External Speakers ohm

Kingmobileaudio

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#1
I pick up two speakers from a local Kenwood dealer "kenwood kes-3 4ohm" for my TM-v71.

I just started looking in the manual and came across External Speakers pag.7

It says
"If you plan to use external speakers, choose speakers with an impedance of 8 ohm.

They recommend using Kenwood SP-50b

Will these speakers damage my radio? Or will they work fine?


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KF5EYR

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#2
They will work. But, the 4 ohm speakers will allow more current to flow from your radio. More current means more heat. If you think your radio will dissipate the heat, and not overheat; you should be fine. As long as you listen at a moderate volume, I don't think it will be a problem. I have 2 Polk speakers hooked to an Icom 2200H. Never had a problem. I don't really that you will.
 

Kingmobileaudio

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#3
They will work. But, the 4 ohm speakers will allow more current to flow from your radio. More current means more heat. If you think your radio will dissipate the heat, and not overheat; you should be fine. As long as you listen at a moderate volume, I don't think it will be a problem. I have 2 Polk speakers hooked to an Icom 2200H. Never had a problem. I don't really that you will.
Thank you! Better safe then sorry!


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N5MAJ

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#5
Sorry to resurrect a five-year-old thread, but I found this post because I want to drive a single Kenwood KES-5 external speaker with a Kenwood TM-V71A, and I'm also concerned about the impedance mismatch between the 8Ω transceiver and the 4Ω speaker.

I'm curious if the original poster proceeded with using the speakers with the transceiver, and if there were ever any issues.
 

Kingmobileaudio

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#6
Sorry to resurrect a five-year-old thread, but I found this post because I want to drive a single Kenwood KES-5 external speaker with a Kenwood TM-V71A, and I'm also concerned about the impedance mismatch between the 8Ω transceiver and the 4Ω speaker.

I'm curious if the original poster proceeded with using the speakers with the transceiver, and if there were ever any issues.


Didn’t really have an issue with it working.
I did not like that they where not loud enough for my install. But that’s due to how small they are


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N5MAJ

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#7
Just for the record, I emailed Kenwood, and almost immediately received a reply back from someone in their amateur radio technical support group. He wrote, "The Kenwood KES-5 speaker will work fine with the TM-V71A. No need to look for anything else."

I thought I'd share that in case anyone else stumbles onto this thread with the same question.

73, N5MAJ
 
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#9
Right from the Kenwood service manual spec sheet:

Low frequency output (8Ω) More than 2W (at 5% distortion).

A lower impedance speaker like 4 ohms will work with the audio amplifier in the TM V71/ 710 radios with some loss at lower audio frequencies due to the coupling capacitor in the audio amp output, 330uF. The audio IC is IC801 a LA4629 and spec'ed at:

PO(2) VCC = 12 V, RL = 4 ohm THD = 10 % 4.0 W
 
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#10
Also, the lower impedance speaker will be louder than the higher one. For years, Motorola sold radios with 8 ohm speakers. But for only $79 extra, you could get a "higher output " speaker for use in noisy environments. It was the exact same speaker, but it was 3 ohms instead of 8. A quick $79 profit for something that cost them nothing extra. And yes, it was substantially louder.
 
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#11
Also, the lower impedance speaker will be louder than the higher one. For years, Motorola sold radios with 8 ohm speakers. But for only $79 extra, you could get a "higher output " speaker for use in noisy environments. It was the exact same speaker, but it was 3 ohms instead of 8. A quick $79 profit for something that cost them nothing extra. And yes, it was substantially louder.
They still do that...7.5W speaker comes standard with most APX radios and the 15W version can be ordered as an option.
 
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