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Poor Man's Surround Headphones - Make surround headphones from a pair of
circumaural headphones and earbuds. The author uses these headphones with the SB Live
PC soundcard, but they will also work with any 4-channel surround recording. "The
surround effect is excellent.... You can tell back from front easily." Designed by
Steve Connors (Circuit design added 01/08) |
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Portable E-field Receiver - Here is a tiny receiver built into an Altoids tin
suitable for use with a laptop computer or portable tape recorder. The prototype
antenna is only 1 foot long when fully extended and the receiver fits into a shirt
pocket.... (electronic design added (6/07) |
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Portable Headphone Amp - Another contributed circuit, this is a complete portable
headphone amp that features crossfeed. (schematic added 6/07) |
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Portable Headphone Amplifier - 3V Battery powered High Performance unit (added
9/04) |
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Pre Distortion Techniques - Tape Linearizer and a Distortion Analyzer (added
4/02) |
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Precision Audio MilliVoltmeter - Measures10mV to50Volt RMS in eight ranges Simply
connect to your Avo-meter set @50µA range (added 9/04) |
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Projector - Intersil Application Block Diagram (app note added 6/06)
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Rctheremin Circuit - (schematic / Circuit design added 9/02) |
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Reader's Xover - This is well worth reading if you can't decide on biamping
(added 6/07) |
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Removing the DC Thump from Audio Circuits - You may be familiar with this effect.
You switch audio equipment such as an amplifier to a different input and there is a
loud click or "thump" in the speaker system. Not all equipment is affected. Some high
end audio systems never suffer, but intercoms switching systems are often
affected....(schematic / Circuit designed by Andy Collison added 9/02) |
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Revisiting Koss "The Plug" Headphones - Koss' The Plugs are inexpensive
canal-type headphones that suffer from a "peaky" frequency response, weak acoustic
isolation and a lightweight sound due to inadequate acoustic damping and poor ear
cushion design. The author describes a series of modifications for The Plugs that
allow this product to reach its full potential.... Designed by Chu Moy (Circuit
design added 01/08) |
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Room Noise Detector - One LED monitors three levels: 50, 70 & 85 dB. Useful to
detect too noisy environments. (electronic circuit added 06/07/08) |
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Satellite Radio - Intersil Application Block Diagram (app note added 6/06)
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Satellite Set-Top Box NTSC/ PAL - Intersil Application Block Diagram (app note
added 6/06) |
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Scanmate Audio Activated Recorded - Add this easy project to your regular scanner
or DX'ing apparatus and never miss action again. Or use this system to check a range
of frequencies for band activity when you're not there. I use it to check a range of
'secret' frequencies overnight when I'm sleeping. Works for me.... [Tony van Roon's
circuit] |
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Sound Detector - (electronic circuit added 7/03) |
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Sound Operated Switch - This sensitive sound operated switch can be used with a
dynamic microphone insert as above, or be used with an electret (ECM) m`icrophone. If
an ECM is used then R1 (shown dotted) will need to be included. A suitable value would
be between 2.2k and 10kohms. The two BC109C transitors form an audio preamp, the gain
of.... [Andy Collison] |
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Spatial Distortion Reduction Headphone Amp - (circuit / schematic design added
6/06) |
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Speaker Box Audio Amp - ….(design added 08/08) [Site is underconstruction right
now] |
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Speaker Measurement Set - Based on work done by Siegfried Linkwitz (reproduced
with his permission) (added 6/07) |
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Speaker Microphone Circuit - This circuit takes an ordinary loudspeaker and
allows it to be used in reverse, as a microphone…. [Andy Collison] |
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Speaker Protector - (circuit added 7/02) |
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Speaker Signals to Line Level Inputs - (electronic schematic added 8/02)
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Spyder an Eight Output Pedalboard Power Supply - Outputs regulated 9V DC (added
4/02) |
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Stereo BroADCast Limiter - Circuit for the Ramsey FM10a/FM25 Transmitter (added
4/02) |
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Stereo LED VU meter using discrete components BC547 transistors - (diagram added
2/07) |
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Stereo Width Controllers - 2 to choose from. Expand or contract the stereo sound
stage(electronic circuit added 7/03) |
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Subwoofer Equaliser - The Linkwitz transform circuit is a hugely flexible way to
equalize the bottom end of a sealed loudspeaker enclosure. A speaker that is corrected
using this method is flat from below resonance to the upper limit of the selected
driver. The low frequency roll off point is determined by the parameters of the
transform circuit....(added 4/02) |
