sound quality problem on whatfedale s77 speakers

[TLS Guy]

would it be easier to just get new caps? and if so by the sounding of whats wrong do you know what i would have to replace?

I have no idea of the circuit. As I said, you are there and I am here.

You can not test a cap with an ohm meter. It takes a small charge and then is infinite resistance. You can get no idea of its function from an ohm meter.

The first thing to do is to compare the good and bad crossovers.

 

[daseraces13]

A frequency generator app would help you troubleshoot. If not, you can find CDs that have individual frequency tones.

Is the issue a difference in level, sound quality or both? Are you prepared to remove crossovers? If so, you can use a multimeter to measure resistance of individual components. Measure without the driver connected. Best if you can compare to known good crossover. Good caps will usually show some varying resistance. Inductors and resistors will have fixed values. If they read zero or infinite, they are likely bad. When caps are across another component, will have to unsolder and measure each individually.

Hope this helps!

Ww

thank you for the reply, the problem is noise level and some clarity but not too major. so i can use a normal multimeter to test the caps? and i would assume i would have to remove the caps because it is on a crossover board.

 

[daseraces13]

I have no idea of the circuit. As I said, you are there and I am here.

You can not test a cap with an ohm meter. It takes a small charge and then is infinite resistance. You can get no idea of its function from an ohm meter.

The first thing to do is to compare the good and bad crossovers.

how would i go about doing that? what would the good cap put out in comparison to the bad?

 

[TLS Guy]

how would i go about doing that? what would the good cap put out in comparison to the bad?

You need to make sure the circuits and components are the same and in the same configuration.
You can NOT test a cap with a multimeter period.

 

[Winkleswizard]

Measuring the caps with an ohmmeter can only give you a rough idea of whether they are good or bad. Whether they have to be disconnected depends on what else may be in the circuit. But trying a resistance measurment can give you some idea on isolating a bad component when comparing to a known good crossover...

Simply put, inductors rarely go bad, a resistor will usually have a value within tolerance, or be open (infinite resistance). If any value wanders as you measure, it needs to be unsoldered and measured out of circuit. Process of elimination leaves the caps.

If you suspect a cap and your meter does not measure capacitance, an ohmmeter can be used for comparison as I mentioned previously. This does have caveats, but you can also swap the caps between the known good board and the bad one if nothing else seems bad.

While somewhat less likely, you may have a bad solder joint or broken PC board trace. In this case, you will need some more help with circuitry. Sometimes it will be visually obvious, but if you are removing the crossovers and have not found an obvious culprit, let me know and will give you some further guidance.

Ww

 

[daseraces13]

You need to make sure the circuits and components are the same and in the same configuration.
You can NOT test a cap with a multimeter period.

so i found my problem. there is a red *dried now* liquid that oozed out of 2 of the crossovers (im assuming thats what they are, they look like wire wound around a metal rod lol i have no idea) so those obviously need replacing. now i would send a picture but any photo is too large. so bare with me. the first says “403.36 then 1.5mH” i know the microferet reading, but whats the 403.36? the volts? or what? and what is the exact name for this type of crossover so i can find a replacement?

 

[daseraces13]

Measuring the caps with an ohmmeter can only give you a rough idea of whether they are good or bad. Whether they have to be disconnected depends on what else may be in the circuit. But trying a resistance measurment can give you some idea on isolating a bad component when comparing to a known good crossover...

Simply put, inductors rarely go bad, a resistor will usually have a value within tolerance, or be open (infinite resistance). If any value wanders as you measure, it needs to be unsoldered and measured out of circuit. Process of elimination leaves the caps.

If you suspect a cap and your meter does not measure capacitance, an ohmmeter can be used for comparison as I mentioned previously. This does have caveats, but you can also swap the caps between the known good board and the bad one if nothing else seems bad.

While somewhat less likely, you may have a bad solder joint or broken PC board trace. In this case, you will need some more help with circuitry. Sometimes it will be visually obvious, but if you are removing the crossovers and have not found an obvious culprit, let me know and will give you some further guidance.

Ww

thank you for your wonderful knowledge lol, but i found large crossovers (look as its a metal rod wound with wire) that at one point leaked a reddish liquid which im asuming means theyre shoy and i found the problem. just the confusing part is the value of one of them for example, is 403.36(doesnt specify if that reading is volts, assuming if it is) and 1.5 mH which id the microferet reading. i want to make sure i know what the 403.36 means before getting replacements..

 

[Winkleswizard]

A bit more followup for the sake of completeness...

If the inductors measure even some fractional positive resistance, they are probably fine. As long as you are pretty sure the drivers are good, replacing the caps and/or resistors on a crossover is way less expensive than buying more instrumentation to fix a single pair of vintage speakers!

You could spend a bit more and replace the inductors too, but would wait to find how the first pass refurbishment goes. If you can isolate the sound quality issue to a midrange or tweeter, those inductors tend to be much less expensive to replace than the large value ones typically used as a low pass filter on the woofer.

Ww

 

[daseraces13]

hello again everyone, ive found the actual problem to this. it was infact the inductor that was the problem in this case. i was having the problem of “missing sound” per say, and i traced it to the tweeter. i opened up the speakers and the high pass inductors looked degraded and frankly destroyed. but i replaced the crossovers first, no luck. i was lucky, having another set of the excact same speaker in good working order, so i could test to see the microhenry value (the inductor was unlabeled). good speakers measured .218 mH and bad ones measured .044. really really bad. i ordered a cheap 30 dollar lcr meter from amazon and it worked great for what i needed it for. the new .22 mH inductors are all soldered in and work great! just wish i wouldve purchased a tweeter with an aluminium horn.... oh well.

 

[Winkleswizard]

Congrats!

Hope you get to enjoy them for many years to come.

Ww