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Nice work! I take it that I don't need to disassemble the cart again, but let me know if there are specific things you want checked. The capacitor in the top right corner is 10 nF.

-- Rolf

Excellent. Thanks Rolf.

Did you upload the design somewhere? I found a couple of Amstrad SSA-1 speech synthesizers which are powered by the same SPO256 chip

Just an added thought about this project.
Don't forget that our Dragons have a parallel port that can be used for 8 bit data output.
I have an alternative speach module using the SP0256-AL2 that I assembled from a kit back in 1984.
It is/was called the Speakeasy and plugs into the parallel port taking it's power from the port.
The advantage is that it doesn't need a 6821 PIA and doesn't tie up the cartridge port.
Plus- it it can be used on many other computers with a parallel port. (Sorry CoCo users)

It uses an LM386 as the audio amp and has a small 8ohm speaker. The PCB is rather crude looking but works just fine.
It uses the SP0256 internal Allophones (no separate eprom) so you have to "translate" words into appropriate numbers.
I have the suggested allophone list - which matches a manual that I have for a RadioShack peripheral for the Model 1 and 3.
I gave a lecture and wrote an article about speech synthesis for the NW TRS-80 user group back then.
I can provide more details if anyone is interested.

This is brilliant!

I'll add it to the Peripherals page on the wiki.

Ramaj is the copper board manufacturer, or the one that designed the kit?

Cheers,
Rob

I think it was the person who etched the board. Sorry I can't remember where it came from.
It came with the enclosure box which is marked "Speakeasy".
I think it was generic in that it was advertised for the BBC and other computers.
The board has holes for a couple of extra Caps and resistors to boost the dB output but I haven't used them.
I will look for the notes that came with it - but no promises. That means a deep dive into my boxes of stuff.

Incidentally I don't see the documentation and scans for the Maplin I/O board or RS232 board which I have.
I used the i/O board to remote control a radio controlled tank using the relays and opto couplers to hook into the transmitter circuit board.
The software I wrote (in Basic) was like a subset of LOGO - and it was the basis of another popular lecture and demo.

Peter Mooney

Thanks for the info!

You should be able to upload your pictures to the wiki, but if you prefer, just put them my way and I'll take care of it.

Cheers,
Rob

Just a little more detail about that Speakeasy device.
Please note that the first image above in the original post (labelled "reversed.jpg" )should be flipped horizontally.
I only reversed it while I was figuring out the traces and was able to lay the ICs on top in order to lable the pins.
Here are a few more images taken in 2007, and the circuit diagram...
Feel free to move them elsewhere.
I have documentation about this board and the SP0256-AL2. Just ask.

Parts List
==========
SP0256-AL2
LM386 Amplifier
74LS00 Quad NAND gate (3/4 used as oscillator, 1/4 as inverter)
Axial polystyrene 220pf
Ceramic plate 100pf (x2)
Metallised polyfilm 0.022µf 400v (x2)
Radial electrolytic 100µf 10v
Axial electrolytic 100µf 10v
Axial electrolytic 10µf 63v
Resistors 10k, 3k3(x2), 330(x2), 100k
Small 8 ohm speaker
2cm jumper wire
DIP sockets 28 pin, 14 pin
Printer cable

Peter Mooney

Nice pictures, thank you!

Looks easy enough even to try on a breadboard