Stan Curtis 60W Class A Amplifier from ETI
Stan Curtis was involved in both engineering and management roles in companies like Quad, Cambridge, Rotel (a family owned Japanese brand) Mission and Lecson to name a few. He is primarily an audio business consultant and remains highly respected and…
UBx Universal JFET Buffer
A while back, one of the diyAudio forum members who was building the nx-Amp (here’s the thread on DIYaudio.com) enquired about either reducing the amplifier’s overall gain, or providing a volume control facility. Since both the 15 W class A …
OPEX-1: A Discrete OPAMP for Audio
This design showcases a discrete opamp for audio applications. It features very low noise, low distortion and a class A output stage that will deliver 1ppm distortion into a 600 Ohm load at 12 V peak. OPEX-1 Discrete Opamp
Solid State Relay with PCB Layout
A complete relay that is smaller than a Tyco RT series EMR Simple_solid_state_relay_Updated . This design uses a small double sided PCB and some SMD components. Here are the Gerber files SSLR. The recomended mosfets for this design are the PSMN4R3-100PS[1] for…

X-Altra Mini One Line Preamplifier
The X-Altra Mini One is a simple line preamplifer based on the National Semiconductor LM4562 (also known as the LME49720) that I built around 2008 and which served me well until about 2014 when it was replaced with newer more…