Resistors, capacitors, inductors! Im about to throw the towel in.

[Xristo]

Today i was so close to picking up my already finished cabinet and tossing it in the bin. I was also so so close to purchasing a pair of wharfedale 9.1 bookshelf speakers, but then i remembered all the hard work and money spent on my DIY bookshelf speakers.

I am trying to make my first set of bookself speakers using the classiv Vifa p17 woofer and the vifa d25ag tweeter. All i need to do is find the crossover components but that is proving near impossible to find the correct values outlined in the schematics.

This is the crossover im trying to build.



My problem is, i cannot find 10 watt 2.5ohm resistors anywhere!! do i have to use that correct value? does it matter if its higher or lower value?

Also for the aircore inductors does it have to be 1.5mm copper, because all i can find is 1.3mm or 1.63mm ? Im ready to give up with this diy stuff so any help will be appreciated. thank you

[Jean]

Make up the 2.5ohm by putting two 5ohm resistors in parallel , or anything that would make up that value. You should be fine with inductors, thicker gauge = lower DCr= little lower losses .

Don't give up

[shusha]

This is L-pad, or attenuation for yout tweeter. You can put two in parallel as Jean told you, but you can also try with diff. values. 2R7 is standard value and it should be fine.
You can also experiment with diff. values for both resistors in L-pad. The parallell one should always be the one of bigger resistance.

The specified 2R5 value 10W is hard to find. Do not forget that high power resistors always have 10-15% tollerancy. You probably wouldn't hear the difference between 2R5 and 2R7. Try with 2R2 also. The only thing that will change is amount of highs.

[DirkD]

Hi there

I found these at Madisound ( http://www.madisound.com/ )

Eagle - Metal Oxide Film Non-Inductive Resistors
5%, 10Watt, 8.5mm x 32mm, 33mm leads

1, 1.5, 2, 2.2, ###2.5###, 2.7, 3, 3.3, 3.5, 4, 4.7, 5, 5.6, 6, 6.8, 7, 8, 10, 12, 15, 20, 25, 30 $1.00 each

And these:

MADISOUND is now stocking PERFECT LAY WINDING audio inductors from Solen Engineering. These are audio grade inductors using 14 gauge wire with the following specifications:

Perfect Lay Hexagonal Winding. Winding Space Factor: 86.7%
Oxygen Content: Less than 200 parts per million on surface.
Insulation: 130 degree centigrade Single coating Nylon-Polyurethane.
Computer Optimized Coil Dimension.
Encapsulation: Varnish dip coating with 4 nylon ties.
No Saturation distortion: Test voltage 1500 VAC
No Hysteresis distortion: Test voltage 1500 VAX
Inductance tolerance: within 1% of value listed.
Conductivity: Better than 101.5% of National Electrical and Manufacturing Association (NEMA) standard sample.
Wire Diameter: .064 inches; ###1.63 mm###. High Purity Annealed Copper

1.63mm diameter wire is close enough to 1.5 not to make much difference.

Also try http://www.solen.ca/ for a good selection of parts.

Regards

Dirk

[rabbitz]

Originally posted by Xristo
I am trying to make my first set of bookself speakers using the classiv Vifa p17 woofer and the vifa d25ag tweeter. All i need to do is find the crossover components but that is proving near impossible to find the correct values outlined in the schematics.

Xristo

Don't give up as that is a nice driver combination and have heard them but with a simpler xo (made from Jaycar parts) from here.

http://users.ece.gatech.edu/~mleach/labsp2/

The speakers heard have the modified L-pad with the resistors changed, 3R to 4R and 15R to 8.2R (read the article for the explanation).

Stick with it........ you won't be sorry.

[Centauri]

As mentioned, 2R2 or 2R7 should be fine for the resistors. As for parts, seeing you are in Melbourne, contact Lorantz Audio Services on 9791 5971 - they can supply caps and coils etc.

Cheers
Graeme

[DSP_Geek]

Originally posted by Jean
Make up the 2.5ohm by putting two 5ohm resistors in parallel , or anything that would make up that value. You should be fine with inductors, thicker gauge = lower DCr= little lower losses .

Don't give up

What Jean said, and if 5 ohm Rs are hard to find, then try four 10 ohm resistors in parallel - that value should be trivial to find. The power will be shared equally in all the resistors, so 2 watts or higher should be fine for the 10 ohm jobbies. The difference between 8 and 10 watts power handling is probably not that important, but 5 watts would give you 20 watts power handling total if you want the extra margin.

Added bonus: running Rs in parallel reduces the series inductance.


Good luck,
Francois.