The competitive portable headphone amplifier market can be a difficult one to approach. Manufactures quickly churn out new designs and form factors so quickly that unless you spend lots of time on HeadFi, it's difficult to keep track of them all. Between Ray Samuels, HeadAmp, HeadRoom, iBasso, Fiio, and many others, there are enough offerings to make your head spin.
The company Decware, known mostly for their non-portable, tube-based amplifiers, released a portable headphone amplifier back in 2008. While it was only four years ago, there have been hundreds, if not thousands, of portable amplifiers released since then that may have made some headphone enthusiasts forget about it. It was reviewed favorably many moons ago by HeadFi member Skylab whose opinion I respect, and Decware is offering the PCBs and chassis on his website, so I figured it would be a nice diversion to put one together and have a listen, even if it is a few years old ;)
|The Decware Zen Head PCB|
One of the nice things about the Zen Head PCB is that there's no SMD soldering to worry about, which is almost a given with more modern portable designs. Just regular old through-hole components here. This may not be the best beginners project as there isn't really any online documentation other than a bill of materials to populate the board. Also unusually, the parts values are printed directly on the board rather than part designations.
Rather than simply ordering the BoM, I opted to try a few other parts. All the resistors are Takman REX carbon film, and there are quite a few of them as seen below.
|Takman carbon film resistors - pretty in pink|
The capacitors were switched with Nichicon / Wima equivalents. Also added were a pair of gold sockets so the OPA2132P op-amps could possibly be rolled in the future. All other parts remained identical to the BoM except for items that were out of stock and necessitated a substitute. After the population of all the parts the board is quite colorful!
|The populated PCB|
The chassis is a little long compared to other portable amps as the battery doesn't fit on or over the board, but in a plastic battery holder in the back. Compared to something like Ray Samuel's Shadow, this amp is massive, but it will still fit in your pocket or transport just fine in a case. A pattern was drilled on the top of the case for heat dissipation, although it's doubtful that much will be generated.
|Zen Head in PCB in case|
I noted that the PCB was a little long and ran into the battery compartment. Since there's no traces at the end of the board, the PCB was sanded down a bit so everything would fit nicely. The battery strap was then soldered in place.
|Attachment of the battery strap|
Next the front plate needed to be drilled. A template was printed from the Decware site that was printed at actual size (not fit to page, very important!) and taped to the front of the plate. The plate was then drilled using a drill press and the holes de-burred.
More to come!
|Drilled front plate|
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Please remember that building circuits and performing circuit modifications can be dangerous to you and/or your surroundings and should only be performed by a certified technician. The owner of this blog and all associated parties can not / will not be held responsible if you attempt a build or modification posted above and cause physical harm to yourself or your surroundings. Many electronics contain high voltages that can kill, and mods, if performed improperly, can be a fire hazard. Please keep this in mind.
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