The Fosgate Signature Headphone Amplifier is one of the very best-sounding amps I've ever used. It was designed by one of the greats, Jim Fosgate, a man who earned 18 audio related patents, founded a number of successful electronics companies -- oh, and he pioneered high-power car audio systems. He was also a big supporter of the very first home surround format -- quadraphonic -- in the early 1970s, and so committed to the format that even as quad was winding down, he designed the Fosgate Tate 101, arguably the finest quad processor of the era. Fosgate also created … Read more
I've been a fan of Musical Fidelity from its beginnings in the early 1980s. The British company's original 30-watt-per-channel stereo A1 integrated amplifier was a hit with budget-minded audiophiles back in the day, and it also offered seriously expensive gear.
Musical Fidelity started making headphone amplifiers long before the current headphones craze started. The model we're looking at today is Musical Fidelity's pure Class A M1 HPA headphone amp ($799).
The HPA has very low output impedance (below 1 ohm), so Musical Fidelity claims it can "drive" any headphones with ease. The circuit is a fully discrete Class A design, with no op-amps in the audio path, so it's built like a small high-end power amp. The HPA has two inputs--line and USB--and there's a variable output, so the HPA can be used as a stereo preamplifier in a hi-fi system. It has two 6.3mm headphone jacks on the front panel.
Some previous generations of Musical Fidelity's styling were a little over the top for my taste, but the M1 HPA is understated and very classy. … Read more
I've reviewed and auditioned a lot of headphone amplifiers over the years, but Red Wine Audio's Isabellina HPA LFP-V Edition stood out from the pack. The amp improved the sound of almost every headphone I used with it.
Priced at $2,500 the Isabellina is very much a high-end audio product. Designed and built in Vinnie Rossi's small factory in Durham, Conn., the headphone amp's elegant functionality belies its technical sophistication. Rossi started Red Wine Audio in 2005, and before that he worked on high-speed laser transmitters for Bell Labs.
The Isabellina is more than just a headphone amp; it features a spectacularly good digital-to-analog converter and a hybrid transistor/vacuum tube audio section. While the Isabellina can be run off an AC power outlet, it sounds best powered by high-current lithium iron phosphate (LFP) batteries. Rossi claims "The batteries use organic, phosphate-based material, providing an ideal combination of performance, safety, reliability and environmental friendliness...in fact, more so than any other rechargeable battery technology."
The amp's digital connectivity options include USB, Coax, and Toslink/optical inputs; there are no analog inputs. The Isabellina has analog outputs, so it can be used as a stereo preamplifier, with a separate power amp to drive speakers, or a digital-to-analog converter in a hi-fi system.
The Isabellina features old tech 16-bit, non-oversampling digital-to-analog converters. Rossi acknowledges the latest chips' specifications look more impressive on paper, but he thinks most of them (even some really expensive ones) sound "quite sterile and artificial" in comparison. The Isabellina will work with digital sample rates up to 192kHz, but it will only playback with 16-bit resolution. … Read more