- #105 [welborne], 18-09-22 12:00請見右邊那個灰色盒仔
- #104 [welborne], 18-09-22 11:57#102: L Cao 用變頻器達成,佢的其他全直熱推2A3和300B也如是。
- #103 [daniel-chui], 18-09-22 11:33[#90]插多幾支真空管在機面,selling price可以mark高D,比錢果位買家自然覺得物超所值.
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- #102 [thomasc2], 18-09-22 11:01#90
當全世界都在出盡法寶去攪直熱管的燈絲hum時,人家竟然話直熱前級用AC點燈絲,仲要係連續兩級直熱,記得很久以前初試26時就試過26共陰放大加26陰出buffer,記得當時的hum聲大到隔離房間都聽到.
雖然對為了直熱而鑑粗搵兩枝高頻五極管(改行三極)毫無興趣,不過真的好想觀摩一下人家的AC燈絲是點做到的. - #101 [tmcc2006], 18-09-22 10:51多謝賜教:-)
- #100 [bambino], 18-09-22 10:17而harmonics係single end線路又吾同push-pull
以下是WE300B datasheet, 呢道只有total harmonics.
最後, harmonics係distortion嘅一種. 啲人種意聽harmonics其實都係種意聽distortion :-)
最後修改時間: 2018-09-22 10:20:08 - #99 [bambino], 18-09-22 10:13#97, 諧波係指Harmonics,一般膽datasheet都冇資料提供. 西電除外.
所以吾可以一概而論. Harmonics亦同工作點和線路有關. 而Harmonics又分Even-Order同Odd-order harmonics. 人耳喜歡even-order.
以下是WE205D datasheet,右手邊見到吾同loading, harmonics都吾同
最後修改時間: 2018-09-22 10:15:26 - #98 [bambino], 18-09-22 10:04#96, 網上真係吾多人用 #30膽做preamp. 如果你識睇datasheet同對基本放大線路有認識都可以試試
- #97 [tmcc2006], 18-09-22 09:31請教直熱膽是否"諧波"特別豐富?
- #96 [CodyChan], 18-09-22 08:34請問有無師兄有30膽的前級線路圖提供呢?
- #95 [bambino], 18-09-22 07:49yes, that's what i understand too
- #94 [hotiron], 18-09-22 05:27According to Howard Tremaine - Audio Cyclopedia, starving Vf on a tube can shorten its life greatly, especially more than 10%.
- #93 [bambino], 18-09-22 00:30some diyers like to have filament starved as a way to reduce hum. some claims it improves linearity. starving filament from 5v to 3.3v is not a small change.
i have tried decreasing Vf by 10%. yes, hum is reduced accordingly but so do energy, dynamic and sound stage. in the end, you may successfully suppress noise. Whether it sounds good is a different matter. - #92 [hotiron], 18-09-21 23:30#67-Pluto2兄,請問為何不用5V燈絲電壓而用3.3V呢?我已ordered globe RCA Cunningham 01A準備試制你的preamp.
最後修改時間: 2018-09-21 23:31:57 - #91 [welborne], 18-09-21 11:28#90: 有趣啵!
- #90 [ck2007], 18-09-21 09:53Welborne 兄:
看你經常留意老曹產品, 有無試過他一部LC300平價聲稱直熱前級(牛輸出)+石後合併;可以作為純前級. - #89 [elo], 18-09-21 00:54係2級放大,6sn7推45.前面细胆係畀有Phono amp嘅型跨,我呢部冇,所以只係裝飾。
- #88 [welborne], 18-09-20 18:32點解dht前好似有兩支細膽?是否兩級放大?
- #87 [elo], 18-09-20 18:21Here is my 45 DHT pre-amp form Supratek.
- #86 [thomasc2], 18-09-20 12:33#45
手上現在都有部26前級攪左一半,一般穩壓點燈絲始終唔得,方向應該都係用電池,但如果用18650,即是要降2V, 當然簡單可加LT1085,但近年見有些開關式的DC to DC converter,效率90%以上,switching rate 300KHz (search XL4005), 想試下.
最後修改時間: 2018-09-20 12:35:33 - 下一頁 (4 of 9)
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