Pieface Posted August 17, 2017 Share Posted August 17, 2017 Hi Gang I saw some interesting looking Swedish speakers in the 'tree and figured I would have a go at something quite different in philosophy to my Tannoys. The speakers are a 2 way d'appolito around a vifa xt25 tweet and i am assuming some sort of vifa/peerless 5.25" midwoofer pair. One of the speakers, the tweeter is not functioning. I pulled it out to check if it was loose wiring but that seems solid on the tweeter and at the crossover board. The tweeter is showing around 4 ohms resistance with my multimeter and the woofers are around 8 ohm which makes sense from my understanding of the speaker design. When I put the multi meter across the wires from the crossover the tweeter wires dont change from the free air reading. The woofer wires change numbers. If i play a music signal the woofer wire reading bumps around. The tweeter wires dont change at all. I didnt have time to pull the working tweeter from the other speaker to try it on the non functioning side but is it safe to assume the problem is on the crossover board at this point? I tried wiggling the wires to the tweeter but they seemed well anchored and nothing showed on the multimeter. Any suggestions from here to solve the issue? Should i go through the process of swapping the tweeters to totally eliminate the driver as the issue? Cheers Link to comment Share on other sites More sharing options...
Sub Sonic Posted August 18, 2017 Share Posted August 18, 2017 Are the speakers biwireable? If so, check the jumper between the upper and lower terminals for contact/continuity. SS Link to comment Share on other sites More sharing options...
Pieface Posted August 18, 2017 Author Share Posted August 18, 2017 9 minutes ago, Sub Sonic said: Are the speakers biwireable? If so, check the jumper between the upper and lower terminals for contact/continuity. SS These speakers are not biwireable. Only one pair of binding posts. Thanks for the suggestion though. I actually always keep an eye out on Gumtree for speakers that are going cheap and look like a missing jumper might be the issue 1 Link to comment Share on other sites More sharing options...
Nigel Posted August 18, 2017 Share Posted August 18, 2017 Putting an ohmmeter on a speaker will report on DC resistance which is close to zero. 4 or 8 ohm is an AC impedance value and not the same thing. Quickest easiest thing is to swap the tweeters, only thing to be careful of is whether there is some fault in the crossover (which I struggle to imagine) that might feed low freqs to the tweeter, which will cause it to heat up (and fail) if you put much power into it. Safe is to swap them, then bring the volume knob up from 0 to1, that will tell you whether the problem is the tweeter (problem has moved to the other speaker) or the crossover (the problem remained on the original side). Fun ! Link to comment Share on other sites More sharing options...
Pieface Posted August 18, 2017 Author Share Posted August 18, 2017 Cheers Nigel. I will swap them over the weekend and see what is what. I wasn't trying to read anything into the values from the multi-meter I was just checking that there was a circuit through the driver. Is that an erroneous assumption on my part? I understand that I could have an electrical circuit through the driver but it is broken for another reason. Any thoughts on the absence of any readings from the crossover side? Link to comment Share on other sites More sharing options...
Sub Sonic Posted August 18, 2017 Share Posted August 18, 2017 Your meter will tell you if the tweeter has continuity, but won't necessarily rule out other problems. A 6 ohm driver will probably have around 4 ohms resistance when measured with a meter, and an 8 ohm driver will usually be somewhere around 5-6 ohms. So if your tweeter is rated at 6 ohms, then 4 ohms resistance would be about right. Regards, SS Link to comment Share on other sites More sharing options...
Sub Sonic Posted August 18, 2017 Share Posted August 18, 2017 @Pieface When you are measuring the tweeter at the crossover, where exactly are you measuring it? if it is after the crossover cap, then it should read pretty much the same as the tweeter. If it is before the cap, you will measure other things such as the woofer's/crossover's resistance. The cap itself of course will not pass DC and will measure open circuit on a DC meter. Link to comment Share on other sites More sharing options...
Pieface Posted August 21, 2017 Author Share Posted August 21, 2017 Had a play. Swapped the tweeters around and pretty confident something is awry in the crossover given the results. It's outside my pay grade to muck around with PCBs and soldering so a trip to someone who knows which way is up seems in order. Looks like there are 6 doo-dads on the HF side of things so hopefully it is straight forward for someone who knows what they are doing to resolve. FX04 Crossover Schematic.pdf Link to comment Share on other sites More sharing options...
Sub Sonic Posted August 21, 2017 Share Posted August 21, 2017 Sounds like it should be an easy fix, perhaps a poor solder joint. Regards, SS 1 Link to comment Share on other sites More sharing options...
Nigel Posted August 21, 2017 Share Posted August 21, 2017 +1 likely to be a solder joint. Can't imagine a capacitor failing completely without having sounded dreadful in the lead-up. resistors and inductors don't fail. Be brave, try pulling lightly on components and the wiring... if one is loose, there's the problem. A little trickier is a "dry" solder joint which may still attach, but not conduct. That's where your meter comes in handy. 2 Link to comment Share on other sites More sharing options...
Pieface Posted August 24, 2017 Author Share Posted August 24, 2017 (edited) And a couple of dry joints in the X-over were the culprit. Should get to set things up this evening and start to see what I make of this modern skinny floorstander buzz vs my Tannoys. Edited August 24, 2017 by Pieface 1 Link to comment Share on other sites More sharing options...
Nigel Posted August 25, 2017 Share Posted August 25, 2017 Congrats on solving the problem. Good luck with everything else. Is Upper Timbuctu near Upper Cambuktity West(?) often referenced on Hey Hey ! Link to comment Share on other sites More sharing options...
Pieface Posted August 25, 2017 Author Share Posted August 25, 2017 Congrats on solving the problem. Good luck with everything else. Is Upper Timbuctu near Upper Cambuktity West(?) often referenced on Hey Hey ! Stereonet gestapo insisted i submitted a profile [emoji15] I am enjoying the speakers now. Very different presentation to my Tannoys. Interesting to compare the varying strengths and weaknesses of each approach 1 Link to comment Share on other sites More sharing options...
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