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I have a pair of speakers from a Kenwood DG55.

Here's the commercial for it from Japan, circa 1989:

It's an ancient system, and the components are not long for this earth, but the speakers are still in great shape. I want to buy a replacement amp instead of ditching everything. The speakers have the following written on them:

Maximum input power: 90W

Frequency Response: 40Hz - 20kHz

Impedance: 6ohms

I was thinking about this amp:

But I heard that if you mismatch the amp with the speakers, it might not work, or worse yet, you could damage one or the other. I really don't want that to happen. How can I be sure that this amp won't fry the speakers, or vice versa?


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migrated from Jan 27 '14 at 15:03

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The key figure is the impedance - if this doesn't match the impedance the amp expects then you can damage the amp or speakers, so you either need an amp that can supply 6 ohm speakers or you need to alter the speaker impedance (4 or 8 ohm are more common so you may need to use an impedance matcher here)

Once you have that sorted, don't try and use to much power. It is always safest to have an amp with a lower power output than the speakers are rated for.

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Thanks for your response! The Amazon page has this footnote: 75 watts per channel (20Hz-20kHz, 8 ohms, .08% THD), 120 watts per channel (1kHz, 6 ohms) It says that it's 8ohms at 75 watts or 6ohms at 120 watts. Does this mean that I'm clear, or I should look for something that only does 6ohms? – StormShadow Jun 10 '12 at 12:18
Thus should be fine then, just remember that the amp will be able to provide 120 watts, and the speakers are rated for 90 watts. – Rory Alsop Jun 10 '12 at 19:16
That's great news. Just to be clear, you're saying that I need to be careful with the volume, right? Anything over 75% volume will damage the speakers? – StormShadow Jun 12 '12 at 4:44
It generally isn't quite as cut and dried as that, as some speakers cope with high peaks better, and some handle continuous high power, but that would be a good rule of thumb, yes. – Rory Alsop Jun 12 '12 at 7:43
Excellent. THANK YOU DOCTOR MAYHEM! – StormShadow Jun 13 '12 at 9:12

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