[QuadList] Seeking DBX-700 digital audio processor--Ping Boston area folks

[Ted Langdell]

Here's a link to a dbx-700 manual, which contains the theory of operation and a number of other interesting details.

http://velero-ii.com/Manuals/dbx_700_Manual.pdf

Ted


On Sep 29, 2012, at 8:56 PM, Ted Langdell wrote:

> On Sep 29, 2012, at 4:07 PM, C. Park Seward wrote:
> 
>> Ted,
>> 
>>  I think you need that exact model to decode.
> 
> 
> Exactly.  
> 
> That's why I'm looking for one. It is an A/D-D/A system that puts the encoded digital data into an analog composite video signal that can be recorded onto videotape. Commonly recorded on VHS, Betamax and 3/4.
> 
> 
> On Sep 29, 2012, at 4:07 PM, C. Park Seward wrote:
>> " Unlike other similar pieces of equipment like the Sony PCM-F1, the Model 700 used a technique called Companded Predictive Delta Modulation, rather than the now-common pulse-code modulation."
>> 
> 
> Here's how the modulation scheme worked:
> http://en.wikipedia.org/wiki/Delta-sigma_modulation
> 
> And here's the Wikipedia item on this particular tool:
> http://en.wikipedia.org/wiki/Dbx_Model_700_Digital_Audio_Processor
> 
> The Model 700 had been designed from the beginning to have many 'tape-like' characteristics, including "soft saturation," and at a time when most professional and amateur recordists were used to analog tape, this was considered a significant feature. It also offered 14dB more dynamic range than 44.1kHz/16b audio, and because of its very high sample rate (644kHz), it did not contain the same anti-aliasing filters necessary in PCM recorders at the time, which were thought to cause undesirable harmonic interference.
> 
> The Wikipedia entry notes that WGBH-FM used one as its STL.  (Which provides a lead!)  
> 
> Perhaps Tom or Paul in Boston has an idea whether there are any floating around.
> 
> Ted 
> 
>> On Sep 27, 2012, at 9:51 AM, Ted Langdell wrote:
>> 
>>> 
>>> Looking for a DBX-700 digital audio processor or something that can decode this digital audio in video format.
>>> 
>>> Rent or buy.
>>> 
>>> Thanks.
>>> 
>>> Ted Langdell
>>> Secretary
>>> Skype: 	TedLangdell
>>> e-mail:	ted at quadvideotapegroup.com
>>> 
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>> 
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> 
> 
> Ted Langdell
> Secretary
> Skype: 	TedLangdell
> e-mail:	ted at quadvideotapegroup.com
> 


Ted Langdell
Secretary
Skype: 	TedLangdell
e-mail:	ted at quadvideotapegroup.com

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