[sdiy] Choosing a DAC

[Jerry Gray-Eskue]

Csaba,

Here is a link to good information on DACs and ADCs, other manufactures have
similar educational material. These are often the best source of free
in-depth training and information.

http://www.analog.com/en/analog-to-digital-converters/ad-converters/products
/over_design_with_adcs/fca.html?ref=ASC-Ad-014



-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl]On Behalf Of Csaba Zvekan
Sent: Tuesday, July 07, 2009 6:50 AM
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Choosing a DAC


Hi guys,

This is really a highly interesting subject. Can somebody explain what
is exactly  happening after the AD558 DAC in the so called "Glide
circuitry".
And why is the 8-bit DAC still capable of producing the 0-5V CV OUT
voltages pretty precisely ?
Especially the 3280 Glide OTA with them rectifying diodes on the
inputs  ? Could I use a CA3080 to experiment and replicate the
circuitry ?
Also how is DAC Scale being done with V SENSE and V SEL by feeding the
V OUT ? Could that be a VRef on another 8-bit type DAC? It would be
nice if somebody could explain a little further?

Thanks a lot

Csaba



On Jul 7, 2009, at 11:26 AM, Tom Wiltshire wrote:

> I was just about to suggest exactly the same thing. Everyone is
> banging on about needing a 12-bit DAC as a minimum. This isn't true
> if you're doing the glide function using analogue afterwards, and
> the Pro-One is the living proof!
>
> T.
>
>
> On 7 Jul 2009, at 05:39, Olav Martin Kvern wrote:
>
>> Hi Stewart,
>>
>> Do look at the way that Sequential Circuits set up the DAC in the
>> Pro-One. It's an Analog Devices AD558, an 8-bit DAC with an
>> adjustable range. They use it as a 6-bit DAC, and feed it note
>> values from 0 to 63 for just over a 5-octave range at 1 volt per
>> octave. Glide is handled by a separate circuit. It's really pretty
>> brilliant (in my opinion).
>>
>> With all of the incredible devices that are available today, it's
>> easy to get hung up on DAC accuracy and resolution, but we can
>> still learn a few tricks from circuitry from 1980.
>>
>> Thanks,
>>
>> Ole
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy