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</span></span></span><![endif]>Hitachi HA12022 was another Blackmer cell VCA. I've heard that it is the best VCA IC ever.<o:p></o:p></p>
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<p>If that’s the one Sony Professional Audio used to use then I agree. Always one of the strong points of their consoles.<o:p></o:p></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Synth-diy [mailto:synth-diy-bounces@synth-diy.org]
<b>On Behalf Of </b>houshu--- via Synth-diy<br>
<b>Sent:</b> 23 October 2021 13:53<br>
<b>To:</b> 'Ben Bradley'; David G Dixon<br>
<b>Cc:</b> 'synth-diy@synth-diy org'<br>
<b>Subject:</b> Re: [sdiy] Blackmer VCA cell<o:p></o:p></span></p>
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<p class="MsoNormal">Hello list,<o:p></o:p></p>
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<p>NEC uPC1252H2 uses a Blackmer cell, which were used in some Roland synths for loudness control, not for VCA with ADSR.<o:p></o:p></p>
<p>I guess Irwin's linearization was proposed later than those. Matching of 2 ICs is another issue.<o:p></o:p></p>
<p><o:p> </o:p></p>
<p>Hitachi HA12022 was another Blackmer cell VCA. I've heard that it is the best VCA IC ever.<o:p></o:p></p>
<p><o:p> </o:p></p>
<p>Sam HOSHUYAMA<o:p></o:p></p>
<p>Kanagawa, JAPAN<o:p></o:p></p>
<p><o:p> </o:p></p>
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------ Original Message ------<br>
<span style="font-family:"MS Gothic"">差出人</span>: "David G Dixon via Synth-diy" <synth-diy@synth-diy.org><br>
To: "'Ben Bradley'" <ben.pi.bradley@gmail.com><br>
Cc: "'synth-diy@synth-diy org'" <synth-diy@synth-diy.org><br>
<span style="font-family:"MS Gothic"">送信済み</span>: <span style="font-family:"MS Gothic"">
土曜日</span>, 2021/10/23 13:41<br>
<span style="font-family:"MS Gothic"">件名</span>: Re: [sdiy] Blackmer VCA cell<br>
<br>
Doesn't the linearized 2164 VCA (the famous Irwin circuit) work more or less<br>
like a Blackmer cell?<br>
<br>
<br>
<br>
-----Original Message-----<br>
From: Synth-diy [mailto:synth-diy-bounces@synth-diy.org] On Behalf Of Ben<br>
Bradley via Synth-diy<br>
Sent: Friday, October 22, 2021 8:10 PM<br>
To: *SYNTH DIY<br>
Subject: [sdiy] Blackmer VCA cell<br>
<br>
[CAUTION: Non-UBC Email]<br>
<br>
I just posted this in a thread on Analog Heaven, and it reminds me to ask<br>
here. There's been a dbx "Blackmer cell" high-quality VCA circuit since the<br>
1970s, but as far as I know its only use has been in recording studio<br>
equipment. Has this device ever been used in a music synthesizer or<br>
(guitar-type) effects pedal? I presume my explanation below (much high cost<br>
than CA3080) is why not, but does anyone know more?<br>
<br>
Post to AH:<br>
<br>
There's a "pro-audio quality" (much lower distortion and noise than<br>
OTA-based circuits) VCA based on a Blackmer cell (apparently Patent #<br>
US3714462) - it's a different circuit from the long-tail-pair based OTA<br>
circuit, and I presume the reason it's not seen in music synthesizers is<br>
because of dbx (now THAT Corp) holding the patent, and only making and<br>
selling chips rather than licensing the patent to anyone else, and the much<br>
greater cost of the chips. As far as I know the chips have always been<br>
several dollars each, many times the CA3080 when it was in production. I<br>
would have thought the Blackmer patent would have run out by now, I don't<br>
know of any other manufacturer using the Blackmer cell design.<br>
<br>
The article in the first link says "The voltage-controlled amplifiers found<br>
in most recording consoles and analog effects products are based on the<br>
"Blackmer gain cell" developed by David Blackmer of dbx, Inc."<br>
- I've been familiar with their use in recording consoles, and the "analog<br>
effects" here surely refers to studio compressors, companders and noise<br>
gates. I've not heard of Blackmer cell VCAs ever being used in effects such<br>
as guitar pedals - I've only heard of CA3080 and similar chips (which when<br>
in production cost less than a dollar) used in such effects and music<br>
synthesizers. I'm a bit surprised no synth maker used these, as they're<br>
worth the extra price in some applications, such as setting the "final<br>
output" volume control for each patch. If I recall correctly, the Chroma<br>
Polaris used a CA3080 there.<br>
<br>
<a href="http://www.thatcorp.com/History_of_VCAs.shtml" target="_blank">http://www.thatcorp.com/History_of_VCAs.shtml</a><br>
<a href="https://www.edn.com/gain-control/" target="_blank">https://www.edn.com/gain-control/</a><br>
<a href="https://patents.google.com/patent/US3714462" target="_blank">https://patents.google.com/patent/US3714462</a><br>
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