ChanServ changed the topic of ##yamahasynths to: Channel dedicated to questions and discussion of Yamaha FM Synthesizer internals and corresponding REing. Discussion of synthesis methods similar to the Yamaha line of chips, Sound Blasters + clones, PCM chips like RF5C68, and CD theory of operation are also on-topic. Channel logs: https://freenode.irclog.whitequark.org/~h~yamahasynths
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<m4t>
does anyone know of any genesis vgm test tracks? like, sine waves at 0db, frequency sweeps, that kind of thing?
<cr1901_modern>
I'm not, though a sine wave at 0db shouldn't be too difficult to manually write out. There was talk about creating a DSL for writing out VGMs like that a while back, but it hasn't made much progress.
<cr1901_modern>
I don't have a 68k toolchain set up, otherwise I'd try myself
<superctr__>
i think i made one
<m4t>
:)
<m4t>
i just wanted to look for clipping
<m4t>
well, and other easily visible issues like oscillation
<superctr__>
i made a frequency sweep vgm when i was testing a lowpass filter for the nukedopn2 core
<superctr__>
but i'll have to find that file...
<m4t>
thanks, let me know if it turns up
<superctr__>
but i think if i don't find it, you could make something quick in deflemask or something
<m4t>
taking a look. yeah i wasn't sure if there was a tracker that'd be suitable
<superctr__>
ok i have one but it's not 0db
<superctr__>
the TL is set to 20 so that's attenuation of 15 dB. but on the other hand 4 operators are enabled
<m4t>
don't mind the blacktopped ym3438, it was free
<m4t>
:D
<m4t>
also the JLCJLCJLCJLC is kind of annoying. i thought they would automatically replace it with the order #, apparently i didn't select the correct option when i ordered
<cr1901_modern>
Ahh building a MegaGrrl? Good stuff!
<m4t>
yeah, 2 of them. one of them is for my coworker who is into chiptunes
<superctr__>
lol, that fake/rebadged ym3438
<m4t>
idk if it works
<m4t>
i have some legit ym2612 if not
<superctr__>
it's really hard to find a real one
<superctr__>
at least one that hasn't been rebadged, it's pretty easy ot take any chip with similar package and just replace the markings
<m4t>
1030 GAGD. i about gagged when i opened the ebay package...
<m4t>
i removed the blacktop with acetone on another from the same batch and i didn't see any markings so we'll see
<KitsuWhooa>
I got one of those too!
<KitsuWhooa>
it's just rebadged
<m4t>
cool
<KitsuWhooa>
still better than those YM2151s I got
<KitsuWhooa>
:p
<superctr__>
those were proper fakes, so to say
<KitsuWhooa>
they produce a sine wave!
<superctr__>
a completely different die, at least it was compatible and make sound
<superctr__>
but the sound quality is much worse than a real one
<KitsuWhooa>
but yeah, 100% not original
<KitsuWhooa>
the packages don't match iirc
<superctr__>
the package is the same but looks different
<KitsuWhooa>
the pin 1 notch is different
<KitsuWhooa>
is what I meant
<superctr__>
same type i mean^
<KitsuWhooa>
and the two round circles are also different
<superctr__>
a real megadrive has neither a discrete ym3438 or a discrete sn76489
<KitsuWhooa>
it has a discrete 2612
<superctr__>
the megadrive 2 (or VA7 revision of the MD1) has a YM3438 and SN76489 integrated into the VDP
<KitsuWhooa>
depending on the model I guess
<KitsuWhooa>
yeah :p
<superctr__>
and the poor sound quality is not because of that fact alone, it's because sega fucked up the amp/filtering circuit
<KitsuWhooa>
the model 2 has terrible sound amps, yes
<KitsuWhooa>
that's why the ccam is a thing :p
<superctr__>
and the MD1 (<VA7) still have a SN76489 integrated into the VDP, and it actually has some audible differences compared with a discrete SN76489
<superctr__>
for example, Sonic 1's hihats will sound horrible with a discrete SN76489, because it handles the frequency register differently
<cr1901_modern>
less than VA7?
<superctr__>
yeah
<superctr__>
the ones with YM7101 VDP instead of the all in one chip
<cr1901_modern>
Meaning it started out with an integrated SN76489 and switched to integrated?
<KitsuWhooa>
the SN was always integrated, no?
<cr1901_modern>
err switched to discrete*
<superctr__>
VA0-VA6 has a YM2612 and YM7101 (containing the PSG), VA7 and MD2 switched to the all in one part (whose part number I forgot) which contains VDP, PSG and YM3438
<cr1901_modern>
ahhh
<cr1901_modern>
I thought the original VDP was mostly an off-the-shelf part except for the "Mark V" gfx mode
<cr1901_modern>
like the Master System
<superctr__>
not quite
<cr1901_modern>
didn't know it also had the sound chip
<superctr__>
the original SC1000 had a TMS9918, the Mark III (and the Master System) added the Mode IV mode, and the MD kept the Mode IV mode, removed all the original TMS9918 modes and added the Mode V
<cr1901_modern>
ahhh
<superctr__>
so for example Master System/Mark III games that used the TMS9918 modes won't work on a MD
<superctr__>
and I think starting from the Mark III and the Master System the PSG was integrated into the VDP as well
<cr1901_modern>
It's bare copper, or "it looks like bare copper but its insulation vanishes when you apply heat"?
<m4t>
i had my first experience with that stuff recently
<m4t>
i had to turn the heat on my jbc up to the max to get the solder to wet it
<whitequark>
"magnet wire"
<m4t>
also, i think opa1662 is the winner so far. very quiet even at max volume w/iems. its spec'd at +/- 1.5v or +3v which might have something to do with it since it's running at +/- 2.5v. opa2211 was quite noisy at max volume, maybe it was oscillating..
<whitequark>
is usually how people call it
<cr1901_modern>
^yes, ty wq, couldn't think of the name :P
<m4t>
anyone know of a seller with unblacktopped ym3438's?
<m4t>
eleleparts had the GAGD's
<Lord_Nightmare>
Foone: 128K x 8 28 pin TC531000
<Lord_Nightmare>
that's what the nes ROM you tried to dump is
<Lord_Nightmare>
it has an extra address line instead of /OE
<Lord_Nightmare>
if your programmer supports TC571001 eproms, you can offset the tc531000 mask ROM down from the top of the socket by 2 pins, and add a jumper wire between what would be pin 32 and pin 30 if it was a 32 pin device
<Lord_Nightmare>
otherwise you need to make a tc531000 to 27c010 adapter out of a 28 and a 32 pin socket and a wire
<Foone>
but a jumper wire is a good idea. I can probably just force that address pin high. I have a datasheet for this actual rom, it's a ricoh chip
<Lord_Nightmare>
for the equivalent '2364 in 24 pins' there was actually an eprom version from motorola, the mc68764, so its possible to dump those with no adapter
<Lord_Nightmare>
even though 2764 are 28 pins
<Lord_Nightmare>
but there's no such oddball device for the 28->32 pin change with 128k 28 pin mask roms vs the 27c010 being 32 pins
<Lord_Nightmare>
so an adapter is necessary
<Lord_Nightmare>
also foone you missed a chance with the dancing baby animation on the pregnancy tester
<Lord_Nightmare>
KevEdwardsRetro is ex-software-creations and has source code and other stuff
<Lord_Nightmare>
if anyone has the original, non-corrupt data for the 'drainpipe' image in pictionary, it would be them
<Lord_Nightmare>
they have the source code to many games that tim follin composed music for
<Foone>
good point. I linked that picture in my original pictionary thread, I should ask them if they can help
<Lord_Nightmare>
eeprom-to-fix-cartridge: probably a tc571001 but you'd need to make sure there's spare space for the 4 'extra' pins to be bent sideways and not hit another chip
<Lord_Nightmare>
Foone: should i quote-retweet one of your tweets about the damaged ROM to KevEdwardsRetro ?
<cr1901_modern>
He gives out snippets of source, but I'm not aware of any full source releases of his work
<Foone>
sure, if you like
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