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Headphone Listening Improver - The 'Super Stereo' effect of headphone
listening is undoubtedly part of the experience for many of us, and adds to the
listening enjoyment when listening is all we are doing. But when you just want
background music to accompany, say the reading of a book, then the 'in your face' (or
more accurately 'in your head') nature of full stereo is an unwanted
distraction.…(electronic design add 6/07) |
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Headphone Monitor Amp - (circuit / schematic added 6/03) |
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Hi-End Transformer-Coupled Headphone Amplifier With Digital Input - A
2-stage transformer-coupled tube headphone amplifier with a DAC front-end. The
amplifier can drive headphones of 300, 600 ohms impedance. The DAC is from a Crystal
Semiconductor CS4390 evaluation board.... Designed by Andrea Ciuffoli (Circuit
design added 04/05/06) |
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Hi-Fi Headphone Amp - The intention is to permanently insert the headphone
amp between pre and power amps, although it can be used as a stand-alone item. The
input relay is operated by auxiliary contacts on the headphone sockets through a
transistor driver (with a small delay) so as to mute the power amp input when
listening on headphones. (diagram added 6/03) |
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Hi-Fi Headphone Amplifier - Can be directly connected to CD players, tuners
and tape recorders. * Tested with several headphone models of different impedance: 32,
100, 245, 300, 600 & 2000 Ohm. * Old 8 Ohm impedance headphones can be also driven,
but these obsolete devices are not recommended. * Schematic shows left channel and
power supply (common to both channels). * Numbers in parentheses show IC1 right
channel pin connections. * A correct grounding is very important to eliminate hum and
ground loops. Connect to the same point the ground sides of J1, P1, C2, C3 & C4. Then
connect separately the input and output grounds to the power supply ground.
….(electronic schematic added 11/08) |
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Hi-Fi Headphone Amplifier (Richard Crowley) - This design for a headphone
amplifier arose after the purchase of commercial equipment with separate pre and power
amplifiers without a headphone output….(electronic design added 02/03/04) |
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Hi-Fi PC Speaker System - Standard LED VU meter, includes simple rectifier
circuit for full wave detection (electronic circuit added 4/05) |
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HiFi Preamp - The PGA2310 is a pretty neat chip. It's capable of attenuating
a stereo source over a 127dB range (-95.5dB to +31.5dB) with 0.5dB steps. It has a
maximum gain error of +/-0.05dB, and THD of 0.0004% at 1KHzS....(circuit added
04/05/06) |
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Hi-Fi USB Audio DAC - Regulator:This board supplies DAC board with +/- 15V
for analog section. MUR860 in rectifier bridge, LM317 and Lm337 as regulator IC's and
BG-STD at the output. LM317, LM337 power supply PCM2702: A little modified version
of....(circuit added 07/07/07) |
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Hi-Fi USB Audio DAC with PCM2702 - The heart of this circuit is low-cost
16-bit Philips DAC. As a SPDIF decoder was chosen Cirrus Logic CS8412 IC with SN75179
as an input driver....(circuit added 07/07/07) |
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High-End Audio Volume Control Attenuator with IR Control - The circuit
provides both audio volume and input channel selection. A stepwise volume control is
implemented with a set of small relays and resistors. In a high-end audio system, a
noticable sound improvement over potentiomeneters can be obtained, also over 'audio
grade' potentiometers. Clearly, the IR remote control provides convenience over
solutions with stepped attenuator rotary switches. The sealed relays will maintain
contact quality over a practically endless lifetime. ….(Circuit design added 11/08)
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