Loading
 
     
 
 
 
     
  << Go Back to Transformers  
     
   

Microphone Transformers

 
     
 
Microphone Input
  Click on the Image to View Full-Size

Microphone transformers are normally used for impedance matching:

•In mic preamplifier input circuits to match microphones to preamp amplifier circuits.
•In tube microphones for matching high impedance tube circuits to normal output impedance.
•In ribbon microphones to match very low signal, very low impedance microphone sensors to normal microphone output levels.

General properties of most Lundahl microphone transformers :
• PCB mount style
• High level capability
• Excellent magnetic and electrostatic shielding
• High mu cores (mu metal or amorphous strip core)


 
 
Type
Turns Ratio
Size
(LxWxH mm)
Max Prim. Level.
1% dist, 50Hz
(Prim. in series)
Applications  
 
LL1527
1+1 : 1+1
38x24x17
+10 dBU
200 : 200 ohms or 200 : 800 ohms
For low impedance input mic preamps such as Jensen JE-990
Lundahl, General Porpuse Transformers, LL1527
 
LL1528
1+1 : 2.5+2.5
38x24x17
+10 dBU
200 : 5 k ohms
Lundahl, General Porpuse Transformers, LL1527
 
LL1530
1+1 : 3.5+3.5
38x24x17
+10 dBU
200 : 10 k ohms.
Also used in DI-boxes 10k : 200 ohms
Lundahl, General Porpuse Transformers, LL1527
 
LL1538
1+1 : 5
+10 dBU
10 dBU

200 : 5 k ohms.
Probably the best 1:5 microphone input transformer available.

Lundahl, General Porpuse Transformers, LL1527
 
LL1538XL
1+1 : 5
38x24x20.5
+13 dBU
200 : 5 k ohms.
High level version of LL1538
Lundahl, General Porpuse Transformers, LL1527
 
LL1550
1+1+1+1 : 4+4
30x22.5x14.5
+2 dBU
200 : 3.2 k ohms if used 1:4.
Many other connections possible.
Lundahl, General Porpuse Transformers, LL1527
 
LL1570
1+1 : 1+1
38x24x17
+10 dBU
200 : 200 ohms or 200 : 800 ohms
For low impedance input mic preamps such as Jensen JE-990
Lundahl, General Porpuse Transformers, LL1527
 
LL1571
1+1 : 1.75 + 1.75
38x24x17
+10 dBU
200 : 2.5 k ohms.
Lundahl, General Porpuse Transformers, LL1527
 
LL1576
1+1 : 7
38x24x17
+10 dBU
200 : 10 k ohms.
Same pinout as LL1538
Lundahl, General Porpuse Transformers, LL1527
 
LL1577
1+1 : 14
38x24x17
+10 dBU
50 : 10 k ohms.
Same pinout as LL1538. For low impedance source.
Lundahl, General Porpuse Transformers, LL1527
 
LL1578
1+1 : 10
38x24x17
+10 dBU
50 : 5 k ohms.
Same pinout as LL1538. For low impedance source.
Lundahl, General Porpuse Transformers, LL1527
 
LL1578XL
1+1 : 10
38x24x20.5
+13 dBU
50 : 5 k ohms.
Same pinout as LL1538. For low impedance source.
Lundahl, General Porpuse Transformers, LL1527
 
LL1587
1+1 : 4
26x17x12
+2 dBU
200 : 3.2 k ohms.
Small size.
Lundahl, General Porpuse Transformers, LL1527
 
LL1636
1+1+1+1 : 10+10
30x22.5x14.5
-14 dBU
Mic Input. DI-box. Moving coil input.
Lundahl, General Porpuse Transformers, LL1527
 
LL1935
1+1 : 5+5
38x23x16
+7 dBU
DI (Direct Input) used 10:1.
Mic input 200 : 20k.
Lundahl, General Porpuse Transformers, LL1527
 
LL1936
(2+1) + (2+1) : 4 + 4
48x29x20
+14 dBU
Can be connected for 75, 150, 300 and 600 ohm microphones into
1200 ohms
Lundahl, General Porpuse Transformers, LL1527
 
LL7903
1+1+1+1 : 2+2+2+2
66x32x21
+16 dBU
200 : 13 k ohms (used 1:8)
This is the ultimate microphone input transformer, designed for high quality tube equipment.
Lundahl, General Porpuse Transformers, LL1527
 
LL7905
1+1+1+1 : 5.6 + 5.6
66x32x21
+16 dBU
High level 600 ohms tube amplifier mic/line input
(used 2 : 11.2) Designed for high quality tube equipment.
Lundahl, General Porpuse Transformers, LL1527
 
Special application microphone transformers.
These are normally used as microphone output transformers.
           
Type
Turns Ratio
Size
(LxWxH mm)
Applications
Comments  
 
LL1940
9: 1+1
31 x 25 x 16
Tube microphones
Silicon-iron C-core, which results in a transformer with more "transformer sound character", compared to a classic mu metal lamination transformer. PCB mount style. Lundahl, General Porpuse Transformers, LL1527
 
LL2912
1: 37
27 mm x
diam. 18.5
Ribbon microphones
Amorphous core. Flying leads. No housing Lundahl, General Porpuse Transformers, LL1527
 
LL2913
1+1+1+1:37
30x22.5X14.5
Ribbon microphones
Amorphous core. PCB version of LL2912. With mu metal housing. Lundahl, General Porpuse Transformers, LL1527
 
LL2914
1+1+1+1:37
38 x24X17
Ribbon microphones
Mu metal core version of LL2913. Lundahl, General Porpuse Transformers, LL1527
 
LL2915
1:37
38mm xdiam.22
Ribbon microphones

Mu metal lamination core. Flying leads. No housing

Lundahl, General Porpuse Transformers, LL1527
 
LL1927A
1+1: 55+55
30x22.5x14.5

Ribbon microphones
(used 1:110)

Amorphous core. Normally requires active output stage

Lundahl, General Porpuse Transformers, LL1527