Трансформатор LUNDAHL LL1620. Инструкция на английском языке

Tibeliusgatan 7                        International    Domestic
LUNDAHL                        S-761 50 NORRTALJE          Phone    +46 - 176 13930   0176-13930
TRANSFORMERS                SWEDEN                      Fax      +46 - 176 13935   0176-13935
Tube Amplifier Output Transformers
LL1620 , LL1623, LL1627, LL9202
The LL1620, LL1623, LL1627 and LL9202 are output transformers for tube amplifiers. All transformers are based on the
same core size, winding structure and secondaries, but differ in number of turns (and thus impedance level) of primaries.
The transformers are highly sectioned with harmonically sized sections, which results in a minimum leakage inductance.
This, combined with a low capacitance coil winding technique results in a wide frequency range.
The transformers have a special audio C-core of our own production, which is gapped for desired DC current.
The transformers are of open frame type suitable for mounting inside an amplifier housing.
Physical dimensions, pin and mounting hole layout for LL1620, LL1627 (all dimensions in mm)
53
Primary connections                                             Secondary connections
18 17 16 15   14 13 12 11
4 x M4
Mounting holes
90
110
Bottom view
1  2  3  4   5  6  7  8                                              26 25 24 23   22 21 20 19
78                             85
Physical dimensions, pin and mounting hole layout for LL1623, LL9202 (all dimensions in mm)
Primary connections                  53                          Secondary connections
1      2   5      6                                                  18 17 16 15   14 13 12 11
4 x M4
Mounting holes
90                            110
Bottom view
3      4   7      8                                                  26 25 24 23   22 21 20 19
78                            85
R031020
LL1620, LL1623, LL1627, LL9202
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Pin spacing module:                                             5.08 mm  (0.2")
Weight:                                                         2.5 kg
Winding schematics:
Coil 1                       Coil 2
3     1        4    2         6    8          5    7
14  22   13  21   20  12   11  19   23  15   16  24   25  17   26  18
« outer      inner »
« inner     outer »
The inner windings have a lower copper resistance due to smaller circumference
LL9202              LL1620            LL1623            LL1627
Turns ratio:                    4 x 26.5 : 8 x 1   4 x 19.2 :  8 x 1   4 x 13.4 : 8 x 1   4 x 8.5 : 8 x 1
Static resistance of primary   600 W (4 • 150 W )   308 W (4 • 77 W )   164 W (4 • 41 W )   56W  ( 4 •14 W )
(all in series)
Static resistance of each           0.4 W               0.4 W             0.4 W             0.4 W
secondary (average)
Primary leakage inductance         20 mH               11 mH             4.6 mH             1.9 mH
(all in series)
Max. recommended primary           125 mA              150 mA            210 mA            350 mA
DC current (heat dissip. 7W)
Max. primary signal voltage   Push-Pull   Single End   Push-Pull  Single End  Push-Pull  Single End  Push-Pull  Single End
r.m.s. at 30 Hz  (all in series)   1180V   525V    860V     380V     610V     270V      380V     170V
Isolation between primary and secondary windings / between windings and core:  3 kV / 1.5 kV
Standard types:    LL9202 / PP       LL9202 / 50mA      LL9202 / 85mA
LL1620 / PP       LL1620 / 40 mA     LL1620 / 60 mA      LL1620 / 80 mA
LL1623 / PP       LL1623 / 60 mA     LL1623 / 90 mA      LL1623 / 120 mA
LL1627 / PP       LL1627 / 90 mA     LL1627 / 140 mA     LL1627 / 185 mA
Other sub-types available on request.
Frequency response example:
The frequency response is dependent on transformer type and connection alternative.
For the LL1623 / 90 mA, connection alt. C,  with    R SOURCE = 650 W
R LOAD = 8 W
you get:
Frequency response          7 Hz - 25 kHz   +/- 0.5 dB
Phase Shift                 @ 20 Hz       2°
@ 20 kHz      13.5°
Group delay (dj/dw)         @ 20 kHz      2.2 µs
LL1620, LL1623, LL1627, LL9202
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Electrical characteristics
Primary Load Impedance,   Primary DC Current    Core Air-gap  and   Maximum Output Power
Secondary connection for 4/8/16 W                   Core Airgap (Delta/2)
(See next page)
-/B/C     B/C/D      C/D/E        25 µ         125 µ           190 µ           250 µ
(Push-Pull)   (Single Ended)   (Single Ended)   (Single Ended)
Primary Load Impedance                      DC current for 0.9 Tesla (rec. operating point)
(transformer copper resistance included)                   Primary Inductance
LL1627     2.3 kW     1.2 kW    0.65 kW    Push-Pull       90 mA          140 mA          185 mA
60 H          18 H            12 H             9 H
LL1623     5.6 kW     3.0 kW    1.6 kW     Push-Pull       60 mA           90 mA          120 mA
150 H          46 H           30 H            23 H
LL1620     11.5 kW    6.0 kW    3.3 kW     Push-Pull       40 mA           60 mA          80 mA
300 H          90 H           60 H            45 H
LL9202      23 kW     11 kW     6.5 kW     Push-Pull    50 mA / 225µ    85 mA / 400µ
570 H         100 H           57 H
Output Power and Loss
62W       125W       250W          Max. Power, Push-Pull at 30 Hz
All types    13W        25W       50W          Max. Power, Single Ended at 30 Hz
0.2 dB     0.5 dB     0.8 dB            Loss across transformer
Our recommendations on how to choose your tube output transformer:
Push-pull output stages:
All our push-pull output transformers have a 25 microns core air gap to allow for a small DC unbalance of your output
circuits.
Step 1    From your secondary load impedance (4, 8 or 16 ohms), we suggest a secondary connection alternative with 0.5
dB loss. This will give you a maximum power limit of 125W at 30 Hz, and a LF -1 dB point at 6.4 Hz for
pentodes and lower still for  triodes.
If you require more headroom at low frequencies, the 0.8 dB loss alternative expands the LF limit one octave.
Step 2    Your tube choice gives you a desired primary load impedance. Select the transformer type having a primary load
impedance which best matches the desired impedance.
The LL1623 (5.6 kW plate-to-plate impedance) or the LL1620 (6.0 kW plate-to-plate impedance) suits many
tubes like the 300B triode or the EL34 pentode. The 6C33 (low voltage, high current) requires a transformer
LL1627 while high anode voltage tubes require the high impedance of the LL1620.
Footnote:  In class A push-pull, each tube will see a load impedance = 1/2 transformer primary load impedance.
In class B push-pull, each tube will see 1/4.
Single-end output stages:
The core of Single End output transformers have an airgap. The purpose of the airgap is to accept the DC current of the
output tube without saturating the core, leaving enough headroom for the sound signal. As a result of the airgap, the primary
inductance is lower for SE output transformers compared to P-P dittos. In addition, the inductance tends to vary with DC
current.  For our high quality C- cores with carefully ground surfaces, the variation is within +7% of rated value.
Step 1    We recommend that, given your secondary load impedance (4, 8 or 16 ohms), you select a secondary connection
alternative with 0.5 dB loss. This will give you a power limit of 25 W at 30 Hz. If you find that you require more
bass headroom, select a secondary connection alternative with 0.8 dB loss.
Step 2    From the tube load line you determine a primary load impedance. This results in a choice of transformer main
type.
Step 3    From the tube data sheet you also select your desired DC current. From the table above you select the transformer
subtype (DC current) which best fits your needs.  For many tubes such as the 300B and the EL34, the transformer
LL1623 / 90 mA is the ideal choice.
Step 4    We define Power Low Frequency Limit, F PL, as the frequency where wL P = R LOAD. (The reactive impedance of
the transformer equals the primary load impedance). At F PL, the output power is reduced to 50%. For the
LL1623 / 90 mA in a 0.5 dB loss connection, F PL = 16 Hz  (R PRIMARY = 3.0 kohms  and L P = 30H).
Step 5    We define Response Low Frequency Limit, F RL as the frequency where a (small) output signal is reduced with
-1 dB due to finite primary inductance. F RL = w / p, if you solve w in
wL P = (R LOAD  in parallell with R ANODE).
For the LL1623 / 90 mA and a 300B triode, F RL  =   7 Hz. (R ANODE = 650 ohms, R PRIMARY = 3.0 kohms and L P =
30H),
LL1620, LL1623, LL1627, LL9202
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