After nodification (小弟第一次自已動手mod機)
動態增加左, 低頻返晒尼之餘重源源不絕添,



最後修改時間: 2012-08-20 12:59:27

before modification

ctscts88,
我都覺得你可先試試先, 如原本數值唔夠, 肯定會無超低頻.
不用買貴料, solen 都可以試下先. 甚至再大D 數值也無妨~

最後修改時間: 2012-04-24 22:43:22

多謝師兄過料
剛和別C Hing 研究過，原來係output的2.0uf並0.01uf的cap(缐路係咁）, 上手只用了一粒0.47uf cap代替的關係，現打算並粒2uf試試！睇下會否有改善！

低頻潛唔得低,如果肯定由前級引致,先要確定頻寬是否足夠,用訊號產生器.AC電壓表.示波器測試,必要時,做低頻補償,可能加兩粒電阻電容,比換零件來得有效,仿名機線路,從來都唔會有原機音效,只不過是沾些名氣,愚人愚己而以.

最後修改時間: 2012-04-24 21:34:15

師兄,
有無相?用甚麼膽?
==========================================
本來跟機係用5751, 之後小弟換左德仔4x12ax7行頭&貓乸2x12ax7行後,
各方面都比5751好好多, 但之不過低頻依然唔多夠, 潛唔得低,

photo



最後修改時間: 2012-04-24 12:27:30

師兄,
有無相?用甚麼膽?
==========================================
本來跟機係用5751, 之後小弟換左德仔4x12ax7行頭&貓乸2x12ax7行後,
各方面都比5751好好多, 但之不過低頻依然唔多夠, 潛唔得低,



最後修改時間: 2012-04-24 12:23:19

有很多因素決定。例如組合，kit很多時用平價料但求有聲也顧不得質素了。先上傳相再硏究。This is very objective. A lot people comparing apple to orange. In other words, They want their hi fi system sounds like Kara ok or AV system. Harsh Hi pitch and rumbling low! Then we are talking in different language.

最後修改時間: 2012-04-23 21:44:21

DIY JP200, 返尼試聽左一段時間, 覺得低頻唔多夠, 潛唔得低,
請問係咁情況下, 如何modify部機, 先可以增強低頻量同質呢?
==========================================
師兄,
有無相?用甚麼膽?

C Hing們
小弟剛從二手區購入左部DIY JP200, 返尼試聽左一段時間, 覺得低頻唔多夠, 潛唔得低,
請問係咁情況下, 如何modify部機, 先可以增強低頻量同質呢?
感謝賜教
Thanks

nice work, like the step attenuator, look like a ladder type ? what type of circuit topology ?

Last one

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This JP20 powered by 2 separate PSU. The end result is you got a focus image and detail of every instrument. Actually I start with a kit and see if I like the sound then I redesign it from scratch. The PSU is on PCB and scaffolding the amp. The housing is made out scrap metal and recycle material. I don't like those housing selling in the market. No Character. They make every DIY amp the same look. Sick of it.
For your reference.

i don't have a M7, or worked on 1 before, this discussion topic seems to be more constructive than some of the others, so i decided to read more here, and hopefully learn something. my questions may seem basic, and the answer may seems obvious to some of you, but asking questions seem to be a good way of learning.

我曾经跟着原版 M7 ， 的真空管位置， 做过一部！ 哈哈。。。 不讲了！ （不想影响 M7 日后的价值 ！）＜＜＜＜

kitahara hing,
舊裝馬七是以矽整流,如改成現時常用的整流二極管 會有什麼改變嗎?

馬七(c22)之類線路我砌過幾個, book 10c 也砌過.
最後都係玩 srpp, 雖然有人認為屬入門級(線路簡單,零件少),邊種線路好唔緊要, 因各人砌出來都唔同.

最好反而係能多些交流, 取長補短, 延續發燒精神.
歡迎任何膽機互訪, 大家都有得益

一般馬7係左右聲道各一支膽負責兩級放大的,最後一支膽係左右聲道共用一支膽,
呢個老人家就覺得唔夠玩味,
因為唔可以每一級放大用唔同品牌既膽黎高聲,
所以改為每一級都是共用一支膽,
令每一級都可以換膽調聲,
而且馬7會因為機身"孩"震令音色定位有所改變,
又係一個玩釘既味兒,
我部機要睇穏唔穏係放係下面既三隻木棋,
找出成部機既重心畫一個圓再放三隻棋
一般係前兩後一
放得唔好會分析力差左,
放到覺得分析力最好既地方就係了
佢話個旋鈕都會是因為"孩"震
但小弟没有真的聽得出有分別,
不好意思
下圖為小弟新改的暫用版前級,