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L-15D D-Amp

The SMSL SA-50 Class T amp had to leave because I built a stereo L-15D amp. It is based on the integrated analog input Class D audio amplifier driver IRS2092 and the digital audio MOSFET half bridge IRFI 4019. PCB designed and manufactured by LJM.

It’s a class D half bridge audio stereo power amplifier with up to 250W/ch. @4 Ohm. It features a self-oscillating PWM topology with a self-oscillating frequency of approx. 400kHz.

As a power supply I choose the Connexelectronic SMPS500R with ±60V (running at ±59V). A separate speaker protection unit by Audiophnics is also included in the design (powered by the ±12VDC aux. output of the SMPS500R). Internal wiring is mainly done with twisted tin-plated single stranded wire of 0,8mm diameter. The electrolytic DC rejection capacitor on board the amp was replaced by a remote 22µF WIMA MKP10 capacitor.

Cost for the complete amp is approx. EUR 280,- including housing, ALPS volume control, power supply, two amp modules, terminals, wires, ferrite cores, consumables and S&H from China and France and Germany.

Compared to the SMSL SA-50 it is a set up in various means such as dynamics, punch and clarity. Just very pleasant sounding with authority when required. Power is more than sufficient for my application.

Here are some pics of it:

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The way it’s built is more than influenced by Saarmichel (and others). Thanks for that!