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100% Brand New and High Quality
Durable and long service life.
The spacing between the two needles is 5.0mm, 0.7mm rough for the pin.
Specifications:
Name: Audio transformer
Model: EE14
AC impedance : 1300:8
Frequency Type: High Frequency
Size:1.4cmX1.1cmX1.2cm(LXWXH)
Material: Plastic, Metal
Color: Yellow
Quantity: 5 Pcs
Net Weight: 5g/1PC
Package Includes
5x Transformers
kukareku
Reviewed in the United States on February 1, 2024
Like other reviewers said, transformer has the wrong ratio, definitely not 1300:8.
Zenbum
Reviewed in the United States on July 12, 2023
Just writing to confirm previous reviews saying these are not 1300:8.From 200 Hz to 20 kHz they consistently yield a voltage ratio of 5.1:1, which means the impedance ratio is at best 210:8.Below 200 Hz, the ratio drops gradually to about 4:1 at 20 Hz, yielding impedance of 128:8.
Moggie
Reviewed in the United States on July 2, 2022
works
Alan Yates
Reviewed in the United States on May 1, 2021
These are absolutely not 1300:8 ohm transformers. I've bought several lots of these from different sellers and they all measure about the same: The transformer winding ratio is closer to 5.1:1 than the 12.75:1 that it should be. All the "1300:8" transformers on Amazon appear to have this problem including the red ones.The primary is about 86 ohms DC resistance and 245 mH at 1 kHz. The secondary is 9.6 mH with a 3 ohm DC resistance. The primary inductance with the secondary shorted is about 1.9 mH and the secondary inductance with the primary shorted is about 65 uH. This means the coupling coefficient is about 0.996. The in-phase inductance of both windings is 341 mH and anti-phase it becomes about 165 mH, meaning the mutual inductance is about 44 mH. The mutual inductance measurement along with the coupling coefficient is consistent with a turns ratio of about 5:1 which I confirmed with open circuit voltage measurements using a few volt 1 kHz sine wave.A secondary load impedance of 8 ohms would reflect about 200 ohms to the primary, not 1300. The primary winding's impedance magnitude is also only about 1500 ohms at 1 kHz (the secondary is around 60 ohms) so it seems to be designed for fairly low impedances as one would typically want the reactance magnitudes to be at least 5 or so times the load impedances.All that said, they are a 5:1 transformer that is still useful, just not as the typical collector/drain/plate load matching application of larger ratios. They might be more useful as an interstage or with a lower impedance to get more power out with a largish standing current in a class-A amplifier. They definitely roll off quickly at lower frequencies, I suspect they were actually designed for a non-audio application. With a pair of modern 32 ohm earphones in series that 64 ohms would be reflected as about 1.6 K which is reasonable for a simple class-A amplifier delivering perhaps 20 mW with a 9V supply, but the lower frequencies would be seeing a lot more of the losses than with higher impedance windings.
Alexander Engelke
Reviewed in the United States on November 24, 2019
I completed the standard ohm resistance tests on the leads of these transformers....nothing works. I tried a second DMM and the same results were achieved. The DMM leads were aligator clipped directly to the leads on the transformer. No luck. These are absolute garbage. Don't buy.
Mr.Phil
Reviewed in the United States on April 10, 2019
I haven't bought these, but the others seem to be finding a lot of broken windings, hence 2 stars. What I add, is, Transformer impedances are Not the same thing as DC resistance of the windings. They can't be measured with a DVM in Ohms range. Transformer impedance is the circuit impedance at 1KHz for which this transformer was designed to work with low losses. The ratio of impedances goes as the square of the turns ratio or the voltage ratio. Meanwhile, the copper wire in different windings can be different. Windings with fewer turns usually have thicker wire, but no rule is strictly observed. So the DC resistance only tells you which winding has the higher impedance, not what the impedance "is". That said, it is nice to hear what the DC resistances are. The vendor usually doesn't bother to tell us...
Van
Reviewed in the United States on September 26, 2018
Only one of five worked at all
Classical Chump
Reviewed in the United States on October 27, 2017
With an ohmmeter, I measured both windings of all 5 transformers, 10 measurements in all. Not sure which to call the primary, secondary; let's call them long (1300) and short (8). On 3 of the 5 transformers, short had a resistance of ~4.5 ohms. On the other two, it was open. On 4 of the 5, long had a resistance of ~82 ohms; on the other one, it was open. This ratio, of the "good" ones, is about 40:1, not 1300:8, which is 162.5:1, off by a factor of about 4. I will try measuring the inductance to see if that accounts for the difference, but I don't have an inductance meter and will have to try the scope trick. Maybe, instead, I'll just build an amplifier and let you know how that works. Thanks for reading.
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