| Jason Hubbard |
I have been unable to find air core inductors suitable for use in a CLC power supply. Most are intended for use in loudspeaker crossover units and are wound on plastic bobbins - i don't trust that they will be robust enough to sustain continuous high DC current of 6amps or more without becoming hot and a potential fire hazard.
The reasoning behind my thoughts is that with a typical DCR of 0.5 ohms or more and a current of 6amps i'm looking at dissipating 18 watts and have doubts about doing that on a plastic spool.
Does anybody know of a source for suitable inductors (preferably in the UK)? |
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| Magura |
I make custom air core inductors up to around 100mH.
You can have pretty much any configuration of materials you please.
If interested, email me.
Magura |
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| Jason Hubbard |
Thankyou for your offer, but custom winds and shipping from Denmark doesn't sound like a cheap option for the quantity i'll require.
My brother in-law winds inductors as part of his job, but it will ultimately cost me more (i.e. i'll owe him a favour and end up labouring for a couple of days building his house extension), so i was looking to see if something more readily available could be found.
I was after 2.2mH, 1.5mm wire and DCR 0.5 ohms air core inductor. |
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| Sch3mat1c |
Um... why aircore?
And in a wider sense... I've always wondered why SS amps use just C, or CRC power supplies, while tube amps are seemingly decades ahead in PSU effectiveness with our use of small, efficient caps and hum-cutting chokes. Really makes 'ya think.
Tim |
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| Jason Hubbard |
In a tube amplifier you draw very little by way of current, so you need little by way of capacitors and have nothing to worry about with choke core saturation, etc.
Solid state pulls many amps, readily saturates small inductors and needs capacitors the size of baked bean cans.
Different problems, different solutions... |
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| Sch3mat1c |
A 100W tube amp consumes 200W just as much as a 100W class AB solid state amp consumes 200W at full output. There is no difference. For an amp this size I would expect the choke to run a good 3" x 2-1/2 x 2-1/2" overall dimensions. (In a tube amp, this would be offset by the rather large OPT and slightly-larger-than-SS-amp's PT, probably leading to some of this confusion.) If you know the equations, current, voltage, resistance and required inductance and capacitance for the filter are related such that voltage and current tend to be exchangable. A 50V 4A supply is about the same size at a 500V .4A supply.
It seems to me that thousands of people go through classes just hearing rumors of large inductors, and perhaps only using a few RFC's in RF circuits. As SS phased out tubes, so have excessive capacitance, resistance and regulators phased out power supply chokes.
Wait a minute, that sounds like a rant :bigeyes:
Tim |
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| KBK |
| That's fine.. I hear you! As for SS amps with chokes... methinks it would be a good thing, considering that bandwidth in audio gear takes them away from any simple power factor calulations. The trick is getting good nough transformers and chokes. I, for one, would only look at plitron chokes, if I could afford it. |
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| Magura |
| quote: | Originally posted by Jason Hubbard
Thankyou for your offer, but custom winds and shipping from Denmark doesn't sound like a cheap option for the quantity i'll require.
.
I was after 2.2mH, 1.5mm wire and DCR 0.5 ohms air core inductor. |
Its something like this youre after...right??
http://www.diyaudio.com/forums/show...t=&pagenumber=2
In that case i can tell you that there is no off the shelf solution.
Ive made a few of them for that reason.
Magura :) |
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| roddyama |
Hi Jason,
Here are 2 examples of companies that could supply what you looking for. The companies are Solen (which I'm using) and Jentzen. |
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| Magura |
my mistake....i thought off the shelf ended at 2mH....it sure does in this end of the world.
Magura:) |
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| tiroth |
| Jantzen is in Denmark! |
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| Magura |
got a link?
Magura:) |
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| Variac |
Anyone have a conversion table for guage/mm ?
Seems like Denmark is a bigger country than I thought ;)
If you put two inductors in series then they must be twice the inductance.
If they are in parallel are they half the inductance?
I don't know, could someone tell me?
Edit: I'd guess that in parallel the inductors have the same inductance as one alone
Edit: MAgura, I meant because you didn't know that Janzen made the bigger inductors hahahah er never mind.. I guess it wasn't very funny :dead: Thanks for the link |
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| Magura |
| quote: | Originally posted by Variac
Anyone have a conversion table for guage/mm ?
Seems like Denmark is a bigger country than I thought ;) |
You would be surprised to find out that it isnt...Denmark is claustrofobically small. :(
Fortunately we have hamburg and berlin right next door :)
http://www.tnt-audio.com/clinica/awg_e.html
There you go:)
Magura |
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| Magura |
Hmm...off the top of my head:
In series: Double DC resistance half inductance.
I paralel: Half DC resistance double inductance.
I may be mistaken!!!!!
Magura |
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| Fuling |
Magura, I think you´re wrong here.
In series: twice the DC resistance, twice the inductance.
In parallel: half the DC resistance, half the inductance |
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| sreten |
Hmmmm........ people totally struggling with inductor basics.
Two inductors in series have twice the inductance.
Two inductors in parrallel have half the inductance
and twice the current capability.
To be effective for regulation inductors must carry a decent
static dc current, which you generally don't get in transistor
amplifiers and do get in class A and Class AB valve amplifiers.
However the inductor will lose any regulation if it saturates.
An active capacitance multiplier is more effective for transistor
amplifiers, and probably cheaper, with no saturation problems.
:) sreten. |
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| Magura |
Fuling...im sure youre right.
I just think ive seen the explanation i made on a different thread. There is something thats different(not the usual way as with resistors) when calculating inductors...im 99% sure.
Anyone?????
Cheers
Magura:)
Edit:
Thanks sreten....i knew there was something.... :) |
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| roddyama |
Hi Mark,
| quote: | Originally posted by Variac
If you put two inductors in series then they must be twice the inductance. |
Yes, and if you place them next to each other with the current rotating in the same direction, you add the mutual inductance| quote: | Originally posted by Variac
If they are in parallel are they half the inductance?
I don't know, could someone tell me?
Edit: I'd guess that in parallel the inductors have the same inductance as one alone |
The inductance stays the same and the DCR becomes smaller. The Solen Lutz coils are just a bunch of parallel inductors wound together. |
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| Magura |
| quote: | Originally posted by roddyama
Hi Mark,
Yes, and if you place them next to each other with the current rotating in the same direction, you add the mutual inductance
. |
Does this mean that you add the inductance from one to the other and vice versa??
Magura |
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| roddyama |
| quote: | Originally posted by Magura
Does this mean that you add the inductance from one to the other and vice versa??
Magura |
The value of the series two inductors will sum plus the amount of mutual inductance. Sorry I don't remember the calculation for the value of mutual inductance and would have to look in up when I gethome from work if this thread is cookin'. |
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| sreten |
How can some of you think two inductors in parrallel have the same value as one ?
Its like saying series capacitors have the same value as one.
The obvious question is, if they are different values, which value ?
Get a grip, :) sreten. |
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| roddyama |
| quote: | Originally posted by sreten
How can some of you think two inductors in parrallel have the same value as one ?
Its like saying series capacitors have the same value as one.
The obvious question is, if they are different values, which value ?
Get a grip, :) sreten. |
Yep. Your right. Sorry guys, brain fade. |
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| Tim F |
Jason
I posted a thread recently (got no replies yet) looking for supplier for Erse Super-Q Inductors in Europe. They are also shown at http://www.partsexpress.com & I wonder if they would meet your needs. I know their not air core but NP seems happy with them for Alephs.
The company in Europe was something like interchinque & I did get a quote for shipping & it was not horrendous.
Hope this helps.
Tim F
PS Hows the Fet matching going? |
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| Variac |
I believe the Parts Express Erse inductors are listed as 16GA
Zalytron.com has Erse listed as 14 GA and 18 GA
So if Zalytron really have 14 and PE has 16 then Zalyttron is the way to go. Nelson specifically mentioned the ones at Zay. |
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