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Old 27th August 2009, 07:50 AM   #1
pcomliu is offline pcomliu  China
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Default My Portable Wireless Headphone Amplifier & DAC

My design, using 2.4GHz digital AUDIO wireless modules, the working distance of 328 feet, 3 Li-ion battery. And converted into a negative 12V. JFET + MOSFET amplifier. DAC with WM8740. Test results:
1.THD at 5 V peak: 0.005%(300ohm load 1kHz)
2.S/N : >86dB

Pls comment, thank !
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File Type: jpg TX_PCB1.jpg (177.3 KB, 649 views)
File Type: jpg RX_PCB_TOP1.jpg (174.5 KB, 596 views)
File Type: jpg RX_PCB_BOM1.jpg (185.1 KB, 566 views)
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Old 28th August 2009, 03:53 AM   #2
star882 is offline star882  United States
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Use 900MHz instead. Don't have it compete for bandwidth with 802.11 devices.
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"Fully on MOSFET = closed switch, Fully off MOSFET = open switch, Half on MOSFET = poor imitation of Tiffany Yep." - also applies to IGBTs!
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Old 28th August 2009, 09:49 AM   #3
pcomliu is offline pcomliu  China
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Quote:
Originally Posted by star882 View Post
Use 900MHz instead. Don't have it compete for bandwidth with 802.11 devices.
Yes, However, this RF module is purchased. in 2006, I designed 915MHz, working distance of approximately 100 feet.
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Old 28th August 2009, 09:53 AM   #4
pcomliu is offline pcomliu  China
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Yes, However, this RF module is purchased in 2006, I designed 915MHz, working distance of approximately 100 feet
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Old 28th August 2009, 10:20 AM   #5
pcomliu is offline pcomliu  China
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100 feet away from the satisfaction of you (customer) requirements?
Sorry,I am poor English skills .
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Old 29th August 2009, 08:42 AM   #6
pcomliu is offline pcomliu  China
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Quote:
Originally Posted by star882 View Post
Use 900MHz instead. Don't have it compete for bandwidth with 802.11 devices.
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Old 31st August 2009, 03:54 AM   #7
pcomliu is offline pcomliu  China
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Pls See Figure:
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File Type: jpg noise.jpg (108.9 KB, 452 views)
File Type: jpg rx_top.jpg (47.0 KB, 96 views)
File Type: jpg tx_top.jpg (45.4 KB, 75 views)
File Type: jpg tx_bom.jpg (77.4 KB, 63 views)
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Old 11th October 2009, 03:13 PM   #8
jalyst is offline jalyst  Australia
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You kidding? This looks awesome!
I only wish there was more stuff flike this around, they're as rare as hens teeth.

Preferably with better quality analogue-out and a built-in DSP for remixing Dolby formats & the like (using HRTF or better) into a format that sounds realistic when outputted to stereo headphones!

The only other notable one around is that 'kleer-based' adapter from SleekAudio. But it doesn't have a DSP, it's DAC aint that special, & they lock you into their freakin headphones! Grrrr

pcomliu modify yours to do what I suggested above & I guarantee it'll sell like mad. The market's crying out for it! Don't compromise on quality and people will knock your door down!

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Use 900MHz instead. Don't have it compete for bandwidth with 802.11 devices.
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Old 11th October 2009, 03:15 PM   #9
jalyst is offline jalyst  Australia
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is this your device?
http://cgi.ebay.com.sg/ws/eBayISAPI....m=290344766900

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Pls See Figure:
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Old 11th October 2009, 05:13 PM   #10
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317USD, really? No wonder it ended without a buyer.
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