
Tube Amplifier Interstage Transformer
LL1635
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
Winding schematics, physical dimensions, pin and mounting hole layout (all dimensions in mm)
Weight Turns ratio Static resistance, each primary Static resistance, each secondary
0.5 Kg 1+1 : 1+1
500 Ω 500 Ω
LL1635 P-P LL1635 /5mA LL1635/20mA
Primary DC current, primaries in series ( for B
0
= 0.9T)
5 mA 20 mA
Maximum DC current before saturation, primaries in series
9 mA 35 mA
Primary inductance (primaries in series)
> 300 H 130 H 30 H
Frequency response, primaries in series
(Source 4 kΩ for PP and 5mA, 2 kΩ for 20 mA. Load 68 pF )
5 Hz - 60 kHz
+/- 1 dB
10 Hz -60 kHz
+/- 1 dB
20 Hz -75 kHz
+/- 1 dB
Group delay @ 20 kHz (Source and load as above)
0.5µs 0.5µs 0.5µs
Max. output voltage @ 30 Hz
2x220 V peak
(tot. 310Vrms)
2x90 V peak
(tot. 125Vrms)
2x90 V peak
(tot. 125Vrms)
Recommended max DC current through any primary section
40mA 40mA 40mA
Isolation between primary and secondary windings / between
windings and core
4 kV / 2 kV 4 kV / 2 kV 4 kV / 2 kV
Application examples. Interstage transformer.
70
Bottom view
4 x M3
Mounting holes
24
52
R030116
1
2
4
6
7
9
12
14
17
19
1 + 1
12
14
17
19
2
1
4
7
9
6
1 + 1
LL1635
LL1635
Push-Pull to push-
interstage
Single-end to single-
end interstage
5 mA
Indicates phase
TRANSFORMERS
Tibeliusgatan 7 International Domestic
S-761 50 NORRTÄLJE Phone +46 - 176 13930 0176-13930
SWEDEN Fax +46 - 176 13935 0176-13935