Sergey Kiselev dug a bit more information:

This card appears to have been designed specifically for the University of Delaware's GUIDO (Graded Units for Interactive Dictation Operations) software:

https://winworldpc.com/product/guido-music-le … rning-system/21

The GUIDO software release notes explicitly mention the following:

In addition, the University of Delaware designed a unique sound card for use with this software.

The system requirements specified at

https://midiguy.com/index.php?main_page=produ … products_id=636

refer to this card as a UD Sound Card.

This very card (or another copy of it) sold for an amazing $2,500 on eBay on June 23, 2023. I had seen it but apparently didn't put it in my watch list. Here are the pictures and a couple snips from the listing:

cyclone3d wrote on 2023-06-27, 00:57:

This very card (or another copy of it) sold for an amazing $2,500 on eBay on June 23, 2023. I had seen it but apparently didn't […]
Show full quote

This very card (or another copy of it) sold for an amazing $2,500 on eBay on June 23, 2023. I had seen it but apparently didn't put it in my watch list. Here are the pictures and a couple snips from the listing:
Front.jpg
back.jpg
Screenshot 2023-06-26 194649.jpg
Screenshot 2023-06-26 194907.jpg

Sorry for the OT but if there's an 'or best offer' option is there a way to find out wether the card actually sold for the advertised price or possibly for much less?

maxtherabbit wrote on 2020-10-22, 01:29:

I'd use it

I guess this is the Vogons version of "I'd hit that"..

Now, someone needs to reverse engineer this and post the gerber files and BOM online 🤣

The card shown looks very professionally done, I think.
It uses classic components, heatsinks, good capacitors, ground planes (not the aerial, hi) , and phono plugs.
If it would use BNC, it would be lab grade. Maybe. ;)

PS: I'd use a small AF tube in my design..

Edit: The TL074 are modern substitutes for the 741 op-amp. Interesting!
Edit: Do they form a push-pull output stage, for the headphones?

Edit: About that card.. Could it be that this one was made as a tone generator?
Not as a melodic card, but as a frequency generator? Sine wave, sawtooth etc ?
It would have been useful in music class or a school's computer lab.

Edit: Are the two phono plugs in parallel? Maybe for use with a stereo system?

Edit: Ok, just read page 1.. Makes sense.
A card as simple as the AdLib was likely to be invented earlier, by another group.
For simple designs, there's often just one way or two ways to approach a situation.
In this case, it is a rudimentary addess decoder and a pair of i/o ports.
Personally, I like the less conventional op-amp design in favor of an 386 amp IC.

@suntac is it possible to get a look under the ICs? To be able to see the traces.

Very interesting ISA sound card with OPL2 chip that predates the AdLib. Looks well designed.

appiah4 wrote on 2023-06-27, 07:17:

maxtherabbit wrote on 2020-10-22, 01:29:

I'd use it

I guess this is the Vogons version of "I'd hit that"..

Now, someone needs to reverse engineer this and post the gerber files and BOM online 🤣

It'd take some extra work to replicate those beautifully hand drawn traces in CAD, though! 😜

Daniël Oosterhuis wrote on 2023-06-29, 08:02:

appiah4 wrote on 2023-06-27, 07:17:

maxtherabbit wrote on 2020-10-22, 01:29:

I'd use it

I guess this is the Vogons version of "I'd hit that"..

Now, someone needs to reverse engineer this and post the gerber files and BOM online 🤣

It'd take some extra work to replicate those beautifully hand drawn traces in CAD, though! 😜

Hand drawn traces are actually superior often.
This has to do with reflections and the thickness of the traces.
Sharp edges with a 45° or 90° angle cause all kinds of weird effects.
Those fluid, wavy, hand drawn traces are fine, though.

Edit: Doodle added. Edges, worst to best.

Polystyrene capacitors, 8 opamps.. - the thing made with attitude and supposed to sound good. Beautiful!

So original ports for this card are 0x39E/39F?