- #52 [kit271], 17-12-22 09:28
- #51 [peter827], 17-12-22 09:03#49
玩音響,爆棚係指標所在,除非套機條件唔得。
Full power一般係套機最差表現嘅狀態,所以最好係爆到個人承受極限時套機係half power。
最後修改時間: 2017-12-22 09:07:59 - #50 [dkyyu], 17-12-22 07:04over 5V 輸出。夠哂用passive preamp.
-
- #49 [phil.ng], 17-12-21 23:26Stereophile 話…關於passive pre, 吾知有幾多成真
“The advice goes this way: Keep your interconnects short. Be sure your power amp can produce full power on 2V. Your speakers need to be reasonably sensitive. It would help, too, if you don't like to listen very loud.”
Read more at https://www.stereophile.com/content/music-first-audio-baby-reference-passive-preamplifier#PTM9gK5AlFuu8XXY.99 - #48 [kit271], 17-12-21 18:55補充多少少, VR放尾會增加個output impedance, 又係麻煩.
- #47 [phil.ng], 17-12-21 18:27From google search, 用/玩pre amp是一門高深學問!
With regard to Nelson Pass' commens
I have a 1996 version of his Pass Labs Aleph P preamp that has separate controls for gain and volume. His advice was to set the gain as low as you can and the volume as high as you can for your basic listening and use the remote to adjust the volume. - #46 [kit271], 17-12-21 17:28我想0db gain只有兩個做法, 1就是bypass左份amp, 2就係FB電阻着手(變成unity buffer).
Bypass左之話就睇吓個VR放係邊樹, 放頭位係一般的做法, 頻率響應同SNR最差, 放尾即passlab Aleph-P做法, 就好容易over削頂.
最後修改時間: 2017-12-21 17:51:07 - #45 [dkyyu], 17-12-21 08:45Dear c-hing,
Thanks for sharing.
With source's output over 5V, it worths every of your effort to try a true and simple passive pre ignoring all the switches control and circuit topology. I believe you will hear the difference even connected with a cheap HKD 1K resistor type.
A true TVC type passive pre (No advertising, I am using Music First Audio Baby Reference) will be even better with the added impedance matching function as well as lower noise level benefit from the step down transformer. Anyway, just my 2 cents. - #44 [phil.ng], 17-12-20 23:27其實部前 in/out 都有不同 ohm switch 去 match source / power amp impedance
不同setting, 極大分別丶所以 (石)前級 最好有這function, 否則 就要一套西裝才好聲丶其中一個原因,可能就是此因素
最後修改時間: 2017-12-20 23:30:45 - #43 [peter827], 17-12-20 22:53#42
同意,三十年前我就係嗰啲左試右試嘅人,直到對電路比較有深入認識了解之後才能脫離產品嘅限制。 - #42 [Kkkkiu], 17-12-20 22:04如果前級本來就係有源,只係有得飛走次級放大功能,唔好聲係正常。真正好聲的無源前級好貴都有,除左音量控制還有考慮輸出入阻抗匹配....好多野除了表面理論之外,還有更深入的精要來達到好聲結果.....好多器材都有gain控制,我部cdp可以當前級用添,有埋輸出控制。但耳朵話比我聽好多器材本身已經在預設下調好左聲,你左調右調好多時帶來反效果。
還有器材級數定位,要用到cdp當埋前級直入後級,如果覺得一個價錢可以好聲過前後級,原因只係靠一個理論的話我覺得唔係太合理。
最後修改時間: 2017-12-20 22:12:23 - #41 [Phil.ng], 17-12-20 20:36Thanks, but....
前是用jumper 去select gain, 如 set 去 0db gain , 就會bypass the gain module, 只有 remote and volume 會function.
最後修改時間: 2017-12-20 20:40:39 - #40 [dkyyu], 17-12-20 20:20是0 db gain, 前級有gain 校、然後只用機內的 電阻matrix volume.
即是將有源前 變成passive
------------
I think there is some confusion. An active pre always remains as an active device even when sound volume level and gain control are set to 0db or whatever value is.
Most of the time, the "前級有gain" acts as a variable resistor base attentuator to offsetting or changing the default pre-amp gain, it is still working as an active pre with gain (either in Voltage or Current). In other words, both volume control and gain control are attenuators. A typical example is found with Nagra PLP.
I guess you can hardly change an active pre to passive without bypassing all the active devices and associated circuits. Setting to 0db doesn't mean bypassing active to become passive.
Usually a passive has no active component in signal circuits, only passive input selector and volume control switch (typical resistor or step-down tranformer type) are found.
Hope this help.
最後修改時間: 2017-12-20 20:24:29 - #39 [phil.ng], 17-12-20 19:03是0 db gain, 前級有gain 校、然後只用機內的 電阻matrix volume.
即是將有源前 變成passive - #38 [dkyyu], 17-12-20 18:47試過set 去 0 db, 行電阻volume, 無動態
_______________
Dear c-hing,
Not logical.
Assuming you are using speakers at normal sensivity, say 87db, the high sound level will burst your ear piece if the output is over 5V and volume setting at 0db. There must be some kind of attenuation in between. Suggest to try the passive preamp. - #37 [peter827], 17-12-19 16:42i/v之後出嘅電壓唔算係放大出來的,可以話係DAC原生嘅第一級電壓訊號,而一般解碼出rca就要降壓到2v這傳統標準,因為你唔跟標準的話燒咗人啲嘢就大鑊,btw識唔跟標準做嘅話就點都得,不過當然後果自負。
- #36 [kit271], 17-12-19 16:22動態同分析力都是基於DAC output current再佩合i/v.
i/v之後再因正反相合成而倍增的電壓, 倍到幾大是沒有意義!
最後修改時間: 2017-12-19 16:27:35 - #34 [Phil.ng], 17-12-19 14:58試過set 去 0 db, 行電阻volume, 無動態
- #33 [dkyyu], 17-12-19 14:50That's why a passive pre-amp has a higher chance to work much better by avoiding unnecssary secondary gain when you have a high output front end source.
- #32 [Kkkkiu], 17-12-19 14:31那不是脫褲子放屁?電壓升到咁大,卻又降到咁細增益,增加了相移問題,又犧牲動態,為何?
- 下一頁 (1 of 3)
- 返回 ...
不過試想想我地聽音樂又經常都係個一兩個level, transforming rate 大約4-3:1左右, TVC看來不錯, 只可惜做工太貴同器材既matching有d麻煩, 要Zin大又要Zout夠細, 用牛做比較雞肋