Modding Cartidges, Diagrams with Stereo & Clock Oscilator ...

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Por WORP3

Paladin (804)

Imagen del WORP3

20-10-2011, 19:20

The MIDI-PAC isn't producing sound only MIDI data so no need for modding Wink
And you are right, the MIDI-PAC has it's own clock, it isn't using the msx clock, it will also work with 7 Mhz, OCM or turbo. Actually it's an ideal way to get a nice music with a modded msx computer Big smile

Por Dhampird

Hero (585)

Imagen del Dhampird

20-10-2011, 20:34

Then, update:

*Need to be fixed with 3.58Mhz oscilator if you use Turbo speed:*

- Konami SCC
- Konami SCC+
- Philips Music Module (NMS-1205)
- Toshiba Music Module (HX-MU900)
- Panasonic MSX-Audio (FS-CA1)
- All MSX-Music cartridges (FM-PAC, FM-PAK, FM-Stereo etc)
- Playsoniq (probably need to be fixed, will be great get confirmation)
. . .

*Not need fix, because include their own crystal oscillator for sound:*

- Sunrise's Moonsound (and its clones: ShockWave, Dal Ri Sol)
- Leonardo/MSXpro's OPL3 Cartridge
- Padial's SAN3 sound cartridge
- Midi Pac
. . .

Por WORP3

Paladin (804)

Imagen del WORP3

20-10-2011, 21:43

It's almost easier to make an adaptor that always supplies a good clk to the cart, regardless the internal msx clk Wink

Por snakepow

Champion (291)

Imagen del snakepow

16-11-2011, 14:51

I think it will be interesting modify a Panasonic MSX2+ for always (normal or turbo mode) provide 3.58 MHz on external cartridge slot. Can this modification be done? Also, internal PSG chip of these Panasonic MSX2+ machines is provided with 6,14 MHz clock when Turbo is enabled, causing this PSG sound distorsion. Can be possible a modification to solve this (i.e. always provide internal PSG chip with 3.58 Mhz clock) ??

I mean solve sound distorsion modifying computers instead of cartridges.

Por RetroTechie

Paragon (1563)

Imagen del RetroTechie

17-11-2011, 03:40

I think it will be interesting modify a Panasonic MSX2+ for always (normal or turbo mode) provide 3.58 MHz on external cartridge slot. Can this modification be done?
Just pick a cartridge slot to use for sound carts, then put fixed 3.58 MHz signal (eg. taken from VDP) on its CLK pin - done. Then other slot can be used for the few carts (like some DRAM-based memory mappers) that need actual CPU clock.

Also, internal PSG chip of these Panasonic MSX2+ machines is provided with 6,14 MHz clock when Turbo is enabled, causing this PSG sound distorsion. Can be possible a modification to solve this (i.e. always provide internal PSG chip with 3.58 Mhz clock) ??
Probably not - clock signal is also used for timing internal DRAM signals (and perhaps for producing other signals). And since that happens internally in the engine IC, you can't pull apart that clock and PSG-clock.

Only option would be to replace internal RAM with Static RAM (so that DRAM control signals aren't used anymore & it doesn't matter if they get f**ked up), modify clock circuit, and then... hope for the best (no guarantees until someone tries it).

Por mister.phr0zen

Expert (102)

Imagen del mister.phr0zen

15-05-2012, 22:08

What about a switch, to enable either clocks on the slots?
Other option will be put the cpu clock in some "unused" pins of slot, and build an small slot extender with this switch. Wink

Por Moniz

Champion (346)

Imagen del Moniz

01-10-2014, 00:02

Dhampird]Hi!, sorry for delay in reply, about:<br />
<br />
<cite>...Just wondering: if you do this for a number of cartridges, why not do that modification inside the MSX machine you're using? Like take out a resistor in a strategic place, and put a switch in the back of the MSX. Or just disable mixing cartridge sound with PSG for 1 of 2 cartridge slots? And then add an extra sound output somewhere in the MSX machine, where you can tap the sound produced by a cartridge separately....</cite> <br />
<br />
[quote
wrote:

-Hello "RetroTechie", yes, you´re right, time ago i thought about it. Will be better install a stereo jack inside machine to avoid install a switch in each cartidge, is one of the things that I have yet to be done. Thanks as always for the good advice.

Quote:

Sorry for bringing up this old topic, but i was wondering (noob question ahead!): is it possible to add, lets say, 3 jack outputs on a machine (one PSG, 1 SCC and 1 FM) so it could be mixed seperatly with an external mixer?
This could be very usefull if people want to use their machine for just making music (especially with Synthe6 comming up) and without making mods to the cards.

Por giangiacomo.zaffini

Champion (267)

Imagen del giangiacomo.zaffini

01-10-2014, 03:28

In my humble opinion, whether MSX/MSX2/MSX2+/MSXturbo internal clock circuitry is neither trusted nor considered good enough, it should be fixed.
And again, if some music cartridges have untrusted clock circuitries, they shoud be fixed.

Por Grauw

Ascended (8615)

Imagen del Grauw

01-10-2014, 18:46

giangiacomo.zaffini wrote:

In my humble opinion, whether MSX/MSX2/MSX2+/MSXturbo internal clock circuitry is neither trusted nor considered good enough, it should be fixed.
And again, if some music cartridges have untrusted clock circuitries, they shoud be fixed.

It’s not about not trusting internal clock circuitry; on MSX machines with 7MHz turbo mode, a common mod, the pitch of music will go up by one octave, or worse, make it distort (some circuitry slows down VDP I/O by switching the clock speed in stead of inserting wait signals). Installing separate crystals on music cartridges prevents this effect.

Por Meits

Scribe (5717)

Imagen del Meits

01-10-2014, 23:25

Prevents it for a great deal...
I have a modded philips music module for turbo mode... done in the 90s and I'm not a hardware geek so I don't know if it's still up to today's standard... Point is, it skips the very first few milliseconds of a random note on event once in a while... That sucks... This happens on 7MHz and on a Panasonic MSX2+ in turbo mode including its internal MSX-Music (quite good audible here)...
Dunno how they managed on Moonsound, but the audiocarts before that fail... At least the ones I heard...

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