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:
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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> thanks got it
<superctr__> I think you can make something better with deflemask. now i don't use deflemask anymore, so I can't really help you with that
<superctr__> I also found this This vgm is not mine, but someone gave me this for testing another part of the nuked core, that is DAC panning using the test register
<m4t> hmm deflemask is 32bit on linux
<m4t> => not found. i'll figure it out :)
<m4t> got it :)
<m4t> still waiting on the 3.5mm jack but everything else (screen, firmware, etc.) seem to work OK
<m4t> i'm going to solder on some wires i guess
<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
<KitsuWhooa> ah yeah
<KitsuWhooa> try not to gag
<KitsuWhooa> :p
<superctr__> anyway, just a fun fact
<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
<KitsuWhooa> fwiw ^
<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
<m4t> works :)
<KitsuWhooa> late, but 21:03:09 <KitsuWhooa> <-- same console with the crystal clear audio mod
<superctr__> yeah, with that mod it will even sound better than a MD1
<KitsuWhooa> they expected the md1s to be plugged in to RF mostly
<KitsuWhooa> I'd assume
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<m4t> a lme49720 absolutely did not work in place of the ne5532 :( super quiet
<m4t> darn
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<m4t> opa2134 and opa2211 seem to work well though
<Foone> this person is working on a custom ISA-to-USB adapter, and naturally they tested it with sound cards
<m4t> that wiring is slightly sketchy
<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> and dump it that way
<Foone> it doesn't support either, it looks like
<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
<Foone> definitely gonna do that one, yeah
<Lord_Nightmare> has part of the fascinating story behind that model
<Lord_Nightmare> tl/dr: it was on a weird addon cd for character creator which the only surviving copy of seems to be on vetusware
<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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