Neve inductors

[gyraf]

Darn, I'm happy to see you here, CJ..

Jakob E.

 

[abbey road d enfer]

P-cores seem to be much less available than RM-cores in Europe. There is no AL863 cores in the RM series. The closest are AL630 or AL1000. I have a preference for AL630 because the larger gap extends linearity and offers a better tolerance. The turn number must be changed accordingly.

 

[gyraf]

The p-cores can be manually gapped by adding a piece of known-thickness hdpe-film between cores if higher saturation level is needed. Surprisingly precise and long-term stable for such a simple hack. Trick is to measure resulting AL with the film-of-choice, then recalculate turns accordingly (see above link to the simple powermagnetics calculator)

/Jakob E.

 

[warpie]

Sorry to resurrect this oldish thread but I decided to experiment a bit with winding my own inductors. I have plenty of questions but for now I'd like to ask what is the process/ technique for measuring the maximum level before the coil starts saturating....

FWIW, I have a couple of DMMs, function generators and scopes.

Thanks!

 

[abbey road d enfer]

Sorry to resurrect this oldish thread but I decided to experiment a bit with winding my own inductors. I have plenty of questions but for now I'd like to ask what is the process/ technique for measuring the maximum level before the coil starts saturating....

FWIW, I have a couple of DMMs, function generators and scopes.

Thanks!

There are two things that happen when core saturates: distorted signal and shift of the boost/cut frequency.
You need a more inquisitive tool; I would suggest you use REW (free software) in conjunction with a computer and soundcard.

 

[warpie]

There are two things that happen when core saturates: distorted signal and shift of the boost/cut frequency.
You need a more inquisitive tool; I would suggest you use REW (free software) in conjunction with a computer and soundcard.

Thanks abbey.

I use REW so that's not a problem. However, I'm still not sure what I'm supposed to do. Can I test just the coil by itself or it should be in the circuit?

For some reason I had the impression that using a function generator -> coil (+cap) -> oscilloscope would be easier but obviously I'm wrong...

 

[abbey road d enfer]

Thanks abbey.

I use REW so that's not a problem. However, I'm still not sure what I'm supposed to do. Can I test just the coil by itself or it should be in the circuit?

Definitely test the whole circuit in real conditions.

For some reason I had the impression that using a function generator -> coil (+cap) -> oscilloscope would be easier but obviously I'm wrong...

It could be done that way, but you must design a test jig that submits the coil to the same constraints as when in circuit.
The simple method you describe does not measure adequately the parameters. You need to build a resonant circuit for evaluating the frequency variation, and a distortion meter.

 

[warpie]

I need a maximum L of 4H. Can someone tell me what AWG of wire I need if I use a N41 RM12 (Al=1000) core? What is the formula to calculate whether I would be able to fit 4000 2000 turns in this RM core?

 

[abbey road d enfer]

4H with a An1000 core results in 2000 turns.
The available space is 72-73mm², according to specs. That gives a square area of 0.36mm² per turn.
The round wire takes about the same space than a square one, so you need to find a wire that has an overall diameter of 0.19mm or smaller.
Why do you want to put 4000 turns? That would make for 16H.

 

[warpie]

4H with a An1000 core results in 2000 turns.
The available space is 72-73mm², according to specs. That gives a square area of 0.36mm² per turn.
The round wire takes about the same space than a square one, so you need to find a wire that has an overall diameter of 0.19mm or smaller.
Why do you want to put 4000 turns? That would make for 16H.

Sorry Abbey, that was a typo. I did mean 2000 turns indeed. I'll amend the post.

So a a AWG=32 or higher wire should be sufficient... Thanks! I might go for 32 because I would wound this inductor by hand so it'll be probably easier to handle.

In regards to saturation levels does it make any difference what AWG I'll use or it totally depends on the core?

 

[abbey road d enfer]

Sorry Abbey, that was a typo. I did mean 2000 turns indeed. I'll amend the post.

So a a AWG=32 or higher wire should be sufficient... Thanks! I might go for 32 because I would wound this inductor by hand so it'll be probably easier to handle.

My chart suggests AWG33...

In regards to saturation levels does it make any difference what AWG I'll use or it totally depends on the core?

No difference. You'll have to watch the DC resistance.

 

[warpie]

My chart suggests AWG33...

No difference. You'll have to watch the DC resistance.

Thanks Abbey. Yes I'm aware of DCR. I ordered some cores and wire to experiment.

Since we are on that, one more question that might sound silly but in a LCR circuit, does the order of the components matter? LCR vs CLR if that makes sense. I believe it doesn't but I thought I'd ask in case I'm missing something... Again, thanks for all your help, much appreciated!

 

[abbey road d enfer]

Thanks Abbey. Yes I'm aware of DCR. I ordered some cores and wire to experiment.

Since we are on that, one more question that might sound silly but in a LCR circuit, does the order of the components matter? LCR vs CLR if that makes sense. I believe it doesn't but I thought I'd ask in case I'm missing something... Again, thanks for all your help, much appreciated!

When they're all in series, the order does not change anything.

 

[nielsk]

I wonder how this circuit would sound with permalloy pie-wound torroidals wound with extremely fine wire, like the great sounding passive EQs employ?
It is interesting how many ways there are to make an inductor for (close to) the same electrical characteristics, and how different they all sound in an EQ circuit.
Easily illustrated in comparing an intact original API 553 to one built with the various air core, metal core, and different to original spec wound torroids that have been offered here in the past. The difference is not subtle.
Same goes for Pultec type.

 

[warpie]

like the great sounding passive EQs employ?

which ones?

 

[nielsk]

Great sounding inductor based EQs? That's a long list, most of which few have had the opportunity to use.
The obvious ones that are likely to have been encountered are actual original Pultecs PEQ and MEQ, Langs, and API 553 (considered by many the best sounding EQ API created, but a tone control not a surgical tool)
The considerable ease of obtaining and making the type inductor used in the 80's series Neve units is a pretty big advantage DIY wise, I am just curious. Sweet Pie wound types, unfortunately, are extremely DIY un-friendly to fabricate and minimum order prohibitive to have one made.

 

[warpie]

Ok then, can someone explain me the difference between N41 and N87 core assuming that AL is the same?

I know it is a different material but in terms of sound/ saturation level, etc.. is one preferred over the other?

 

[abbey road d enfer]

Ok then, can someone explain me the difference between N41 and N87 core assuming that AL is the same?

I know it is a different material but in terms of sound/ saturation level, etc.. is one preferred over the other?

N41 and N48 are more linear than N87. However, for an identical Al, the N87 core will have a longer gap, which will somewhat compensate.
Traditionally N41 and N48 are preferred for audio filters, but I never compared directly. You know what you need to do now...

 

[warpie]

You know what you need to do now...

I know indeed Thanks!