| soundNERD |
Hi, I have a some LM4881 chips and have built a headphone amplifier for my portable CD player. The sound is excellent, so I would like to bridge them. The problem, though, is that they only have one input. Is there any way to bridge them short of using something like a DRV134 to invert one amp's input?
thanks!
mike |
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| Alexander Rice |
| just stick an inverting buffer before one of the amplifiers |
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| soundNERD |
like the DRV134 right? that takes one signal, invertes it, balences the inverted and non-inverted inputs then has two outputs of the same signal, inverted and non-inverted.
The only problem with that is I only have one and would need two for stereo. I don't think with headphones you would notice the difference when one amp is inverted and not the other, so I could just stick an inverting opamp before the input of one of the amps, right? |
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| Alexander Rice |
| that is what i said :) - inverting buffer = inverting op amp with unity gain, any old thing'll do as long as it i unity gain stable since even TL072 will have a bandwidth well into RF, i reccomend the NE5532 for this type of thing for it's low noise and good value |
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| soundNERD |
OK!
Thanks!
-mike |
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| paulb |
| Do you plan to modify your headphone cable to separate the common connection to each channel? Bridging won't work with a 3-wire cable; you need all 4 wires. |
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| soundNERD |
yes, my cable is from a standard pair of headphones, so the connector splits into two seperate cables, one with L and gnd, and the other with R and gnd.
thanks for pointing that out though.
-mike |
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