[sdiy] Roland System-500 Filter pcbs

[Florian Anwander]

Hello,

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.
I checked th thomann.de <http://thomann.de> pages for the pictures of 
the module and got a little worried

This is the pcb of the 510 (should be one four stage OTA filter and a VCA)
https://bdbo2.thomann.de/thumb/bdb3000/pics/bdbo/13948871.jpg

This is the pcb of the 521 (should be two four state OTA filters)
https://images.static-thomann.de/pics/bdb/379516/10742587_800.jpg

This is the pcb of the 505 (it should be a tranistor ladder filter)
https://bdbo2.thomann.de/thumb/bdb3000/pics/bdbo/13948906.jpg



The pcb of the 505 is full of LM37000, while there is no OTA in the 
original Circuit.
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.

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


Can you identify what are 6 pin parts on the pcbs for the 521/510?

Florian


-- 
http://www.florian-anwander.de/

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