About this project
The Sicphones Amplifier
The Sicphones headphone amplifier is the best sounding headphone amplifier you will find without spending many times more. Based on a solid class A circuit design using a newly available Silicon Carbide transistor, it offers unprecedented quality and clarity in a headphone amplifier. Every part has been carefully selected to offer uncompromising quality at a reasonable cost. To compliment the electronics, we designed a heavy duty case that is sure to impress with top notch aesthetics. Not only does it sound amazing, but it looks amazing too!
We really need your help gearing up for a production run large enough to bring the price down. With your support you can have our awesome Sicphones headphone amplifier for a fraction of what a similar quality headphone amplifier would cost!
Who Needs One?
Short answer: Anybody who loves audio and demands quality.
Whether you are a musician, a producer, listening at home or at the office - heck, even if you are translating foreign language and have to listen closely all day long - the Sicphones headphone amplifier will significantly improve your experience by offering greater detail and clarity without fatigue. Whether you are using ear buds or large studio headphones, the limiting point generally is the amplifier. No matter what headphones you use, from ear buds to big cans, the Sicphones headphone amplifier can dramatically improve your listening experience.
What Makes It So Great?
It's all in the details:
- Silicon Carbide class A gain stage
- Big ALPS potentiometer
- Cardas RCA jacks and solder
- Nichicon Muse capacitors throughout
- Mills and PRP resistors
- Neutrik headphone jack
- Solid 2 ounce copper PC board
- External power supply
- 11 gauge steel chassis
- Stunning aesthetics
If you know what any of that means, you will easily recognize that you are getting an amazing value with your commitment to the Sicphones headphone amplifier.
This Sicphones headphone amplifier is compatible with most headphones with 1/4" stereo termination. We have made sure that it works well with everything from earbuds to high impedance studio headphones. Here is a brief list of headphones that we have tested: Apple Earbuds, AKG K240, Grado SR80i and Beyerdynamic DT-880 (600 ohm), just to name a few.
Tell Me The Story
Darren Crisp of Crisp Recording Studios interviewed me at his studio about the story of Sicphones:
What People Are Saying About It
- Tyll Hertsens at Inner Fidelity has slated the Sicphones headphone amplifier among some other extraordinary products for developing new specification tests: http://www.innerfidelity.com/content/innerfidelity-september-2012-update
- Srajan Ebaen at 6moons has been extremely supportive of the Sicphones headphone amplifier by providing a wonderful write-up of the story of our project: http://www.6moons.com/industryfeatures/sicphones/1.html
- Steve Guttenberg, The Audiophiliac at CNET, had the following to say about his experience with the Sicphones headphone amplifier: http://news.cnet.com/8301-13645_3-57504427-47/an-awesome-sounding-headphone-amplifier-kickstarter-project/
Production and Delivery
The Sicphones headphone amplifier uses 2 ounce copper on a double sided PC board featuring soldermask, silkscreening and hot air solder leveling to make for a high quality and easy to assemble product. All of the parts are high quality (just look at the list in the previous section!) and are sourced from the most cost effective vendors. The chassis is a three piece design using 11 gauge laser cut steel on the top and bottom, and 14 gauge steel on the back panel. After cutting, breaking and deburring, the chassis is powder coated to give it a durable, attractive finish. The external power supply is compatible with most worldwide electrical systems from 120 - 240 VAC, though comes standard with a US grounded, three-pronged plug.
The Sicphones headphone amplifier uses a novel Silicon Carbide transistor in the gain stage that we were fortunate enough to have been able to sample right after it was introduced. As of our launch, this transistor has just been introduced commercially and has a reasonable supply lead time. We have made our best effort to estimate delivery based on information available to us, and will keep you updated as as more information comes to our attention. We are just two guys assembling these by hand in our garage, so depending on the response to our project it may take some time to assemble all of the amplifiers. We will do our very best to keep to the time frame, and will definitely keep everyone posted. Our intention is to be able to have these ready before the holiday season.
Please note that our prices include shipping in the continental United States. For international shipping the simplest solution for single amplifiers and kits is flat rate USPS international and will incur a $40 added shipping fee. The double amplifier package (or an assembled and a kit) will not fit in the flat rate box and is more expensive. The typical international cost is an additional $70 beyond what we are including for domestic shipping. PCB, PCB + transistors, and the shirt can be shipped internationally in a large padded flat rate envelope. This will incur an additional $30. No, that is not a very good value, but there is nothing I can do about the rate of postage. Canadian shipping is a little cheaper than the overseas shipping. An amp is $30 additional, PCB or PCB + transistors is $20 additional.
I have inquired of Kickstarter about how international shipping payments are reconciled. Kickstarter does not have the means of adding the shipping on at the end of the project. The simplest thing is to make sure when you pledge to add in the relevant additional cost to your contribution. Please do this, as it will eliminate difficulties in reconciling the shipping later. Sorry about any confusion this has caused.
Fun Custom Colors!
The Sicphones headphone amplifier can be fabricated in your choice of powder coat colors. The below rendering card illustrates some of the possibilities, from variations on the elegant look, to classic Chevy colors, to the truly boutique. You just have to use your imagination!
We would like to thank the following people who made our Kickstarter campaign possible. Our thanks to Seth Baldwin, Andrew Beekman, Sam Friday, Ben Hundley, Jessica Keahey and Spencer Lee for starring in our video. Special thanks to Darren Crisp at Crisp Recording Studios for auditioning our amplifier and providing testimony in the video, as well as interviewing me about our story; to Tyll Hertsens at Inner Fidelity for taking the time to listen to our headphone amplifier and provide feedback both on the amplifier as well as the product launch; to Steve Guttenberg, The Audiophiliac at CNET, for taking the time to listen to our amplifier and discuss the evolution and aims of the project; and to Srajan Ebaen at 6moons for consideration of the how our project fits into the audio community and introducing this project to the 6moons community. Our profound gratitude to Jon Earls for writing an original score for the video. A special thanks to our friends and families who have supported our spending countless nights working tirelessly to bring this great amplifier into being. Without all of you we wouldn't be able to do what we are doing. A final after-the-launch thanks to all of the people who have seen this project, taken an interest in it, and asked good questions or made good comments. It is humbling from how far and wide the support has come. Thank you all.
It is an enjoyable aspect of understanding audio to be interested in the linearity of an amplifier, the flatness of response, the frequency range that it amplifies, the absolute phase error incurred by using it -- all of the wonderful quantitative aspects of understanding and controlling the behavior of a piece of equipment. I have enjoyed this aspect of the interest we all share and probably will do so again at some point. However, the approach taken with this amplifier was different than that philosophy. What I have learned is that there are a great many qualities of what something sounds like that do not relate very well to most specifications. As well, sometimes we loose sight of trying to develop a language for what matters when the language is inherently murky or hard to make objective. But these more subjective measures (words like "fast" or "transparent" rather than +/- 0.2dB from 10Hz-38kHz) are in some ways more meaningful. The answer to "so where are the specs" really is "why, if I like what it sounds like, do I care all that much since it doesn't really tell me what it sounds like." It is an experiment to try something new, to learn something, to understand something in a new way, to encourage questioning assumptions about things. To me this is what makes it very interesting. Of course, there is merit to the camp of designers and listeners who seek the most transparent product by minimizing distortion and other measurable objective features. This amplifier inherently has some distortion, it is a single ended class A design. We can only hope that the opinions that people have are relative to the design and what it can and cannot set out to achieve, and that it is attempting to be excellent for what it is. Also, there are some specifications that do not make as much sense for a constant current sourced amplifier as other types of amplifiers. Furthermore, peer review is always better than whatever gibberish someone might say about their own product (especially if you have no brand reputation, as is the case here), and on that count the lineup Tyll Hertsens over at Inner Fidelity has with this amplifier and several others is a very sound way of actualizing the specifications.
It never was the intent to stir up such a buzz with forum posts theorizing on the topology and other such issues. It is a very simple constant current sourced class A amplifier. There are some slightly unconventional design decisions that have mostly to do with the size (physical size, power consumption, power supply voltage), but on the whole it is quite predictable. It is a single stage circuit using a depletion mode Silicon Carbide JFET from SemiSouth. It shouldn't be a big surprise which one if you look in the catalog. There is no blatant global feedback, but there is a slight bit of intrinsic degenerative feedback. It is a low gain circuit employing a JFET exhibiting fairly low transconductance, and as such does not have the problems with parasitic feedback and stability possibly found in some high bandwidth amplifiers. The current source is very simple, in part to further showcase the JFET and keep the kit simple, in part to maintain more than adequate distance from an extremely well known designer and community contributor with whom I do not want to be on bad terms.
Silicon Carbide isn't actually the magic bullet. It is the part about it being a depletion mode power JFET with some desirable electrical properties that is more critical. Silicon Carbide is a fantastic material with very high electrical resilience and thermal resilience. It is a popular material for industrial controls and parts that live in exotic places experiencing wide and extreme operating temperatures. To improve switching speed and facilitate smaller, more efficient power control, the JFET came back into popularity after becoming virtually extinct in the power world with the introduction of the MOSFET years ago. What gives these parts a unique temperment for audio is that they are JFETs. The response of JFETs is different, and they do not exhibit some of difficulties with the insulated gate that can lead to instability in high bandwidth amplifiers. The way that they react to temperature change in a circuit such as this amplifier is also desirable and helps minimize thermal drift.
Historically I have always liked excessively heavy linear regulating supplies with their inherent large transformers and capacitors. They help solve the problem of keeping the floor down. It was rather stepping out there for me to even think that a switching supply might be acceptable. I feared high pitched squealing, possibly outright malfunction. Price, size and weight are meaningful parts of this project, so after some convincing I tried the external switching supply. The internal power for the amplifier is regulated for each channel, with enough headroom to account for power supply variation, and enough capacitance to diminish incoming ripple. Of course the regulators help with ripple rejection too, as well as further preventing the probably non-existant problem of power supply coupled channel crosstalk. The power supply that is used is sufficiently derated for this application to have a long working life, and sports a wide input voltage range to satisfy nearly anyone anywhere in the world.
Yes, with caveats. If you get the PCB kit you can use pretty much any choice of component you want for the power jack, switch, potentiometer and audio jacks. We use a 10k potentiometer as this is a good match between reasonably high input impedance and low enough for adequate gate drive. You should not choose something much higher than this value, or you could just not use one, for example if you use a preamp. For these components you will need only run a cable from whatever/however you intend to mount your choice of component to the PCB. While not quite as simple, you can do the same thing for lighting by using a cable from where the LED solder holes are on the PCB. You might consider simply not populating the board and designing your own lighting external to what the PCB is made for. There is a little bit less freedom when it comes to the board mount components that make up the guts of the amplifier. For the most part you can do whatever you please so long as it physically will fit on the board and makes sense electrically. There shouldn't be too many difficulties when it comes to resistors. So long as you plan on using capacitors that mount similarly and can fit a profile similar enough to the Nichicon Muse that we are using, you should be able to make it work. If you are wanting to use your existing random workbench parts, that should be feasible. The biggest issue is that the substitutes that you intend to use are viable choices electrically for the amplifier, and that they fit with the way the board is designed. You can see the board in the video enough to get a sense of the relative sizing. No, your enormous screw terminal 33,000 uF capacitors may not be the best choice, as they are not sized in scale with the rest of it (though of course by all means use them if it works for your idea). I know, I have been there, you can use jumper wires if you have your heart set on the larger value and longer lead lengths. There are probably a variety of heat sinks that can work with the spatial restrictions that are present on the board, including reworks of heat sinks from defunct electronic equipment, or re-purposed random aluminum extrusions. The heat sinks that we use on the amplifier have solder pins to ensure excellent physical stability. You can probably find various others that will fit, or will fit with minimal modification. You can get a sense of the dimensions for the heat sinks in the video as well. Having spent years building amplifiers in non-production enclosures, we are very excited to see what those who are interested in the PCB or PCB + transistors options come up with, and would love it if you keep in touch after you build it.
We consider the kit to be intermediate in terms of difficulty. This isn't to say that you couldn't build it as a first kit, but if that is the case you should be fairly handy with tools and you should probably practice soldering on something else first. We have made great efforts to ensure that the solder pads are large enough for simple assembly, spaced enough apart to avoid bridging, the silkscreen labels for components are clear, and that the recommended order of assembly minimizes frustrations. If you take your time, you can do it as a novice, but based on the number of parts and the marriage of the electronic and mechanical aspects of assembly, we feel claiming intermediate difficulty is a better rating. We do provide the solder for the kits, which, just as with he finished product, is Cardas Quad-Eutectic. The tools that you will need include a soldering iron, small and medium sized screw drivers, needle nose pliers, diagonals (small wire cutters) and a 3.5mm Allen wrench for the chassis hardare. You might find it additionally useful to have regular pliers or a crescent wrench available, as tightening the nuts on the jacks with needle nose pliers, while possibly, risks scuffing the powder coating. While for most of the kit there are no surprises in order of construction, you would be best served at least skimming the assembly instructions as there are a couple of areas where the order of board population matters. The assembly instructions serve both as a step-by-step guide and a general overview of what we have found to be best practices for assembly, depending on what level you are and how inclined you are to read instructions.
You are always welcome to make contact and drop by if you are in the area. Now or any other time, we are always up for discussion, listening, whatever. We will also be attending (as participants, not as exhibitors) the Rocky Mountain Audio Fest, though will only be there for the full day on Saturday, October 13. We would love to see anyone and everyone while we are there.
You need to add the appropriate shipping for what you are interested in to your total pledge when you choose to support this project and are outside the continental United States. The basic international shipping charges (the difference between the actual charge and what we have included in the price for domestic shipping) is listed in the main project description. For example, if you are in Australia and would like the basic assembled amplifier, you would pledge $279 + $40 = $319. Kickstarter does not have a robust built in way to reconcile the international shipment, and their recommendation when I wrote was to do it this way. Please, to prevent administrative difficulties and having to find an alternative method of payment for shipping after the project period is over, just add the appropriate shipping to your total pledge. If you have a question about a shipping charge for a combination contribution, please do not hesitate to ask. For simplicity, convenience with customs, and the generally consistently low shipping charges quoted, we are shipping exclusively with USPS. Our apologies for any confusion about international shipping, we were not aware that there was no method for automatically adding it before we launched the project.
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