Toy12 Plasma tweeter Diy-7

Prepare close shielding-net I buy a big heat sink from internet.
Heat sink drill holes for mount 120w resistors.


Measure pitch distance.


From rear side to Drill holes to fix heat sink.


Finish heat sink and resistors assembly at rear side.


Rear view.


Top view.
I put on a current meter for monitor high voltage.



Another picture.

Toy12 Plasma tweeter Diy-6

Order 120W VR for step down high voltage.


Put resistors on wood rack and finish high voltage connection.


After long time debug a tiny flaming just pop out.
So far I could make sure my circuit of RF TUB amp. is workable.
But I still need to tuning work voltage and current of PL519 to improve flaming make it large.



Zoom in picture.


Re-modify working voltage and current 480V and 0.2A.
No sound modulation in and Just carry frequency radiation.



Modify flaming size.

Toy12 Plasma tweeter Diy-5

After  check high voltage generate have a problem cause by step-down resistor.
Because PL519 will take 580V/200mA so resistor of step-down is hot .
Step down voltage about 250V by 0.2A ...74W.  Estimate need cascade a 200W resistor for low temp. profile operation.



Finish IF circuit high pass filter and measure modulation out about 105V ...in spec.
But ECL82 and 6C45pi Plate-voltage need check again when replace high voltage resistors.



Because RFC inductor is hard to buy on internet So I  use a 20 ohm resistor hand make a RFC.



Top view.

Hand make Ring wire for PL519 feed back circuit.

Toy12 Plasma tweeter Diy-4

This week finish audio amp. (6C45pi) and IF modulation (ECL82) circuit.


For good shielding reason I design to build a small space for IF module.
But this cause it's hard to hand make and modify circuit.


Finish IF high-voltage and prepare for 6C5pi,ECL82,PL519 heater test.
Meanwhile I measure PL519 (insert already) heater voltage only 36.4V.
I got check spec. of  PL519.  So far the transformer of heater  is one way ticket.



The PL519 heater light is turn on.

Toy12 Plasma tweeter Diy-3

Fix shielding net on front side and assemble power bottom panel.
Mid panel for fix volume knob.


Fix shielding net on rear side and assemble AC connector.
Mid panel for fix Audio in RCA jack.


High voltage Design in a delay on relay (about 10 sec.) for heater turn on first.
High voltage I usage 2 times frequency boost to 1000V then step down to about 600V.
Finish L channel C-R-L-C filter.


Finish R channel high voltage connection.
IF frequency high voltage about 500v than step down to 350V for ECL82 plate and setp down to 190V for 6C45pi plate-voltage.



Two times frequency boost to 1000V Rectifier tub is 5U4G.

Toy12 Plasma tweeter Diy-2

Fix front plate and rear late.


Placement IF components.


Placement high voltage components.


Prepare net of copper.


For radial issue to prepare shielding nets.



Extend shielding nets for each block of plasma tweeter.

Toy12 Plasma tweeter Diy-1

Design wood rack for Plasma tweeter system and size must small and compact suitable for put on woofer box.


Assemble and estimate rack design. I put Aluminum plate in each layer for shielding RF influence.


Paining wood racks for good looking.


Prepare Layer 1 components and parts.


After placement design and finish assembly Layer 1 module for Plasma tweeter high voltage generate.


Put Layer  1 module into wood rack and estimate hand make process flow.
Put  in step by step list.


Design Layer 2 module and put in wood rack for estimate hand make process flow.
This layer module main function is feed Audio-in and generate I-F modulate signal.


Design Layer 3 module and put in wood rack for estimate process too.
This Layer module will design for high voltage radiation , like RF power amplifier.

For band 5K~40K audio signal radiation.