|
=
Output=20
Transformer =
Testing |
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|
| The results of Transformer testing underline =
herewith are=20
performed under following scenario: =20
Associated=20
Test Equipments: |
|
Fig.1 |
|
The=20 Frequency Response Testing according to Fig.1 represents = the=20 ability of each transformer to perform under real working=20 condition with 70mA unbalanced DC at relatively high power = level=20 (18Vp-p output or 5 Watts RMS to 8 ohms load). = |
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The=20 Pulse Behavior (square wave) Testing according to Fig.2 = represents=20 the ability of each transformer to response to perfect = square=20 waveform. Since square waveform composes of fundamental = frequency=20 plus indefinite number of harmonic 2nd, 3rd, 4th, 5th and = so on.=20 This test puts transformer to its extreme condition. = Output=20 Transformer must handle high number of harmonics at one = pulse=20 cycle and will show out its unique characteristic. Good = transformers =20 could be observed by smooth waveform with minimal raise/fall = time. Good =20 transformers also exhibit less ringing behavior even at = high power=20 level. |
|
Model Picture |
Brand |
Silk Transformer |
|
|
Model |
S-325 |
|
Description |
3K/20Watts output transformer with EI (M6) =
Lamination.=20
Although S-325 can not go as high as Tango XE-20S but =
comparable=20
to U-808. It has smooth waveform response. (No peak, No =
dip) With=20
its high inductance, S-325 also performs very well in bass =
region.=20
(see 40Hz waveform that tilt less than =
U-808) | |
|
Primary Impedance (ohm) |
3.0K | |
|
Secondary Impedance (ohm) |
8 | |
|
Primary DCR (ohm) |
197 | |
|
Primary Inductance (H) |
19.6H/16.5H | |
|
Leakage Inductance (mH) |
2.8mH/7.5mH | |
|
Quality Factor (Pi/Li) |
7000/2200 | |
|
Primary Capacitance (nF) |
1.15nF/102.9nF | |
|
Frequency Response |
||
|
Square Wave Picture | ||
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|
| |
|
40 Hz |
1 KHz | |
|
|
| |
|
10 KHz |
20 KHz |
|
Model Picture |
Brand |
Tango |
|
|
Model |
XE-20S |
|
Description |
Universal output transformer with oriented hi-B =
cut core.=20
With hi-B core, the transformer has lower primary turn =
(Less=20
copper loss) than U-808 but also lower primary inductance. =
Excellent High Frequency response that could go above 100KHz =
but=20
be observed the small ringing waveform. | |
|
Primary Impedance (ohm) |
3.5K | |
|
Secondary Impedance (ohm) |
8 | |
|
Primary DCR (ohm) |
114 | |
|
Primary Inductance (H) |
12.2H/10.7H | |
|
Leakage Inductance (mH) |
6.3mH/13.4mH | |
|
Quality Factor (Pi/Li) |
1936/798 | |
|
Primary Capacitance (nF) |
1.9nF/154nF | |
|
Frequency Response |
||
|
Square Wave Picture | ||
|
|
| |
|
40 Hz |
1 KHz | |
|
|
| |
|
10 KHZ |
20KHZ |
|
Model Picture |
Brand |
Tango |
|
|
Model |
U-808 |
|
Description |
Universal output transformer with EI core. The=20
transformer processes very linear frequency response with =
smooth=20
waveform. Due to its small core size, it has limited =
primary=20
inductance compare to other big irons. | |
|
Primary Impedance (ohm) |
3.5K | |
|
Secondary Impedance (ohm) |
8 | |
|
Primary DCR (ohm) |
210 | |
|
Primary Inductance (H) |
17.1H/14.8H | |
|
Leakage Inductance (mH) |
5.7mH/117.8mH | |
|
Quality Factor (Pi/Li) |
3000/125 | |
|
Primary Capacitance (nF) |
1.4nF/116nF | |
|
Frequency Response |
||
|
Square Wave Picture | ||
|
|
| |
|
40 Hz |
1 KHz | |
|
|
| |
|
10 KHz |
20 KHz |
|
Model Picture |
Brand |
Audio Note |
|
|
Model |
Trans-152 |
|
Description |
2.5K non-potted output transformer with M6 EI =
core.=20
Although it has small primary turn (around 1,800T-1,900T) =
due to=20
its large core size, TRANS-152 has moderate primary =
inductance. A=20
dip in frequency response presents at 40KHz. Waveform is =
on=20
par. | |
|
Primary Impedance (ohm) |
2.5K | |
|
Secondary Impedance (ohm) |
4, 8 | |
|
Primary DCR (ohm) |
157 | |
|
Primary Inductance (H) |
13.5H/14.13H | |
|
Leakage Inductance (mH) |
11.33mH/15.41mH | |
|
Quality Factor (Pi/Li) |
1,015/916 | |
|
Primary Capacitance (nF) |
1.88nF/133nF | |
|
Frequency Response |
||
|
Square Wave Picture | ||
|
|
| |
|
40 Hz |
1 KHz | |
|
|
| |
|
10 KHZ |
20KHZ |
|
Model Picture |
Brand |
Golden Tube |
|
|
Model |
SE-40 |
|
Description |
1.9K SE parallel output transformer extracted =
from Golden=20
Tube Audio model SE-40. Perform well considering it was =
mass=20
product in mid range price. | |
|
Primary Impedance (ohm) |
1.9K | |
|
Secondary Impedance (ohm) |
8 | |
|
Primary DCR (ohm) |
120 | |
|
Primary Inductance (H) |
8H/10H | |
|
Leakage Inductance (mH) |
NA | |
|
Quality Factor (Pi/Li) |
NA | |
|
Primary Capacitance (nF) |
NA | |
|
Frequency Response |
||
|
Square Wave Picture | ||
|
|
| |
|
40 Hz |
1 KHz | |
|
|
| |
|
10 KHz |
20 KHz |
|
Model Picture |
Brand |
James |
|
|
Model |
JS-6123HS |
|
Description |
Universal output transformer with EI core that =
performs=20
far behind Tango U-808. Observe the big -12.0dB dip at =
around=20
80KHz and bounce up to resonant up to =
2.0MHz! | |
|
Primary Impedance (ohm) |
3.5K | |
|
Secondary Impedance (ohm) |
8 | |
|
Primary DCR (ohm) |
181 | |
|
Primary Inductance (H) |
12.6H/13.9H | |
|
Leakage Inductance (mH) |
167mH/NA | |
|
Quality Factor (Pi/Li) |
75.4/NA | |
|
Primary Capacitance (nF) |
2.0nF/124nF | |
|
Frequency Response |
||
|
Square Wave Picture | ||
|
|
| |
|
40 Hz |
1 KHz | |
|
|
| |
|
10 KHz |
20 KHz |
|
Model Picture |
Brand |
Hammond |
|
|
Model |
|
|
Description |
5K output transformer with EI (M6) lamination. =
It has=20
highest inductance in the group but also has excessive =
primary DCR=20
of over 400 ohms! (A lot of copper loss) Hammond has 10 to =
15KHz=20
frequency dip of -4.0dB! The waveform is anomaly beyond=20
5.0KHz. | |
|
Primary Impedance (ohm) |
5K | |
|
Secondary Impedance (ohm) |
8 | |
|
Primary DCR (ohm) |
439 | |
|
Primary Inductance (H) |
64.5H/40.78H | |
|
Leakage Inductance (mH) |
28.7mH/40.5mH | |
|
Quality Factor (Pi/Li) |
2247/1006 | |
|
Primary Capacitance (nF) |
374pF/43.05nF | |
|
Frequency Response |
||
|
Square Wave Picture | ||
|
|
| |
|
40 Hz |
1 KHz | |
|
|
| |
|
10 KHz |
20 KHz |