BillFitzmaurice.info

Hi,

I would like to ask for your advice.

Can I use the below detailed inductor for the 1.2KHz low-pass filter of OT12?
(Eminence deltalite II 2512; NSD2005)
This is the smallest gauge available here (15AWG)

Jantzen Audio
1,000mH +/-3%
0,285Ω aircore
1,40mm = 15AWG
OD-71 / 21mm

Any advice would be appriciated!

Lustyik wrote: Any advice would be appriciated!

If the specs are correct they're correct. But the plans call for 1mH, not 1,000 mH. Are you using commas where you should use periods?
The plans call for the lightest available gauge for the high pass filter inductors, not the low pass inductors. The low pass gauge is based on DCR. You also should be able to find solid core for a lower price than air core.

Bill Fitzmaurice wrote: Are you using commas where you should use periods?

Numbers are not universal. Some countries universally switch the comma and the period. The way he wrote it is perfectly valid in his country (Hungary).

If you think that's weird, look up the crore and lakh system. Once you wrap your head around that, start looking at all the places that use systems other than base 10.

Tom Scott did an excellent video for the Numberphile channel on the topic:

Thank you for the quick answer! ...and the excellent video

I just copied the parameters from the web site. Inductor is 1.0mH (1.4 mm) of course.

For high-pass filter, I find the following inductor:
Jantzen
air core
9.1mH +/-3%
0.290Ω
1.40mm = 15 AWG
OD-54 / 30mm
This is the lightest available gauge that I find here actually.
Should I further investigate to find a lighter gauge for high-pass filter inductor?
For instance I saw on the website of the factory the fallowing conductors:
0.9mH 1.6mm = 14 AWG and
0.9mH 1.8mm = 13 AWG.

Lustyik wrote: Should I further investigate to find a lighter gauge for high-pass filter inductor?

The point of using the lightest possible gauge with the high pass is that neither current nor DCR is a concern, and the lightest gauge is the least expensive.

For instance I saw on the website of the factory the fallowing conductors:
0.9mH 1.6mm = 14 AWG and
0.9mH 1.8mm = 13 AWG.

Those are larger than 15 ga. Wire gauge is just like shotgun shell gauge. The smaller the number the larger the diameter, so when we say go lighter than 15 ga. that means to a higher gauge number, not lower. It's confusing to be sure.

Bill Fitzmaurice wrote:

Lustyik wrote: Should I further investigate to find a lighter gauge for high-pass filter inductor?

The point of using the lightest possible gauge with the high pass is that neither current nor DCR is a concern, and the lightest gauge is the least expensive.

For instance I saw on the website of the factory the fallowing conductors:
0.9mH 1.6mm = 14 AWG and
0.9mH 1.8mm = 13 AWG.

Those are larger than 15 ga. Wire gauge is just like shotgun shell gauge. The smaller the number the larger the diameter, so when we say go lighter than 15 ga. that means to a higher gauge number, not lower. It's confusing to be sure.

Thank you again!

Gauge confused me. I am familiar with shotgun shell gauge, so now it is clear.

In conclusion bought conductors would be good for me, but the other side, I can select cheaper inductor for high-pass filter (above 15 ga). Am I correct?

Apologise for plenty of questions.

Lustyik wrote:Thank you for the quick answer! ...and the excellent video

Just hoped to foster some understanding. Tom Scott's videos should be required viewing in schools worldwide IMHO.

We Americans as a whole tend to be a bit ignorant of international matters like this. This country is so darn BIG that what for us might be a daily commute or a short haul to another state for an event would be an international trip in parts of Europe. While there are regional variances oin customs and dialect, it is nothing like one finds elsewhere in the world. Most Americans have mutual comprehensibility with each other, and we use similar non-verbal language cues, and have a similar cultural core. We have states that are bigger in land area than some european countries.

This isn't an "America is great" speech (and it is, in my opinion, of course), just an observation that the sheer size of the country has an effect on how we see the world.

Finally I find better option I guess:

For High-pass filter
Air Core Coil 0.9 mH +/-3% 0.67Ω wire 0.8mm=20AWG OD-38 / 15mm

For low-pass filter
Air Core Coil 1.0mH +/-3% 0.245Ω wire 1.6mm=14AWG OD-61 / 30mm

(Jantzen products)


Thanks for your help!