Chokes any good for Pultec EQ ?????????

[gary o]

Would these inducters be any good for Pultec type EQs I read somewhere lower DC res is better ?, I dont no much about all this so could be leading you on a wild goose chase I also just read a post about Toko may stop makin theres so could these be any use ? Heres some info copied & pasred from the Farnell site.





CHOKE, QUAD ISDN; Inductance:22mH; Resistance:1.2R; Approval Bodies:EN 60950, BABT, CSA C22.2 No. 950-95, UL 1950, EN41003; Depth, external:14.3mm; Inductance, leakage:10µH; Inductance, primary:22mH; Length / Height, ext


Farnell InOne INDUCTOR, 47MH; Inductance:47mH; Frequency, resonant:0.12MHz; Q factor:100; Resistance:52R; Tolerance, +:10%; Tolerance, -:10%; Current, DC max:13mA; Case style:Radial; Inductor type:Inductor; Diameter, body:10.5mm; Diam


Radial 13 mA 0.12 MHz 47 mH Inductor In Stock
£0.97


3031482 RN114-0.3/02
SCHAFFNER
Farnell InOne CHOKE, COM/ASYM MODE 2X47MH 0.3A; Inductance:47mH; Frequency, resonant:250kHz; Resistance:1.75R; Current, DC max:0.3A; Case style:RN114; Voltage rating, AC:250V; Inductor type:Com/Asym Mode Choke; Approval category:VDE,


RN114 0.3 A 250 kHz 47 mH Com/Asym Mode Choke In Stock
£2.46


3031524 RN122-0.6/02
SCHAFFNER
Farnell InOne CHOKE, COM/ASYM MODE 2X47MH 0.6A; Inductance:47mH; Frequency, resonant:2200kHz; Resistance:1.18R; Current, DC max:0.6A; Case style:RN122; Voltage rating, AC:250V; Inductor type:Com/Asym Mode Choke; Approval category:VDE,


RN122 0.6 A 2200 kHz 47 mH Com/Asym Mode Choke In Stock
£2.67


3031550 RN222-0.6/02
SCHAFFNER
Farnell InOne No longer stocked


RN222 0.6 A 220 kHz 47 mH Com/Asym Mode Choke No Longer Stocked
£2.71


3247132 B82731H2501A30
EPCOS
Farnell InOne CHOKE, COM MODE 2X47MH 0.5A; RoHS Compliant:YES; Inductance:47mH; Resistance:2000mR; Tolerance, +:50%; Tolerance, -:30%; Current, DC max:0.5A; Voltage rating, DC:250V; Voltage rating, AC:250V; Inductor type:Common Mode C


0.5 A 47 mH Common Mode Choke In Stock
£2.35


3247200 B82732W2601B30
EPCOS
Farnell InOne CHOKE, COM MODE 2X47MH 0.6A; RoHS Compliant:YES; Inductance:47mH; Resistance:1400mR; Tolerance, +:50%; Tolerance, -:30%; Current, DC max:0.6A; Voltage rating, DC:250V; Voltage rating, AC:250V; Inductor type:Common Mode C


0.6 A 47 mH Common Mode Choke Short Lead Time
£2.54


3247260 B82734W2132B30
EPCOS
Farnell InOne CHOKE, COM MODE 2X47MH 1.3A; RoHS Compliant:YES; Inductance:47mH; Resistance:560mR; Tolerance, +:50%; Tolerance, -:30%; Current, DC max:1.3A; Voltage rating, DC:250V; Voltage rating, AC:250V; Inductor type:Common Mode Ch


1.3 A 47 mH Common Mode Choke In Stock
£2.96


3265791 EH24-0.5-02-47M
SCHAFFNER
Farnell InOne CHOKE, COM MODE HZ 2X47MH 0.5A; Inductance:47mH; Resistance:1900mR; Tolerance, +:30%; Tolerance, -:30%; Current, DC max:0.5A; Voltage rating, DC:250V; Voltage rating, AC:250V; Induct; Available until stocks are exhausted


0.5 A 47 mH Common Mode Choke In Stock
£1.08


3266424 RN143-1/02
SCHAFFNER
Farnell InOne CHOKE, COM/ASYM MODE 2X47MH 1A; Inductance:47mH; Resistance:0.88R; Current, DC max:1A; Case style:RN143; Voltage rating, AC:250V; Inductor type:Com/Asym Mode Choke; Approval category:VDE, UL; Flammability rating:UL94V-0;


RN143 1 A 47 mH Com/Asym Mode Choke In Stock
£2.54


3266620 RN214-0.3/02
SCHAFFNER
Farnell InOne No longer stocked


RN214 0.3 A 47 mH Com/Asym Mode Choke No Longer Stocked
£2.53


432283 22R476
C & D TECHNOLOGIES
Farnell InOne INDUCTOR, 47MH; Inductance:47mH; Frequency, resonant:0.33MHz; Q factor:120; Resistance:115R; Tolerance, +:10%; Tolerance, -:10%; Current, DC max:30mA; Case style:Radial; Inductor type:Inductor; Diameter, body:7.2mm; Diam



Radial 30 mA 0.33 MHz 47 mH Inductor In Stock
£0.47


520809 B82722A2301N1
EPCOS
Farnell InOne CHOKE, COM MODE 2X47MH 0.3A; RoHS Compliant:YES; Inductance:47mH; Resistance:2500mR; Tolerance, +:30%; Tolerance, -:30%; Current, DC max:0.3A; Voltage rating, AC:250V; Inductor type:Common Mode Choke; Approval category:V


0.3 A 47 mH Common Mode Choke In Stock
£2.88


520822 B82722J2301N1
EPCOS
Farnell InOne CHOKE, COM MODE 2X47MH 0.3A; RoHS Compliant:YES; Inductance:47mH; Resistance:2500mR; Tolerance, +:30%; Tolerance, -:30%; Current, DC max:0.3A; Voltage rating, AC:250V; Inductor type:Common Mode Choke; Approval category:V


0.3 A 47 mH Common Mode Choke In Stock
£2.59


523641 B82724B2102N1
EPCOS
Farnell InOne CHOKE, COM MODE 2X47MH 1.0A; RoHS Compliant:YES; Inductance:47mH; Resistance:880mR; Tolerance, +:30%; Tolerance, -:30%; Current, DC max:1A; Voltage rating, AC:250V; Inductor type:Com; Available until stocks are exhausted


1 A 47 mH Common Mode Choke No Longer Stocked
£3.35


525467 B82732R2601B30
EPCOS
Farnell InOne CHOKE, COM MODE 2X47MH 0.6A; RoHS Compliant:YES; Inductance:47mH; Resistance:1400mR; Tolerance, +:50%; Tolerance, -:30%; Current, DC max:0.6A; Voltage rating, DC:250V; Voltage rating, AC:250V; Inductor type:Common Mode C


0.6 A 47 mH Common Mode Choke In Stock
£2.54


525510 B82734R2132B30
EPCOS
Farnell InOne CHOKE, COM MODE 2X44MH 1.3A; RoHS Compliant:YES; Inductance:47mH; Resistance:560mR; Tolerance, +:50%; Tolerance, -:30%; Current, DC max:1.3A; Voltage rating, DC:250V; Voltage rating, AC:250V; Inductor type:Common Mode Ch


1.3 A 47 mH Common Mode Choke In Stock
£2.99


870377 B82731R2401A30
EPCOS
Farnell InOne CHOKE, COM MODE 2X47MH 0.4A; RoHS Compliant:YES; Inductance:47mH; Resistance:2400mR; Tolerance, +:50%; Tolerance, -:30%; Current, DC max:0.4A; Voltage rating, DC:250V; Voltage rating, AC:250V; Inductor type:Common Mode C


0.4 A 47 mH Common Mode Choke In Stock
£2.17



CHOKE, COM MODE 2X100MH 0.35A; RoHS Compliant:YES; Inductance:100mH; Resistance:4500mR; Tolerance, +:50%; Tolerance, -:30%; Current, DC max:0.35A; Voltage rating, DC:250V; Voltage rating, AC:250V; Inductor type:Common Mo


0.35 A 100 mH Common Mode Choke Awaiting Delivery
£2.35


3266412 RN143-0.5/02
SCHAFFNER
Farnell InOne CHOKE, COM/ASYM MODE 2X100MH 0.5A; Inductance:100mH; Resistance:2.9R; Current, DC max:0.5A; Case style:RN143; Voltage rating, AC:250V; Inductor type:Com/Asym Mode Choke; Approval category:VDE, UL; Flammability rating:UL9



Cheers guys.......................Gary O.

 

[gyraf]

Remember that a 47+47mH inductor - when wired in series - won't give you 94mH, but 188mH...

But yes, those inductors may work just fine for the pultec...

Jakob E.

 

[gary o]

H Jakob, im afraid I dont understand much about inductors but I was thinking of 2x 100mh 1x 47mh & a 22 mh for your srpp Pultec type EQ which works great by the way thanks using toko inductors at mo just wondered would these others sound any better/ different, your right about that srpp make up amp it does add a lovely tubey sweetness to the sound, thanks once again.


Gary O.

 

[CJ]

Maybe some of those inductors on the list should be put in the Pultec Meta, if they are not there already. Anybody use any of those on the list? It would be nice to verify the ones that get put in the Meta.

 

[Lukpio]

[quote author="gyraf"]Remember that a 47+47mH inductor - when wired in series - won't give you 94mH, but 188mH...

But yes, those inductors may work just fine for the pultec...

Jakob E.[/quote]

I'm afraid this is not entirely true. The rule stated by Jakob apply to inductors that have COMMON magnetic path, i.e. are wired on the same core. Then doubling the number of turns increases the inductance four times. BUT when the inductors are separate they add just like resistors when connected in series.

As for the Pultec's inductors I belive that the original were mu-metal cored, but I'm pretty sure that every modern commercial Pultec-influenced equalizer (including my own) uses ferrite core. They are much more predictable. I recommend pot cores.

All of you who want to wind their own inductors have to know that every magnetic material for the core (especially ferrite) changes its permeatibily with age and usage. The effect is VERY dramatic at the beggining of the life of such a inductor, so the only way to obtain satisfying results (i.e. stable frequencies) is to "pre-age" it with presence of a strong signal flowing through such a inductor.
After a few days of doing this (like 72 hours CONSTANTLY or even more), the core characteristics settle down.

Happy winding...

 

[gyraf]

Thanks, Lukasz!

Good info.. :thumb:

Jakob E.

 

[alk509]

[quote author="Lukpio"]The rule stated by Jakob apply to inductors that have COMMON magnetic path, i.e. are wired on the same core.[/quote]

Isn't that exactly what a 47mH+47mH inductor is? Have you ever seen a commercial 47mH+47mH inductor consisting of two cores/coils in one package?

Peace,
Al.

 

[Lukpio]

Hello Al,

I have seen a commercial component that consists of two separate inductors and a capacitor in one enclosure.

I'd be very suspicious about using RF chokes as audio inductors. They are designed to be used in high frequency range. The best choice is to use high-AL pot cores. They are easy to wind, are quite immune to external magnetic fields and don't require special magnetic shielding, when the power transformer is positioned correctly and the power supply is designed right.

There is a very simple, but extremely useful tool for checking the peak boost circuit on Pultec-type EQs. It turns the equalizer into oscillator. If there's any interest I will start a new topic about it.

 

[gyraf]

There is a very simple, but extremely useful tool for checking the peak boost circuit on Pultec-type EQs. It turns the equalizer into oscillator. If there's any interest I will start a new topic about it.

Please do so, Lukasz!

Jakob E.

 

[CJ]

I found this calculator on the web. I like it:

http://www.cvs1.uklinux.net/cgi-bin/calculators/ind_imp.cgi

Don't forget to set the multipliers, use 1 for henries, 1 for ohms, etc.

Here is a good ref for ferrite material:

http://www.amidon-inductive.com/aai_ferritecores.htm

cj