Third party AC adapters for SNES - found a good one yet?

[brento]

Yeah, I will take back my comments indicating that the third party power supplies are not right for the system, as they do work. It's just odd that they produce that static if and only if you are also using a third party av cord.

[brento]

Interesting. I noticed when the SNES is powered on, and the NES's cord is touched with my finger, about half of the 'snow' disappears. Why would that be? Grounding issue?

[Andromeda Stardust]

Interesting. I noticed when the SNES is powered on, and the NES's cord is touched with my finger, about half of the 'snow' disappears. Why would that be? Grounding issue?

Well SNES and NES are center negative, so if you touch the tip you will be touching the ground, and if you touch the sleeve, you are touching the plus side before it enters the regulator. Also be aware some 3rd party AV cables are terrible and unshielded. I bought a Genny 1 AV cable that was so shitty the composite was terribly blurry and worse than the RF. Then I ran to Radioshack and bought a MIDI cable and shielded RCA and basically rolled my own AV cable. Picture was flawless after that.

 

If you are getting cleaner signal by touching the NES adapter tip, there is a chance the filter cap on the power supply is insufficient to remove the ripple. You could try a digital multimeter in AC mode to try and measure the ripple current on the tip, but in reality you need an oscilliscope to accurately check ripple voltage. Ripple peak to peak should be no more than a few millivolts on a clean DC adapter. If the audio is buzzing, this is an indication of ripple in the DC feed.

 

It is possible that a poor audio cable will pick up buzz moreso than a proper shielded one. It's also possible a piss poor DC supply ripple will add buzz or other audible noise. My theory is the poor cables do not adequately shield out the buzz, and the poor DC adapter is supplying the source of noise.

 

Just get a regulated 9V DC adapter from Radioshack (it's $20 but you get what you pay for) and get the 2.1x5.5mm barrel tip (or is it 2.5x5.5mm - I can't remember?), and electric tape it onto the plug in the negative tip position. Test polarity with multimeter. Order the Super Nintendo adapter dongle from Console5 as Radioshack does not sell these tips. Now you can run NES, SNES, Genesis, Turbografx, Famicom all from the same adapter.

[brentonius]

So I seem to have fixed the issue. I used a shielded AV cable, a new third party one that has thicker cables and is actually good. I used the Retro bit AC adapter. Perfect picture quality.

[brentonius]

Kosmic stardust, your explanation was very helpful... Thank you.