Wharfedale W90 crossover schematic.

[saabracer23]

It seems there were a few changes to the W90. I’m rebuilding a pair and working with the crossovers at the moment. My crossovers looks to be different than any others I’ve seen.




The top photo is one I’ve stolen from the net and the bottom is my own. As you can see in the top photo, the single positive wire goes to the middle tap of the inductor which is wired into the mid and tweeter caps. In mine, the single positive wire goes to the outside tap and the positive feeding true mid and tweeter cap are then coming from the center tap.

That means on mine the entire speaker circuit must go through that first bit of inductance. I looked into this because the tweeter don’t should all that “airy”. They seem to have the top end rolled off.

I hope I’m explaining this well, if not please let me know. Here is a very crude drawing of the beginning of the circuit. I left out the pots/L-pads and not sure how to draw an inductor with 3 taps.



As you can see, the positive goes straight into the inductor first and then feeds the driver’s circuits.

Thoughts? Is this a normal circuit? It all looks to be stock solder joints except for where I replaced the caps.

Dan

 

[bigaltx24]

Here's a good place to start.

https://www.audiokarma.org/forums/index.php?threads/anatomy-of-the-wharfedale-w90.270394/

Also look at Gang Twanger's other threads, he's the W90 expert around here. I haven't seen him posting much lately though. One thing to realize about Wharfedales is that any documentation is hard to find. The factory burned down at some point and they lost all their records. Also it depends on if they are from the factory in England or from Hong Kong (Radio People). There can be differences between them.

 

[saabracer23]

Here's a good place to start.

https://www.audiokarma.org/forums/index.php?threads/anatomy-of-the-wharfedale-w90.270394/

Also look at Gang Twanger's other threads, he's the W90 expert around here. I haven't seen him posting much lately though. One thing to realize about Wharfedales is that any documentation is hard to find. The factory burned down at some point and they lost all their records. Also it depends on if they are from the factory in England or from Hong Kong (Radio People). There can be differences between them.

Thank you much, according to his profile page it looks like his last activity was Oct 1st 2016, so I doubt we’ll hear from him on this thread.

I measured the inductance of that first portion of the coil and it’s .296 mH. Now depending on the actual impedance that it’s seeing, that should be rolling off fairly low. If the tweeters (two wired in parallel) have a nominal impedance of 4 ohms then that means it’s rolling off at about 2200hz. In this case I think it would be rolling off first order so it would be down 6bd at 4400hz, and 12db at 8800hz.

Am I thinking wrong? I just don’t understand why they would do this.

Dan

 

[telejunky]

Thank you much, according to his profile page it looks like his last activity was Oct 1st 2016, so I doubt we’ll hear from him on this thread.

I measured the inductance of that first portion of the coil and it’s .296 mH. Now depending on the actual impedance that it’s seeing, that should be rolling off fairly low. If the tweeters (two wired in parallel) have a nominal impedance of 4 ohms then that means it’s rolling off at about 2200hz. In this case I think it would be rolling off first order so it would be down 6bd at 4400hz, and 12db at 8800hz.

Am I thinking wrong? I just don’t understand why they would do this.

Dan

Hi Dan

The W90 tweeters are 15 ohm. Use that number in the crossover calculation and see where they cross.

 

[R Keiffer]

I'm not sure where these wires connect