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Destroyer x Amplifier...Dx amp...my amplifier
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Old 17th April 2009, 09:30 AM   #5981
SDF is online now SDF  France
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Can I use only one pair of output transistor with supply rail of +/-40V ?...and without changing anything else in the schematic?
 
Old 17th April 2009, 01:01 PM   #5982
destroyer X is offline destroyer X  Brazil
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Default Yes, you can.. and without need to change things


No problems.

regards,

Carlos
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Restriction removed ; ttps://www.youtube.com/watch?v=3ioyOjAzDt0; https://www.youtube.com/watch?v=uFcnddpe3MU
 
Old 17th April 2009, 01:38 PM   #5983
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Thanks!
 
Old 17th April 2009, 09:22 PM   #5984
destroyer X is offline destroyer X  Brazil
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Default Sounds alike this one


http://www.youtube.com/watch?v=warJLziW6gk

This one uses the same schematic, same topologie...sound is almost the same.

Also you have, into youtube, audio testing made with the Dx Amplifier:

http://www.youtube.com/watch?v=SoZA5f7wJhM

regards,

Carlos
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Restriction removed ; ttps://www.youtube.com/watch?v=3ioyOjAzDt0; https://www.youtube.com/watch?v=uFcnddpe3MU
 
Old 18th April 2009, 10:44 PM   #5985
destroyer X is offline destroyer X  Brazil
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Default It is very important to use a good supply to the Dx Amplifier


I will show you my supply, the one used to test.

It is using, now a days, 27000uf plus 27000uf.

The voltage without load is 44 plus 44 volts.

When i am draining 2.6 amperes each rail the voltage goes to the nominal voltage suggested to the Dx Amplifier, 36 plus 36 volts.

So, the supply is correct to the amplifier.... when producing 100 watts over 4 ohms loads, the voltage will be the correct one....

Using it to 8 ohms loads you gonna have much more than 50 watts RMS, as voltage drop will be smaller.

Here you can see the supply voltage.

Under load conditions... supply is loaded with 14 ohms resistance (2 resistances of 7 ohms and 70 watts each one of them)

regards,

Carlos
 
Old 18th April 2009, 10:46 PM   #5986
destroyer X is offline destroyer X  Brazil
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Default Here you can see the current beeing measured


The supply was measured using 7500uf plus 7500uf as filters.

regards,

Carlos
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File Type: jpg rail consumption when voltage is 36 volts.jpg (88.2 KB, 433 views)
 
Old 18th April 2009, 10:50 PM   #5987
destroyer X is offline destroyer X  Brazil
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Default Here you can see the ripple.... and this was measured


while the supply was loaded..... a rail beeing loaded and the ripple was around 1 volt peak to peak.

Observe the scope channel two is adjusted to 1 volts peak to peak... this represents a very small power into 8 ohms speaker.

The amplifier will be producing more than 100 watts RMS, while the mains noise, the ripple power, will be lower than 50 miliwatts RMS...so... you will not even listen.

So.... when reproducing music, full power, you will not have strong mains frequency noises (ripple) mixed with your audio.

regards,

Carlos
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File Type: jpg 25k filters, even this way, this is ripple..jpg (98.7 KB, 421 views)
 
Old 18th April 2009, 10:57 PM   #5988
destroyer X is offline destroyer X  Brazil
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Default What this really means.


If you plug a 8 hertz tone into your amplifier, and adjust to full power.... or 100 watts RMS into 4 ohms loads, then you will not listen audio, as 8 hertz is not audible to humans...you feel vibrations only..... but if you have ripple, then you will listen the ripple..in our case..this small ripple is almost inaudible..you have to almost touch the speaker diafragm with your ears to listen it clear...and may receive a big punch from the speaker into your

face.... be carefull with that..also air pressure into your ears may be dangerous..use some cotton to attenuate.

Well...you may say:

- "What a hell.... who cares about no audible tones.... what's the advantage not to listen noises when i am also not listening to the tones"

Well..this will happens with music too..with the tones you listen..they will not have this dirty ripple poluting your audio clarity.

5000uf each rail to each ampere is the minimum filter...better to use more than that.... i am using, now a days, 27000uf each rail, not only to the Dx Amplifier, but also to the DHR Turbo.

regards,

Carlos
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File Type: jpg dhr turbo supply.jpg (90.3 KB, 419 views)
 
Old 18th April 2009, 11:03 PM   #5989
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Default I have increased my DHR Turbo supply that was not using all the capacitance needed


This way i have reduced the 2.8 volts peak to peak ripple to less than 1 volts peak to peak.

Capacitance increased from 12.000uf plus 12.000uf to 27.000uf plus 27.000uf.

And i really think that 40K each rail would be even better.

regards,

Carlos

.................................................. ............................................

Before this encreasing in capacitance i was able to listen some noise..some ripple...not difficult to listen...but now a days sittuation is much better.
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File Type: jpg fotos 3480.jpg (40.3 KB, 439 views)
 
Old 21st April 2009, 05:08 AM   #5990
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Default Re: I have increased my DHR Turbo supply that was not using all the capacitance needed

Quote:
Originally posted by destroyer X

This way i have reduced the 2.8 volts peak to peak ripple to less than 1 volts peak to peak.

Capacitance increased from 12.000uf plus 12.000uf to 27.000uf plus 27.000uf.

And i really think that 40K each rail would be even better.

regards,

Carlos

.................................................. ............................................

Before this encreasing in capacitance i was able to listen some noise..some ripple...not difficult to listen...but now a days sittuation is much better.


Carlos, would you recommend CRC with 15,000 uF --R-- 15,000 uF or is it better to drop the resistor and do a 30,000K straight capacitor power supply (each rail) with DX II?
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