PC-Engine Core Grapfx Modded, Slight Audio Whine!?

[lettuce]

Ok i have modded my Core Grafx system with an RGB AMP...







The picture is perfect but am noticing i slight whine coming from the speakers, you can hear it the more you turn the volume up, i also did my White PC-Engine with the same RGB AMP and that has the same issue. When a game is actually playing you cant hear it but atm i have Special Criminal Investigation on in attract mode (there is no audio in attarct mode for this game) and i can hear the whine.

Is this just common place for PC-Engine's to have this or is it a cap??

[kamiboy]

Common place for any console I've ever owned that had analogue audio output. You can reduce the hum by using a separate audio lead instead of carrying all vide and audio signals in one cable.

[ApolloBoy]

Pretty sure he's not talking about a ground loop problem, all PC Engine and TurboGrafx consoles have a distinct audio whine.

[lettuce]

Pretty sure he's not talking about a ground loop problem, all PC Engine and TurboGrafx consoles have a distinct audio whine.

Ah good to know that its perfectly normal, i thought it might be as it would be extreamly uncommon (or bad luck) to have 2 systems that did the same, as i never notice this with my NES, SNES or Megadrive systems

[EmperorIng]

I wondered about this as well, since my Duo-R does the same thing (low sustained chip noise in the background, occasionally). At least the issue is widespread.

[lettuce]

I wondered about this as well, since my Duo-R does the same thing (low sustained chip noise in the background, occasionally). At least the issue is widespread.

So theres no way to eradicate it then?.

I guess Tim's, 'AV-DRIVER: Universal RGB A/V Amplifier' would solve the issue??

[donluca]

Is this whine noise like a very high pitched noise? Like the ones 15Khz CRT monitor do?

If that's the case, you can just put a low pass filter on the audio output to cut everything above a certain frequency: it's just a resistor and a capacitor per channel.

[ApolloBoy]

I guess Tim's, 'AV-DRIVER: Universal RGB A/V Amplifier' would solve the issue??

No. The whine comes straight from the HuC6280 so nothing can fix it.

[kamiboy]

RGB jailbars and audio whine. I guess those HU chips suffered from design flaws.

[lettuce]

RGB jailbars and audio whine. I guess those HU chips suffered from design flaws.

Luckily i Haven't noticed any jailbars on the 3 systems ive modded

[kamiboy]

They are not clearly visible in all games. At first I didn't think I had them either. Ignorance is bliss though, so I do no recommend going jailbar hunting.

[edomatic]

Is there really no way to eliminate this whine coming from the huc6280?
I have it too on my Duo R and find it so annoying
I have a decent cable which reduces the normal buzz and humm sound but this high frequency interference is killing me..
I tried to put an equilizer in between the audiopath but it seems to be pretty must all over the place , i have a 31 band dual channel equalizer and had to turn nearly everything down from 2,5K to somewhat eliminate this whine..that can not be the way this was designed to work
Has anyone found a solution for the high frequency whine emitted by the huc6280 chip?

[kamiboy]

Jailbars were fixed using decoupling caps of a higher rating for the HU chip. Perhaps the same can be done for audio hum. If the source of the hum is the internal working of the chip itself then there is nothing that can be done.