fsclub 发表于 2010-4-6 22:47:39

买了一些运放(OPA627,AD797,OP275等)，还有甲类缓冲器BUF03。准备回去改造AD1853 DAC

东西是二手的，因为便宜！
运放是贴片的，因为便宜！！

http://cache.amobbs.com/bbs_upload782111/files_28/ourdev_544148.jpg
(原文件名:AD797_1.jpg)

http://cache.amobbs.com/bbs_upload782111/files_28/ourdev_544149.jpg
(原文件名:OPA627.jpg)

http://cache.amobbs.com/bbs_upload782111/files_28/ourdev_544150.jpg
(原文件名:OP275.jpg)

http://cache.amobbs.com/bbs_upload782111/files_28/ourdev_544151.jpg
(原文件名:BUF03_1.jpg)

http://cache.amobbs.com/bbs_upload782111/files_28/ourdev_544152.jpg
(原文件名:BUF03_2.jpg)

millwood0 发表于 2010-4-7 06:38:13

you could have saved lots of money by using a xdsl driver chip (cfb) inside a modem. those chips are bloody fast and can deliver enough current to drive speakers.and they are typically dual.

they are equivalent to a high speed opamp + a buffer: most of those cfb opamps use diamond buffers (bf03 for example) in their output stages.

crazy_stone 发表于 2010-4-7 09:55:38

好像xdsl driver 并没有反相输入端的样子，并且输出也是BTL的，怎么用作耳放呢，恳请millwood0 给个电路参考参考，非常有兴趣，谢谢呵

armok 发表于 2010-4-7 09:58:02

lrzxc 发表于 2010-4-7 10:08:27

lz的这些哪里淘的，发个链接行不？

gzhuli 发表于 2010-4-7 19:47:15

回复【2楼】crazy stone
好像xdsl driver 并没有反相输入端的样子，并且输出也是BTL的，怎么用作耳放呢，恳请millwood0 给个电路参考参考，非常有兴趣，谢谢呵
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AD812，THS6012，参考电路看datasheet就行了。

gzhuli 发表于 2010-4-7 19:57:14

回复【3楼】armok 阿莫
回复【楼主位】fsclub 绿林好汉
东西是二手的，因为便宜！
运放是贴片的，因为便宜！！
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哈哈，大胡子很钟情好玩、性能强大、价格便宜的东东啊。
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淘宝的拆机OPA627贴片￥8，DIP ￥25，TI官方报$12.25，digikey全新DIP $25+，不是差一点点啊。即使$12.25国内也没几个人舍得买。
所以国内大部分买OPA627摩机的都是买拆机DIP的（也有说法是DIP比贴片好声），于是DIP的比贴片的贵几倍。
大胡子属于特节俭的那种。 :)

millwood0 发表于 2010-4-8 06:13:44

xdsl drivers are always differentially driven: so that there is no dc current through the transformer.

that means each "xdsl driver" has two opamps in it.

see the schematic for ad815 - one of the earliest cfb opamps.

some key performance spec:

at least 400ma drive current into 10ohm load.
900v/us+ slew rate.
120Mhz bandwidth (not gain dependent, unlike vfb opamps).
practically non-existent distortion within the audio band.
...


http://cache.amobbs.com/bbs_upload782111/files_28/ourdev_544395.GIF
(原文件名:ad815 xdsl driver and thd.GIF)

fsclub 发表于 2010-4-8 09:03:45

回复【6楼】gzhuli 咕唧霖
回复【3楼】armok 阿莫
回复【楼主位】fsclub 绿林好汉
东西是二手的，因为便宜！   
运放是贴片的，因为便宜！！   
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哈哈，大胡子很钟情好玩、性能强大、价格便宜的东东啊。
-----------------------------------------------------------------------
淘宝的拆机OPA627贴片￥8，DIP ￥25，TI官方报$12.25，digikey全新DIP $25+，不是差一点点啊。即使$12.25国内也没几个人舍得买。
所以国内大部分买OPA627摩机的都是买拆机DIP的（也有说法是DIP比贴片好声），于是DIP的比贴片的贵几倍。
大胡子属于特节俭的那种。 :......
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哈哈，我买的8.5元。AD797和OPA627都是这个价。
没办法，买了些运放电容又花了200元。已经在LD容忍的极限了。。。。
那个BUF03有点贵，16一片。

STM32_Study 发表于 2010-4-8 09:10:40

这样买二手件，如何鉴定真伪呢？

特别是8脚运放，无论是贴片还是插件的，太多假货了呀

fsclub 发表于 2010-4-8 09:38:20

只有听了+测静态电流+静态输出电压

fengpc 发表于 2010-4-8 09:41:30

拆机片也有很多假的。别说运放，1块钱一个的拆机wima电容也有假

puff 发表于 2010-4-8 09:50:33

LZ说一下哪里买的吧。
我想买些buf03.

谢谢啊

fsclub 发表于 2010-4-8 11:28:17

http://store.taobao.com/shop/view_shop-10a61f1d48c60db0f50ceefcda14edad.htm


我在这家买的。买者自愿，不是广告。

BUF03应该是做不了假，因为市场上没有看到有同类的便宜货。

lrzxc 发表于 2010-4-8 12:48:16

谢谢大胡子

yulan1999 发表于 2010-4-8 17:05:27

上细节特写，表面
627这么便宜，很可能是假的

millwood0 发表于 2010-4-8 18:38:17

"那个BUF03有点贵，16一片。"

it is very difficult to find buf03 now as they are not in production anymore.

when you can find them, they typically cost over $30 a piece: mine cost me $50+ each.

so if your buf03 is real, you should buy them all and resell them for a fat profit.

fsclub 发表于 2010-4-9 09:03:59

I don't know if you can read Chinese.
But I said that this ops is secondhand.

I want to know if there is a same production with cheap price as the BUF03??

I DO NOT think so.

jimo 发表于 2010-4-9 10:22:53

绿林好汉: 你的那个of应该是if吧？

ckvlhf 发表于 2010-4-9 10:29:18

回复【18楼】jimo
绿林好汉: 你的那个of应该是if吧？
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嘿嘿。

fsclub 发表于 2010-4-9 10:41:15

嘿嘿。

ppsen 发表于 2010-4-9 15:53:41

没看懂，顶一下

gzhuli 发表于 2010-4-9 18:00:26

millwood0能看中文的，不过人应该不在国内，所以不清楚国内拆机片的行情吧？

wenming 发表于 2010-4-9 18:07:54

大胡子哥哥,希望你早日做好~~

millwood0 发表于 2010-4-9 20:15:04

"I want to know if there is a same production with cheap price as the BUF03??"

there is no dedicated buffer like buf03 that are in production today. Most of the (diamond) buffers are now incorporated into a high current CFB opamps.

TI continues to produce some buffers, buf634/602 with lower spec vs. buf03. Intersil has HA5002 which has lower spec as well.

BUF03 is very difficult to find and when you do find them, they are very expensive.

tangzn 发表于 2010-4-10 01:31:00

呵呵，millwood0应该是在国外，系统是英文的，打不了中文字！

90999 发表于 2010-4-10 02:21:04

还有HA5002，LT1010，BUF634

fsclub 发表于 2010-4-10 08:24:04

回复【24楼】millwood0
"I want to know if there is a same production with cheap price as the BUF03??"
there is no dedicated buffer like buf03 that are in production today. Most of the (diamond) buffers are now incorporated into a high current CFB opamps.
TI continues to produce some buffers, buf634/602 with lower spec vs. buf03. Intersil has HA5002 which has lower spec as well.
BUF03 is very difficult to find and whe......
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I mean that if some one want to fake BUF03, he must use a cheaper one with the same packege, but I do not know somewhere to exist this production, so, the secondhand BUF03 must be true.

xjf20072608 发表于 2010-6-11 02:35:58

好

luan_dahai 发表于 2010-6-11 15:10:26

前阵子脑袋一热。rs了两片ad8620a还好不是b啊

tfdsensor 发表于 2010-6-13 09:01:34

回复【24楼】millwood0
"i want to know if there is a same production with cheap price as the buf03??"
there is no dedicated buffer like buf03 that are in production today. most of the (diamond) buffers are now incorporated into a high current cfb opamps.
ti continues to produce some buffers, buf634/602 with lower spec vs. buf03. intersil has ha5002 which has lower spec as well.
buf03 is very difficult to find and when y......
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我不懂音响, 如果millwood0需要这些拆机件buf03, 我可以帮你在淘宝上拍几个快递过去. 能够帮助高手,实在荣幸

millwood0 发表于 2010-6-13 09:24:08

thanks. I don't use those buffers: I use either a common emitter to buffer an opamp for desktop applications, or to use a current feedback xdsl driver (which has built-in diamond buffers) for portable applications.

But thanks for your kind offer.

90999 发表于 2010-7-1 21:25:28

今天帮人家修一套机器，用的是797的，结果检查8路有2个坏了，剩下6个也是很热的.....怀疑是自激振荡了（DIY货来着）

RS=650ohm ,Gain = +1 ...........8pin 6pin 间接50p瓷片无效。奇怪了，换成5534或者072这类也没有问题，TLE2071也可以......

示波器送修快回来了，真是没示波器什么也干不了

90999 发表于 2010-7-5 00:38:46

用示波器也找不到问题，后来发邮件给ADI，人家说，“AD797 在±15V下就是那么热，SOIC的还要更热一点，最好加散热片！！”

结果原来就没问题，吓忙一场，静态电流9.8ma（正常）

fsclub 发表于 2010-7-5 06:50:55

我的换上AD797后，手都不敢放到运放上，烫手啊！我的是双18V供电的。

90999 发表于 2010-7-6 12:25:50

回复【34楼】fsclub绿林好汉
我的换上ad797后，手都不敢放到运放上，烫手啊！我的是双18v供电的。
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看来热热更健康~~~~

fsclub 发表于 2010-7-8 14:06:02

OPA627也烫手，不过比AD797好点。

gzhuli 发表于 2010-7-9 03:15:20

不烫的OPA627是假货。 :)
好声的运放基本上都热。

ep1c3 发表于 2010-7-13 12:43:54

mark

diyer_zhou 发表于 2010-7-16 00:31:49

回复【37楼】gzhuli咕唧霖
不烫的opa627是假货。 :)
好声的运放基本上都热。
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学习学习

cxbbb 发表于 2013-1-9 12:25:41

opa627是发热，我用的双12v供电的，声音是不错。
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查看完整版本: 买了一些运放(OPA627,AD797,OP275等)，还有甲类缓冲器BUF03。准备回去改造AD1853 DAC