Dim D (Was: Re: [sdiy] picture of 19" 1U rackmount Triple Chorus)

[anthony]

I'd like to come up with a system that doesn't use an NE570 or an NE571. 
Many of you may have heard about me go on and on about National 
Semiconductor's LM1894, DNR "Dynamic Noise Reduction" System. It works a lot 
like Dolby except it's single-ended - meaning you don't have to preencode 
it. It's basically a VCF that opens and closes depending on the spectral 
content of the source.

With a BBD, you'd just attentuate the signal to the max the BBD can take, 
have the DNR after the LPF after the BBD. It'd probably work best if you 
controlled it via a sidechain from the INPUT side of the BBD - which is 
easy.

You can still buy them new, but I think you actually have to have a license 
to use them - like Dolby. But I have about 10 of them.

I'm working out how to eliminate the NE571 from my DOD R-870, which is a 
good piece of gear except the compandor makes it have either distortion or 
noise. You take your pick. I think tweaking the filter before the control of 
the expander part. But doing it with an LM1894 I think would sound better.

but I digress...

It's too bad the SA575 and the SA572 aren't drop-in replacements (or 
available in DIP for the former...).

aa
> Small Bear Electronics stocks the NE570 and have a price break at 100 
> pieces.  I assume there are enough around.
>
> Dave
>
>
> JH. wrote:
>> In case I'm going to make a run of Dim D PCBs - are there enough NE570 / 
>> NE571 / SE571 chips left, or should I go for a completely different 
>> compander?
>>
>> JH.
>>
>>
>> ----- Original Message ----- 
>> From: "Andre Majorel" <aym-htnys at teaser.fr>
>> To: <synth-diy at dropmix.xs4all.nl>
>> Sent: Friday, January 25, 2008 11:24 PM
>> Subject: Re: [sdiy] picture of 19" 1U rackmount Triple Chorus
>>
>>
>> On 2008-01-25 22:15 +0100, JH. wrote:
>>
>>> But speaking of the BL3207: I have just bought a couple of
>>> these, and when I find the time I'll make some tests.
>>> Then I might use them for a Dimension D clone PCB project. :)
>>
>> Excuse me while I borrow Grandpa's drool cup...
>>
>
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