EC88 dirver PL84 push-pull,DIY with a picture tells a story.

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EC88 dirver PL84 push-pull,DIY with a picture tells a story.

Postby turing » Sun Jan 17, 2016 10:27 am

PL84, it is 15v of EL86, compare EL84, has a lower resistance, gifted audio born. Single-ended output is about 5w, push-pull is up to 17.5w. It can be described as a small tube big power.

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Mullard of EC88 here also have a good performance.


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British Edison PL84 superior sense of hearing.


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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby turing » Sun Jan 17, 2016 10:28 am

First test is the level hum of the machine. Amateur environmental manufacturing, has 0.7mv hum. From the size point of view, it is not very good, from the frequency analysis, the hum from the power supply filtering. 350uf electrolytic capacitor two, there is no power filter choke hum 0.7mV100Hz bring to final output, from a practical point of view, this is already small enough. 93db sensitivity JBL4425 ear does not hear.

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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby turing » Sun Jan 17, 2016 10:29 am

Distortion level whole wide for everyone concerned, the following figure provides spectrum analysis data output is 1v time.

Seen from the figure, the second harmonic distortion -60.253db about 0.095%


Third harmonic distortion -67.138db about 0.03%


Distortion far below the level hum.

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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby turing » Sun Jan 17, 2016 10:29 am

10v output distortion when what is it? 10v output power 12.5w

In this case, second harmonic distortion of about 0.4%, about 0.2% third harmonic distortion

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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby turing » Sun Jan 17, 2016 10:30 am

When output 1v sweep 20hz-20khz + -0.2db

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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby turing » Sun Jan 17, 2016 10:30 am

When sweep output 10v 20hz-20khz frequency remains outside the curve -0.2db + sound change slightly.

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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby turing » Sun Jan 17, 2016 10:31 am

Sweep and FFT spectrum analysis looks abstract, or square wave diagram to illustrate it.

The figure is a square wave 1khz

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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby turing » Sun Jan 17, 2016 10:34 am

100hz
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20hz
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10khz
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20khz
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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby turing » Sun Jan 17, 2016 10:35 am

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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby Geek » Sun Jan 17, 2016 4:59 pm

Ain't that a purty build!! (love)
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby db56 » Mon Jan 18, 2016 9:38 am

Something is wrong at first tube:
At cathode: 1V/197R=5,076mA (Rk=197R=150R+47R)
At plate: 40V/22000R=1,818mA (Ub=200V, Ua=160 Ura=40V)
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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby soundbrigade » Mon Jan 18, 2016 11:29 am

Very nice build. At first I thought it was 3D images from a CAD-program, but that was real life photos! So cool! (y)
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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby DeathRex » Tue Jan 19, 2016 7:44 pm

Excellent, flawless.
At first I wanted to be a ET. Now I are one.
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Re: EC88 dirver PL84 push-pull,DIY with a picture tells a st

Postby turing » Wed Jan 20, 2016 3:16 am

6062 aluminum alloy sheet, strip coating, the surface is very smooth. Ready to start looking for a good center.
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Started the first hole. You can use the cutting method, cutting down the aluminum block is not large, anyway, cnc machining, simply are hollowing out.

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The first hole machining is completed. It takes approximately 4-5 minutes. Everything is in accordance with a pre-set program automatically. The whole process takes approximately 4-5 hours. Until this side completely finished processing.

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Surface treatment, a total of seven steps. 1, the surface de-oxidation
2, the surface to the oil
3, the surface texture of the handle
4, the second to oil
5, anodizing
6, surface passivation
7, closed

The figure below the surface texture process ..........................

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