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Pass X0.2 前級交流篇

Amhlee
上次取 VFD 有冇PCB跟呢?       忘記了

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無的,正在等。
唔做死硬派,泥頭,奶頭,菜頭都玩.....

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Building X0.2 with new boards and I have some questions about power supply:

* How to adjust 5K trimpots and how to measure correct output voltage ?
* Ok to use 2x35V 120VA,  1x9V 15 VA  - AC voltage input ?
* For large MKP Capacitor near Diodes - is it ok to us 0.033uF, 310VAC, X2 MKP ?
* Are UF5404 Diodes ok ?

English answer preferred - google translation does not work well.
Thank you !
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建设与新议会X0.2和我有一些有关电源的问题:

*如何调整5K trimpots,以及如何衡量正确的输出电压?
*确定使用2x35V 120VA, 1x9V 15VA,交流电压输入 - ?
*二极管附近的大MKP电容 - 这是确定我们0.033uF,310VAC,MKP X2的吗?
* UF5404二极管OK?

英语回答首选 - 谷歌翻译不能很好地工作。
谢谢!

[ 本帖最後由 dsdjoy2 於 2011-11-24 Thu 06:00 編輯 ]

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No need to translate into Chinese, we all can read English.
1. 5K trimpots is to measure the distortion of the upper and lower sine wave, you need a signal generator and oscilloscope  to adjust.
2. Should be ok but it is better for the 9V to be around 30VA
3. 0.01 100VA but no harm to use 0033
4. the diodie is suppose to be around 1A 500V, you are free use any but I will recommend fast recovery type.

Welcome our friend from Germany........
唔做死硬派,泥頭,奶頭,菜頭都玩.....

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>>Welcome our friend from Germany........
Xie xie

5k trimpots - I mean the ones in the power supply. I guess they are for adjusting voltage.
Where to measure, and what voltage should I have ?

For the trimpots on the amplifier PCB, do you have instructions for adjustment ?
Thank you.

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The voltage should be +- 32V after the regulator.

For the trimpots on the amp, pcb amplifier adjustment will leave to those who have experience to describe it.
唔做死硬派,泥頭,奶頭,菜頭都玩.....

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Some tips for adjustment:

We look for 32 Volts DC on the output of the power supply.
So, you might want to look for 30 Volts AC Transformers. This gives you 42 Volts DC after rectification.
Using higher 35 Volts AC Transformers might be too high - 49 Volts DC after rectification. It could give you problems to bring it down to desired 32 Volts DC using the 7815/7915 regulators and 5k trimpots on the power supply.

The 5k trimpots on the amplifier board are for adjusting absolute and relative offset.
Instructions for symmetrical input and output:
On the input of the amplifier connect - and + with ground pin of the XLR plug.
On the output measure voltage between + and ground.
Bring it down as much as possible using one of the two 5k trimpots.
On the output measure voltage between - and ground.
Bring it down as much as possible using the other trimpot.
Measure difference between + and - on output
Bring it down as much as possible using the two 5k trimpots.
Then repeat all over.....

It is an iterative process to bring both relative and absolute offset down as much as possible. This takes time. In ideal case you get close to zero Volts for both relative and absolute offset values.

[ 本帖最後由 dsdjoy2 於 2011-11-26 Sat 04:31 編輯 ]

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I could not sleep over the question:
How do we get 24Volts on relais, when you have 40Volts after IRF9610 on power supply.
Also others reported their relais are not working – and it is needed to lower the series resistors.

Well, I figured it out:

With 2x30V AC transformer we get  30V * sqrt(2) = 42 Volt DC.
We loose some 2Volts at the Diodes – so we end up with 40 Volts DC.

A Nais DS2Y-S-DC24V relais has a coil resistance of 2280 Ohm.
With a series resistor of 2200 Ohm we have a total resistance of: 4480 Ohm.

With a voltage of 40Volts, we have a current of:

    I = U/R =  40/4480 =  8,9 mA

This gives a voltage on the relais coil of:

    U = R * I = 8,9mA * 2280 Ohm = 20,4 Volt

Both current and voltage values are within the allowed ranges for DS2Y-S-DC24V.
Also the pick-up voltage of this relais type is 70%*24Volt = 16,8 Volt.  As our 20,4 Volt is well above 16,8 Volt – this will work fine.

A bit strange is that a 1.5K series resistor is used for K7 instead of 2.2K. I think that in the original X0.2 a DS2E-M-DC24V relais is used for K7. This relais has a coil resistance of 1.44K.

So:  
DS2Y-S-DC24V with 2.28K coil resistance and 2.2K series resistor
DS2E-M-DC24V with 1.44K coil resistance and 1.5K series resistor

If you have different types of relais, you can check the relais datasheet to see what the minimum voltage and coil resistance of the relais is.

[ 本帖最後由 dsdjoy2 於 2011-12-7 Wed 05:28 編輯 ]
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經過了1個多月的奮戰,Pass x0.2終於會唱歌了
送上電源組合,全MUNDORF電容+ELNA SILMIC II
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師兄可否講講全全MUNDORF電容+ELNA SILMIC II的表現嗎?

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公起晒,4號機終於出現

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勁!

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勁! 期待到府上家訪

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我仲努力緊...兼等緊隻牛

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上張請老飄測量原機工作點的圖
RCA輸出的關鍵在於LED的電壓
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Thanks!

唔洗估!!!

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C-hing
For your reference - DB 25 Control Cable Pin Code (amp. side)

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有師兄話想要幾張新版本的相:

[ 本帖最後由 Gary33 於 2012-1-8 Sun 19:37 編輯 ]
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C-hing
精神 VS 金銀
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引用:
原帖由 Gary33 於 2012-1-8 Sun 19:19 發表
有師兄話想要幾張新版本的相:
Thanks!!!

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好似只係需要改一面就可以...
不過都要諗下點改

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有無師兄有多74HC595

Thanks!

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終於裝好左啦
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Tommy兄:
74HC595你要多少?

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I need 3 pcs.......Thanks!

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Tommy兄:
我看看有沒有.

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團購的Neturik 插用了扁腳,逐粒挫會好煩,大家有何高見?

另外今日先發現RCA插座, 負極唔見有接線的.....即係以case作GND, Nelson pass 真慳家!

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各位ching,
想訂X0.2机箱,但有
標準 430x292x74
加深 430x362x74
同加深加高板 430x362x100
請問那一個更適合?

[ 本帖最後由 shumgaryhk 於 2012-2-8 Wed 21:27 編輯 ]

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標準板,但要3個!
唔做死硬派,泥頭,奶頭,菜頭都玩.....

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