What's currently the best AV mod for the Famicom?

Ah I see.

Its quite confusing.

 

Any thoughts on this pseudo-stereo mod?
http://www.disgruntleddesigner.com/chrisc/nesstereo.html
My plan was to use pin 46 as the mono audio that gets mixed with the potentiometers. I'm wondering how cart audio (like akumajou densetsu and doki doki panic, among others) would sound. My worry is it would be too soft compared to the rest.

 

Speaking of audio, I've heard something about certain games (Famicom Disk System games I think) having problems depending on how you choose to do the audio mod. Does anyone know how to resolve this?

 

You have to pull audio from Pin 46 of the cart slot, rather than from the conveniently-labelled "SOUND" contact on the motherboard of older-model Famicoms.

 

I've missed it a couple of times when FireAza has called me by one of my other internet name thingies since I'm used to being called that as well XD

 

So that's the story is it? Do you need to amplify the signal or is it good to go straight from the chip?

If you would just use the same handle everywhere you went, we wouldn't have this problem

Back to the AV mod, I asked earlier if there were specific types of components I should be using, as I've read something about ceramic capacitors being better for the Famicom. Any thoughts guys?

 

The diagram shows a polarised cap, so its not ceramic.

 

I mean for the whole "put a 100uf capacitor on pin 22 and 20" thing, I had heard something about it being better to use a ceramic capacitor for this.

On the subject of components, does the resistor's watt rating have any bearing? From what I've read, this rating is only important when you're working with high watt electronics, and this won't be the case here, so any rating should be cool so long as they're 300 ohms/110 ohms right? The 220uF capacitor I already have is is 10v, last time we talked about capacitor voltage, it was determined that the voltage doesn't matter, only the microfarads measurement did. I'm assuming this is the same here? When on Earth does the voltage rating matter? :confused-new:

 

The watt rating of a resistor is a limit. If you try to dissipate more than that amount of power through it, it'll fry.

1/4W will be stacks for a video circuit.

 

Yeah, that's what I thought, thanks!

What about the two capacitors? RE: ceramic and voltage? I'm not even sure ceramics even come as high as 100uF :|

 

I dont think you will find a 100uf ceramic capacitor very easily. Ceramics are usually low value, which kinda answers the question for you..

 

Will a plane Jane capacitor still be OK? Polarized or non-polarized?

 

A lot of time polarized electrolytic cap will be fine. A non polarized version exists at higher cost but seemed to work better for some video amp. If you're using polarized, the +_ side generally goes to console (toward video chip or amp if you are using amp) and the - side for video output.

 

Are you talking about the capacitor that's part of the video circuit or the capacitor that put on pin 22 and 20 to help fix jailbars? I'm reading your post and I'm not sure which one you're referring to.

 

Ah it's for the video out, I thought we were still on the AV mod thread topic. I'm not sure about the cap for jailbar mod, I haven't done it. From a quick search, pin 20 is ground so if you use polarized cap the ground lead probably should go to pin 20. I'd double check this to be sure.

 

From what I've been reading, non-polarized capacitors are suppose to be better for filtering (which I'm assuming is the purpose of this capacitor) and physically smaller than polarized. The last point will probably be handy, as it needs to fit between the board and the case.

 

You want the largest value within reason to MINIMIZE the high-pass filtering of the series AC coupling capacitor; 220-470 uF are good candidates. Larger is wasteful, smaller will affect some TV's ability to sync to the video. You technically do not need an AC coupling capacitor on the output at all which yields the best quality signal, but they save power by removing the DC bias from the amplifier output and also somewhat protect the output from short-circuit which is their main purpose.

You always position the capacitor's positive lead towards the greater voltage--since TV inputs are terminated to GND it's correct to face it towards the amplifier output. When a cap is facing an amplifier input (such as in many audio circuits) it's because that cap is also an AC coupling capacitor and is oriented back to back from the previous stage's output coupling capacitor, effectively making a non-polarized capacitor of reduced value. Without it the bias voltage of the input could possibly damage the previous stage's output and the reduction in capacitance is OK because the input will always be very high impedance which also minimizes the high-pass filtering.

 

Hmmm, I think, I understand what you're saying here... You're saying I should should go for something beefier than 100uF and that a polarized capacitor shouldn't be a problem?

 

I'm pretty sure Calpis is talking about the capacitor for the amplifier circuit, not the one that would go between pins 20 and 22.

 

Ah. Just for clarification fellas, I'm all good for the capacitor on the amp circuit (I already have a suitable capacitor in fact), we're currently discussing the 100uf capacitor that does on pin 22 and 20 of the ppu.