Help with Sonus Faber Extrema issue
Maybe OP should disconnect the jumper and test the treble section and mid/woofer section separately Agreed but first maybe the op wcheng2 OP should let us know, What’s actually happening, is there nothing from the tweeter or nothing from the mid-bass Cheers George |
George, From the Stereophile review:
Maybe OP should disconnect the jumper and test the treble section and mid/woofer section separately. |
(mine came from Stereophile, your doesn’t say, except diy)
Which ever xover it has, the OP has to say to us. What’s actually happening, is there nothing from the tweeter or nothing from the mid-bassOnly then can this problem be sorted before dismantling the speaker. https://www.hifisentralen.no/forumet/attachments/diy-og-utvikling-ha-yttalere-forsterkere-etc/228418... If it does have this xover then the mid/bass unit should be what the voice coil is of that driver my guess around 4ohms). And the tweeter should be around 7.5ohms (because of the 2 x paralleled 15ohm series resistors and the almost short of the inductor) Cheers George |
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The tweeter pair should measure open circuit because of the cap in series .George, Extrema treble section has no series capacitor but a inductor connected in parallel with the tweeter and a resistor in series to match the output of the woofer. |
wcheng2, You need a volt /ohm meter. You can get one cheap. https://www.amazon.com/AstroAI-Digital-Multimeter-Voltage-Tester/dp/B01ISAMUA6/ref=sr_1_4?crid=25A5L2Z8KUDEW&keywords=volt+ohm+meter&qid=1571097024&sprefix=volt+o%2Caps%2C160&sr=8-4 There is a short in that speaker. Again, if they are still under warranty let the dealer deal with it. If not you are on your own. You have the good speaker for comparison. Good luck, Mike |
Yes you got two sets, one for the bass and one for the tweeter. The tweeter pair should measure open circuit because of the cap in series . The bass will measure what ever the resistor is in series, (does anyone know what that is?) . https://ibb.co/BNtQdtJ One of the speakers periodically will exhibit significantly lower volume (down to almost no volume) in the middle of a listening session.BTW: you haven’t said what’s actually happening, is there nothing from the tweeter or nothing from the mid-bass or very little from the tweeter or very little from the mid-bass Cheers George |
I hear you, George, but it happens with two amps. I guess the way to be certain is to repeat the failure mode, turn off both amps and immediately measure the resistance across both speaker's terminals and compare. If one is way higher than the other then it's the resistor. If both are the same it's something else. (The only other thing to check is to swap cables at the speaker terminals instead of the amps to rule out a flaky cable connection). |
I agree with the crossover problem. There is a power resistor in series with the tweeter. If it is failing, the resistance rises with temperature and the signal voltage is converted to heat instead of music.It wouldn’t cause this explanation, just muted high frequencies, he would still have all the bass and midrange. " will exhibit significantly lower volume (down to almost no volume)" Try another amp first, as these Extremas are put together like a Swiss watch, it would be a shame to break/damage all the seals to find out they’re fine. Cheers George |
I agree with the crossover problem. There is a power resistor in series with the tweeter. If it is failing, the resistance rises with temperature and the signal voltage is converted to heat instead of music. Explains why it's only one speaker, happens after it running and returning to normal when cool. |
Awesome combination btw, JC1’s and Extremas, best Esotar dynamic tweeter with the high bias setting on the JC1 should sound absolutely maaaaaaaagic!!! Hope it’s not the speaker. See if you can try another amp, before pulling the speakers apart. There is nothing to the xover to really do what your saying, the inductor across the mid/bass unit either works or doesn’t the resistor the same, can’t really go semi faulty, and the cap on the tweeter would knock out the highs if open. http://www.stereophile.com/images/archivesart/sfefigB.jpg Cheers George |
wcheng, it might be the speaker tripping the amps overheat safety shut off. Disconnect the speaker cables from the speakers and check the resistance of each speaker with a meter. They should be very close to the same. In order to trip the amp the speaker's impedance would have to go below 2 ohms. A short anywhere in the speaker could do this and you should be able to see it with a meter. If that speaker reads low then check each driver independently then the cross over. If they are still under warranty let the dealer deal with it. |
Winston, the amp could still be the problem...if you are still connected to the same mono bloc..If not, then I would definitely suspect the x-over. Probably one of the x-over parts is getting hot and is therefore acting up. Once it cools, you are temporarily ok. The age factor that you mention is the culprit. BTW, thought you had sold the SF's...great speaker BTW! |
