fm-pac modifcitation

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By poke-1,170

Paragon (1782)

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13-03-2014, 23:30

ah , so cutting that pin will avoid the mixing of both signals ?
mail received ^_^

By luppie

Paladin (869)

luppie's picture

13-03-2014, 23:33

Meits wrote:

Is your recent one a Panasonic FM-PAC?

Is the pope Catholic ?
Are the bananas krom ? Tongue

A FM-Pac is always Panasonic, otherwise it would be a FM-Pak, FM-Paq, FM-Pack hahahaha

By poke-1,170

Paragon (1782)

poke-1,170's picture

13-03-2014, 23:35

@ meits: see above comment Tongue

Aren't the PAK etc the ones with separated PSG and FM ?

By poke-1,170

Paragon (1782)

poke-1,170's picture

13-03-2014, 23:39

@meits interesting by the way, the output I had originally looks very very similar. Maybe someone used to do these modifications a lot ?

By meits

Scribe (6530)

meits's picture

13-03-2014, 23:39

I had it done by a friend who only did his and mine... He left the scene in 1996 so I bet it wasn't him who did a lot Smile

By meits

Scribe (6530)

meits's picture

14-03-2014, 07:58

luppie wrote:
Meits wrote:

Is your recent one a Panasonic FM-PAC?

Is the pope Catholic ?
Are the bananas krom ? Tongue

A FM-Pac is always Panasonic, otherwise it would be a FM-Pak, FM-Paq, FM-Pack hahahaha

You're quite wrong there.
I've had an FM-PAC by MK Wink. This FM-PAC was made (and also released) by Digital KC. MSX Club West Friesland released this particular version as well. Sadly that's the only version I could find a picture of.
Then there are probably even more FM-PACs around the world we've never even heard of... Plus FM-PAC is a widely used name for an MSX-Music cartridge and it's even wrongly used for built in MSX Music in computers. Can't always blaim the ignorant for believing MSX-Music=FM-PAC.

So, the pope is a heretic and bananas are straight :D

By Daemos

Paragon (2044)

Daemos's picture

14-03-2014, 09:57

Just make sure you are speaking about noise here. Noise is being blamed for nearly everything in electronics and audio but there are other audible factors that sound like noise but are not noise:

1.) hum, caused by bad unstable power supply
2.) crossover distortion, caused by bad mixing of the audio signals
3.) overamplification, which is noise caused by taking too big steps during amplification
4.) distortion and overdrive, again caused by bad amplification
5.) electric interference, very high frequency waves creating unwanted sound. Bad internal shielding or using to low voltages on the signal path.
6.) GND loops, again creating electrical interference.
7.) clicking from electronic switching of power hungry nearby devices.

Noise is the product of using very bad components or components that are not intended for the use in audio. Carbon film resistors, germanium transitors and diodes, many trimmers within the low level signal path etc, long wires, cost reduction on the use of filter and stabalization capacitors. Avoid any of these.

The best way to find the source of unwanted sounds is by poking around with a good scope and find where the problems occurs withing the audio chain. You can easily detect them if the output/input of the audio is kept silent or grounded.

By Manuel

Ascended (19273)

Manuel's picture

15-03-2014, 14:27

Well, the MM sounds and looks like a 50Hz noise, most often solved with proper GNDing.

The FMPAC sounds.... interesting Tongue Isn't it possible to record this and use it to filter it out from the complete recording aftwards? (If it's white noise, that won't work of course.) It looks like it has some regularity in it, but I can't tell what it is. It does seem to have a 50Hz component as well. Just load it in Audacity and check the spectrum.

By Daemos

Paragon (2044)

Daemos's picture

15-03-2014, 20:26

both sounds are not noise. So your FMpak is fine. This sounds like electric interference. So as manuel says there are some grounding problems.

It looks like you are picking up some frequencies from somewhere. It could be shielding, could be grounding. There is some hum too. Sounds like there is an input somewhere in the amplifier that is not properly shielded or grounded.

By Daemos

Paragon (2044)

Daemos's picture

15-03-2014, 20:31

Are there any schematics available on the FMpak?

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