- #3637 [WilliamsonAudio], 24-03-13 21:54
- #3636 [johnnykmtang], 24-03-12 16:53The Monolith SLA-02/2- line output transformer is configured for 2:1. The overall gain is 20.
I need higher gain at the line stage because the power amp is only 2 stages which has lower input sensitivity.
Johnny - #3635 [niceday009], 24-03-12 12:25Johnny, How much voltage gain can you get from 5842 in SE input?
最後修改時間: 2024-03-12 12:34:06 -
- #3634 [johnnykmtang], 24-03-12 08:05Here is the picture of it.
只牛牛夠大未,又大又足秤,重係 Amorphous 鐵芯.
最後修改時間: 2024-03-12 08:07:52 - #3633 [johnnykmtang], 24-03-12 07:59Upgraded the line amp from parallel 6DJ8 to 5842Q. Running it at 120V B* and 12mA. The reason for the change because 5852 has some more gain and almost distortion free.
It sounds much more musical and fuller body than the 6DJ8.
I love it.
最後修改時間: 2024-03-12 08:08:39 - #3632 [niceday009], 24-03-11 18:00Audionote 果D前級牛非常大隻,是否有必要?我覺得要加埋客户心理,俾錢成廿萬買部M8, 隻前級牛夠巨型心都舒服D,呢種心態主要來自功率輸出牛,越大越好是事實,但呢種情況是否可apply前級牛
EMY JPA66前級輸出牛形成对比,佢隻牛用Permalloy EI細細隻佢話仲好過D大大隻,都係賣廿幾萬,你會点選擇
前級輸出牛冇乜功率傳送
最後修改時間: 2024-03-11 18:20:38 - #3631 [niceday009], 24-03-11 16:46#3629 >>怎樣判斷鐵心含鎳量 /高斯多少?
我是用以下方法去檢測各種磁芯導磁及磁通飽和, 判斷是否買啱材料及材料供應商有否呃人, 並非可以找出實数
普通DIY是沒有關量度磁体儀器,自己揸住磁芯去檢測導磁率(relative permeability ur)及磁通量飽和(B max),只能用冷軋取向矽鋼片Z11作比較數值大小,例如用真正Z11作數值比較而不能準確讀數, 可用一隻可調自耦式变压器,500W, 0 至350V 可調
測試舉例:
A. 常用之Z11 B max 1.8T, relative permeability 圍繞在1200,用此作測試參考
B. 含鎳成份合金 B max 有0.4T至1.5T(低鎳成份有1.5T), ur 圍繞在2000到60000(視乎你買鎳與铁成份比例, 鎳成份可由3%至80%,高成份鎳就可以稱為坡膜合金),先當這例子50%鎳,B max 在0.6T, ur 30000,呢种铁片我幾年前買過EI 76片,大陸都有賣,應該係日本或台灣原材料,大陸只負責切片
C. 鉄基非晶(有分唔同成份比例做唔同型号),例如日立AMCC 叫K101, B max 1.5T, 日立catalog冇寫relative permeability 實數,但一定比冷軋取向矽片Z11高
比較特性,Z11及50%鎳成份合金,各自攞EI76x40叠厚,繞3000圈初级,3000圈次級,0.13mm氣隙
(1)檢測導磁率:
次級並一粒5K 5W电阻,用自耦牛先調至50V 50Hz RMS 入初級,初級一端串粒100 ohm电阻,量度100 ohm电阻兩端电压,电阻兩端电压/100求出通過100 ohm电阻电流,50V除以此电流揾出當時感抗XL. 用XL=2x3.14xFreqxL公式求出L,L就是此磁芯於3000圈0.13mm 氣隙之电感值,此电感值係有load次級
A. 用Z11磁芯,此3000圈計算出电感為25亨
B. 用50%鎳磁芯, 此3000圈綫包出电感為70至75亨
C. 鉄基非晶冇EI片只有C Core,可以用相約重量4隻C做双C,放入此3000圈綫包一樣0.13mm氣隙,計算出电感為約31亨
(2)檢測磁通量飽和点
A,B,C 是相同体積(非晶相同体積會比矽鋼片及鎳合金輕一点), 現在慢慢調大自耦牛輸出电压,直致磁飽和,去到近磁飽和時,感抗由原先值瞬間跌至三份一至一半(即係初級果枝串聯100 ohm兩端电压突然增加,計返其感抗XL突然变少),持續一分钟個磁芯會变熱
A. Z11 EI76x40芯於50Hz可出到4watt 唔太大变型,計埋变哂型电力有6W(次级V^2/5K)
B. 50%以上高鎳合金50Hz只有1W至1.5W
C. 冇係呢個例子試非晶,鉄基非晶此体積可能係呢個例子只有3W,我只有用較大鉄非晶輸出牛與相約体積Hi B牛比較過
此實驗只能告訴你是否買对軟磁材料
最後修改時間: 2024-03-11 17:02:45 - #3630 [niceday009], 24-03-11 13:17#3627
我冇度過,但以一般MC升压牛3種impedance setting, Technics 305係:
3 ohm 約23倍
15 ohm 約14倍
30 ohm 約10倍
最後修改時間: 2024-03-11 13:20:03 - #3629 [ablerockau], 24-03-11 12:42Niceday 兄
DIY做一對.輸出牛. 怎樣判斷鐵心含鎳量 /高斯多少? - #3628 [WilliamsonAudio], 24-03-11 07:47#3625
Eric,
是,Weiss DAC 內裡的discrete opamp 就是例子, 質感也是高密度的。 Weiss , Cello 也是discrete opamp 設計。 - #3627 [W.lo.bc], 24-03-11 01:29Niceday 兄,
請問你有無Technics SH305 step up ratio 參數可以分享?
謝謝。 - #3626 [niceday009], 24-03-11 00:43仔細分析睇下頂峯單端胆机用D乜零件,賣成兩三百萬,唔會用一般大眾零件和物質去做牛
Audionote Legend 隻10Y interstage 係55%鎳合金
我曾經介紹過,高成份鎳合金(50至80%鎳)同鈷基非結晶(Cobalt Based Amorphous) 磁芯, 兩種都超高導磁率軟磁体,係非常適合用作高电感值(120H以上) interstage 和MC升壓牛,但呢兩種磁芯並不適合做功率輸出牛,因為磁通飽和点只有5000至7000高斯
我自己有呢兩種超高導磁率磁芯之升压牛(Technics SH305MC, SONY HAT50,Cobalt Based Amorphous ,以及Denon AUS1 , Micro MT500 Nickel based Permalloy), 鈷基非晶升压牛比高成份鎳基合金聽感上更快速有力,而鎳基合金磁芯升压牛就中低頻厚度好一些, 好consistent, 論速度動態Sony , Technics 係Micro 同Denon之上,而Micro 及Denon牛比Sony 同Technics 厚声,Audionote 高級机永遠用高成份鎳合金,而從來咯用非結晶磁芯,可能是声音之取向
用作輸出牛,是要用鉄基非晶磁芯Fe based, 磁飽和用新日立AMCC有15000高斯,而用典型冷軋片鉄主成份有3至6%鎳渗入合金片,亦有約15000 guass.
現金最新版本日立Nano Crystalline 納米結晶磁芯,擁有高鎳成份合金之超强導磁率,以及接近八九成冷軋矽鋼片之磁通飽和, Nano Crystalline 有16000 guass(冷軋Hi B有20000 guass), 而矯頑力與Amorphous 一樣低磁滯,認識到Nano Crystalline 係所有參數及性能之優越性在於一身,其他磁芯只有一兩項特別好, 好明顯用Nano Crystalline 做牛係可以少好多圈
Nano Crystalline 可能今頂班胆机牛之主要材料,現時我知只有Monolith 前級牛及interstage 用Nano Crystalline ,而日本長空STC4212 150萬胆机也用Nano Crystalline 做interstage 及output 牛,Tango ISO 及Lundahl 有否使用Nano Crystalline 我未知
Monolith 只有小型牛(interstage 及前級牛)用Nano Crystalline, 點解冇output 牛?可能Nano Crystalline 好貴未普及,上網查Nano Crystalline 係冷軋矽鋼片9倍價錢
最後修改時間: 2024-03-11 00:58:41 - #3625 [niceday009], 24-03-10 23:35Wilson line amp 用原子粒op amp 或有feedback discrete 制作都有靚声例子,速度可能冇zero feedback 快如閃電但靚NFB type line 整体實体感可以好好,Mark仔頂班preamp 有D用靚op amp, D声質感好夠重量, 至多話佢無咁快速無咁多中高頻多空氣,當然我自己用錢買永遠係zero feedback
最後修改時間: 2024-03-10 23:41:04 - #3624 [WilliamsonAudio], 24-03-10 23:19#3619
Eric,
DAC/CD analog output 零回輸設計只是占少部分。大部份是opamp 或 discrete 的 opamp的設計。也就是有回輸。
知道Ayre 是用零回輸。
整套HIFI , 既然前級後級也是non-feedback, 所以也希望 DAC analog 部分也是non-feedback.
最後修改時間: 2024-03-10 23:23:00 - #3623 [niceday009], 24-03-10 23:14Audionote Legend 隻10Y interstage 係55%鎳合金
- #3622 [niceday009], 24-03-10 23:11Audionote Legend
- #3621 [niceday009], 24-03-10 23:10Audionote Legend
- #3620 [niceday009], 24-03-10 23:06Audionote 新旗艦 Legend, 可能超過300萬
最後修改時間: 2024-03-10 23:07:40 - #3619 [niceday009], 24-03-10 23:05#3619
>>但如果以整個體系去分析, DAC / CD 輸出部份的電路,都是有回輸的。
Wilson, 唔太明,有DAC analog 部份係零負回輸,我部Ayre D1xe, QB9 DSD 都係Zero feedback
最後修改時間: 2024-03-10 23:05:41 - #3618 [niceday009], 24-03-10 23:02Threshold Stasis 只係功率級無負回輸,佢电压放大級仍用loop feedback
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出自Audio Research
Choosing the best output taps.
Many of you know this, but others do not. When connecting speakers to the output binding posts on a tube amp, people usually choose the impedance taps that are closest to the impedance of their speakers. Have a 4-ohm speaker? Then they use the 4-ohm taps. 8-ohm speaker? Then they choose the 8-ohm taps.
There is, however, a little more to it. What the speaker manufacturers specify are nominal impedances, while most speakers vary, some by quite a bit. That's why we recommend experimenting using different output taps.
Some speakers like Magneplanars have a very flat impedance, in their case 4-ohms, and sound best that way. The same was true for Thiel speakers. With other manufacturers, YMMV. Vandersteen Quatros sound great using the 16-ohm tap, for example, even though the impedance is specified nominally at 8-ohms.
We found that Wilson speakers, which are all rated at 4-ohms, have always sounded better using the 8-ohm taps. We have been rather dogmatic about that–always use the 8-ohm tap!–but it is not the case all of the time, or with all Wilson models. The new Sasha V is a wonderful speaker, for example, but there are instances where the 4-ohm tap sounds better. (That was not the case for the previous Sasha DAW model, which we thought always sounded better using the 8-ohm tap.)
What am I getting at? Don't be afraid (or too lazy) to try different output taps, you might like it better in your system. Nothing can be damaged because of the output transformer; the only thing that could go wrong is having a mismatch that creates sound that is not as good or well-balanced, which can be easily corrected.
Have fun, and happy listening!