Question on Tango XE-20S

[MlinarS]

Hello,
Can any of you guys please help with information on maximum current rating for Tango XE-20S OPT. Or if anyone can provide link to a WEB site that lists the parameters it would be very appreciated.
Thank you

[Alain Dupont]

MlinarS

Tango XE-20S OPT

Look at:

http://purer.myrice.com/trans/tango.htm

Regards.

Alain.

[tubetvr]

Can any of you guys please help with information on maximum current rating for Tango XE-20S OPT.

It depends on which one, i.e what the primary impedance is, as an example the one I am using in my SET is XE-20S-600 with 600 ohm primary made especially for 6C33C and is optimised for ~200mA. For other XE-20S Tango gives design current value as 80mA for types with 5, 3.5 and 2.5kohm primary impedance but the lower impedances can take more current for same low frequency limit, max allowed current is 160mA.

See here for data taken fom Noguchi Transformer WEB page and translated:

Primary 5kohm (160mA or less) Secondary 8Ù and 16Ù
The first inductance/16H or more (DC80mA)
Electric power loss 0.26dB(16ohm)
The maximum output 20W(50HZ)
Frequency 35-70KHZ(±2.0dB)

Primary 3.5kohm (160mA or less) Secondary 8Ù and 16Ù
The first inductance/16H or more (DC80mA)
Electric power loss 0.33dB(16ohm)
The maximum output 20W(40HZ)
Frequency 25-90KHZ(±2.0dB)

Primary 2.5kohm (160mA or less) Secondary 8Ù and 16Ù
The first inductance/16H or more (DC80mA)
Electric power loss 0.47dB(16ohm)
The maximum output 20W(35HZ)
Frequency 20-90KHZ(±2.0dB)


Note that SE transformers are optimised for a certain current where they perform best, if the current is too high there will be loss at low frequencies and if current is too low there will be higher distortion and more high frequency loss than with an optimum sized transformer.


Regards Hans

[MlinarS]

Hi,
Alain and Hans thank you for information. Hans are you happy with performance of the transformer?
I like idea of being able to play with diferent impedances of the primary but I'm a bit concerned about the following:
1) The Tango is rated at 80mA for the optimal performance. The output stage of my amp runs at 90mA. I don't know how will this afect the overal performance.
2) The secondary on Tango has tabs for 8 and 16 Ohm. The speakers I have are rated 8 Ohm but I'm surre they go dovn to 6 or lower. Also don't know what imact will this have on the overal performance.

I didn't purchase Tangos jet so I'm not obligated to buy them but I heard so many good things about their performance.
Any opinions?

Thank you.

[tubetvr]

Hans are you happy with performance of the transformer?

Yes, I think that Tango transformers are very good and that is also confirmed by many in measurements and subjective comparisons but maybe they are a bit costly, the amp I have with the XE-20S measures and sounds well so I can recommend the transformer.

The Tango is rated at 80mA for the optimal performance. The output stage of my amp runs at 90mA. I don't know how will this afect the overal performance.

This will have a small effect on the low frequency response but probably not noticeable.

The secondary on Tango has tabs for 8 and 16 Ohm. The speakers I have are rated 8 Ohm but I'm surre they go dovn to 6 or lower. Also don't know what imact will this have on the overal performance.

Shouldn`t cause any problem at all, the idea is to connect speakers with 8 ohm nominal impedance to the 8 ohm tap, a 8 ohm speaker will always have a dip somewhere the goes lower than 8 ohms but it has always been like that and as long as you dont use any extreme speaker design disasters that goes down very low it should be OK.

A probably bigger problem is the output impedance of a SET amp, if it is in the normal range of ~2 - 4 ohms then the frequency response especially in the low end can be greatly effected so check how your speakers sound with a SET amp before you build one or use feedback.

Regards Hans

[MlinarS]

Hi,
The calculated output resistance of the amp is 2.2 Ohm. This calculations are based on the load line with slope of 2K5. Do you think that this high resistance will couse early roll off at low end.

Thank you.

[tubetvr]

Do you think that this high resistance will couse early roll off at low end.

On the contrary, the problem with high output impedance is that the speaker will give a peaky response at the resonance peak where the impedance is much higher than the nominal, 20 or even 40 ohm is not unusual for a 8 ohm speaker.

Another related problem is that most speakers have a rising impedance at very high frequencies, for instance my Lowthers are ~20ohm at 15kHz which gave a pake in the response when I was using these speakers with a SET amp, I introduced a correction by paralleling the speaker terminals with a series combination of 1.5uF and 12ohm which compensated for the peak so the impedance stayed between 7 and 9 ohms for the whole range from 1kHz to 20kHz.

Regards Hans

[MlinarS]

Thank you Hans.