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Concept, design: Bruno Putzeys
Schematics, layout, prototyping: Sander Sassen
Article text: Sander Sassen, Bruno Putzeys
***Update 10-12-2014: Updated stuffing guide***
The silkscreen for the amplifier PCB contains an error where the labeling of L1/R6 is swapped.
If you've already built the amplifier, please swap L1/R6 around as the amplifier will see a large(r) DC offset and reduced performance due to this error.
***Update 01-12-2014: parts value change***
With a simple parts value change the ExtremA amplifier sees an improvement in slew-rate, step response and overall stability, so it is recommended making these changes. There's four capacitors that need to be changed:
C1/C2 = 68pF - COG or NPO - 5mm pitch (Vishay NP0 ceramic)
C4/C9 = 220pF - film capacitor, polypropylene or polyester - 5mm pitch (WIMA FKP2)