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merging headphones output to 1 speaker
merging headphones output to 1 speaker
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Old 22nd August 2012, 12:17 AM   #1
viewgsm is offline viewgsm  United States
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Question merging headphones output to 1 speaker


I have an output from a chip that drive headphones
PO: 13 mW (RL = 32 Ω)
PO: 25 mW (RL = 16 Ω)
I need to drive a single 8ohm speaker (.25w) instead of the headphones,
both channels share GND on the chip, can I just connect L to R and and feed that to the speaker (with GND to the other side of the speaker)

will I get double that output ?

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Old 23rd August 2012, 02:40 AM   #2
PeteMcK is offline PeteMcK
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maybe, but it's more likely that you'll get smoke & a dead amp...
Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency
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Old 23rd August 2012, 03:09 AM   #3
Kindhornman is offline Kindhornman  United States
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merging headphones output to 1 speaker
I think what you want to try is one output on each side of your speaker. I can't say this for sure but if you tie the two outputs together I think that you will smoke the chip amp. I think that most headphone amps are made to drive 600 ohm loads, at least that is what I remember. Leave the ground wire out of the loop.
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Old 23rd August 2012, 05:07 AM   #4
gmphadte is offline gmphadte  India
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25 mW will not drive any speaker to listening level.

Gajanan Phadte
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Old 23rd August 2012, 06:32 AM   #5
sofaspud is offline sofaspud  United States
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You'd be much better off using a conventional two-resistor summing circuit feeding a LM386.
It is error only, and not truth, that shrinks from enquiry. - Thomas Paine
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Old 24th August 2012, 01:51 AM   #6
Ron E is offline Ron E  United States
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Originally Posted by gmphadte View Post
25 mW will not drive any speaker to listening level.
Depends on listening level and sensitivity 10* log(.025)=-16dB, so it will drive a Klipschorn to 87dB peaks, and a typical home speaker to ~70dB peaks

Running an output to each speaker terminal will give a L-R or R-L signal.

A summing circuit to a small amp is the right answer.
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