- #42 [Kkkkiu], 17-12-20 22:04
- #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。 - #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 -
- #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. - #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 - #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. - #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.
- #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 - #50 [dkyyu], 17-12-22 07:04over 5V 輸出。夠哂用passive preamp.
- #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 - #52 [kit271], 17-12-22 09:28小弟覺得output voltage唔係咩大問題, 問題在於個output impedance, TVC隨着唔同output level有着唔同Zout.
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 - 返回 ...
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