can anyone identify this RIAA Phono

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glennjarrett

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Joined 2010
Hi
I purchased this pcb off ebay with no info
after studying the tracks i have managed to get it working and it sounds very good
i am using a MM cart
the pcb has a switch on it which is shown in the schematic sketch i have drawn
with the switch open the sound is clear
when closed sounds dull and no top end
am i right in saying the closed switch setting is MC ??
mistake in pic the feedback is connected before the 4.7uf output cap

20201126_134152 by glenn jarrett, on Flickr
20201126_134106 by glenn jarrett, on Flickr
 
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PRR

PRR

Member
Joined 2003
Paid Member
There are other errors. See attached.

Yes, the switch puts 100 Ohms (||10nFd) across the cartridge which sure will roll-off the treble on nearly any moving-magnet needle.
 

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U230421

U230421

Disabled Account
Joined 2017
PRR is a drawingmaster!


Is IC2 really inverting the signal this way?
And a bleeder is missing after the output capacitor - connect a 10kΩ to gnd there to avoid popping.
Anyone with the datasheet of this SSM2134? Curious because of direct connection to +input.
 
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