SPDIF Out for Synth w/Analog out only

[electromusician]

Hi Fanatics,

I have an Ensonq SQ-1+ 32 voice synth circa 1995. Its digital but only has analog outs. If I didn't like and use this keyboard so much that wouldn't be a problem.

However its my main composition tool and nothing else can substitute for it. The trouble is running those analog outs to anything but the best A/D produces substandard results.

Can anyone here help me add a SPDIF digital out to this synth so I can go direct and skip another conversion??

I know a little about SPDIF driver chips- particularly AKM. There must be a point on the SQ-1 circut board where the 16 bit digital signal enters the D/A circut. Tapping into that with a proper SPDIF driver circut should do the job- unless I'm missing something- and I very well could be.

Someone out there must have done this with one digital keyboard or another. Its not something that seems radically difficult or theoretically impossible. From what I've read on these message boards I know there are people here who could not only tell me if this would work, but could probably do the whole thing during a typical commercial break! A very knowledgable group indeed!

In any case, thank you for any advice or help you can offer!!

Electro

ps- I'm posting this in the music section also.

[Giaime]

Well, first of all - are you sure that the keyboars IS digital? Because many people when they see a digit display they think the whole thing is digital. And remember that if the key is digital, most of the brands include a digital output.

And are you sure the key is processing a signal at 16bit, 44.1kHz, and all else? If not that's gonna be difficult to built a converter... but someone here could do it.

Good luck!

[electromusician]

Its definately digital but it was designed at a time when digital outputs weren't common on keyboards (early 1990's). There wasn't much around back then that could take a digital input.

So a converter circut is not needed because the samples are all 16bit and one of the features of this keyboard that was considered special at that time was 44kHz sampling rate.

Do you have any advice on how I should started on adding a SPDIF circut?

Thanks!
Electro

[Enzo]

I was an Ensoniq authorized repair center until they closed down the service netwrok at the merger with Emu. They were always very close with the schematics. ALl service was done with board swaps. Later they released schematics of the older units, but even the service centers were charge $100 for the set. This was prior to the SQ1, though I have SQ80.

DOn't know if schemos for the later things are generally available now or not. We could contact Emu and ask.

Unless the SQ1 is different, I an not so sure it is as digital as you might think. It starts life as a digital signal, but much of the sound that comes out of it is created by the filter networks - a bunch of Curtis chips - VCFs. SO the digital info will be lacking in what the filters add, what the envelopes would be and so on. Plus it is multiplexed.