WD25a standard tweeter Crossover modification.

[Cobblers]

Originally Posted by Brian

When I was using the WD25A's I heard no difference at all between bi-wired and single wired.

I also changed from one type of cable to another (heavy gauge multi strand to a flat cable with a handful of seperated cores) even then it was subtle.
I would say tonally it was indistinguishable, but the sound opened up slightly.

The difference was tiny compared to the resistor change from 0.47 to 0.68 ohm. This I feel is very worthwhile and made a comfortable improvement. However for many this would be subtle too.

[Brian]

Originally Posted by Cobblers

I also changed from one type of cable to another (heavy gauge multi strand to a flat cable with a handful of seperated cores) even then it was subtle.
I would say tonally it was indistinguishable, but the sound opened up slightly.

The difference was tiny compared to the resistor change from 0.47 to 0.68 ohm. This I feel is very worthwhile and made a comfortable improvement. However for many this would be subtle too.

I added a resistor of around .68ohm in the HF section in an attempt to knock it back a little. It didn't make any significant difference that I could hear.

Brian

[naimart]

Originally Posted by Brian

I added a resistor of around .68ohm in the HF section in an attempt to knock it back a little. It didn't make any significant difference that I could hear.

Brian

We will always have different views on changes etc. etc. but was this with the STD version or the XL?

Thanks to Cobblers! (I do really mean thanks) I have ordered new parts to build another Xover - but because I didn't get on with the STD Stage 4 Xover - it will be the original STD Stage 3 version - a different factor again, then I have to introduce the Solens to replace the alcaps, then there is the external location, then there is the element of adding extra cable in the chain ... does anyone know if Ross Brawn is free

Regards
Robert

[Brian]

Originally Posted by naimart

We will always have different views on changes etc. etc. but was this with the STD version or the XL?

Thanks to Cobblers! (I do really mean thanks) I have ordered new parts to build another Xover - but because I didn't get on with the STD Stage 4 Xover - it will be the original STD Stage 3 version - a different factor again, then I have to introduce the Solens to replace the alcaps, then there is the external location, then there is the element of adding extra cable in the chain ... does anyone know if Ross Brawn is free

Regards
Robert

XL

[Cobblers]

Thanks Naimart,
I haven't done anything original, everything had been suggested before elsewhere. the 0.68 ohm resistor change/mod is outlined in the last part of the standard tweeter article for tuning to taste.

Petercom has acknowledged that the XL tweeter version was a little sharp sounding and has very recently modded the crossover for the XL version.
The standard tweeter was deemed smooth in the lower treble.

Changing to 0.68 resistor smoothens the sound getting rid of the slight edginess to lower treble acknowledged in the stage 4 crossover.

Changing to the polypropylene 50uf Solen and external mounting the crossover brought further refinement and a cleaner, more detailed and spacious presentation. Obviously this high value polypropylene and external mounting would have made the original kit too expensive (the Soniqs cap's are very much more expensive than the Solens for this value).

Petercom had stated electrolytics add a warm colouration to the sound (where Polyprop's make the sound cleaner) this is probably welcome with the original relatively exposed (though high quality) treble and in combination with the tight, articulate bass.

I can see a lot of people prefer the cuddly plummy looser and generally less defined bass of reflex designs, but if you want to hear what is going on in the bass in a smaller room WD25a is incredibly good.

At the time I gambled on WD25a I was looking for a valve friendly decent closed box design with an 8 inch doped paper cone. I often prefer closed box bass control to ported designs, especially with tube gear (I don't need loudness).
Obviously I am glad to have found them, I couldn't say I prefer these or the first generation LV Auditoriums, they are that good.

[Joel]

Hello Cobblers,
I have a WD25T v2. Please tell me if the R5 and R6 are reversed compared to the above photos. According to the instructions I received, the resistor closest to the card edge is
2R7. Your photo shows R47. Please let me know which is correct.

[Joel]

Hello Cobblers,
I have a WD25T v2 STD tweeter. According to the instructions, the resistor closest to the card edge is 2R7. Your photo shows R47. Please let me know which is correct position. I may have my resistors reversed.

[Cobblers]

I have answered this for you in a reply to your PM.

[Cobblers]

This should help. Just follow the circuit diagram for component order.

if your resistors are in different positions then they should still be wired in the correct order, which can be ascertained by looking at the bottom of the board and comparing to this circuit diagram.


This is the final crossover for the WD25 speaker (when using the Seas prestige type tweeter) which World Designs refers to as "standard".

WD25 standard tweeter final crossover.JPG