Prototype For Sale

I'm no longer in need of my original prototype, so I'm going to sell it as-is or part out the individual components. I plan to post the sale on eBay, Craigslist and some Facebook groups dedicated to audio. When I get a chance to take some photos, I might update this post. If you are interested, feel free to contact me at gregg dot plummer at gmail dot com.

This first prototype consists of a combination of amp modules and a FireWire audio interface in a utilitarian aluminum chassis. I was pretty concerned with overheating because of the 5 high powered amps so I used a fairly thick aluminum to help dissipate any heat. It's also vented at the top, just above the amps and there's a very quiet 120mm fan to blow air out the back. BTW, I worked with a mechanical engineer who did some thermal analysis on the prototype to make sure we dissipated the heat. It was probably a little overkill. My price for the prototype is $825. My cost, not including the considerable amount of time designing, building and testing were about $2,500.

The components included are:

Aluminum Chassis - this includes the 120mm fan, special mounting plates for the power supplies and mounting brackets for the audio interface. On the back is the A/C receptacle with a switch (A/C line cord included) and a 10A Bussman time delay fuse socket. On the front, there's a momentary pushbutton switch that has 2 operation modes. In one mode, the audio interface is powered on while the amps remain off. The other mode switches on the audio interface and all the amps. Not sure if anyone would be interested in this because the layout is designed specifically for the rest of the components. The price for the chassis is $295 $100.

Power supplies - At the time of this design, the only practical choice for the system were linear power supplies. I really wanted to incorporate SMPS (switch mode power supplies), but ones with the characteristics I wanted for this high-quality audio application were not available. I used different amps for the front and rear channels, so the system utilizes 2 different power supplies.

• The power supply for the rear channels includes a 400 VA (115/33 Vx2) toroidal transformer and a Hypex HG power supply. My prices are $65 for the 400VA toroid and $100 for the Hypex HG PS.
• The power supply for the front channels includes a 1000 VA (115/45 Vx2) toroidal transformer and a Hypex HG power supply. These are $100 for 1000VA toroid and $100 for the Hypex HG PS.

Amplifier modules - I used the highest quality Hypex UcD amp modules that were available at that time. This prototype only needed to provide power to 5 channels because, in a typical 5.1 home theater system, the subwoofer is self-powered (channel .1). To each amp module, I attached an aluminum plate heat sink with fancy Neutrik speaker binding posts.

• The 3 front channels - right, center, left use Hypex UcD400AD amp modules. These are each rated at 400W RMS into 4 ohms. Unfortunately, only 2 of the 3 are currently working. The one I was using for the center channel has a faulty component that causes the amp to output a terrible thumping sound. So, I'm including it for free with either of the other working modules. I think it just might need a new cap but I'm not sure and Hypex no longer services this amp. The price for the working UcD400AD modules is $85 each or $165 for the pair. 
• The 2 rear surround channels use Hypex UcD180AD amp modules. They are rated at 180W RMS into 4 ohms. My price for a UcD180AD module is $65 or $125 for the pair.

Audio interface - this is the device that your PC will use as the audio device or soundcard in your HTPC. It was the AudioFire8 and was sold by Echo Audio for something like $750. This is a high quality 8 channel FireWire audio interface typically used for audio recording and mastering. I took mine apart and reinstalled it inside my chassis. A rectangular port is cut into the front of my chassis to access the front of the AudioFire8. I also paid Echo Audio $5000 to write a custom multichannel driver so my device could output surround audio. Since my center channel amp stopped working, I used the AudioFire8's software console to reroute the center channels to the front left and right channels balanced evenly. It's now a working 4.1 system and still sounds great. I can put the AudioFire8 back in its original chassis and sell it for $175. Echo Audio still has drivers on their website that you can download for Windows 7, 8 and 8.1. They are no longer developing audio interfaces and have discontinued further updates so it may not work on Windows 10.

Misc components - A handful of components were included to complete this system. To avoid the loud click that normally happens when you turn on the amps, I added Hypex's softstart module. To connect the AudioFire8 to the amps, there are custom cables with 1/4" TRS connectors. Also included is all the hookup wire between toroids, power supplies, and amps.

UPDATE 2/14/2018: Items that have sold are indicated as such by striking the text. I've listed the remaining items on Craigslist here:

https://madison.craigslist.org/ele/d/diy-amplifier-components/6494593237.html

I've reassembled the Echo Audio AudioFire8 and reduced the price to $100:

https://madison.craigslist.org/msg/d/echo-audio-audiofire8-audio/6494579793.html

I'm also selling an M-Audio FireWire 410 for $75:

https://madison.craigslist.org/msg/d/audio-firewire-410-audio/6494554911.html

AND, I'm selling the 5.1 speaker system that I used to demo my prototype. These are awesome speakers:

https://madison.craigslist.org/ele/d/era-design-5-speaker-system/6476114140.html

Modular / Open Architecture Design

I like the fact that you can purchase the building blocks to assemble a PC to your exact specifications. The technically savvy person can buy the chassis, power supply, motherboard, cpu, memory, graphics card, sound card, disk drives, etc., etc., from several different manufacturers and put together a system that costs less or performs better than the pre-assembled systems from the major PC manufacturers. Of course, if you are not technically savvy, you can also purchase a complete system from the hundreds of retailers. Since there are so many PC manufacturers, the prices are very competitive. This is possible because of the open architecture of the PC. I think this might have contributed to the popularity and growth of the PC. On the other hand, Apple's proprietary products may be considered a little higher quality, and that may be due to the fact that Apple has greater control over their supply chain, but they also charge more for their PCs. When you compare market share, the open architecture PC is the clear winner.

Open architecture or modularity might work for an audio system similar to the way it has for PCs. Standard components could be available for the power supply(s), PC audio interface, preamp, amp modules and chassis. The preamp would be similar to a PC's motherboard. This is where the source devices would be selected and routed to the amp modules, plus it could include circuitry for analog volume control. The PC audio interface would have all the functionality of the PC's sound system. It would include the interface to the PC using USB or FireWire, along with the DSP, ADC and DAC chips. An amp module would provide the power for one channel or speaker output. Or maybe some manufacturers could design modules that provide stereo pairs at less cost. Amp modules of different power ratings, like 100W, 200W, 400W, etc. could be available, just like we currently can choose hard drives with different storage capacities. These amp modules could also come with integrated power supplies like the ASP Series from IcePower shown on the left. The chassis could be designed with standard layouts and connectors similar to what is currently available for today's PCs. There might be small cases for 2 channel stereo systems, larger 5.1 or 7.1 surround or even huge tower systems that could house enough channels for a sizable whole house audio system. Someone could choose a very basic chassis with a plastic or painted sheet metal skin and save some money, while others could purchase an expensive thick gauge aluminum chassis with a polished finish.

This open architecture approach has a few serious challenges. To be successful, the components have to be designed with standard connectors and form factors. Just like the hard drive's enclosure is designed with a 3.5" form factor and standard connectors for data and power or a PCI card that fits into the connector on the motherboard, has standard heights and widths and includes the backplate to attach to the back of the chassis. It will probably be difficult to get the component manufacturers to agree on standard connectors and form factors unless they are confident there is a large market for these standardized products. In the early PC days, the IBM architecture was very popular because IBM was a well established, respected company. I don't know of any other manufacturer that could have accomplished this level of standardization and there really isn't anybody in the audio industry with that type of clout today. Besides, most of the manufactures prefer to offer their mostly proprietary solutions.

In addition to the open architecture with standard components, there's also modular design. By this, I mean providing specific components for certain tasks. Separate components for the PC interface, the preamp, amp modules, power supplies, chassis, etc. There's also the separate components you can purchase for your home theaters and sound systems. For example, you can buy a CD and/or DVD transport, D/A processor, preamp, and amplifiers. The specialized components usually sound better, look better and cost a lot more than an integrated solution. Amplio's prototypes have been integrated solutions that include the PC interface, DAC/processor, power supplies, and amp modules all in the same chassis. However, some customers might prefer the flexibility of separate modules. We could provide different products like a preamp that combined the PC interface, DAC, volume control, etc., and amps that can be purchased in mono, stereo or multichannel configurations. Two flavors of preamps might let you choose between a 2 channel or 8 channel solution. The combination of an 8 channel preamp and 3 - 2 channel amp modules plus 1 mono amp module would result in a good 7.1 system. Here's an example of an interesting modular design for PCs called the UNI Computer. Maybe we could do something similar for the preamp and amp modules.

If you have any thoughts or questions about modular and/or open architecture design, I'd love to hear from you. Please feel free to post a comment!

Open Architecture

In previous posts I've mentioned that we'd really like to design a product that has the modularity and flexibility of the personal computer. Not the closed or proprietary architecture of the Mac, but the open architecture of the PC. Then people could choose the amp modules, power supplies, case, audio interface (soundcard), etc., that would meet their needs for number of channels, sound quality and budget.

From Wikipedia:

"Open architecture is a type of computer architecture that allows users to upgrade their hardware in all of the computer hardware & components (for example the IBM PC had an open architecture). This is the opposite of a closed architecture, where the hardware manufacturer chooses the components, and they are not generally upgradable (for example the Amiga 500 home computer had a closed architecture).

Open architecture allows potential users to see inside all or parts of the architecture without any proprietary constraints. Typically, an open architecture publishes all or parts of its architecture that the developer or integrator wants to share. The open business processes involved with an open architecture may require some license agreements between entities sharing the architecture information."

I'm not sure if we will ever be able to do this, but it is something I am interested in achieving. I think there is great potential here. It may even turn part of the consumer electronics industry upside down or inside out. Of course, this may not appeal to the ultra expensive, high end, "audiophile" producers and consumers, but I think it would really be great for the rest of us.

What do you think? As a consumer, would you like to purchase a system that could be expanded from 2 channels to 8 channels? Or upgrade the DACs or amplifier modules when a new generation is released? Be able to choose from a variety of case manufacturers to have one that best fits your style?

If there are any reps from manufacturers of amplifier modules, power supplies (the best technology for this would be switching power supplies or SMPS), or sound cards reading this, I'd love to hear what you think about this idea? Do you think it would expand your market, or not? Do you think the technical hurdles for designing your components to meet a specific form factor and use of standard connectors would be too limiting? Maybe someone like Creative would offer a version of their X-Fi that would be compatible -- and like the "Intel Inside" promo, they could have "X-Fi" inside. Of course, we could also have "UCD powered", etc.

So, When Will It Ship?

I've been asked several times about the ship date for our product. I don't have an answer for that, but I can tell you about the changes or improvements we need to make to the current prototype before we are ready to ship a commercial product. In this post, I'll give a general overview of improvements needed for each of these subsystems:

1. the chassis
   
2. power supplies
   
3. amplifier modules
   
4. soundcard section
   a. computer interface
   b. drivers/software
   c. digital/analog section - DACs, ADC, etc.
   

I will provide more detailed information about each of these sections in future posts.

As you can see from the prototype photos, the current chassis is not something many people would want in their living or family rooms, unless they're really into the industrial design style. They actually might look kind of cool in an a loft space or something, but that is sooo 90's :). So we need to come up with a more aesthetically pleasing design. We would also like to minimize the size and weight, and allow for optimal heat dissipation. Fortunately, the internal components are relatively small and don't generate too much heat so we should be able to create a chassis that isn't a monster. We'd also really like to design a chassis that would let do-it-yourself (DIY) people build or upgrade their own systems. Much like you can do with PC today. This means the inside of the chassis would include the framing to mount things like power supplies, the printed circuit boards and amp modules. Ideally, the amp modules would simply slide into slots in the back of the chassis.

The main changes we plan to make with the power supplies for our commercial product will be to replace the linear power supplies with switch mode power supplies (SMPS). The latest SMPS technology designed for audio applications is very promising. Compared to general purpose SMPS, the SMPS designed for audio applications usually have much larger capacitors to provide a larger energy reserve for the faster and deeper current demands. General purpose SMPSs are typically designed for fairly constant loads, so they don't usually have large enough capacitance at the outputs for audio applications and adding capacitance to a general purpose SMPS wouldn't work very well because the feedback circuit doesn't take into account this additional capacitance and the added phase shift and oscillation would make it unstable. The main benefit with using the SMPS instead of the linear supplies is since they operate at a much higher frequency, they can be much smaller and lighter than the equivalently powered linear supplies we were using. Since a SMPS recharges its capacitors about 1000 times faster than the rate of a linear power supply, which needs a fairly large transformer and big capacitors to keep up with the current demand, the SMPS can get by with smaller capacitors.

We are pretty pleased with the amplifier modules in the conceptual prototype. The amp modules we've tested are from Hypex Electronics, a Dutch amplifier manufacturer who has developed a very good reputation for high quality products. There are a few things that can be done to optimize these for our application, which will be done if we decide to use their UcD amps in our commercial products. Since we started this business, we have discovered a few other class-D amplifier modules from other manufacturers worth considering. And there is also the possibility of developing our own class-D amp, but unlikely considering the development costs and time. To accommodate our modular chassis design, we would really like to find an amp module that will fit into a small enclosure. This enclosure would be similar to the case of a hard disk drive. It would protect the circuit components, dissipate heat and would allow for an easy method to insert the amp into the back panel of the chassis. If the sizes were standardized, you could upgrade or replace amp modules when newer, better designs were available by simply unplugging the old amp and replacing with the new. We would also be happy to support more than one amplifier manufacturer. Some of the class-D amp modules have a reputation for being very accurate and transparent to the source. These amps sound great, but if the source material isn't very good, like a poor recording, the flaws are pretty noticeable. Other class-D amp modules might be a little more forgiving of these types of recordings. I guess it all depends on your listening preferences. I think it would be nice to have a choice. Now, if only we can find a few manufacturers to work with us on a design for these standard amp cartridges. Wouldn't it be great to have the options of different amp modules just like you currently have with hard drives or video graphics cards?

The soundcard section is where we have the most work ahead of us. The current unit in our conceptual prototype was designed primarily for pro-audio applications - recording and mixing. There are quite a few components that aren't needed in a music playback or home theater system. For example, we don't need 8 balanced inputs if the audio source is the PC. The analog outputs of the pro-audio soundcards are good and usually sound better than your average A/V receiver, but they may not sound quite as good as the high-end dedicated preamp/processors. Their outputs are designed to be good enough for an audio engineer to monitor a mix, but might not meet the needs of someone that is really into critical listening. Our goal is to design a soundcard that sounds as good as some of the high-end dedicated prepros, but at a much lower cost. We've also got a lot of work to do on the software - both the drivers and the control panel applets for controlling things like volume, channel mixing, etc.

Like I said, we'll cover each of these areas in a little more detail in future posts. Please let me know what topics you would like to learn about first.