#5565
""
之前一直間中困擾市电噪聲問題，我幢大厦天台租咗俾中國移動做轉發射站，有時突然一段時間D高音標高好多而中低音縮減，一直未解決，直至前幾日又出現，攞返隻買咗成十年但未用過嘅大陸三百蚊全新八達电源濾波插座，本著冇乜太大期望，一插入power amp 專用濾波插頭，D声正常返好多

大家有冇類似事件可分享一下，因為當大厦市电干擾大時，D声係唔聽得，而係夜晚十一二點時，D声鬼咁靚又滑又豐潤，想了解大家点處理？""""""


根據資料，分析如下，

加入line filter 后，有改善，證明扞擾來自電源的傳導(conduction)扞擾。在那一刻， 無線電""輻射""(radiation)嘅干擾係同時間存在。 但係當你加入咗濾波器之後聲音改善就證明係電源嗰部分進入嘅，所以應該集中喺電源嘅傳導性嘅問題去處理。

最後修改時間: 2025-12-13 00:22:24

Wilson, 呢位JimmyDIY 師兄係懂得牛比交連电容好，唔係好少少係好好多，當然隻牛要做得正確靚声才可以，就因為咁Audionote 就賣55%鎳合金前級牛要5萬蚊一对......除咗FM, Audionote 係第二位最搶錢Hi Fi 廠家

當然的果隻Triode 用plate choke load 然後直接交連係最好，係唯一嘅最好，唔係其中的好

最後修改時間: 2025-12-12 23:39:28

Hi Eric,


https://www.review33.com/avforum/index.php?topic=69200803122315&item=&page=1


JimmyDiy 是R33 其中一位師兄

呢幾日去咗朋友個場，我想大家去買單端牛前理解牛芯物質音色特性，最近我將对新繞鎳合金(查過原來只係27%鎳成份)interstage去朋友處裝落佢部前一期Ultimate 845, 其聲音变化係好明顯，鎳合金的中低頻活躍性係最突出，厚潤度亦最高，Audionote 咁鍾情鎳合金仲賣到殺人咁貴係有原因

不過又唔可以全部人都選擇，我另外兩位朋友好注重中高頻細節及整體分析力，超微粒果種，Glass metal之非晶或Nano Crystalline(也是Glass Metal其中一種，是將原來非晶再做熱處理令導磁更高)係可以在任何場合都可以提供超多細節，就算係大堆頭交响樂背景所有細微細節都可以聽得清楚

如果你套組合和喇叭平時高頻分析力弱而渾厚声底，Nano Crystalline 係可以幫到手將套Mid Fi 变成Hi Fi, 尤其是用貴價全音喇叭

但如果你套組合和喇叭本身已高份析力，Glass Metal可能令声音偏冷and dry, 反而鎳合金係可以令此組合增加質感和動感，国内都有些有經驗關於铁芯物料，下則是我刚在網上睇到，完全同我聽到一致

"JimmyDIY 发表于 2011-12-8 17:44

[i=s] 本帖最后由 JimmyDIY 于 2011-12-8 17:45 编辑 [/i]

我比較喜歡用鎳合金的牛芯,中高音的密度很高,泛音很豐滿,一聽就立即中毒!其次是Hi-B鐡芯牛,全頻很乾淨通透,頻寬在各種牛中最闊,低頻潛得很深,高頻上得很高,非晶牛音色平衡就很不習慣,高頻很多音色很冷,聽得很不舒服,個人不會選用."



最後修改時間: 2025-12-12 21:17:14

Hi ilovetheboy13,

Thank you for your good question. As a DIYer, there are just so many things I would check on an amplifier to see how good it is.

1. Circuit design.
2. Components used - tubes, resistors, capacitors and transformers.
3. Componets layout.

The FFT analysis and THD specification don't mean much. There are many ghosts hidden from these test. I believe we shall look into the distortion at each stage rather than looking at the final output.

This is a very big topic. I would not take too much time writing all the details here.

Anyway, what I would say is that it is difficult for me to tell whether the amp is good or bad from few tests.

If you have further question, I would try to share my experience with you.

Cheers,
Johnny

你好，johnny。

小白想了解一下，假若師兄手中有一臺國產膽合併机在手，你會測試它在THD 1%最大輸出、FFT奇次和偶次失真、1K 10K 20K輸出波型等基本數據, 還有其它特別影響聲音好壞的測試嗎？

黃藥師, Thank you.

I really wish I could have the opportunity in testing on the Chinese tube amps. Then, I can provide my findings how good they are.

Recently, I got the Audio Note M5 line preamp from a friend who asked me for repair. Then, I can check it out many details that puzzled me for a very long time.

Cheers,
johnny

Nothing want to say. Promise is promise, I will cut the crap as long as the poor guy "welbourne" make speech here. I have no attempt to break the harmony.

Yesterday, I just posted wrongly which I did post regarding hifi donation.

Very simple, where the hypocrite "welbourne" is, where I am, fight to end.

God bless here no longer for my crap being posted

最後修改時間: 2025-12-11 16:42:41

Tamura output transformer specification

Found the schematic of the driver circuit of the SunValley S1628D 211/845 tube power amp.

I would say this amp was made with kits at affordable price. Surely, the quality of the components used are not the best. I found the output transformer used is Tamura F-475 5K ohm which is only rated 7.5 watts and max DC idle current of 45mA. With this specifiction, this OPT would cause great degrade in the performance of the amp. Oh dear.

I believe having low cost output transformer in other low cost power amps would have the same problem like this SunValley.

Johnny



最後修改時間: 2025-12-11 15:58:32

Hello 黃藥師,

Your two posts are blank. Anything you want to say?

Johnny

Cheap 野！

re :#5576,你部前置用Ｄ好靚既12AX7,個gain有100, 可以在FM band做放大,(或者我估錯,你可能用6DJ8膽)

我中學嘅時候砌過一部膽前級，可以聽到的士call台

wakakakaka!!!!!!!

My experience on RF interference to the tube amps. The tube amp can pick up the noises when it is nearly them.

RF noise can be from the WiFi router and Plasma TV.

Expose the tubes of the amps looks so cool. However, there are risk they can pick up noises or radio broadcast.

Johnny

如果玩胆機，而沒做好RF屏蔽的話，不同長度的胆屏極和接線也自然會成為大功率手機台的近距離接收天線了！

在外國玩音響，有獨立接地故然好，但本地的多層大厦的接地系統有五年一次的WR2 (定期測試證明書)屬於EMSD的法例要求，應該可以信賴，但個別用戶並不需要WR2,所以家居配電箱到牆蘇的地線是否良好是需要用户自己負責的，另一方面如果大厦屋頂有手機發射站的話，就更要將接地保持低阻抗，否則在大功率手機發射站的高频干擾下，那條地線本身會成為一條非常有效的(1/2、1/4、1/8λ)天線（如下圖的頻率波長”λ”列表）：

DY 師兄午安，不好意思，我説的同業是指＞#5566 Daniel-chui 師兄。

DY兄，你建議的，也可一試，畢竟每個人的聽音環境都不同，其他方便，便宜的方法也是可以考慮的！