Thanks Galu.
A quick search reveals that small value Iron Core Inductors are similarly priced to Air Core types. The savings appear to only kick in with higher values. There is a saving with electrolytic over poly caps, but when I factor two lots of shipping there's not much in it over going poly. Then I can't find electrolytics with the precise values I'm after.
Wagners closest electrolytic is 10µF (require 8) and Inductors aren't cheaper.
Speakerbug have everything one stop shop but no electrolytic suitable.
RS have expensive electrolytics.
Altronics don't have suitable Inductors.
Mouser the same.
Element14 thin on suitable Inductors.
Radio Parts no inductors
Jaycar very limited inductors
Also the prices I listed are higher than if I used correct values.
This is because I'm using caps given to me from the failed Technics project.
For example for 8µF I'm using a 6.8µF & 1µF, for 3.3µF I'm using a 2.2µF & a 1µF.
If I buy Inductors from one place and cheap electrolytics from another that's a double shipping fee which tips the balance.
A quick search reveals that small value Iron Core Inductors are similarly priced to Air Core types. The savings appear to only kick in with higher values. There is a saving with electrolytic over poly caps, but when I factor two lots of shipping there's not much in it over going poly. Then I can't find electrolytics with the precise values I'm after.
Wagners closest electrolytic is 10µF (require 8) and Inductors aren't cheaper.
Speakerbug have everything one stop shop but no electrolytic suitable.
RS have expensive electrolytics.
Altronics don't have suitable Inductors.
Mouser the same.
Element14 thin on suitable Inductors.
Radio Parts no inductors
Jaycar very limited inductors
Also the prices I listed are higher than if I used correct values.
This is because I'm using caps given to me from the failed Technics project.
For example for 8µF I'm using a 6.8µF & 1µF, for 3.3µF I'm using a 2.2µF & a 1µF.
If I buy Inductors from one place and cheap electrolytics from another that's a double shipping fee which tips the balance.
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I see your problem, Cliff. It would appear that there's no 'one stop shop' where you live! 😱
I've also checked out the relative cost of the different inductors types, and you are quite right about the similarity in prices.
More importantly, the smallest ferrite core inductor value I can buy from my one stop shop, Wilmslow Audio, is 1.0mH. Components and accessories
So, we are looking at air core coils! Look for a choice of wire gauge/diameter when browsing - the thinner wire, higher DC resistance coils are the least expensive and good enough for this project.
If you have any spare coils kicking around, you can reduce a large inductance to a smaller one simply by unwinding turns until you get the desired reading on your inductance meter. Just mentioning this as a possibility!
I've also checked out the relative cost of the different inductors types, and you are quite right about the similarity in prices.
More importantly, the smallest ferrite core inductor value I can buy from my one stop shop, Wilmslow Audio, is 1.0mH. Components and accessories
So, we are looking at air core coils! Look for a choice of wire gauge/diameter when browsing - the thinner wire, higher DC resistance coils are the least expensive and good enough for this project.
If you have any spare coils kicking around, you can reduce a large inductance to a smaller one simply by unwinding turns until you get the desired reading on your inductance meter. Just mentioning this as a possibility!
Polypropylene motor run capacitors are relatively cheap. I've used these in high-end loudspeaker crossovers with great results. Why not use them? They are both high-end and cheap as chips.
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Hi Galu.
My order came through today.
Air core Inductors.
For the L2 I went for 0.52mH as the supplier didn't have 0.5
A little disappointed:
Both the 0.52mH Inductors measure 0.44mH and
Both the 0.2mH Inductors measure 0.17mH.
That's lower by a 15% variation.
Is this acceptable?
cheers Cliff
The manufacturer may have measured the inductances at a different frequency than that employed by your inexpensive LCR meter.
Whatever the reason for the measured differences, the inductors are acceptable in the context of our simple experimental crossover circuit.
The crossover slopes are shallow and quite forgiving of component value variation.
Whatever the reason for the measured differences, the inductors are acceptable in the context of our simple experimental crossover circuit.
The crossover slopes are shallow and quite forgiving of component value variation.
Thanks Galu.
I'm thinking for future upgrades, and DIY builds where it would be nice for parts I purchase to meet their design values.
All the Jantzen caps measure close to spot with the tester.
These Inductors are also marked for resistance.
The 0.52 mH Inductor quotes 0.59Ω resistance but measures 1Ω
The 0.2 mH Inductor quotes 0.45Ω resistance but measures 0.9Ω
Is resistance also affected by frequency used?
I'm thinking for future upgrades, and DIY builds where it would be nice for parts I purchase to meet their design values.
All the Jantzen caps measure close to spot with the tester.
These Inductors are also marked for resistance.
The 0.52 mH Inductor quotes 0.59Ω resistance but measures 1Ω
The 0.2 mH Inductor quotes 0.45Ω resistance but measures 0.9Ω
Is resistance also affected by frequency used?
I have a number of Dayton (unused) resistors.
Tests using my tester are showing up an average of 35% off the stated resistance of the resistors.
I'll be assuming the tester is only good for measuring caps and appears to be significantly out for Inductors and Resistors.
Tests using my tester are showing up an average of 35% off the stated resistance of the resistors.
I'll be assuming the tester is only good for measuring caps and appears to be significantly out for Inductors and Resistors.
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I can't comment on that. Your inductance and resistance measurements would have to be confirmed by a third party before questioning the figures given by the supplier.
Galu beat me to it.
Lead resistance, does it measure dcr or impedance, and what frequency does your meter use to measure inductance ?
Lead resistance, does it measure dcr or impedance, and what frequency does your meter use to measure inductance ?
Very interesting test Galu.
Their resistance equates to the resistor variance.
That makes the resistance testing spot on once the test leads are discounted.
The only remaining issue is the Inductor variance.
I repeated the Inductor tests without the test leads.
Inductor measurements remain the same as previously tested.
Out by 15%.
The tester was supplied without instructions nor specs.
It uses a 9V dc battery.
There are no switches.
The tester decides what is being tested and displays accordingly.
My lcr meter allows multiple test frequencies from 100hz to 100khz.
The measured inductance will change by 100% depending on the test frequency.
If your meter doesn't even give you its base line parameters, I wouldn't trust it as far as I could throw it.
Then there's always the issue of having a tool and not understanding how to use it.
The measured inductance will change by 100% depending on the test frequency.
If your meter doesn't even give you its base line parameters, I wouldn't trust it as far as I could throw it.
Then there's always the issue of having a tool and not understanding how to use it.
Cliff, you totally edited one of your posts after I had replied to it, which disturbed the logical flow.
I think you will now realise that the supplied inductors are "up to spec".
A starter LCR meter such as yours can only give ball park figures for the inductance of crossover coils.
Allow for that 15% in future, or buy a much more expensive meter.
I think you will now realise that the supplied inductors are "up to spec".
A starter LCR meter such as yours can only give ball park figures for the inductance of crossover coils.
Allow for that 15% in future, or buy a much more expensive meter.
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Hi Galu.
Sorry for the long absence. My lifes challenges.
I recently executed your design and am thoroughly satisfied with the result.
The Silcrons are no longer harsh and are much more listenable.
Also the exercise added to my crossover experience and knowledge.
Thanks heaps.
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It's good to hear from you, Cliff.
I've been hoping all was well with you and that you'd be back in touch.
I'm glad I've been of some help in developing your loudspeaker renovation skills.
I've been hoping all was well with you and that you'd be back in touch.
I'm glad I've been of some help in developing your loudspeaker renovation skills.
Thanks Galu.
You're my mainstay when it comes to Audio.
I haven't been traveling too well of late with high stress levels.
Hence my disappearance.
Before your crossover design there just seemed something wrong about these speakers.Now, in a large room, they're worth listening too. 🙂
You're my mainstay when it comes to Audio.
I haven't been traveling too well of late with high stress levels.
Hence my disappearance.
Before your crossover design there just seemed something wrong about these speakers.Now, in a large room, they're worth listening too. 🙂