Tweeter trouble

[Phil Oliver]

I have a problem with one tweeter which cuts out with higher volume but if I turn the loudness button off and back on it returns but not for long , anyone got any ideas?
1971 nos Wharfedales unit 5 kit
Cheers

 

[crazy-in-az]

Do the speakers have fuses to protect the tweeter from overload? I'd check those first. If they are okay, remove the tweeter and use a multimeter to check for continuity.

 

[WaynerN]

First, you shouldn't be using a loudness button at higher volumes. This button produces the Fletcher-Monson curve that compensates for the ear's lack of sensitivity to bass at low volumes. At higher volumes, it is not required.

I believe that your tweeter's problem could be from several causes. I would not think that the voice coil is warped due to that fact that it works, even if it is at lower volumes. Does the speaker have a level control for the tweeter?

 

[F1nut]

I agree with WaynerN, do not use the loudness button at higher volume levels.

It is possible your speakers use a polyswitch (thermal reset device) to protect the tweeters. They become hypersensitive after being tripped too many times. The solution is either replace with like/kind or remove and replace with a resistor of the same resistance, perhaps 0.5 ohms to maintain the same overall values. However, the resistor will not protect the tweeter.

 

[WaynerN]

Ah, good point F1, a thermal switch.......

How loud are we playing the new (old) speakers?