Lundahl Transformers

Tibeliusgatan 7, 761 50 Norrtälje

Phone: +46 176 139 30

Fax: +46 176 139 35

September 2019

LL5607

September 9th, 2019|

LL5607 is a C-core line output transformer designed for Calrec Audio, probably used as a 1.5 : 1 transformer. LL5607 has an internal Faraday shield and a mu metal housing. Pin configuration (as seen from PIN side) 6, 5, 4, 3, 2, 1 12, 11, 9, 8, 7 Usage (1.5 : 1): in+ pin 1 [...]

April 2019

LL2612

April 30th, 2019|

LL2612 is a line input transformer, 1:1, with double Faraday shields. LL2612 pin-out (pin side) 4, 2, 1 8, 7, 6, 5 In + 1 In - 4 Shield in 2 Out+ 8 Out- 5 Shield out 6 Housing 7

January 2018

LL1522

January 9th, 2018|

LL1522 is a high impedance line input transformer, normally used 2:1 It has been discontinued for many years. LL1522 pinout (pin side) 4, 3, 2, 1 8, 7, 6, 5 For high impedance line input, 2:1 use as follows: In+ 4 In- 2 Connect 1+3 Out+ 8 + 5 Out- 7 Ground (shield) 6

December 2017

Calrec line output LL5608

December 6th, 2017|

LL5608 is a line output transformer designed for Calrec Audio, turns ratio 1.55+1.55 : 1+1 Pin configuration (as seen from PIN side) 7,  6,  5,  4,  3,  2,  1               14, 13, 12,     10,  9,  8 Usage (1.55 : 1 ) in+ pin 1 in- pin 5 connect pin 7 + 3 out+ pin 8 out- pin 12 connect pins 10 + 14 Housing [...]

November 2016

I have bought some LL1673/10H from you, but the measured inductance (with my inductance meter) is only 6H. What is wrong?

November 1st, 2016|

Our power supply chokes are designed to work at 100/120Hz and with voltages around 100V. Most induction meters work at a few volts or less, at around 1kHz. This is not the correct operating point for a power supply choke, and the reading on the induction meter is usually around half the specified value of [...]

September 2016

LL5006

September 12th, 2016|

LL5006 is a line output transformer designed for the Danish company NTP Turns ratio 1.2 : 1 + 1 5      4     3     2    1 10    9          7     6 Usage (for 1.2 : 2 line output) in+ pin 5 + pin 1 in- [...]

November 2015

Is there a CAD library for Lundahl Transformers products?

November 19th, 2015|

EAGLE CAD Lundahl library (created by Bob Starr of RTZ Audio): https://cadsoft.io/resources/libraries/?query=lundahl CADSoft EAGLE PCB Design Software is a CAD software available for a number of different platforms. A limited function version is available free of charge for personal use. Please see http://www.cadsoft.io for downloads.

October 2015

What could be the possible disadvantage to use LL1540 (line input transformer) as output transformer?

October 23rd, 2015|

An audio line is a cable transferring an audio signal from the output of one device to the input of another. Normally the input impedance is fairly high, >1k for mic preamps and >10k for line inputs. If the impedances in both ends of an audio line are high, any noise current picked up by [...]

September 2015

What is the sound difference between mu metal and amorphous core transformers?

September 16th, 2015|

Many customers ask us for the difference in sound between our mu metal lamination transformers and our strip core amorphous transformers. We have forwarded the question to Kevin Carter at K&K Audio. Here are his impressions: “When I first encountered the Lundahl LL1544A and LL1545A line level transformers, which use the same coils, but these [...]

June 2015

LL1660s Data Sheet Confusion. How come an LL1660S/10mA is used at 18mA?

June 22nd, 2015|

I guess you are right. It _IS_ confusing. If we assume a certain DC current, there are two ways to reach a desired core operating point: 1. With a given coil, adjust the core air-gap or 2. With a given core air-gap, adjust the number of turns on the coil The type number LL1660S/18mA is [...]