说说为声卡更换运放吧～～以SQ200AT为例，，说一下

sd-iori

8 U: W! [0 A& P
SQ200AT上面，，有一个运放插座，，
% B( l  g+ C5 ?1 v, U这个插座，，能方便大家更换运放，，
! i. k! Z1 h  m& a: w  s' D
% d  F+ `: {" i) e0 a:charles: 水平菜，这里电子高手超级多，，，有错误的地方，，欢迎指正:charles:

我说说选择打磨声卡运放的方法，，这是自己YY出来的
$ z, ^- {1 _" r5 F1 a) q由于声卡和攻防，，DAC一类的不同，，受电压的限制，，不能随意选择运放，，
攻防等，，直接给运放最佳电压，，运放就有最好的表现，，所以选择运放，，看参数，，也可以
到了声卡，，情况就不一样了，，由于声卡的供电，，一般就是5V或者12V
所以我们要看这个运放在5V或者12V的性能，，这样才有价值
正是由于这个原因，，网上很多对运放的主观测评，，放在声卡，，不一定适用，，甚至完全相反

至于性能嘛，，我就看THD和Slew Rate，，:charles: 因为这是最重要的，，而且，，，，其他的，，我也不懂，，咔咔
Slew Rate对电压不敏感，，
# B- e# l( |. [所以我选择运放，，就看Slew Rate和声卡供电电压下的THD

' C* J$ y3 h. O# D0 |2 w7 n  v当然，这些是前期资料选择
具体，还要放到声卡上试听，，才能作准
$ `1 }& r! p% M! Y. M% J: j所以，，这里，，以SQ200AT为例:charles: 因为，，我正在用这个卡
$ |' c6 o# e! `, J6 F" p
" g# O0 o* b. h# g9 R# n. V[ 本帖最后由 sd-iori 于 2008-3-4 23:11 编辑 ]

sd-iori

向来说说原配的JRC4580，，

要二奶前，，应该先了解原配，，，

■ GENERAL DESCRIPTION ■ PACKAGE OUTLINE
% H3 p: L. S! p2 k+ l; yNJM4580 is the dual operational amplifier, specially designed
for improving the tone control, which is most suitable for the
1 T1 q* z0 ]+ B1 o- O2 M% saudio application.
Featuring noiseless, higher gain bandwidth, high output
3 A8 d4 f) t8 u4 X* ]$ rcurrent and low distortion ratio, and it is most suitable not only
for acoustic electronic parts of audio pre-amp and active filter,
8 z* Y& R8 C/ k' Z& }but also for the industrial measurement tools. It is also suitable
for the head phone amp at higher output current, and further
9 C7 h1 a$ Y7 k; q1 J! V  B( lmore, it can be applied for the handy type set operational
) l7 ?  ^1 V% |( R: wamplifier of general purpose in application of low voltage single
' ]5 {. Z5 |! Y, t5 Asupply type which is properly biased of the low voltage source.
■ FEATURES
% Q2 u3 ]* R8 ?: l● Operating Voltage ( ±2V~±18V )
● Low Input Noise Voltage ( 0.8μVrms typ. )
! L: z4 c. ~5 N3 _* {7 F● Wide Gain Bandwidth Product ( 15MHz typ. )
1 _: ^/ Y% @& ?● Low Distortion ( 0.0005% typ. )
8 J7 R# g9 ?  C1 u7 x● Slew Rate ( 5V/μs typ. )
8 O3 a# q5 ?9 e5 t● Package Outline DIP8,SIP8,EMP8,SSOP8,DMP8
2 m5 J! k/ X4 ~% _: G! O$ M! ]

3 a; ~) E1 e9 s- C4 u" L* B6 S7 d2 j
这是4580的针脚定义，，
8 q8 C& Z; |! n5 u# H# A2 M
" c$ Z+ i% L& r! x8 U9 _9 y
7 O* L9 T3 M$ n
) l, C( a" r6 e4 k3 l  @& @9 g
" v2 R4 g- L( Y3 N, t  V  h" \
从上图可以看出，，JRC4580在低压下，也就是5V下，
有较好的音质，，总谐波失（THD）真最小，，
; }+ X8 X- e% \; l, T( z这应该是众多声卡选择JRC4580作为运放的原因吧

[ 本帖最后由 sd-iori 于 2008-3-4 23:13 编辑 ]

sd-iori

:sweatingbullets:JRC4580，，是低压的双运放，，

5 c% S; {" S  E转换速率（Slew Rate）只有5V/μs typ.
比较差劲，，会影响，，动态和解析度，，，
7 C( ]: N6 u" `0 a( H
[ 本帖最后由 sd-iori 于 2008-3-4 00:28 编辑 ]

flygg2006

继续哎~~~:loveliness:

bill_max

图看不懂，术语听不懂:whistling:
有没有基础教材介绍啊

luckytowns

发贴有点结巴:funk:

nocturne

原帖由 luckytowns 于 2008-3-4 09:59 发表
8 z$ Z1 d  E0 g1 e发贴有点结巴:funk:

这个，，，
其实呢，，，
2 p, P/ F+ t4 t( N是阿娇的一贯风格啦。。

一生相随

等我的功放，，弄到手后，，就找吖娇，，弄个SQ200AT，，玩玩:lol:
. X; k! J+ M4 t4 I" z+ u3 Y% C0 ]6 ^这东西的，，兼容性，，驱动，，做的如何？:p

语蓝

继续:lol:

ljm_ljm

看这个THD N 图。

JRC 4580 适合输出2V 左右失真最小呢。

& O3 t& c/ f3 v/ g4 N# ]  f另外最好有FFT 分析  TH D 成份:lol:

sd-iori

原帖由 ljm_ljm 于 2008-3-4 15:11 发表
. D# \" Q+ J+ ]看这个THD N 图。

! X0 h% U' l) R" BJRC 4580 适合输出2V 左右失真最小呢。
) [* m- r7 d, X$ x& f( c4 N+ S
2 a7 v& C: r+ \2 X3 v7 b; D另外最好有FFT 分析  TH D 成份:lol:

1 B( h6 a" N' R. _( s:charles: 新头像，，不错啊，，，，

agrantleung

换了头像都没有反应过来是阿娇呢，呵呵~
  h* C9 N3 V7 q/ S0 s5 {5 p  a干脆换个阿sa上去~

鲁爾

原帖由 nocturne 于 2008-3-4 10:29 发表

& M6 m2 @6 `* m3 |* [* D5 E& n5 X) R这个，，，
: M) d& ]. j* w! M" q. X其实呢，，，
% u; g' v8 Q1 C0 I2 W* U是阿娇的一贯风格啦。。

  j+ k7 P7 @% A" ~9 B$ t:lol: :lol:

sd-iori

OP275，，，这个运放，，适合SQ200AT，，
8 ?5 N0 l8 D2 R2 G; [/ z9 L9 r, k
% t2 q8 {% q- x$ @先从引脚方面看，，和JRC4580是一样的
, |- ^+ J! r5 ~- }
+ {) ?& {; J# j1 @( G! B, A/ @
) A* n6 l$ D+ j2 c* w8 N7 |, _
, H0 `' g; Z4 b9 Y我们来看看，，，OP275的介绍
- O  e. _1 D: ?* K! d5 M4 M
' O8 d& b( L4 @! T# d* dExcellent Sonic Characteristics
  N5 o( N7 ~9 F& l; CLow Noise: 6 nV/ÖHz
$ N; K5 _8 U* }. ^% S! q% nLow Distortion: 0.0006%
0 R5 s# R$ d! j7 U/ I+ {High Slew Rate: 22 V/ms
Wide Bandwidth: 9 MHz
Low Supply Current: 5 mA
Low Offset Voltage: 1 mV
" t( F8 v, o/ j, V  dLow Offset Current: 2 nA
1 j8 K+ _8 R5 a  r4 i2 n4 yUnity Gain Stable
$ y; W- O5 D6 Y( U' GSOIC-8 Package

Power Supply Rejection Ratio（PSRR）V = ±4.5 V to ±18 V
% O# a. y8 W* R
0 A) }" k0 w' O0 a& ICommon-Mode Rejection Ratio（CMRR）VCM = ±10.5 V
1 j$ q5 T0 k8 |+ Q. E/ S! N: @
& e2 M! e/ V  g: i
8 d% ?  G! J1 }Improved dc performance is also provided with bias and offset
8 t) m8 S( w. k8 Acurrents greatly reduced over purely bipolar designs. Input offset
* ^& }9 w$ y) ^6 H0 K8 V' Nvoltage is guaranteed at 1 mV and is typically less than
. Q9 O# c  f' G# F. k0 A% M200 mV. This allows the OP275 to be used in many dc coupled
or summing applications without the need for special selections
2 c# X7 ~4 b8 }* @. sor the added noise of additional offset adjustment circuitry.
2 L8 b" I* \$ C' U. i+ D! F* Y! \, _The output is capable of driving 600 W loads to 10 V rms while
maintaining low distortion. THD + Noise at 3 V rms is a low
, R7 j' D7 W1 ]1 `9 t7 J0.0006%.

从这些参数来看，，
5 E) K6 c) V# xOP275在SQ200AT的12V的电压下，，性能比JRC4580好
High Slew Rate也比JRC4580好很多，，
所以解析度和动态方面，，OP275都比较好
7 d! i- u6 K" P  B
, l; ^; o' ~8 {1 t; z- S[ 本帖最后由 sd-iori 于 2008-3-4 17:51 编辑 ]

luckytowns

SQ210W也同理么？:lol:

ChrisVinyard

大学里面学了2年数电和模电。。。。。结果全还给老师了。。。。。。:w00t):

sd-iori

原帖由 sd-iori 于 2008-3-4 17:34 发表
Total Harmonic Distortion
: V7 d# w9 J" ^Total Harmonic Distortion + Noise (THD + N) of the OP275
is well below 0.001% with any load down to 600 W. However,
this is dependent upon the peak output swing. In Figure 2 it is
seen that the THD + Noise with 3 V rms output is below
) H" U* r( P4 h" f* s& e$ s) Z0.001%. In the following Figure 3, THD + Noise is below
0.001% for the 10 kW and 2 kW loads but increases to above
0.1% for the 600ÊW load condition. This is a result of the output
swing capability of the OP275. Notice the results in Figure 4,
3 Y. K" e2 J8 \+ V$ `9 Y: oshowing THD vs. VIN (V rms). This figure shows that the THD
+ Noise remains very low until the output reaches 9.5 volts rms.
& K* B2 }3 B7 m3 I' k) H# PThis performance is similar to competitive products.
+ |5 N  u, }4 g& _( g) G
. O5 }6 n! D* c& c. l2 A+ @# IThe output of the OP275 is designed to maintain low harmonic
& |; [: n9 ]6 T/ ]4 m$ h1 Q  ddistortion while driving 600 W loads. However, driving 600 W
- m+ B- b) E! m/ p/ q% \# U3 Vloads with very high output swings results in higher distortion if
clipping occurs. A common example of this is in attempting to
! t. Q9 y: V( |: Gdrive 10 V rms into any load with ±15 volt supplies. Clipping
# a4 W7 u  A, z0 ~& z8 Qwill occur and distortion will be very high.
To attain low harmonic distortion with large output swings,
2 T( K) k; T# U+ Z% usupply voltages may be increased. Figure 5 shows the performance
of the OP275 driving 600ÊW loads with supply voltages
; ~6 I0 J; i1 l  R/ l. A/ {- Xvarying from ±18 volts to ±20 volts. Notice that with ±18 volt
- m$ p9 }* [4 a9 @, usupplies the distortion is fairly high, while with ±20 volt supplies
it is a very low 0.0007%.

4 N1 [6 ?6 T' a这是OP275 THD的说明，，
1 T5 B& k$ y6 k0 V* S大概意思是说，，3V，，THD为0.001，，，
失真最少，，是20V以上，，，0.0007

9 x% a9 E7 ?: g. m' _:charles: 不知，，有没有理解错误





7 [  ~+ k7 ]$ `* s: L& ^" A: Q/ N
  v. @, d! ]" i" I:sweatingbullets: 找不到12V下的，，数据，，
/ U1 J4 P( d- W# j- Z) Y- ]! l3 U不过PDF，，里面，，也没有说列出电压对THD影响，，只是一味强调温度，，
6 J7 j% O3 p6 Q+ n& N+ g5 g从15V和18V的曲线看，，区别不大
2 n) g% x* |3 x8 {1 l& t# {OP275对电压不敏感

4 ^/ R1 A6 F* o[ 本帖最后由 sd-iori 于 2008-3-4 22:46 编辑 ]

flygg2006

那2132呢~~~:loveliness:

MrGlass

我上学时的<脉冲与数字电路>这门课是和老师拉关系才过关的
* x3 j4 ~9 y7 {% ~$ H+ D<电子线路>这门课最后补考不及格...发毕业证前被拉回去考试
! H7 Q# H4 Q. H7 Z: C" @很惨的说

MrGlass

看其它的帖子里有朋友说那个2132是很配SQ210W的
阿娇大姐能不能给来点形象些的对比啊,这些数据和图表虽然高手喜欢,但是确实很让人头痛啊

另外为什么他们要叫你"阿娇"呢?