Are Hammond reactor good for woofer crossover?

[ygg-it]

Hello I need an inductor of about 30mH in series to my 8 ohm woofer.

Max speaker power is 45W/90W. Amplifier no more than 40 watt RMS output.

Are these inductors ok for a crossover?

195P5
Hammond Manufacturing
FIXED IND 30MH 5A 230 MOHM CHASS

195P5 - Hammond Mfg.

 

[wolf_teeth]

Not really the right part, and they have pretty high DCR.
Wolf

 

[AllenB]

I might guess a reactor could produce some distortion. I wouldn't use it unless I had it and could test it first.

 

[ygg-it]

Not really the right part, and they have pretty high DCR.
Wolf

Hey Wolf 0,23 ohm for a 30mH indictor, don't think is so high.

 

[ygg-it]

I might guess a reactor could produce some distortion. I wouldn't use it unless I had it and could test it first.

Which is the difference between this reactor and an inductor?

 

[markbakk]

Seems a laminated steel E-core coil to me. If it's wound properly I think it will do audio just fine. Though I know of one (1) old design with a 30mH series inductor, I'm really curious how you got to this crossover setup...

 

[ygg-it]

30mH is in series with a woofer.
This cell (woofer+inductor) is in parallel to another identical woofer to enhance 40-100Hz octaves.
Both work in two separate vented volumes

 

[celef]

I do not think .23 ohm is that much either

I guess this large coil can have some microphony issues if not constructed well or baked, so it is better to keep it outside the speaker box and far away from the listening position

 

[ErikdeBest]

maybe you know it, but this unit is meant for filtering a DC power supply. For that it needs an airgap. Due to the airgap it needs a much bigger core, Due to bigger core it needs more wire, therefore higher DCR.

You do not need to handle DC current, so you could go for a much smaller core, lighter and lower DCR. I am not saying these smaller cores will be cheaper though

Another thing. The specification of 30mH is with the 5A DC current. Besides tolerances that may change this value, if there is no DC current the actual inductance will probably be higher.

 

[markbakk]

Try this one or this one.

 

[Lojzek]

Give Erse Audio a call and ask a quote on a Super Q 16awg 30mH or get some of a lower value, then wind additional magnet wire.

 

[ygg-it]

Another thing. The specification of 30mH is with the 5A DC current. Besides tolerances that may change this value, if there is no DC current the actual inductance will probably be higher.

This is scaring me!

So which the relations, which value should I order?

 

[wolf_teeth]

Even if dcr is low enough, sorry about my memory there, it's not meant for the application of xover.
Goals are very different. Yeah, get a superQ and wind up.

Wolf

 

[markbakk]

So which the relations, which value should I order?

Won’t post the links again, what is your hesitation about? The E96 will do fine, like they did about 30 years ago already.

 

[ygg-it]

If we check this:

Monacor LSI-15T Tranformer Coil 15mH

it has exacltly the same construction of the Hammond (EI transformer)

Also this has the same construction:

MUNDORF N300 Zero Ohm Self Coil 6.8mH - Audiophonics


So I still don't understand why the hammond, or similar reactor/ transformer coils, would not work good in a crossover, and why should change its inductance in AC.

 

[steveu]

1. Any kind of core vs air core is going to create some distortion.
2. A 40 Hz crossover must be for a sub which needs a lot more power and gain than the rest of the audio so a separate amp is the best plan and allows you to use an electronic crossover without the issues of a passive XO.
3. A direct connection between amp and speaker is much better for buffering factor.

You don't necessarily need a 40Hz high-pass for the rest of the system since most speakers are done below 40 Hz. The only reason might be to get more mid band etc power in the other channels.

 

[markbakk]

I really suspect the Hammond coil to be just fine, as it obviously uses the E-core that compares well with the E-96 or E-130 from Intertechnik. There won’t be no air gap, 99 per cent sure. But the jump to 100 per cent will demand ordering one and measure it. I don’t need such a coil though. And even if I would, I’d get the E-96 from IT. I know that one and it’s good.

 

[celef]

Monacor LSI-15T Tranformer Coil 15mH.

Sure, you can put two in series and get 30mh and still have a low serie resistance

But the ones i have tried had serious trouble with microphony

 

[ErikdeBest]

I really suspect the Hammond coil to be just fine, as it obviously uses the E-core that compares well with the E-96 or E-130 from Intertechnik. There won’t be no air gap, 99 per cent sure. But the jump to 100 per cent will demand ordering one and measure it. I don’t need such a coil though. And even if I would, I’d get the E-96 from IT. I know that one and it’s good.

You mean the Hammond has no gap? Here is the datasheet, it is there (and there is a +-15% tolerance). https://www.hammfg.com/files/parts/pdf/195P5.pdf

My audio experience is mostly into tube amplifiers and from them I know the Hammonds, used a lot in smoothing the DC supplies. This unit would do nice as a smoothing coil for a nice SS class AB amplifier.

 

[AllenB]

Which is the difference between this reactor and an inductor?

A reactor is often used in a current control situation, eg current limiting, or as a ballast. They are sometimes seen in audio amplifier power supplies. In that application they are known to have an inductance that varies with current. Attached is an example which is rated to give a fivefold difference in inductance over a tenfold variation in current.