Pultec Inductors again...

[maxwall]

Drpat,

Did you unwind the pultec inductor ( CJ Style ) to get turns and AL values at 100 turns or 1000 turns or just take measurements from each tap like Inductance and DCR only ?

Also , I have a question about the winding wire ....

It sure is hard to solder on , seems to resist solder , not sure why ?
I finally tried silver solder , which seems to work better than 60/40 type.

Also , like CJ said about influences from pitch and number of times circling 360 degrees around the core , My question is , how many times (360 degrees) around the core to complete the whole process ? or how many individual turns per 360 degrees of the toriod core

ex : 246 turns to complete 360 degrees of the core one time.

Approx how much wire is needed at 34 AWG to do approx 1400 turns ?
I'm finding it challenging to get all this wire on a stick so I can thread it thru the toroid core as one single length of wire ( 1400+/- turns worth )

I've gone thru many feet of wire already on one core. I'm guessing at 60+
since my spool said 70ft. This could be wrong , but I'm going off of what was on the package of wire in a zip bag at the local electronics store.

Just want to get an Idea , about total wire allocation.

 

[khstudio]

[quote author="drpat"][quote author="khstudio"]We are lucky enough to have Pats DATA... at this point, it's the closest to original I think your gonna find unless someone rips apart a REAL Pultec to do it.[/quote]

I hope everybody understands by now, that I DID rip apart a real Pultec to do this.

It was a huge undertaking, and the EQ stayed in that state for a couple of weeks, till I wound an inductor that sounded like the original.[/quote]

I meant REAL Pultec "INDUCTOR" :green:

maxwall,
I think you're looking for EXACT DATA... & like I said, this is as close as you're gonna get.

So far I wound 2 like Pat did ...& I'm Pretty sure he's done a few more & his method has worked for both of us.

Whatever cores are getting you close to that magic # will probably sound GREAT! The Ferrite Toroidal Cores I wound sound good too but don't have the same "Magic"... but plenty usable.

 

[maxwall]

We'll if I don't ask then I'll never know. But now that I know, then I think I have enough to work with. When I find out more after many windings and experience , I'll report back. But I'll need to hear them before I wind more.


Actually , It's not my soldering craft that is giving the trouble its the wire. The solder wont stick to it and the enamel is completely off. Maybe the wire is siphoning heat away from the solder area acting like a heat sink so the area being soldered is cooling too fast. tried adding additional flux , but the same issue. Looks like I 'll need a hotter iron :twisted: :twisted: :grin:

Nonetheless, thanks Drpat, Khstudio , CJ for making this thread interesting. :thumb:

I'm sure I'll have some good inductors soon

 

[CJ]

Hey Pat, wat up.

The Start and Finish question...
If you were to take apart the original Pultec Inductor, do you think that the tap with the least turns would be the first one wound, or would they start with the tap with the most turns, and finish with the tap with the least turns?

It is confusing because when you unwind a coil, you are starting to unwind it from the Finish lead of the coil, so you have to reverse your final drawing in order to have the coil structure illustrated from Start to Finish.

The Start would be the lead that you tape to the core when you start winding.
It is at the center of the core, as opposed to the outside.

Soldering hi temp wire is a pain.
You have to get it really hot, and this is not good for the copper wire part that we want to tin.

Most people use a solder pot, but I guess you will have to suffer until you buy your next spool of 85 C, not 105 or 120 C wire.
Some of this Kevlar stuff they have today is impossible.
You need a mechanical stripper.

Try an exacto blade on the wire before you tin it.
Do not use an open flame, you will melt the wire.

 

[khstudio]

More interesting stuff CJ.

Most people use a solder pot

What is that???


Max...

Try an exacto blade on the wire before you tin it.
Do not use an open flame, you will melt the wire.

This is good advise from CJ... i just use a slightly dulled razor blade sometimes.

You MAY have some "High Temp" coated wire there. :?

Even the regular Temp wire can be a little tough to get it to stick.

 

[ioaudio]

[quote author="drpat"]In a lengthy phone conversation with Paul Suborits, an ex long term Torwico employee, he advised me that the core was most likely "molly perma powder core" (I think I wrote that down correctly) material.[/quote]

that is a nice hint - molypermalloy powder core (MPP core)
so there is some nickel in there!

http://www.mag-inc.com/powder/mpp_cores.asp

 

[ioaudio]

try to contact someone from the ham-radio scene - they use small toroids and propably you find someone who offers winding smaller quantities. should not cost much, once you´ve found the best core.
maybe try finding typical molyperm suppliers from the time when they where originally wound?

 

[khstudio]

To help others I'm reposting this email:

what AL value were you getting on the Ferrite toroid cores ?
you said these sounded good but not as good as the pultec like ones.

Thanks for all the help already .
I got the audio gear bug , I guess, can't help it.

Maxwall

Yes... the DIY bug gets me too.

I have to be honest... I don't remember the AL of the Ferrite Toroidals & I didn't even do the "Math"
It was VERY HIGH though!
I just wound them & measured until they were close to the Cinemag inductor values I had... so I could just drop them in my unit in place of the Cinemags for a comparison.

I didn't even care about the resistance... it was really low, like = 1 or 2 ohms.
Remember, the resistance is part of the "Q" or Bandwidth... so with them installed, I just don't go as low with the Bandwidth control.

The TOTAL amount of turns was around 200-220 - for the 150mH Taps.

Kevin

 

[CJ]

This is the inductor I wound for a 1 Hertz Pultec:


http://video.google.com/videoplay?do...62384802328397

Somebody made a DIY Toroid Winder:

 

[emrr]

[quote author="ioaudio"][quote author="drpat"]In a lengthy phone conversation with Paul Suborits, an ex long term Torwico employee, he advised me that the core was most likely "molly perma powder core" (I think I wrote that down correctly) material.[/quote]

that is a nice hint - molypermalloy powder core (MPP core)
so there is some nickel in there![/quote]

Twice now:

http://www.groupdiy.com/index.php?topic=25482&postdays=0&postorder=asc&start=16


:razz:

 

[CJ]

Here is a mock up from Pat's data.
Let me know if you see any mistakes or want to add something.

 

[okgb]

o.k. you guys are killing me , all i want is peace , love & understanding
but i can see a authentic pt inductor may be in my future ,
great info !

 

[ioaudio]

[quote author="emrr"]
Twice now:

http://www.groupdiy.com/index.php?topic=25482&postdays=0&postorder=asc&start=16


:razz:[/quote]

yes, but the pultec inductor is not very high Q at 150mH & 30 ohm
its maybe higher permeability than the ferrite available at that time, dont know.

 

[khstudio]

[quote author="emrr"] a Q of several hundred are possible.[/quote]

What does that mean? ... several hundred what?

 

[mikeyB]

[quote author="khstudio"][quote author="emrr"] a Q of several hundred are possible.[/quote]

What does that mean? ... several hundred what?[/quote]

Q doesn't have units (I don't think) - isn't it just a factor/ratio to indicate bandwidth?

 

[CJ]

Q = Reactance@f/DCR@f.

Note that DCR has no frequency response that we care about, unless you want to talk skin effect in RF circuits and stuff, so you could write it as

Q=Reactance@f/DCR.

or something that is actually usable:

Q=6.28fL/R

Example:

Q = 6.28 * 100 Hertz * 100 mH/10 Ohms
= 628 * 0.1 Henries/10
= 62.8/10
=6.28

The number D that you might see on some Inductance Meters is simply 1/6.28, what ever that turns out to be.

 

[ioaudio]

q factor or quality factor for inductors is just inductance divided by DC resistance. Q=L/R
in order to get high Q factors we need a high permeability core.
today we have nano christal iron cores with Al values > 19000nH, sized like a quarter. they where not made for audio, and saturate in a very unpleasing way (though i didnt try all types )

 

[emrr]

[quote author="ioaudio"][quote author="emrr"]
http://www.groupdiy.com/index.php?topic=25482&postdays=0&postorder=asc&start=16[/quote]

yes, but the pultec inductor is not very high Q at 150mH & 30 ohm
its maybe higher permeability than the ferrite available at that time, dont know.[/quote]

I bet it was the best for the application at the time.

 

[Wagtbtoobz]

yes, as ferrite was used in IF of receivers (over 60kHz area) many many years ago , the first "audio " use of them was in the 60' as freq multiplex telephone long distance was developped . The oldest i own were produced in 1961 for KLANGFILM Telecinema correctors (mag tape) or in my REVOX G36 for the premag / erase oscillator . I don't know the Al of them , 3H1 is the material .. Very good sound and easy to tweak Pierre

 

[CJ]

I think the Germans and English were the first to really get into it.

If you look at Seimens and Phillips, there are a ton of different mixtures that have been made over the years.

You just tell them what frequency and how much power, and they build a core, if you need ten million.

A huge Ferrite warehouse in England burned down about a year ago, I hope they are back.

There are online catalogs full of powdered cores.
Magnetics is the main US company, along with Fair-Rite.

I found the exact match for a tapped inductor for a console for Soundguy a while back, forgot which console, a famous one, Quad or MCI or something, I forget.

Ahh Trident, I believe.
Supposedly a good eq.