Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Discussion about old sound cards, MIDI devices and sound related accessories.

Re: Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Postby Great Hierophant » 2019-4-15 @ 20:12

Benedikt wrote:I have added an additional resistor pack to the FTL Sound Adapter replica for short circuit prevention.

FTL_Sound_Adapter_replica_3d.png

Without these additional resistors that are connected in series with the control lines, using the joystick port could potentially damage CMOS-based parallel ports. (Or anything else that uses push-pull outputs.)
Older TTL-based ports should be safe, either way, because they use pull-up resistors to create the high-level.


Does the joystick port actually work with Dungeon Master? The game supports it, and that is how the port was implemented (absent extra resistors), but does it actually allow the cursor to be controlled in the game? I would definitely buy one if it did.
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Re: Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Postby matze79 » 2019-4-16 @ 09:52

i soldered a db9 connector to my covox some months ago and it works, but i did not add Resistors.
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Re: Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Postby Benedikt » 2019-4-16 @ 20:02

matze79 wrote:i soldered a db9 connector to my covox some months ago and it works, but i did not add Resistors.

It is good to hear that it does indeed work. Most parallel ports will not need the additional resistors, but any port that connects a control line directly to +5V when it is switched to 1 might get damaged in their absence.
I believe that FTL renamed it to "future expansion port" for liability reasons. If someone fries their parallel port by plugging a joystick into a random "future expansion port", they cannot sue the company.
My intention is to write some sort of TSR driver, as well. That driver could then e.g. emulate cursor keys and space bar or something.

Change of scene: The SoundJr replica. It looks like I'm stuck again, because I cannot see through the resister packs. Everything else is complete.

SoundJr_replica_PCB_incomplete.png

Those three traces that go beneath the resistor pack on the front layer have to go somewhere and I'm not quite sure where that is.
They start at pin 1 of Q2, Q3 and Q4, respectively.
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Re: Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Postby Paralel » 2019-4-17 @ 20:49

So, what you're saying is, we have to disassemble one, slightly, to complete a proper reconstruction?
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Re: Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Postby Benedikt » 2019-4-18 @ 07:25

Not further than has already been done. One would have to probe around with a multimeter and find connections with near-zero resistance. So there's no need to get out the soldering iron.
Once that is sorted out, only the value of the filter capacitors remains unknown, but that can be determined via trial and error, i.e. by comparing the frequency response.
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Re: Replicas of Covox Speech Thing, FTL Sound Adapter and SiliconSoft SoundJr

Postby Paralel » 2019-4-20 @ 21:46

Ah, ok. I should be able to do that, once I locate mine.
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