Congratulations. 😎

awesome! I bought a clone from a Spanish shop IIRC some time ago and here are the insides:

😊 😊

RacoonRider wrote:

However, when I recorded the tunes with iriver MT30 mp3 player, the noise was there, a lot of it. It must be due to LPT port implementation as I can hear scratches and squeaks while moving the mouse.

Software that's old enough to use parallel port DAC for sound output predates the ECP or EPP methods of using the parallel port, so no DMA, fully interrupt driven. Very CPU intensive at sampling rates high enough for audio.

I'm actually very impressed! Sounds fantastic.

The sound quality is very nice, much better than you would expect a circuit solely comprised of sixteen resistors.

Has anyone ever opened a true Covox Speech Thing? There are several diagrams for a Covox-type circuit, but has anyone actually seen what is inside the original?

Thank you guys 😉 😉

keropi, your device is electrically the same, it utilizes different resistors for each step of the ladder... Cheaper to produce in quantity, harder to make individually 😀 Anyway, do you like how it sounds?

SquallStrife, thank you, I'll look into it. I didn't make any extra configuration with LPT ports.

so a covox is just resistors, thats amazing

I did record Pinball Fantasies with it about a year ago: http://www.youtube.com/watch?v=jFtFju1Gf4w
btw if you start cronologia with setup then it shows also a resistor design for lpt1.
A lot of early demos had infos for this included, such as Unreal 1.0 from FC.

Inertia Player 1.22 has support for LPT1 too.

Wow that looks awesome.

How does it work?

Damn that sounds nice.

If you were to make more, how much would you charge? 😉

elianda, thank you for your information 😀 I've seen several youtube videos featuring Pinball Fantasies on covox and they all seem to sound differently. I wonder if that's different covox builds or just software/codec/recording device issues.

vetz, free of charge, provided that I have a good company while making it 😀

Well, as Racoonrider said, the Resistor values vary and there are several more or less sophisticated designs.
And there is of course always the way how it was recorded in the end involved too.

Just as side note, the large speaker of the IBM PS/2 has already nearly the same sound quality as the Covox.

the place I got my clone still sells them: http://retrocables.es/tienda/index.php?id_pro … oduct&id_lang=4 (I also made a thread back when I was looking for one: vogons link)

RacoonRider it sounds acceptable... you get sound allright but it has "static" with it 🤣
I also have an original Disney Sound Source, I wonder how to test it witn mods

edit: modplay supports all speaker/covox/disney devices 😁
http://www.awe.com/mark/dev/modplay.html

I can make an illustration for this too (like the sli cable for voodoo 2).

Stojke, that would be great!

Cool, but there are multiple schemes i found, we need to work out which one is the best:

Some of these schematics use different value resistors, while the other one is 20k and 10k.
If somebody with a bit more experience could lend a hand, i can draw everything from LPT cable to complete project.

Also, ive managed to find 1% resistors where i live, 20k and 10k. The prices are 0.03$ for piece on the online catalog, will go and check in other electronics stores.

Wow 😀 You've got good prices out there, I bought mine for 0.06$ a piece and 1% were around $1.

It does not really matter what values you chose as long as you keep the 2:1 scale of the ladder.

If you remember physics, most circuits can be resolved to equivalent circuits:

As long as the resistors have the same value, the first is R/2 and the second is R+R:

So basically, if you compare scheme 2 and 3 of your post, there's not much of a difference resistance-wise.

The other thing is capacitors. I think they are there to filter out some part of the static noise, but I never used one. I think I just wanted to start with the easiest possible solution.

Yeah L and T filters. Low pass, high pass and band pass.
Hmm, i didnt do much electronics for a long time, but i do have knowledge. Maybe we can design/upgrade the existing scheme to get the most out of it? An filter certainly would be a good addition.

I can make illustrations for the most basic and advanced version, that isn't a problem.

Neat! I've been meaning to try building one of these for my little 486 project computer. Only problem then is I lose the ability to use my 10BT LPT ethernet adapter. Does this work with any game or does it specifically have to support Disney Sound Source/Covox? I bet playing back this mp3 on your cpu must have absolutely hammered it.