Re: Looking for YMF262

From: Richard Atkinson (
Date: 1999-06-28 13:16:59

On Mon, 28 Jun 1999, Levente [iso-8859-1] Hársfalvi wrote:

> > Ah. In that case it's likely that all OPL3s out there will be SMT, since
> > the ones in the first SoundBlaster that used them were SMT. Unless anyone
> > finds some standard 0.1 inch DIL versions, I will be unlikely ever to
> > build the upgraded stereo version of the sound expander myself.
> W..why?

OK, so I was a bit melodramatic - just annoyed at not being able to find
0.1 inch OPL3s even though the documentation I have states that they

> Well, it's a bit harder to make an SMT board, ...even soldering,
> desoldering an SMT chip is horrible; but it's definitely possible. Once
> I needed a 62256 Sram, so I removed one from a HDD (SMT, of course);
> then placed the thingy to a DIL28 socket, soldered the pins to the
> socket's pins by small wires, then applied some glue (epoxy) to fix
> everything in its place. It still works ;-)

It might come to that, yes... incidentally, that would get round the
problem of the OPL3's different pinout - just solder the SMT pins to
different IC socket pins :)

> Guess designing the appropriate board is much like designing a THT one.
> Well, producing the board and soldering the components into place is
> much harder.

Sorry - what is THT?

> But you don't have to make everything with SMD's. Only the YMF chip is
> involved, all others can still be normal THD's.

The YAC512s will probably be SMD, or I could use YM3012s instead (not too
sure about this). This is the DAC element of the new expander - the
original used the YM3014B but that was for mono. Both devices are two
channel stereo, so two would be needed for the full four channel support.

> > Last night I succeeded in desoldering all the TTL logic chips on the
> > board, sadly at the expense of the chips themselves, but never mind - I'll
> > buy replacements today. I aim to have the schematic finished by next
> > weekend. Putting in an OPL3 chip is simply a matter of deciding which
> > address line to use for the chip's extra address pin (A1) and doubling or
> > quadrupling the amount of DAC / op-amp circuitry. Apparently OPL3 has four
> > channel sound output.
> I like this idea.

The analogue upgrades are the messiest part - finding two channel DACs and
adding the extra op-amp stages will make the board very messy.

> That's just another thing besides this, I like FM sounds.

The 4 operator FM in the OPL3 has 4 algorithms - there are 4 missing from
the usual Yamaha DX21 set of 8. This should still allow some quite good
sounds - almost up to the standard of the MSX FM expander thingy I have.

Well, as I said I should have that schematic ready by the end of the week.
Must get back to work now ;)


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