Audiophilepure

The Bryston will never be confused with a tube amplifier, but texture and tone through the HD800?

Hell hath frozen over. 

The Bryston BHA-1 blurs that line rather significantly offering up a cleaner sounding and more detailed presentation than any of the tube amplifiers in my collection, but with a warmer tonal balance than I would have expected. 

The final button controls the crossfeed filters. Crossfeed mixes some of the right signal into the left channel and vice versa, usually through a time delay and/or equalization filter to give more of a loudspeaker-like sound and soundstage to headphone listening. On the Liberty amp, there are 5 settings: two filter styles with normal and high levels of crossfeed, and off. The button also selects mono mode if you should desire. These crossfeed circuits are not documented. You just pick the setting you like the best. This brings up my one complaint about the Liberty THX AAA amplifier: the manual. None of the controls are documented in the manual at all. There is a video on the Mytek website where Mytek’s designer Michal Jurewicz goes over all the controls. But I really wish they would make the effort to write it down in the manual. It wouldn’t be that much work. 

I employ the Dan Clark Audio Stealth headphones for the focused portion of this review, and to provide a more worthy comparison, I forego using my $650 SGA-1 Soncoz Headphone Amplifier that, while an excellent value for the money, is a lighter-bodied pinot noir to the bolder HPA-1’s cabernet sauvignon. Hence, I enlist the services of the powerful, but discontinued Cypher Labs Prautes tube headphone amplifier with a rebuilt power supply.

I had been very impressed by the Prautes when I reviewed it in 2019, and Joe Jerzec, who was a reseller and lent me the review sample when he ran JAM’n Audio (he’s currently a partner at Purity Audio Design), lent it to me again. A veritable tank, only 50 units were made, retailing for $3900 (that would be $4714 in 2023 dollars, according to Amortization.org). One of its standout features is an impedance selector switch to accommodate various headphone and speaker impedances, as follows: 300 Ω, 100 Ω: Standard for many Studio headphones, 32 Ω: Standard consumer headphones, 8 Ω: Speakers or very low impedance headphones, and IEM: In-Ear-Headphones.

Now, the Stealth headphones have a 23 Ohm impedance and a sensitivity of roughly 86 – 87 dB/mW, so they’re not the most efficient headphones, meaning you have to crank up the volume on a headphone amp to hear them properly. 

Flipping the K11 reveals a well-thought-out back panel for the price, housing a variety of inputs and outputs, including USB, optical, and coaxial, alongside 4.4mm, 6.35mm, and RCA jacks. This assortment of connections makes K11 ready to pair with a broad array of sources, from consoles to phones and computers. The details extend to practical considerations as well; the big and wide silicone anti-slip pad ensures the device stays firmly in place, while the adjustable RGB logo lighting on the top adds a customizable visual appeal or can be configured to provide visual feedback on the audio format being played.