ToyX project EQ Linearizer study case6

Finish analog EQ channel L connection and make each band a test.

Left down corner is band 3 -1Khz,Right down corner is band 5 -12.8kHz.


Put on copper post for boost up analog EQ channel R module.


Lock screw for channel R module and finish wire jump.


Ten knobs look .....
How about... look familiar with someone?
So far this project take me about one year. 
Just prepare into pre-test phase  for tone color.
Analog EQ test 後記...
R channel D/A->(銀線)->300B->speaker.
L channel D/A->(銀線)->EQ(機內超軟銅線, 燒至900度 氮氣退火)->300B-speaker.
經Analog EQ可調出一致的聲音.

Discovery 1...
就是 L channel EQ 8~100Hz and 100~400hz 有一定的衰減,就可
覆製R channel 300B,聲音細緻.無銀線,銅線差異.
A-B test 蔡琴, 鄧麗君, 常安, 董麗,王菲,羅時豐.

Discovery 2...
發現原來300B聲音細緻的一種僻性,且1.6K(4khz knob)至~19.2K(12.8K Knob) gain較大.
所以聽起來較飄逸.

Discovery 3....真是越前面,越主動,改善越多.
但就怕音色走樣.排序改變..
Analog EQ 30%.
D/A 15%.
pre-amp 10% (前題pre-amp 要好過D/A)
amp. 10%
cable & etc ...5%
Pre-amp,Amp,Cable 有些錄差的是啥都改善不了.

Discovery  4...一音路架構Analog EQ 與主動分音應從新檢視.
because ....

經驗證,analog EQ線性器不能有相差.

實際系統上每一極都是8Hz~20kHz的連續阻抗匹配包括cable.
整個加總起來造就Hifi(音色)特性.
舉例一般換銀線聽感低頻差, 高頻好, 就是銀線8Hz~20kHz的連續阻抗匹配
讓銀線改變總體連續阻抗匹配 8Hz~20kHz的阻抗匹配使然!

analog EQ線性器串在內, 可有效權重,影響加總起8Hz~20kHz的阻抗匹配 ,較差的匹配 所損失的訊號強度可補上.
我的altec288 配對不佳 影響音色 ......可補.
夜市賣的劉文正CD錄不好.... 可gain.
because不可能買的CD 每一都是發燒片.

Toy11 VT4C 211AMP -3

Because VT4c-211 too hot so I design a water cooling platform to setup TUB.


Second hand GE VT4C-211s .

Top view. The cooling heatsink is close rear but no contact case.


Rear view. I open a window for water pipe through.


Another cooling platform view.


Finish 6C45pi and 211 cathode bias voltage.


For tone color issue to fine tuning 6C45pi and 211 cathode's capacitors.

Change 211 cathode resistors and mount cooling platform too.Because too hot.

ToyX project EQ Linearizer study case5

Put L channel EQ module and check out the hole of screws.


Assemble copper cylinder prepare for put on R channel EQ module.


Check out two channel EQ modules structure.Meet design or not.


Another view.


Assemble Fuse,RCA connectors,Volume knob,power switch.

Finish wires jump between each band and volume knob.

Another view.

Toy11 VT4C 211AMP -2

After estimate placement too many components so I decide to build mono mono amp.
Drill holes for mount component.
Rectifier tub is 5U4G.
Signal driving tub 6C45pi.
Amp tub VT4c-211.


High voltage for 211 plate voltage I usage C-L-C balance circuit .
Two chocks one is for 211 B+ another for GND.


Top side picture.
Left corner is OPT.
Right corner is High voltage transformer and heater transformer.


Rear view.


C-L-C High voltage I cascade 3 capacitors for 1800V (no Tub insert).



High voltage I usage 2 times frequency boost to 1600V.

ToyX project EQ Linearizer study case4

Finish each band circuit by jump wire.

Finish EQ power circuit and do placement estimate.


Test two bands EQ function together (by cascade).


Feed SG signal in band 4 for function test.


Measure output signal form band 5 and estimate circuit where need modify for meet design.


Band 4 top view.


Today receive EQ box order from two month ago.
This is front view with ten volume knobs. Each channel with five knobs to control EQ.


Inner picture.



Rear picture.

Toy11 VT4C 211AMP -1

Start to prepare the component and box.


Estimate the placement for good signal and easy hand make.



Estimate placement picture.

ToyX project EQ Linearizer study case3

Tuning each inductor value for meet LC band pass filter.


Finish each band pass  structure.


Test each band the frequency of drift .


Side view picture.

Estimate EQ  Linearizer outline and prepare drawing  of  EQ case.