Getting external audio on an NES top loader!

Started by 2A03, July 31, 2011, 05:42:36 pm

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2A03

Thought this mod was worth sharing: http://nesdev.parodius.com/bbs/viewtopic.php?t=7880

I tried it out myself and it seems to work alright. The PowerPak audio is a bit too loud and audio from actual Famicom carts is kinda quiet but it's well worth trying!

petik1

instead of resistors, try potentiometers. That will allow you to adjust the volume.

Xious

August 04, 2011, 03:24:54 am #2 Last Edit: December 27, 2011, 03:43:21 am by Xious
You also want a 1-turn=1000 pot with a range of around 1000 to 4800-Ohms. A lower bottom-end is fine; you don.t really want a higher top-end.

I need to amend this, as there is little need for a multi-turn pot. A basic 1-turn pot will work, as long as you select a good track resistance; 2KΩ is probably just about right, or maybe 2.5KΩ, as you can dial it back as needed, in an audio configuration.   :bomb:

Drakon

good that saves me having to try and find unused expansion pins on the nes 2.  I have a game genie that I'm soldering a nicer nes socket to.  Then I'll just wire the game genie as a passthrough with that expansion port pin swapped for the powerpak.

Lum

Ah man. If I'd known this I wouldn't have sold my AV mod NES top loader in favor of AV famicom. :(
*bzzzt*

satoshi_matrix

You still made a good choice there. AV Famicom rocks.

Drakon

I love the av famicom too.  I did make a discovery that the nes 2 has just as nice video quality as the av famicom...I even desoldered the rf box/back plate from my nes 2 and installed a back plate that I took out of an av famicom and wired up a multi av to my nes 2 to a rgb / s-video / composite video kit



Don't worry the av famicom I took the back plate from still works fine it just has no back plate.  It still has the multi av port and I soldered in a power jack that I took from a parts toaster after I desoldered the entire rf box from that toaster.

Still the av famicom is just as good and it doesn't need any special modding to add a multi av port.

And you can run the av famicom off of a model 1 sega genesis / sega megadrive power brick.

2A03

Thought I'd post here again in the hopes that Xious can help me out with this one. Anyway, when I use my modded PowerPak with my NES-to-Famicom converter, which has been modded for PowerPak audio, I only get expansion audio. However, when I disconnect the wire going from pin 51 to pin 54 on the PowerPak, all audio is normal. What exactly is going on here?

Xious

December 27, 2011, 03:40:00 am #8 Last Edit: December 27, 2011, 03:45:11 am by Xious
Oh my, it seems that I'm now taking requests. :)

The way I'm reading this, with the jumper wire inside the PP disconnected, you are getting no EXP sound normally, and with the jumper wire bridging (PP Pin-51 to PP Pin-54) you are hearing the EXP sound, but not the base sound? Is that correct? I'm somewhat confused by your choice of words ('all audio is normal'), as that to me means that you are getting properly mixed sound, which I presume is not the case, so i want to verify that in advance.

Assuming this is the case...

What resistor value did you use on the NES-101 mainboard? I would say that it is possible that the audio is overpowering the base sound, or causing distortion. Did you use a pot, or did you use the 1.2KΩ resistor, and (if the latter) are you sure you used the correct value?

If you used a potentiometer, did you wire it as an audio dial, or as a trimmer?

I should correct my original potentiometer values: Although 1KΩ=1 Turn is usable, you actually want something much finer with a base near 1.5-2.5KΩ, due to the audio design for the NES-101.The original suggestion was what I used on a different project, and I didn't give it enuogh thought at the time as it is less appropriate here.  I think using a 1-Turn trimmer somewhere in the range of 1.2KΩ to 2.5KΩ, is ideal. (4KΩ is likely going to be far too high.) Log may also be preferable, although I have not tried a log versus a linear one for this application.

It would be easier if you could fetch an audio sampling somehow with rthe supposedly mixed signal, and if you posted photos of the modification that you have done (clear, high-resolution) so that I can visually inspect it and see if I note anything incorrect.

I would need to check your solder work, as there isn't a very good reason that it should have stopped working on you unless you ended up overheating something, or with a cold joint, etc.. Did this work correctly before; or did it give you trouble? :bomb:

2A03

Quote from: Xious on December 27, 2011, 03:40:00 am
The way I'm reading this, with the jumper wire inside the PP disconnected, you are getting no EXP sound normally, and with the jumper wire bridging (PP Pin-51 to PP Pin-54) you are hearing the EXP sound, but not the base sound? Is that correct? I'm somewhat confused by your choice of words ('all audio is normal'), as that to me means that you are getting properly mixed sound, which I presume is not the case, so i want to verify that in advance.

Actually, this is when I use the PP on a Famicom, not the top loader. With the jumper wire disconnected, I'm getting normal sound along with the expansion audio, but with it connected I only get expansion audio and no 2A03 audio, no matter the game. I checked all my solder joints on the mod to my NES converter and it all checks out fine.

Xious

You also wired your NES-->FC converter to use the modified PowerPak EXP pin and no other pin; correct?

If you are going to attempt to use the same pin for every system, then you should have wired your converter as follows: NES-72F Pin-51 (EXP-09) to FC-Edge (60M) Pin-46 and Pin-45 via 10KΩ (1/8W) resistors.


Inside the NES72F-->FC60M Adapter:
NES-Pin-51* o-------------[ 10KΩ 1/8W ]---------------o FC-Pin-45*
            |                   R1
            |-------------[ 10KΩ 1/8W ]---------------o FC-Pin-46*
                                R2
Be sure that pins 45 & 46 are not otherwise joined on the PCB; some adapters use one gold contact for both pins, or bridge them, or tie them to GND.



Should you also need fix the MMC5 compatibility at the same time...

Inside the NES72F-->FC60M Adapter:
VRAM /CE (NES-Pin-57)* o----------------------------o FC-Pin-48*
CHR  A13 (NES-Pin-58)* o----------------------------o FC-Pin-49*

Be sure that pins 48 & 49 are not otherwise joined on the PCB; some adapters use one gold contact for both pins, or bridge them, or tie them to GND.




2A03

December 28, 2011, 10:20:38 pm #11 Last Edit: December 28, 2011, 10:29:20 pm by 2A03
I modified my NES-to-Famicom converter like you described, but I'm still having the same problem. I get 2A03 audio now with games that don't have external audio, but for those that have external audio, I'm not getting the 2A03.

EDIT: The PowerPak's NSF player also has the same problem, no 2A03 audio whatsoever.

Xious

On the adapter, you only have Pin-51 wired for audio, correct? (e.g. not Pin 51 and 54,or pin-54)

Does it work correctly on your NES-101, or does it exhibit the same symptoms?

Please post photos of your converter so that i can check for any problems.  :bomb:

2A03

Quote from: Xious on December 28, 2011, 11:02:46 pm
On the adapter, you only have Pin-51 wired for audio, correct? (e.g. not Pin 51 and 54,or pin-54)

Does it work correctly on your NES-101, or does it exhibit the same symptoms?

Please post photos of your converter so that i can check for any problems.  :bomb:

I only have pin 51 wired up now, as per your instructions. I originally had it at pin 54 after I got the PowerPak. It works fine on my top loader, no problems there. I've tried my converter on three Famicoms, an AV modded original Fami, an AV Fami and a Twin Fami. Here's my converter...



Although it doesn't really show it in the second pic, both pins 45 and 46 on the converter are not bridged.

Xious

December 28, 2011, 11:32:16 pm #14 Last Edit: December 28, 2011, 11:45:06 pm by Xious
Disconnect the solder point on P-54 on the adapter first, then test and report back. I assume that you bridged the PowerPak P-54 to P-51 internally, on the PowerPak itself, correct?

I also think that either you need only bridge to the system audio input, or you need to use the two resistors in series. I'd need to check what I actually did to be sure; I only checked my reference docs earlier.  The original mod that I saw was actually more like this:


Inside the NES72F-->FC60M Adapter:
NES-Pin-51* o-------------[ 10KΩ 1/8W ]------o---------o FC-Pin-46*
                                R1            |
                                              |---------[ 10KΩ 1/8W ]-------o FC-Pin-45*
                                                           R2

You may also want to use a continuity tester to ensure that your solder points and resistor leads aren't bridging. It certainly looks as if they are... :bomb: