- #21 [ktli], 19-07-16 18:15在兩支柵極接負壓處斷開,分別把電阻接到一可變電位器的左右兩接腳,這兩接腳再接電阻接地,電位器中點接負壓,很多電路都用這方法。例如Lux A3700
- #22 [ktli], 19-07-16 22:31下圖是A3700 的負偏壓供電電路
- #23 [伊雲士], 19-07-16 23:06唔識 點解唔跟返原mk3電源-bias電路呢?!
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- #24 [ktli], 19-07-16 23:38推測機主想盡量減少上下兩管的電流差異,原機的偏壓電路是沒有這功能
- #25 [伊雲士], 19-07-17 02:02Curico mk3 6922 driver board不是有AC同DC balance的嗎?
知唔知點用?
The original Dynaco 6AN8 design we believe was inferior to the 7199 driver used in the Stereo 70. Therefore applying the same circuit that we developed for the Stereo 70 to the Mark 3 resulted in a dramatic improvement over the stock amplifier topology. This design coupled with the robust and high quality output transformers in the Mark 3 produced a truly stunning amplifier - both balanced and delicate yet powerful. The spectral balance is perfectly neutral and the imaging has the depth and focus of the best amplifiers. The circuit is identical to our upgrade circuit for the ST-70 (cascode gain stage direct coupled to the split load phase inverter) with higher current capacity in the phase splitter to drive the 6550's or KT-88 output tubes. Like the ST-70, it retains its musicality with both standard as well as premium audiophile components (although the benefits of the latter are evident). We included a few optional features that many of you requested as well including a DC Balance potentiometer (to balance the DC bias in the output tubes) and an AC Balance potentiometer to perfectly balance the phase inverter stage. Installation is perfectly straightforward since the board is exactly the same size as the original including the exact labeling of the connectors. You simply de-solder the connections from the original board, drop in the upgrade board, and reconnect the wires to the same pads. So, within an hour you will be enjoying your Mark 3 like never before. Download our comprehensive installation manual to see for yourself just how easy it is. You may purchase the board blank or fully assembled & tested. You may also purchase the board and parts as a kit.
最後修改時間: 2019-07-17 02:08:33 - #26 [ktli], 19-07-17 04:35看官網資料,那直流和交平衡,都是選購品,看電路,和PCB,除了裝交流平衡要拆換電阻,兩組平衡都是直接插焊電阻和電位器各一,是很簡單的焊接而已。
- #27 [ktli], 19-07-17 04:40原板電路圖,就如樓上師兄所說,機主是不懂安裝和使用?
如果機台是小弟的,真要提升性能的,便會把原電路板換上單面PCB,或金屬片,用搭棚方式,把馬蘭士8那組電路搬過來,個人不喜歡屏陰分相電路,更不喜歡使用SRPP.。
最後修改時間: 2019-07-17 05:01:05 - #28 [wesan], 19-07-17 23:20#26: 對,小弟正是想盡量減少上下兩管的電流差異.上手沒有選購 P1 P2,如兄所述, 可以自已動手,P2 用10K 好嗎? 請賜教.麻煩了各位,歉甚!
用 M8 的方法,弟電子知識淺薄,有時間才想一想,恐犯錯. - #29 [ktli], 19-07-17 23:36看官網列出來的零件表,調整DC的電位器是500K,調整AC的才用5K,如果沒有設備的,便不用考慮調AC平衡了。原則上,那500K電阻值寧大莫小。
最後修改時間: 2019-07-17 23:42:13 - #30 [hotiron], 19-07-17 23:39建議各位細心参考以下Eico ST70 push-pull amplifier modification by Stephen Lafferty. IMO, 這是最好的pp amp circuit, 有齊ac driver balance, power tube dc balance, 只用一對coupling capacitors.
http://www.tronola.com/html/st-70_mods.html - #31 [wesan], 19-07-18 23:09再謝各位大哥.
#26的圖真是令小弟喜出望外,但是 trim pot 線路如何接駁我找不到,煩請 Ktli兄可否再指點一下?
感激! - #32 [羅密歐], 19-07-18 23:49
- #33 [ktli], 19-07-19 00:06師兄應去官網下載一份安裝說明書,看安裝指引,如果有買直流平衡版本,便會有一小方形電位器,否則,便自己去配,也可以用大一些的,把電位器固定在機殻上,再用接線連到PCB。
安裝指引下載連接
http://www.curcioaudio.com/MK3-DVR-DOC.pdf - #34 [wesan], 19-07-20 22:25多蒙各位師兄無私相助,又有http://www.curcioaudio.com/MK3-DVR-DOC.pdf 這個 link,現在明白了.
R33 一定有存在價值,只要虛心受教,自然有高手幫忙,在此拜謝! - 返回 ...