Quad safety impedance

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11-Apr-2019 07:45 AM

richy

richy

Posts: 9

Hi. I purchased dada quad 405 boards last year and am thinking of using 4-ohm nominal impedance speakers, the minimum impedance is 2 ohms. Do you think this is safe.

Thank you

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12-Apr-2019 08:33 AM

EJP

EJP

Posts: 1617

It's safe, as the boards have current-limiters on them, but if you stray into the current-limiting area with too much volume you will experience distortion.
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19-Apr-2019 08:26 AM

richy

richy

Posts: 9

Yes, getting big distortion. I do not think the dada boards like 4 ohms impedance.
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25-Apr-2019 07:58 AM

richy

richy

Posts: 9

Hi. I am getting a loud high-frequency cracking kind of sound when i power down the amp, is there a fix or any advice on how to get rid of this.

Thanks.

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25-Apr-2019 08:42 AM

EJP

EJP

Posts: 1617

Make sure you have the 220uF capacitor across D7, or else the shunt resistor across R7 or R8, whichever it is, as described in the Revision notes.

But I think you have bigger problems. You shouldn't run into 2-ohm current limiting except at rather loud volumes.

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26-Apr-2019 08:28 AM

richy

richy

Posts: 9

Hi. Thanks for the reply.

Yes, i am getting distortion using 4 ohm speakers so have gone back to 8 ohm.

But even with 8 ohm speakers i am still getting  loud crackling high-frequency noise when powering down. Should the capacitors and resistors you mentioned all ready be installed in the dada boards or is this something i have to do myself.

Thank you.

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26-Apr-2019 09:52 AM

EJP

EJP

Posts: 1617

Sorry, I missed that bit, thought you had just done a standard revision. I think you should send them in to Stefaan for review.

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