Astrotec S70 Hybrid Driver Truly Wireless Earbuds with Bluetooth 5 Coming Soon to Indiegogo

The new Astrotec S70 true wireless will soon be available with a crowdfunding campaign on Indiegogo (another example of a large manufacturer using the platform to promote and have pre-production sales) and will feature both dynamic and balanced armature drivers in a hybrid design that uses Bluetooth 5 connectivity and includes a USB Type C fast charging case, providing 36 hours of playtime. The earbuds have an original form factor with behind the ear hooks, are water resistant and weight only 10g.

Tubes or transistors? Whatever your prejudices, this article may make you change your mind about how you view hybrid designs. audioXpress featured this modular hybrid amplifier project in February 2001, which was referenced multiple times by other authors in many subsequent projects. The project features a shunted regulated push-pull (SRPP) stage design, using the ECC82/12AU7 tube combination, followed by a power stage, using two to eight complementary power MOSFETs in parallel.

Published in two separate parts in audioXpress October and November 2007, this hybrid amp design is a detailed and interesting project, frequently referenced by other DIY audio enthusiasts. We thought it was time to make it available online in its entirety, in the best possible quality. The article discusses the unity-gain, single-ended MOSFET output stage, the valve voltage amplification stage and wraps up with the power supplies, printed circuit boards, and construction.

Simon Brown rethinks what he needs as the amp that will be the centerpiece in his own audio system and perfects a previous design with a true hybrid design. As he writes, "This amp is a “hybrid” in many ways. There is the obvious way in which it uses both valves and MOSFETs. But it’s also a hybrid in its use of enriched Class A/B, which means it is running Class A up to a few watts. This is deliberate." Read the complete project now. This article was originally published in audioXpress, March 2007.

In this article from audioXpress archives, originally published in July 2003, Charles Hansen describes four hybrid power amps that anyone might consider for their own designs. Starting from the idea that an op amp provides both a differential input stage and high overall gain in one package, Hansen explores the ramifications of using an op amp as a combined input and voltage amplifier stage in power amplifiers. As he writes, “I did not build the four amplifiers shown in this article, but I did run a SPICE simulation to verify that they did perform as audio amplifiers."

The all new Audeze LCD-4 planar magnetic technology reference headphones were introduced at RMAF CanJam 2015. The LCD-4 features Audeze’s nano-grade diaphragms and unique Double Fluxor magnet arrays for the most powerful magnetic flux density in existence, an incredible 1.5 Tesla! At RMAF 2015, Audeze also unveiled its new The King Headphone Amplifier designed by Bascom King.

With a little know-how and some basic parts, you can design a hybrid amplifier in fairly short order. This project combines the best attributes of both tube and transistor technologies.