Lundahl Interstage transformer, LL1635-20mA

Tube Amplifier Interstage Transformer LL1635-20mA

LL1635 is an interstage transformer for tube (valve) amplifiers available in Push-pull or Single-end versions. The transformer is highly sectioned, and wound with a special low capacitance winding technique which results in very good frequency response. The transformer has a special high flux, low distortion audio C-core of our own production. NOTE: LL1635 is not suitable for SE to PP interstage. For this application we suggest transformer LL1660 or LL1660S.

Turns ratio 1+1 : 1+1
Static resistance, each primary 500 W
Static resistance, each secondary 500 W
Weight 0.5 Kg

Primary DC current, primaries in series (for B0 = 0.9T) 20 mA
Maximum DC current before saturation, primaries in series 35 mA
Primary inductance (primaries in series) 30 H
Frequency response, primaries in series 20 Hz -75 kHz
(Source 4 kW for PP and 5mA, 2 kW for 20 mA. Load 68 pF) +/- 1 dB
Group delay @ 20 kHz (Source and load as above) 0.5s
Max. output voltage @ 30 Hz 2x90 V peak (tot. 125Vrms)
Recommended max DC current through any primary section 40mA
Isolation between primary and secondary windings / between windings and core 4 kV / 2 kV