switch (i.e. what the original Atari 2600 used). Channel selection was, like the NES, on the back of the console.

Oops, sorry, my AC adapter is 10V DC (it was this one specifically, except I reversed the polarity). Though I would advise you to check any adapter with a multimeter before using it. Occasionally they won't do what it says on the box (this one happened to be fine).

-10 V DC... isn't that a Sega Genesis power brick?

As for 'RF Switch', the little gray box actually does the switching between the cable or antenna and the RF module's output.

rainwarrior wrote:As far as sound output goes, on my AV-modded famicom the sound is bright and unfiltered compared to the NES (which has a mild lowpass on the way to its built in AV-out).

Regarding your original Famicom that's AV-modded -- for the audio did you simply run wire straight off the audio output pins on the CPU? If so, then that explains how you managed to bypass the resistor arrays (I think that's what they are?) used for low and high-pass filtering on the Famicom. :-)

In fact, NSFplug has low and high-pass pre-sets for each of the console models that fairly accurately reflect how they sound (non-modded). Options -> Easy Setup; see difference between Famicom and NES base presets. Like I said, these sound pretty accurate when compared to the real thing. The "New Famicom" base preset (which should, BTW, be renamed "AV Famicom") I have no way of confirming -- but if NSFplug is correct, it's identical to the NES, which means Nintendo Co. tended to like the way the NES audio path sounded (just a minor high-pass filter). :-)

I noticed that when I connect my NES by RF, the audio is far more lowpassed than when I connect it by AV cables. The video is also horrible when connected by AV cables to a VCR, so I use RF instead.

koitsu wrote:Regarding your original Famicom that's AV-modded -- for the audio did you simply run wire straight off the audio output pins on the CPU? If so, then that explains how you managed to bypass the resistor arrays (I think that's what they are?) used for low and high-pass filtering on the Famicom.

Yes, I was referring to the "standard" AV mod which takes the audio directly from the cartridge return. I know the NES AV path has a mild lowpass filter, but when using RF output such a filter would be entirely redundant since the signal will get a very strong lowpass from the RF modulation/demodulation process. I haven't checked famicom schematics to see if there is a similar filter, but I think it's kind of inconsequential since it normally only had RF output anyway.

koitsu wrote:In fact, NSFplug has low and high-pass pre-sets for each of the console models that fairly accurately reflect how they sound (non-modded). Options -> Easy Setup; see difference between Famicom and NES base presets. Like I said, these sound pretty accurate when compared to the real thing. The "New Famicom" base preset (which should, BTW, be renamed "AV Famicom") I have no way of confirming -- but if NSFplug is correct, it's identical to the NES, which means Nintendo Co. tended to like the way the NES audio path sounded (just a minor high-pass filter).

I wouldn't presume any of the presets are really "accurate", but I'm sure they do approximate some characteristics of each setup. I don't have a way to verify it myself unless somebody wants to provide me with good reference recordings. I am trying to keep the default setting tuned to be like an NES AV out, though from comparing recordings from different NESes I have to try to average it out, since there's a fair bit of variation.


On another note, I'm back at home now, so I tried the stuff you did in your Famicom RF video tutorial but still no luck. I don't get anything output on channels 3 or 4 by my Famicom with my NES RF adapter, no matter which what I set the switches.

I think the "audio path" is completely different on various consoles.
As far I know :
NES : Many stages of amplification, ones involving a normally digital IC inverter, some involving transistors, and many stages of filtering with passive componants.
NES2 (toploader) : No amplification at all, just some passive componants and the output goes straight to the RF-box (or in the case of my modded console : To the output jack). I have to pull the volume louder to compensate for this, but the sound quality is perfectly OK.
Famicom : A single stage of amplification with a digital IC inverter, which is also used for some logic somewhere else. Very likely this will add a lot of noise, and non-linearities, to the output signal. I have no way to confirm this exept the famicom scematics which used to be there on the NESDEV main page.
New Famicom : Unknown

It makes sense the sound would be low pass filtered when carried through RF as the bandwidth for the audio is limited. I think it's not much a good thing, I like square waves to sound crisp and clear

When it comes to power plugs, I have literally dozens of them at my home, it's very likely at least one of them would work on the FC. It's no use to use an official one, since it was made for 100V and we have 230V in my country, this would of course blow up everything.
10 V with reverse polarity is definitely something rare, 9V or 12V are more common. I'd assume 9V would work too, wouldn't it ? Since it takes DC as input, very likely it's directly connected to the 7705 linear regulator, which is normally robust. I don't know if there is a 7705 in the FC like there is in the NES though, pehaps they used a crappier/cheaper powering circuit which is more likely to blow up.

rainwarrior wrote:On another note, I'm back at home now, so I tried the stuff you did in your Famicom RF video tutorial but still no luck. I don't get anything output on channels 3 or 4 by my Famicom with my NES RF adapter, no matter which what I set the switches.

That's really bizarre. I know Canada is NTSC, but do you guys have some kind of weird channel difference (frequency-wise) than we do down here? I.e. are Canadian TVs somehow different than the ones in the US? It just doesn't make any sense. Maybe it has something to do with the fact that I'm using an old CRT monitor and you're using an LCD monitor -- not that CRT vs. LCD has anything to do with it, but maybe the RF modulator in your LCD TV is "less accepting" or "less friendly" (I dunno how on a technical level) than my TV?

There is no difference between TVs sold in the U.S. and Canada, to my knowledge. I tested this on two TVs, one of which was actually purchased in California.

If it's a shitty RF receiver problem, it's a problem with both TVs here. I dunno, since it seems to be increasingly uncommon to use a TV as a tuner for broadcast television (everyone I know seems to have a separate device supplied by the TV service), it could be that this feature is very poorly supported by a lot of modern TVs. It seems strange to me that this would be a problem with two televisions, though. (Also they have no problem with the regular NES RF signal on both channels 3 and 4.)

Have you considered there might be something unusual in your setup that somehow puts the signal on channel 3 and 4? I haven't actually seen anyone suggest that this could be done with a Famicom before. Most people say use an NES RF adapter and use channel 95/96.

For what it's worth I'm in the US as well and I have to go to channel 96 to get my original famicom to work with my (US/NTSC) NES RF switch. I don't get anything around ch 3/4. My TV is probably 10-15 year old CRT by RCA.

The video quality is crap (kinda fuzzy/grainy) with that setup so modding over to A/V seems the only decent solution to get something that looks okay. I'm curious as to how yours is working exactly koitsu, do you have more than one RF switch to test with? I wonder if there is something special with that one, or do you have some sort of multi-input selector or other filter in there that could be doing something?

I have two RF boxes (the gray things) which I can test with. One is from top-loader NES, and one from my front-loader NES. The one I'm using in the video is from my top-loader NES.

If you want me to make a video showing me swapping out the RF box with the one from the front-loader (in real-time), I'll be happy to do it.

You saw quiet clearly in the video there is no other device/filter/whatever hooked up (that's why I showed the cable and the back of the TV).

There's absolutely nothing special about my TV either -- standard Sony Trinitron KV-13FS100. I even got mine from Amazon. If you want the User Manual, Google for "Sony_KV13FS100.pdf". If you want the Technician/Service Manual, here you go. I've been in the service mode in the past, but only to look at features -- everything is pure stock. If I had adjusted something that'd explain this behaviour, I'd be telling everyone what I did. :-)

I don't think anyone's in disbelief, but nobody besides you (so far as I've heard/seen yet) has been able to make this work for them.