7.1 USB for under 20 bucks

[cakemonster]

http://www.newegg.com/Product/Product.aspx?Item=N82E16829180006&cm_re=USB_audio-_-29-180-006-_-Product

What do people think? My audio is working, but it pops quite often, just curious...

 

[ne0shell]

It may not work with Mac OS. They give no details on the chipsets it uses so there's no way to tell other than they don't list Mac as one of the compatible systems.

A lot of the USB audio "soundcards" are "driverless" when in fact the drivers are inside the chipset on the device board. Usually it's a very cheap USB chip, a crappy DAC (digital to analog converter) and a transistor based amp (op amp).

Pro: It's bigger than a quarter where a lot of these USB sound cards are very small because they use a tightly integrated, all integrated circuit configuration. In this case the size may be due to having all those outputs and inputs.

Con: Sound quality is probably ****. Might not work with Mac OS.

Even the audio quality of the Gigabyte ALC 8xx chipsets is pretty dismal. I like the USB audio concept as it's taking a pure digital signal from the computer and handling the conversion separately. You "can" get very high quality / audiophile sound but not from any of the cheap devices made for PCs.

I'm building a gamma2 DAC http://www.amb.org/audio/gamma2/ for my Hackintosh (last of the parts finally arrived) and I'm waiting on the hybrid IC / tube headphone amp I bought last week to arrive. http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=120553426345 It's actually a preamp but with a couple of minor changes in the circuit it will drive my headphones / speakers just fine.

I'm not using surround sound so I decided to go this route and get rid of the crappy ALC 888 sound. It's loud but listening to the new Deftones made me realize just how incredibly noisy and distorted it is.

 

[rich]

ne0shell can i use the gamma2 DAC with headphones that dont require amplification and powered speakers? i.e.

ALC889a -> optical -> gamma2 -> analogue phono output

i presume you cant use both at the same time, so some type of splitter is needed.

 

[ne0shell]

ne0shell can i use the gamma2 DAC with headphones that dont require amplification and powered speakers? i.e.

ALC889a -> optical -> gamma2 -> analogue phono output

i presume you cant use both at the same time, so some type of splitter is needed.

The Gamma DAC can drive a wide range of headphones by itself, including high impedance ones. The build plan calls for changing a pair of capacitors for a set of audiophile caps that maintain full frequency and eliminate a low freq roll off the standard caps cause.

I'm using the tube preamp in line with the DAC just to warm up the sound on my jazz and classical audio files, otherwise the DAC by itself works just fine. You can split the signal for a headphones plus powered speaker arrangement.

The gamma can be configured to take a USB input (bypassing the mobo audio stage completely), a SPD/IF input (fed from the ALC chip) or all the above. By using the USB input I can ignore making the ALC audio chip work in future upgrades since I probably won't use it at all. I plan to build a digital switch to flip between my Hack, xbox and DVR.

The gamma itself has an input switch and volume pot on it. I could connect the USB, optical from xbox and coaxial from the DVR all direct to the DAC and use the built in switch to select my inputs.

It has digital inputs, digital outputs, 2 headphone outputs and 1 set of RCA analog outputs. The volume knob is an add on not shown in the photos posted. The DAC is full pass and convert - in other words you can connect any digital input and use any digital or analog output. You can use the USB input and run optical or coaxial outputs, RCA analog and headphone outs all at the same time or vice versa.

 

[timg]

http://www.newegg.com/Product/Product.aspx?Item=N82E16829180006&cm_re=USB_audio-_-29-180-006-_-Product

What do people think? My audio is working, but it pops quite often, just curious...

For some reason, I had that problem after trying one of the legacyHDA kexts. It then kept happening with everything I tried after that. The only way I got rid of the popping was restoring a good SuperDuper clone. I'm back to zero popping. The other thing known to cause audio issues is the iMac smbios.

Tim

 

[rich]

ne0shell can i use the gamma2 DAC with headphones that dont require amplification and powered speakers? i.e.

ALC889a -> optical -> gamma2 -> analogue phono output

i presume you cant use both at the same time, so some type of splitter is needed.

The Gamma DAC can drive a wide range of headphones by itself, including high impedance ones. The build plan calls for changing a pair of capacitors for a set of audiophile caps that maintain full frequency and eliminate a low freq roll off the standard caps cause.

I'm using the tube preamp in line with the DAC just to warm up the sound on my jazz and classical audio files, otherwise the DAC by itself works just fine. You can split the signal for a headphones plus powered speaker arrangement.

The gamma can be configured to take a USB input (bypassing the mobo audio stage completely), a SPD/IF input (fed from the ALC chip) or all the above. By using the USB input I can ignore making the ALC audio chip work in future upgrades since I probably won't use it at all. I plan to build a digital switch to flip between my Hack, xbox and DVR.

The gamma itself has an input switch and volume pot on it. I could connect the USB, optical from xbox and coaxial from the DVR all direct to the DAC and use the built in switch to select my inputs.

It has digital inputs, digital outputs, 2 headphone outputs and 1 set of RCA analog outputs. The volume knob is an add on not shown in the photos posted. The DAC is full pass and convert - in other words you can connect any digital input and use any digital or analog output. You can use the USB input and run optical or coaxial outputs, RCA analog and headphone outs all at the same time or vice versa.

thanks for the concise, yet informative info!

what do you mean changing the capacitors? do you need to buy extra and use them instead when constructing?

good to know that you can use USB or SPD/IF and has 2 phone outputs and a volume knob. i would just be using one digital input (hackintosh) and 2 analogue outputs (headphones and powered speakers). is there something simpler that would suit me better? maybe the gamma1? but seems too limited.

 

[ne0shell]

what do you mean changing the capacitors? do you need to buy extra and use them instead when constructing?

good to know that you can use USB or SPD/IF and has 2 phone outputs and a volume knob. i would just be using one digital input (hackintosh) and 2 analogue outputs (headphones and powered speakers). is there something simpler that would suit me better? maybe the gamma1? but seems too limited.

Most people buy the gamma in kit form and solder it together themselves. There is a guy from the DIY Audio forum who sells them all built and tested.

In the plans there are lists of specific parts to order from Mouser or Digikey or wherever. If you want to modify the output stage to drive headphones you just order a different pair of caps from what is in the default plan - it's all in the instructions.

The gamma 1 is just the old version of the DAC. It's not really any simpler than the gamma 2, people just came up with improvements by trying different components and modifying the circuits. Also a couple of improved ICs have come out since them which is normal.

There's one small company that makes audiophile PCI soundcards which are lightyears better than the commercial ones from Creative and M audio but it sells for around 1k. I think I spent maybe 75 bucks on all the parts, PCBs and the custom faceplates for my gamma. There are other "homebuilt" DACs for sale on eBay which are cheaper and all ready built / ready to go if you don't mind waiting for shipping from Taiwan / Hong Kong.

 

[ne0shell]

I've been into DIY audio and video gear in addition to my computer building hobby for quite a while but the issues with OSX clones and audio drivers really got me twisted.

I'd like to take the gamma DAC or another affordable / high quality design and modify it so it goes into a PCI slot for power and maybe digital audio I/O (though using the mobo pin headers sounds easier to be honest). If I could get my hands on a PCI slot spec to know where to connect for the power and all that I could connect up the input and output jacks and mount them in the back or maybe just run the wires from existing jacks (if the case supports / has them).

I'll keep tinkering with it and if I come up with a design I'll build and post it here, maybe come up with a group buy for the PCBs if anyone else wants one. I do like having the power stage separate from the PC w/ the only connection between them being digital though. It should make the sound much, much cleaner. With a decent mobo like these Gigabytes with the 3x copper traces and a quality power supply the noise issue should be manageable though.

 

[rich]

thanks for the reply.

im wanting to get an external DAC so it inhibits electric noise from the PC being outside the case and inside its own aluminium case.

 

[ne0shell]

thanks for the reply.

im wanting to get an external DAC so it inhibits electric noise from the PC being outside the case and inside its own aluminium case.

The noise thing is completely manageable. I'm talking to one of the original designers of the gamma2 right now about partnering up with me on a project. I think the time has come for someone to provide open source audio components with audiophile quality and "driverless" configuration so they'll work the same no matter what OS is used.

There really isn't much out there in the way of truly decent audio cards right now. Creative is extremely proprietary and nerfs OS support to force users to upgrade, M Audio and others use really crappy components and poor digital sampling / signal processing.

Imagine a truly open source component the community can improve on with hardware and software modifications....

We're looking at a PCI slot version as well as a drive bay unit. They would be powered via molex or PCI bus and also have an external power input for situations where noise might be an issue. The design of these is very noise proof as is though - you'd have to use one incredibly cheap power supply in the PC for it to be an issue.

Anyway, updates as they come. This guy sells ready built gamma2's also - I'm waiting for his price list on the various configurations and will post it here when I have it.