I hope you do not mind me going off on tangents like this, if you dont, you just blame #80sArcadeKid for putting me up to this! Hot damn, I couldnt find the TKG2 schematics, so I finally thought to google for the Radarscope schematics and Voila! The Internet archive is just amazing, sponsor them if you must spend money! Must - continue - writing - post - cannot - study - schematics). Anyhow, they did assert their copyright in the manual, so maybe this is (a pdf of) one of those rare copies without the copyright sign? (Yes while figuring out the code of the core and the schematics, I learned a bit about especially collectible cabinets, very interesting. This manual is in principle copyrighted content, the manufacturer being who they are, can this wiki get into trouble for this post? Of course, they have nothing on me: this is a citation of their work in my very new and original work of art. There are also two places where you could capture Video (1 and 1*).ĭkong_av_ (275.56 KiB) Viewed 1632 times A and A* should be the same signal, but the others could all sound different. I looked at the operation manual of the TKG4-UP board model, and there are at least four connector pins (A, A*, B, C) where you might record a sound signal. Ok, so as I said I am an Arcade Noob: I have no idea how one would go about connecting the "Mr Video" to the Arcarde hardware. You said it uses samples, for analog which is probably the issue I assume? All I know is the speaker sounds and captured sound is similar and the FPGA is way off. I really don't know the answer to this, I use the "Mr Video" on default settings I believe goign directly the the GV-USB2 capture dongle. Then we would still have to take a look at the pseudo-analog effects. It seems to me, that, with correct clock speed, 1.9 kHz filter and envelope generator (the last is probalby the trickiest), the digital waveform generator spectrum of the FPGA implementation would be more accurate than the MAME implementation (of course that is still hot air until its there). If no one else is already working on this, this seems to be something I can fix, although it may be a bit tricky, because running this part at the non-system clock will require securing some asynchronous transitions (although it seems the original board has no problems with it). This 2.4% difference seems small, but the human ear can distinguish a diffence of 3.6 Hz at about 1kHz, which is about ten times less ( ).Īlso, I think it amazing that your board audio oscillator apparently still runs at 6 MHz after all these years! (or is this a case of the "Ship of Theseus"?) This probalby means that the real system has some non-linearities in the digital waveform generator path.įinally, it seems that the small duration and pitch difference (2.4%) is due to the Digital Waveform Generator running at 6.144 MHz instead of 6.000 MHz the schematics shows. One thing that the real recording spectrum shows, but neither MAME nor FPGA is some extra (2nd) harmonics. I guess Jopdorp already found out that getting a simulation that is equal to reality is actually quite hard.ĭoes you know if a real setup including the original speaker also sound like the MAME version? Strange enough I think MAME is simulating this filter even when (other) filters are not compiled, but it seems that the simulation does not correspond to your recording. The 47kOhm output resistors of all audio paths, combined with C159 of 100 nF of the monitor path give 1st order cut-off of 1/(2 pi 47 * 0.0001) = 30 Hz !? It seems that MAME implements something like this (not 30Hz though), this seems to cause the underwater sound on the MAME recording. This is a bit strange, because the brown output path until the Monitor sound (that, I think, MAME always simulates) is strange: When processing comparison waveforms with audacity, ot looks like adding the 1.9 kHz lowpass will make the FPGA digtal sound quite close to the PCB. I assume that you have the default version with filters, let me know if I am wrong. ![]() ![]() This could be one reason for MAME sounding so dull. MAME Donkey Kong can be compiled with or without both the 1916 Hz 2nd order lowpass and the additional components on the amplifier board next ot the monitor, but by default, all filters are there. ![]() ![]() This signal is again connected to another amplifier board (next to the monitor?).ĭid you record the speaker signal (component side of board) or tv audio signal (solder side of board) ? (second is most likely, if you keep SW2 on default) The side-edge connector on of the TKG4 board has two audio outputs: Monitor out (brown path) and Speaker out (not colored, right next to the brown path), I think the monitor out path is normally connected (for upright cabinets ?, controlled by switch SW2). Sorry submitted previous early by accident
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