Lundahl Interstage transformer, LL1671-PP

High Current Tube Amplifier Interstage / Line Output Transformer LL1671-PP

LL1671 is a high current interstage / line output transformer for tube amplifiers. The transformer is available with various core air gaps optimised for PP or SE drives. The transformer is wound with a special low capacitance winding technique to achieve best high frequency performance. The transformer has a special high flux, low distortion audio C-core of our own production. The LL1671PP is assembled with a small core air gap to allow for some DC current unbalance. For the S.E. versions of the LL1671, the core air gap is chosen such that the denoted DC current (30mA for a LL1671/30mA) generates a no signal core flux density of 0.9 Tesla when used with all primaries in series. This leaves a flux density swing of 0.7 T for the signal.

Weight: 0.75 kg
Turns ratio: 1+1+1+1 : 2+2
Static resistance, Winding A 88 ?
Static resistance, Winding B 69 ?
Static resistance, Winding C 156 ?

Max. current through any single section: 100 mA
Isolation between primary and secondary windings / between windings and core: 4 kV / 2 k

(*) The source impedances used in the tables indicates a recommended upper limit, unless freq. response can be compromised. At lower source impedance resonance peaking will occur. It can be reduced using secondary load resistors.