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<div class="moz-cite-prefix">Hi Florian and all,<br>
</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">On 30.07.2021 18:41, Florian Anwander
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:33868cbd-d795-e840-d166-6d98f1c6ba44@mnet-online.de">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div class="">Hello,<br class="">
<br class="">
Inspired by the Alex Ball Video mentioned over at analogue
heaven I wanted to update my page about roland filters with the
information on the System 500.<br class="">
I checked th <a href="http://thomann.de" class=""
moz-do-not-send="true">thomann.de</a> pages for the pictures
of the module and got a little worried<br class="">
<br class="">
This is the pcb of the 510 (should be one four stage OTA filter
and a VCA)<br class="">
<a class="moz-txt-link-freetext"
href="https://bdbo2.thomann.de/thumb/bdb3000/pics/bdbo/13948871.jpg"
moz-do-not-send="true">https://bdbo2.thomann.de/thumb/bdb3000/pics/bdbo/13948871.jpg</a><br
class="">
<br class="">
This is the pcb of the 521 (should be two four state OTA
filters)<br class="">
<a class="moz-txt-link-freetext"
href="https://images.static-thomann.de/pics/bdb/379516/10742587_800.jpg"
moz-do-not-send="true">https://images.static-thomann.de/pics/bdb/379516/10742587_800.jpg</a><br
class="">
<br class="">
This is the pcb of the 505 (it should be a tranistor ladder
filter)<br class="">
<a class="moz-txt-link-freetext"
href="https://bdbo2.thomann.de/thumb/bdb3000/pics/bdbo/13948906.jpg"
moz-do-not-send="true">https://bdbo2.thomann.de/thumb/bdb3000/pics/bdbo/13948906.jpg</a><br
class="">
<br class="">
<br class="">
<br class="">
The pcb of the 505 is full of LM37000, while there is no OTA in
the original Circuit.<br class="">
The pcbs of the 510 and 521 show not a single OTA, but many
parts which seem to be double transistors - which I would expect
for the 505.<br class="">
</div>
</blockquote>
<p>You can see the ladder at the top end of the PCB. C15 to C18, and
two transistors next to each. No dual transistors but two singles.
<br>
</p>
<p> I recon that quite a few of the OTAs are used for signal routing
/ switching.<br>
</p>
<blockquote type="cite"
cite="mid:33868cbd-d795-e840-d166-6d98f1c6ba44@mnet-online.de">
<div class=""> <br class="">
After a first comparison of the 510 and 505 I thought Thomann
mismatched the pictures, but the 521-pcb looks too similar to
the 501-pcb<br class="">
<br class="">
<br class="">
Can you identify what are 6 pin parts on the pcbs for the
521/510?<br class="">
</div>
</blockquote>
<p>Toshiba HN1C01FU and HN1A01FU. Dual NPN and PNP. <br>
<span style="left: 94.4867px; top: 137.68px; font-size: 44.8px;
font-family: sans-serif; transform: scaleX(1.06506);"
role="presentation" dir="ltr"><span style="left: 94.4867px; top:
137.68px; font-size: 44.8px; font-family: sans-serif;
transform: scaleX(1.06506);" role="presentation" dir="ltr"></span></span></p>
<p><br>
</p>
<p>Best,</p>
<p> René<br>
</p>
<p><br>
</p>
<pre class="moz-signature" cols="72">--
<a class="moz-txt-link-abbreviated" href="mailto:synth@schmitzbits.de">synth@schmitzbits.de</a>
<a class="moz-txt-link-freetext" href="http://schmitzbits.de">http://schmitzbits.de</a></pre>
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