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2008 7月-12月 第1項課程召集 - (1) 夏季 DAC 原理和製作班 (10月11日繼續組裝)

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 樓主| admin 發表於 2008-9-8 12:44:51 | 顯示全部樓層

額外送一堂安排

因這次的DAC班有多位學員想深入了解技術問題, 現集合大家意見來加送一堂在9月11或15號. 請各學員發表你的意願.

選擇1: 9月11日 晚上7:30-10:00
或選擇2: 9月15日 下午2:30-5:00 其中一日

或選擇3: 跟原定時間9月20日 下午2:30-8:00

因9月20日是原定課程日期, 如選擇1或選擇2有學員不能出席, 11/9或15/9只開放作組裝, 20/9 才主力講解理論.

正式日期會在星期三中午左右確定
 樓主| admin 發表於 2008-9-8 13:00:33 | 顯示全部樓層
GOFFIC: 9月15日 下午2:30-5:00
sugargar 發表於 2008-9-8 13:01:54 | 顯示全部樓層
KK Sir,

I can join choice 1 or choice 2 class.

Sugargar
geneltd 發表於 2008-9-8 13:40:48 | 顯示全部樓層
I prefer 選擇1: 9月11日 晚上7:30-10:00
joepet 發表於 2008-9-8 14:04:10 | 顯示全部樓層
KK Sir,

I prefer 選擇2: 9月15日 下午2:30-5:00 since I need to work on Friday.
Besides, I miss the class on 5/9 night, hope U can explain more to me. TKS!

Joe6 from Macau
 樓主| admin 發表於 2008-9-8 14:22:47 | 顯示全部樓層
lamhenry: my choice is 15/9.  Tks
tonywang 發表於 2008-9-8 15:29:59 | 顯示全部樓層
我9月15日唔得閒 , 選擇 1 OR 3 都無問題的



選擇1: 9月11日 晚上7:30-10:00

或選擇2: 9月15日 下午2:30-5:00 其中一日

或選擇3: 跟原定時間9月20日 下午2:30-8:00
gm08 發表於 2008-9-8 16:13:50 | 顯示全部樓層
Admin,

Do you mean that if we choose anyone day for the special DAC theory course on 9-11 or 9-15, the original course plan will be shortened, day 2 & day 3 will be skipped as shown below,

Night 1 : Simple introduction, 3 type of DAC circuit analysis. ( Already have the class ).
Day 2 : Function of each 5 block. Detail operation of TDA1541A, 47 DAC ( will be skipped )
Day 3 : Function of each 5 block (cont). Detail operation of AD1955 DAC ( will be skipped )
Day 4 : Advance modfication tips. ( As schedule )
mak_cw 發表於 2008-9-8 17:14:56 | 顯示全部樓層
Hi Admin,

     Both Choice 1 and Choice 2 are OK for me. Thanks.

MAKCW
 樓主| admin 發表於 2008-9-8 17:33:30 | 顯示全部樓層
20/9 will continue no matter which choice. This is a bonus lesson only

Originally the course is 2 days only. This bonus day can let u understand more about the technical details if everyone can join.

If not everyone can join, then 11th or 15th will only be opened for assembly only as to be fair to everyone, theory will be taught on 20th Sept
autumnleaf 發表於 2008-9-8 23:03:37 | 顯示全部樓層
Thanks admin and KK for this bonus class on DAC design !!

It is better to learn more details as soon as possible and plan for next step of our own DAC design. If every things are already assemblied but a possible upgrade is taught afterwards, then it may be too late / too difficult to implement the upgrade change on our DAC design.

So I would prefer bonus class being held on 11 SEPT. Or post teaching material topics of bonus class in advance and let us prepare our questions well before attending the class. Time is too tight in class.
kk_ho 發表於 2008-9-8 23:57:22 | 顯示全部樓層
Cat and all,

For the upcoming class, I will use another method of teaching.

Using our white board and label the signal flow.

So, you may need to drop it down.

Time is too tight and hope every body understanding the signal flow. I don't have time to make my powerpoint waveform moving.....

Digital Receiver, Digital filter, DAC will be use white board + power point.

Low pass filter and Output buffer will be use Power point + datasheet + Simulation Software.

Will try to skip all mathmatics due to I don't know everybody background.

KK.
autumnleaf 發表於 2008-9-9 00:28:35 | 顯示全部樓層
Thanks KK for your outline of the bonus class. This helps a lot.

You may quote the maths and equatoins lightly for those who can handle.  Simulation is a good idea since we can get LTSpice for free.
 樓主| admin 發表於 2008-9-9 09:39:34 | 顯示全部樓層
tai chi : I choose option 1, ie 11Sep08 (this Thursday) for the theory class. I guess 20Sep is best kept for building as this kit is complex and we need more time soldering before returning with the PCB.
 樓主| admin 發表於 2008-9-9 09:40:11 | 顯示全部樓層
mat_tli: 1&2 我不在香港, 我選擇3
 樓主| admin 發表於 2008-9-9 12:35:21 | 顯示全部樓層
一半一半... 有點難搞...

這樣吧 -

11/9 7:30-8:00pm KK 會在旺角友誠(1/F)大快活等大家來拿其他零件. 大家回家連同新零件組裝

(已改為Office Hour後個別送出, 7:30-8:00不會在旺角友誠等)

15/9 10:00am-12:30pm Default 版本學員 在 HiFi Fever 測試底板

15/9 2:30pm-5:00pm Plan A 版本學員 在 HiFi Fever 測試底板

20/9 理論, 最後裝箱..
joepet 發表於 2008-9-9 13:41:07 | 顯示全部樓層
So, I only come to pick up the 零件 and 測試底板 on 15/9?
kk_ho 發表於 2008-9-9 14:09:03 | 顯示全部樓層
10/9 7:30-8:00pm KK 會在旺角友誠 1/F 大快活等大家來拿其他零件. 大家回家連同新零件組裝, you can order the upgrade parts at that time too.

11/9 7:30-8:00pm XX (Time and person will be announce later) 會在旺角友誠 1/F 大快活等大家來拿其他零件. 大家回家連同新零件組裝

(已改為Office Hour後個別送出, 7:30-8:00不會在旺角友誠等)

// KK will be leave 大快活on time. Please drop down my mobile no. 93067521. Send SMS to me first if you are on the way.
If default 版本學員 have your own components and already soldering on board, you are no need to pick the 其他零件.

15/9 10:00am-12:30pm Default 版本學員 在 HiFi Fever 測試底板
15/9 2:30pm-5:00pm Plan A 版本學員 在 HiFi Fever 測試底板

// Major testing the voltage after first stage of discrete regulator. (8 group of discrete regulator), tunning the +/- 15V output to Analog power supply.
If everything OK, people should soldering back 9 piece of LM1117-5 and LM1117-3.3V LDO. And clean your PCB by supplied liquid.
Suppose : Testing each module : 10 min
Tunning +/- 15V output : 4 min
People soldering back LM1117 X 9 pcs : 30 min.
Check and Clean : 3 min.

Please make sure you are soldering all of components for power supply unit before you come.

20/9 理論, 最後裝箱..
// The decoding section will be test when you finish all of your connection, drilling and finish assemble of your chassics.
geneltd 發表於 2008-9-9 17:29:37 | 顯示全部樓層
I am the student that require the assembly service.  When should I come and test the DAC? By the way, I have ordered
the usb module. Will you assembly it all together?
joepet 發表於 2008-9-9 17:40:14 | 顯示全部樓層
KK SIr,

Tomorrow, I will come from Macau after work directly, I hope before 20:00p.m. arrive MK. Please wait. Do I need to bring a big bag for this kit? What I need to perpare first? Thanks.
kk_ho 發表於 2008-9-9 18:06:13 | 顯示全部樓層
Your board will assemble and test by me. Also, I will let you know what need to test at Final assemble class.

The USB module is a KIT solution.
You need to solder the QFP IC. Total 32 pin Square shape monster.
kk_ho 發表於 2008-9-9 18:08:26 | 顯示全部樓層
I will call admin tonight to pack the unit to you.

Are you totally default pack or Plan A / B ?

Please let us know.

I can wait you a longer bit, but hope to receive your SMS if you come late.
I think this is no good to sit too longer in a restruant.

Please drop my phone no : 93067521.
sugargar 發表於 2008-9-9 19:46:19 | 顯示全部樓層
KK Sir,

I am AD1955 default 版本學員 but I really need the digital meter to check all the resister before soldering.  I want to buy 1 digital meter ($2xx) and 1 USB module from you, can U bring those thing on 10thSept night and I can pick up all default parts also? I will paid you money at that night ok?

Sugargar
kk_ho 發表於 2008-9-9 22:30:58 | 顯示全部樓層
Sugar,

I will bring one DMM to you, please prepare the $.

For the USB module, let me collect all reply from classmate and arrange at same time.

KK
sugargar 發表於 2008-9-9 22:49:49 | 顯示全部樓層
KK Sir,

Thanks a lot

Sugargar
ricky42c 發表於 2008-9-10 00:15:50 | 顯示全部樓層
[quote:b3762a8c51="kk_ho"]我想問加個USB codec 容易嗎?

// Easy, soldering 4 wire in, 4 wire out. 2 wire for 9V power. 4 wire for USB input

(同價錢方面....) 

// hope to be below $250.

同已知cdm9同pro2一樣不能使用I2S連接,但我部cdm9應用那方法連接?同支持那個數位fs?(Setting方面可否在課堂上指導指導?)

// SPDIF.[/quote]


KK Sir,

如加個usb codec可以當電腦sound card用,我都想加!
但果9V係邊取電?要加多隻牛嗎?
kk_ho 發表於 2008-9-10 00:25:47 | 顯示全部樓層
No need adding additional power transformer.

Basically, if only 1 IIS in (USB in), you can draw the power from BUS. *USB bus power.

We are adding a logic gate (74HC157D) to do the selector.

When no USB signal (5V), the device will toggle to IIS (RJ45 input)

When USB in (5V detected), the device will swich over to USB output.
 樓主| admin 發表於 2008-9-11 15:33:12 | 顯示全部樓層
11/9 (已改為Office Hour後個別送出, 7:30-8:00不會在旺角友誠等)

15/9 10:00am-12:30pm Default 版本學員 在 HiFi Fever 測試底板

15/9 2:30pm-5:00pm Plan A 版本學員 在 HiFi Fever 測試底板

20/9 理論, 最後裝箱..
lifu9 發表於 2008-9-12 10:25:59 | 顯示全部樓層
kk sir
I want to buy the digital meter, Is it still available?
kk_ho 發表於 2008-9-12 10:53:10 | 顯示全部樓層
Still available, 3 remain stock, first come first serve at 15-Sep.
 樓主| admin 發表於 2008-9-12 17:57:11 | 顯示全部樓層
Arrangement on 15-SEP

15/9 10:00am-12:30pm Default 版本學員 在 HiFi Fever 測試底板

15/9 2:30pm-5:00pm Plan A 版本學員 在 HiFi Fever 測試底板

20/9 理論, 最後裝箱..

Requirement : People should complete the basic soldering before coming.

Except : having trouble on SMD soldering. Do not start soldering job at 15-SEP. Otherwise 20-SEP (last lesson) cannot be finished.

20-SEP is for theory, mechanical assemble and final testing.
sugargar 發表於 2008-9-13 17:11:43 | 顯示全部樓層

Problem about 1955Pro parts No. (LM1117-3.3 & LM1117-5)

Dear KK Sir,

I've already soldered LM1117-3.3 & LM1117-5 into the PCB already, do I need to remove them before testing on 15/9? If don't remove those parts , can do the testing also?

"Major testing the voltage after first stage of discrete regulator. (8 group of discrete regulator), tunning the +/- 15V output to Analog power supply.
If everything OK, people should soldering back 9 piece of LM1117-5 and LM1117-3.3V LDO. And clean your PCB by supplied liquid."

Sugargar
kk_ho 發表於 2008-9-13 23:11:57 | 顯示全部樓層

Re: Problem about 1955Pro parts No. (LM1117-3.3 & LM1117

I've already soldered LM1117-3.3 & LM1117-5 into the PCB already, do I need to remove them before testing on 15/9? If don't remove those parts , can do the testing also?

// If don't remove the LM1117, if any failure at primary regulation section, the over voltage will kill LM1117 then feed into DIR / DAC, all kill and bye bye la.
sugargar 發表於 2008-9-14 00:52:17 | 顯示全部樓層
KK Sir,

Removed them and ready to test, see all at Monday.

Sugargar
autumnleaf 發表於 2008-9-14 09:46:07 | 顯示全部樓層
Hi KK sir,

I am using default plan since I want to look for my dream component set myself. However it is really extremely hard to find all the components I desired in the market. Therefore I asked you and william for the upgrade plan late on yesterday. But William replied both upgrade plan A and B were not complete right now (some missing parts in both plans) because I was too late to request.

"Both heads cannot reach the shores", "兩頭唔到岸", 好慘! 頭髮白晒!

I think I cannot complete soldering my dac before Monday. 仲撲緊零件

BUT I would come on SEPT 15 to look at you testing for other c chings. I think I have no problem testing mine at home since in fact I have built several dac before: (3623, 8412, 8420, 5843, pcm63pk, 1704.......) If not many issues, I could handle the test at home.

話晒都係紅褲仔出身麻 !

If possible I would bring a small bottle to take some cleaning fluid home to wash the PCB myself. I know the washing procedure.
kk_ho 發表於 2008-9-14 20:44:00 | 顯示全部樓層
All,

We have some Plan A and Plan B (not complete, but close) components at hififever.

First come first serve, see you 10:00AM for default, 2:30 for Plan A.

Remember bring Cheque or Money.

No EPS / VISA

Good luck.
mak_cw 發表於 2008-9-17 12:00:34 | 顯示全部樓層
Hi KK Sir,

     I have been assembling the TDA1541 MkIII kit. I find the following parts missing:

     a. The 24 pins IC socket for SAA7220 is missing

     b. The four Op Amp NE5534 are missing

     Secondly, I am thinking to add the tube buffer as the output for the TDA1541 MkIII kit. Please advise the pricing for the tube buffer kit. Thanks.

MAKCW
kk_ho 發表於 2008-9-17 12:35:39 | 顯示全部樓層
a. The 24 pins IC socket for SAA7220 is missing

// Will give u back.

     b. The four Op Amp NE5534 are missing

// Yes, will give you on the test.

     Secondly, I am thinking to add the tube buffer as the output for the TDA1541 MkIII kit. Please advise the pricing for the tube buffer kit.

// You need to change LARGE CASE because you need Tube amp buffer.
Admin will quote you a total price.
rting 發表於 2008-9-21 02:54:40 | 顯示全部樓層
Hi KK sir,
forgot to ask today, I'm making the 1547, is it possible to add USB in for
computer use?  any software driver needed for the computer?
thanks
ricky
kk_ho 發表於 2008-9-21 14:21:05 | 顯示全部樓層
autumnleafcat,

Asking the transformer manufacturer last night, the shielding wire is shorted together (start winding short to end winding, one layer winding on top of the body).

Just same as your expected one.

KK.
kk_ho 發表於 2008-9-21 14:34:44 | 顯示全部樓層
RTING,

The Digital Filter SM5842 did not support IIS input mode.

If you planning to make high end USB DAC, please wait our web announce later.

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autumnleaf 發表於 2008-9-22 12:39:34 | 顯示全部樓層
Theory of flux band to reduce leakage flux in power transfromer:

We firmly wind one turn of copper foil (with its width slightly smaller than bobbin width) on the outside of the transformer core and perfectly short-circuited the foil. Since this one turn is not in the main flux path of the core (you can imagine the difference in winding geometry of primary, secondary and this copper-foil windings), it will not induce emf from flux inside the core because the resultant flux is zero for this one turn, so it will not affect normal tansformer operation.

Only the leakage flux from the transformer core will induce emf on this one turn. Since this single-turn copper foil has almost perfect zero impedance from both dc and ac sense (super low DC resistance and ultra low inductance, that's why use copper foil instead of wire), the short-circuited induced current in this copper foil has no power loss. By Lenz law, a magnetic field is generated from this single-turn to oppose the leakage field and thus giving us the leakage cancellation.
autumnleaf 發表於 2008-9-22 13:51:54 | 顯示全部樓層
Flux band concept:

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autumnleaf 發表於 2008-9-22 14:00:16 | 顯示全部樓層
practical example of power transformer incorporating flux band.

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autumnleaf 發表於 2008-9-22 14:11:06 | 顯示全部樓層
Looking inside flux band construction:

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autumnleaf 發表於 2008-9-22 16:40:01 | 顯示全部樓層
If ching wants to further reduce the leakage flux, one should use core belt wearing around the core. Core belt is made of highly magnetic conductive material to absorb stray field. However Core belt usually a custom built part to suit particular core. Therefore it is seldom use except certain product. You can cover the transformer by a steel/mu-metal can. But mu-metal does not sell in small quantity.

But flux band is only for reducing leakage magnetic flux from core. Certainly not 100%. For those who want to supress noise from power line, the transformer should add a faraday shield between primary and secondary winding. By connecting the faraday shield to ground. High frequency noise will capacitively couple to ground. The noise suppression is also not 100%. Adding a line filter can help a lot.
geneltd 發表於 2008-9-23 00:15:44 | 顯示全部樓層
interesting information
autumnleaf 發表於 2008-9-23 12:45:55 | 顯示全部樓層
Transformer is not simple.
joepet 發表於 2008-9-25 08:36:36 | 顯示全部樓層
KK Sir,

Do we have leson on this weekend?
kk_ho 發表於 2008-9-25 10:35:50 | 顯示全部樓層
It depends on

Need to check the classmate have finish the soldering or not.
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