Hi!
I'm having a strange issue with davis acoustics 3-way speakers made in France. They're not mine and came to me with 2 blown mid drivers (I think they are 17KLV6A). I sent them to davis acoustics for repair because I don't have the voice coils for these speakers. In the end they changed everything (spider, coil, kevlar cone and suspension) on both and they worked perfectly for about three months but now one is back, again with a blown mid driver (voice coil is open). The amp is a Vincent SV-233 that works perfectly, the volume stayed below 1W of output and there was no noise prior to the failing, both woofer and tweeter are fine. I've heard from someone with the same problem that Davis recommended placing a cap in parallel with the driver to solve this but he sold the speakers and doesn't remember what the value was. When I contacted Davis Acoustics they had no trace of this and could not tell me anything more. Here's a basic drawing of the crossover (I measured the inductor with a simple component tester so I don't know how close this is to the actual value). All other component measure within 5% of their announced value with 0.5% voltage loss on the electrolytic (47µF and 0.1% on the film cap (6.8µF) and very low esr. Does this filter seem adequate and would there be some kind of mod that could protect these drivers without altering the frequency response ?
I'm having a strange issue with davis acoustics 3-way speakers made in France. They're not mine and came to me with 2 blown mid drivers (I think they are 17KLV6A). I sent them to davis acoustics for repair because I don't have the voice coils for these speakers. In the end they changed everything (spider, coil, kevlar cone and suspension) on both and they worked perfectly for about three months but now one is back, again with a blown mid driver (voice coil is open). The amp is a Vincent SV-233 that works perfectly, the volume stayed below 1W of output and there was no noise prior to the failing, both woofer and tweeter are fine. I've heard from someone with the same problem that Davis recommended placing a cap in parallel with the driver to solve this but he sold the speakers and doesn't remember what the value was. When I contacted Davis Acoustics they had no trace of this and could not tell me anything more. Here's a basic drawing of the crossover (I measured the inductor with a simple component tester so I don't know how close this is to the actual value). All other component measure within 5% of their announced value with 0.5% voltage loss on the electrolytic (47µF and 0.1% on the film cap (6.8µF) and very low esr. Does this filter seem adequate and would there be some kind of mod that could protect these drivers without altering the frequency response ?
Last edited by a moderator:
Perhaps the voice coils are wound in alumimum and the soldering to terminals failed. 1W can't blown such a speaker.
That is why I don't understand what's going on, the wires from the filter are connected to the speaker with connectors so no soldering was involved.
I mean internal soldering from voice coil to elastic wires that carry signal into it. If the speaker only stop jobing, it may be a fake soldering.
The ends of the voice coil extend outward on the edge of the cone and are soldered directly to the braided copper wires connected to the terminals, I measured right at the ends of the voice coils and got nothing. As there is at least one other person that had issues with these speakers repeatedly blowing the mid drivers I really suspect something else is wrong.
Indeed, I knew that already 😛, my question is, they shouldn't be because they had been rebuilt only a few month ago, so what can cause this and is there something that can be done about it ?
Difficult to say. But, again, if you only use a couple of watts and considering the (small) looses in the L of the filter, no reason for blown.
I had a similar problem with the motor of my clothes washer. Once it refused to start. Thus dissasemble the control panel, and the motor was open, both windings. Dissasembed the motor, surprise: wound with aluminum wire. The junction between two coils (fwd and rev) was overheated as a poor contact. Cut last cm of wire and re-did the join. No more issues. Until now 🙄 .
I had a similar problem with the motor of my clothes washer. Once it refused to start. Thus dissasemble the control panel, and the motor was open, both windings. Dissasembed the motor, surprise: wound with aluminum wire. The junction between two coils (fwd and rev) was overheated as a poor contact. Cut last cm of wire and re-did the join. No more issues. Until now 🙄 .
I sent the speaker back to davis because it was still under warranty from the last repair. I'll see what they say and ask them for a picture of the actual coil itself.
how does measure the 47 uF lythic cap ? That is a very old kit. Time to change this cap perhaps also if the capacitance value has increased and put the high pass lower ? Check if this cap is not shorted too.
As mentioned before the cap tests perfectly (48.2µF 0.5% voltage loss and 0.8ohm esr). Davis acoustics just answered that the voice coil definitely got hot.
ah missed that. Well this kit is from the father of the actual ceo, so he (the son) should be able to answer to your problem, they were hundred of those kits sold in France.
What do you mean by kit ? these weren't sold as kits ? I'm in contact with the techs at davis that repaired the driver the first time and now have it again, they say that apart from just playing it too loud they don't know what could have caused this... and don't know of any modification suggested by them in the past.
Sure seems like a lot of trouble.
Why not just try another driver? Hard to source? I don’t mean to be rude, I’m sure you’ve considered that already
Why not just try another driver? Hard to source? I don’t mean to be rude, I’m sure you’ve considered that already
I'd like to keep these original ! I'm really not a fan of just swapping a driver for another even if characteristics are close. There's a good chance I would have to adjust the crossover anyway by doing this.
So if not the Kristel kit, what's the name of this loudspeaker, they made (still?) kits but also ready made loudspeakers as well for the local market indeed. I believed it was the famous high end Kristel kit that had this mid driver iirc and was famous at that days. https://davis-acoustics.com/kits/
Ask the tech to check the filter shematic as well, sometimes there are mounting error in plants...
Good Luck
Edit : just saw the thread : So the Cesar loudspeaker it is... not their worse.
Ask the tech to check the filter shematic as well, sometimes there are mounting error in plants...
Good Luck
Edit : just saw the thread : So the Cesar loudspeaker it is... not their worse.
Last edited:
