I've just finished making some Visaton Alto II speakers (ALTO II)
They sound nice but one speaker is significantly quieter than the other one. The resistance across the input terminals of the speaker is 12 ohms in the quiet one and 5 in the louder one.
Is this normal? Could it be cause by using slightly different speaker wire, or different hand soldering on the cross over or something?
Any suggestion welcome!
Thanks
They sound nice but one speaker is significantly quieter than the other one. The resistance across the input terminals of the speaker is 12 ohms in the quiet one and 5 in the louder one.
Is this normal? Could it be cause by using slightly different speaker wire, or different hand soldering on the cross over or something?
Any suggestion welcome!
Thanks
Sounds like you lost a driver at least, or a connection. 
Check all the internal connections on the "quiet" speaker and see if you can wiggle anything to make the impedance jump. When you fix it up you should see the impedance drop.
It's also possible you have a bad driver or component, but this is the simplest test.
Best,
E
Check all the internal connections on the "quiet" speaker and see if you can wiggle anything to make the impedance jump. When you fix it up you should see the impedance drop.
It's also possible you have a bad driver or component, but this is the simplest test.
Best,
E
Hi everyone - think I've got it fixed...the terminals now read 4 ohms anyway.
The problem seemed to be where the negative input, woofer and tweeter terminals joined. I noticed a bit of corrosion on the copper wire of one of these joins, which then snapped off as I was looking :S The multimetmer also showed no conductivity from the -ve input (which can't have been right, there was sound coming out!).
Anyway, soldered all three off, exposed new copped and soldered back on, and the terminals now read 4 ohms!
The only things I can think are
1) Dodgy solder causing corrosion. I did just find it lying loose round in my garage. Could acid based solder do this? Or god forbid, pluming solder (I've never bought any pluming solder, but who knows what's lurking in my garage)
2) Perhaps I didn't tin the arm of the 0.33 mH inductor properly first time round, and maybe there was plastic coating left on it.
Anyway - thanks for the help. Hopefully they sound good when I put them back together
Niall
The problem seemed to be where the negative input, woofer and tweeter terminals joined. I noticed a bit of corrosion on the copper wire of one of these joins, which then snapped off as I was looking :S The multimetmer also showed no conductivity from the -ve input (which can't have been right, there was sound coming out!).
Anyway, soldered all three off, exposed new copped and soldered back on, and the terminals now read 4 ohms!
The only things I can think are
1) Dodgy solder causing corrosion. I did just find it lying loose round in my garage. Could acid based solder do this? Or god forbid, pluming solder (I've never bought any pluming solder, but who knows what's lurking in my garage)
2) Perhaps I didn't tin the arm of the 0.33 mH inductor properly first time round, and maybe there was plastic coating left on it.
Anyway - thanks for the help. Hopefully they sound good when I put them back together
Niall
Always good to hear how it turned out, Niall!
I'm not sure I exactly followed that, but what you need to know is that inductive coils are made from insulating enamelled copper wire. It's metal with a sort of varnish coating.
This is good, because they can then be wrapped round each other without electrical short. The bad news is that when you solder the ends, you need to scrape off the insulating enamel to get a good connection.
Don't feel foolish. After 50 years in this game, I'm still learning stuff. Like how modern non-poisonous lead-free solder needs very clean surfaces, and high temperatures and 40W irons.
I'm not sure I exactly followed that, but what you need to know is that inductive coils are made from insulating enamelled copper wire. It's metal with a sort of varnish coating.
This is good, because they can then be wrapped round each other without electrical short. The bad news is that when you solder the ends, you need to scrape off the insulating enamel to get a good connection.
Don't feel foolish. After 50 years in this game, I'm still learning stuff. Like how modern non-poisonous lead-free solder needs very clean surfaces, and high temperatures and 40W irons.
there's a secret coven of alchemists that have possession of all the lead that's been removed from solder and they're gonna turn it into gold soon...
i'm ok with some of the aims ROHS but i think they've gone to far in some respects. when was the last time you chewed on a piece of leaded solder? and with recycling far less is able to re-contaminate the environment.
i'm ok with some of the aims ROHS but i think they've gone to far in some respects. when was the last time you chewed on a piece of leaded solder? and with recycling far less is able to re-contaminate the environment.
turk 182, LEAD added to your other intake of poisons is one of the great scandals of the C20.
Thomas Midgely always swore that lead was harmless.
He was lying. He used to pour Lead Tetraethyl over his hands and claim it did him no harm. In fact LEAD killed him. It made his hands shake and his nervous system rot. The financial upbeat was it made Petrol cheaper. Which doubtless made profits for someone.
In the same way that other heavy metals (Cadmium, Mercury, Strontium and for all I know, Uranium...) are lethal to life on Earth. TBH, there's little that I admire about the EU, but on heavy metals, and the ROHS legislation, they got it right.
I will happily struggle with lead-free solder, rubbish as it is. At least it doesn't kill me.
Thomas Midgely always swore that lead was harmless.
He was lying. He used to pour Lead Tetraethyl over his hands and claim it did him no harm. In fact LEAD killed him. It made his hands shake and his nervous system rot. The financial upbeat was it made Petrol cheaper. Which doubtless made profits for someone.
In the same way that other heavy metals (Cadmium, Mercury, Strontium and for all I know, Uranium...) are lethal to life on Earth. TBH, there's little that I admire about the EU, but on heavy metals, and the ROHS legislation, they got it right.
I will happily struggle with lead-free solder, rubbish as it is. At least it doesn't kill me.
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