The Beresford Capella Headphone Amplifier
We are in the final stages of getting my new headphone amplifier ready for launch. Here are a few pictures of the first one that was completed. It's a bit covered in fingerprint marks, so I shall take some new pics next week and update them.
http://www.beresford.me/images/aos/T...0FRONT-900.jpg
A view of the front.
http://www.beresford.me/images/aos/TC-7110%20FL-900.JPG
Sideways
http://www.beresford.me/images/aos/TC-7110R-900.jpg
The back panel
The new controls explained
Some of the controls on the Capella are no doubt unfamiliar to headphone users, or even the purpose of them. So here is a quick explanation and purpose of them.
GAIN:
Most headphone amps have to drive headphones from say 32 to 300 Ohms, with only the volume control available to adjust the output level. Unfortunately a 32 Ohms headphone only needs a small turn of the volume control before it is loud enough. A 300 Ohms headphone will need to be turned up by a far larger amount in order to sound just as loud. So some headphone amps have a switch to select between low and high gain for different headphones. Unfortunately this is not good enough in many cases. So the Capella uses a variable gain to cover both headphone impedance and sensitivity.
DAMPING:
Different headphones have a different resonance frequency and bass response level. Using a bass control to iron out those differences does however also affect the low frequency extension of the headphones, and the impact of the bass response in general. So headphone designs tend no to have a bass control of any sort. The Capella uses a little circuit to provide one of four selectable current/voltage levels to control the voice coil damping. This gives a far more solid bass at its optimum setting. No two headphones are the same in the bass region, so that's why provided four settings to choose from.
HF:
Some headphones have a very pronounced treble, which can ruin an otherwise brilliant listening experience. Some headphone users also suffer from ringing in the ears etc. from even a modest amount of treble. the Capella uses a kind of HF flattening circuit to dampen the HF response gradually so that excessively bright headphones can be tamed to a more acceptable user requirement. The hf control won't give you more treble. It will only give you a reduced dynamic response in the high frequency range between the 12PM and 5PM position. So you'll still hear the treble in the music in that range, just that you can adjust the overall "loudness" of it. Below 12PM you start reducing the treble content, which would be useful for headphone users who suffer from HF discomforts.
DEPTH:
Depending on the design of some headphones, the vocals and some instruments can sound a bit detached from the rest of the music. It can sound a bit too far back, or far too forward. Once you combine that with a headphone amp that has a presentation that is already laid back or forward, the listening experience can be quickly ruined. The DEPTH control on the Capella can offer a reasonable amount of control of the apparent forward/backward position of the music.