
High Current Tube Amplifier Interstage Transformer
LL1677
LL1677 is a high current interstage transformer with a 1:2 step up ratio.
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.
For the LL1677, the core air gap is chosen such that the denoted DC current (80mA for a LL1677/80mA)
generates a no signal core flux density of 1.2 Tesla when used with all primaries in series. This leaves a flux
density swing of 0.4 T for the signal.
Winding schematics, physical dimensions, pin and mounting hole layout (all dimensions in mm)
Weight Turns ratio Static resistance,
Winding A
Static resistance,
winding B
Static resistance,
winding C
0.75 Kg 1+1+1+1 : 4 + 4
88
Ω
69
Ω
800
Ω
Max. current through any single primary section: 100 mA
Isolation between primary and secondary windings / between windings and core: 4 kV / 2 kV
Type
LL1677/80mA
Connection Alt A
SE to SE Interst.
1 : 2
Primary DC current for
1.2 Tesla
80 mA
Primary Inductance 24 H
Suggested termination for best
freq. response
22k in series with
330 pF
Freq. Response (+/-1dB) @
source impedance (*)
Secondary terminated as above
23Hz - 34 kHz
1 k
Ω
Max output
voltage @ 30 Hz
145 V r.m.s.
(410V peak-peak)
73
Bottom view
4 x M3
Mounting holes
36
56
53
61
Tibeliusgatan 7 International Domestic
S-761 50 NORRTÄLJE Phone +46 - 176 13930 0176-13930
SWEDEN Fax +46 - 176 13935 0176-13935
2 3 4 5 7 8 9 10
13 16 18
21
13
16
4
3
5
2
21
18
A
B
8
9
B
7
10
A
C
C
3
2
4
5
7
8
9
10
16
13
18
21
V+
To grid
Alt. A
1 : 2
Single End to Single End Interstage
R020128