Amp1 was my first production headphone amplifier, in “upgrade” form it was highly regarded from audiophile customers, headphone newbies and even where it received an award.

Blue Moon Award

Enter Amp1 v2.0, what’s new?  Everything inside!  What’s the same?  Everything on the outside.  While working on designs for Amp8S and Amp4 I found that some of these new concepts and components could be scaled back slightly and fit in Amp1.  This all started when testing the IEM output of Amp8S which will have a dedicated IEM signal path for very low noise and appropriate gain so the volume control is actually usable.  This was the basis of Amp4 which took the basic topology added buffers for higher current output.  However with a less expensive buffer and only 2 channels (vs 4 in the balanced configuration of Amp4) it would fit both the physical size requirements and the price point of a revised Amp1.  This began as a few tweaks to the Amp1 design incorporating parts of the power supply from Amp8S and Amp4, along with the buffers and gain topology.  The further I went the less and less remained of the original design, and it finally hit a point where I started with a clean slate and only the input connectors, output connectors and volume potentiometer remained in the same location.  Everything else is new, the power supply is vastly improved because it was designed for IEM use in Amp8S, with an ultra low noise floor.  The output buffers have been optimised and stand alone vs being inside the negative feedback loop of the main gain stage.  This non feedback design has resulted in a much more open and natural sound while maintaining excellent measured performance by optimising the buffer circuitry independently.  The amp has socketed op-amps, however at this point I don’t recommend changing the buffers.  The amp won’t initially be available as a kit because I had to move to mostly surface mount parts.  The length of the signal path in the original Amp1 was a longer than ideal, because of this Amp1 v2.0 has been optimized for performance using mainly 0805 smd components.  Not crazy small like 0402’s or 0201’s but not the most friendly for someone new to smd soldering.  Of course reflow soldering is also a much better way to do smd and is the method I will be using to produce Amp1 v2.0.  If I can find a cost effective solder paste stencil I may release it as a kit including solder paste and the solder paste stencil.

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Of course I think it sounds better, but it’s not just “better” it’s been improved on all levels.  The power supply is drastically better, the core topology is better, output current is higher,  output impedance is lower, the noise floor is much lower, detail and resolution are on a whole new level, the soundstage and instrument placement is wider and more stable.  Once I’m happy with the first prototypes they will go out to a few reviewers and I will start small scale production.  Introductory pricing will be $199US which is only $4 more than Amp1 Upgrade with a significant improvement in performance.  After the introductory period the price will be $229US.


Amp1 v2.0 will be available mid 2014.