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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.








Mullard of EC88 here also have a good performance.







British Edison PL84 superior sense of hearing.

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.

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.

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

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

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

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

The figure is a square wave 1khz

100hz


20hz


10khz


20khz

Ain't that a purty build!!

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)

Very nice build. At first I thought it was 3D images from a CAD-program, but that was real life photos! So cool!

Excellent, flawless.

6062 aluminum alloy sheet, strip coating, the surface is very smooth. Ready to start looking for a good center.




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.





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.







































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