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[#1] Luxman A3700II tube bias    
Any Ching know how to adjust the output tube bias of Luxman A3700II (using four KT88)? Please help. Thanks.
pizzalo
個人訊息 正式會員
220.xxx.xxx.132
2011-08-18 18:29
[#2] Luxman A3700II tube bias    
唔知A3700II和A3700差別大唔大。

我部A3700每聲道近電源位置用一個tune pot校兩支膽負柵壓,另外近強放膽位置有一個tune pot調校兩支膽平衡,每支膽陰極落地都有一支10ohm(10W)電阻,用萬能錶量度阻兩端電壓可計算出Bias電流。約行40ma。

校完左邊才校右邊,扭個tune pot要慢逐少來。

最後修改時間: 2011-08-18 21:01:56
孟波
個人訊息 正式會員
218.xxx.xxx.240
2011-08-18 20:58
[#3] Luxman A3700II tube bias    
孟波 Hing,

Oh, a high hand comes out and helps. Thank You very much.

I bought the amp from Hifido. It will be shipped to me next week. But they say the manual is in Japanese after I paid (the cover page is all in English, it is misleading!).

I cannot fully understand your advice because I don't know electronics or tubes. I will look at the manual to see if there is any diagram and also your advice. Hope I can do it.

I bought the amplifer all because you said your A3700 (using KT88) is more detailed and smooth than Mainland single end. I have not listened to A3700 before. I believe in your judgement and bought it.

It comes with four Gold Lion KT88, hope they are still working. It is very expensive: 128k yen plus shipping!

Happy listening.

pizzalo
個人訊息 正式會員
121.xxx.xxx.132
2011-08-18 22:11
[#4] Luxman A3700II tube bias    
pizzalo兄:

我應該係話3700接5極還比大陸機接3極幼細(用同一set膽),3極推挽和3極單端唔同。

無論如何你買A3700II係正確既,重係跟金獅膽,呢個價錢在HK夠買套二手GEC咋。

最後修改時間: 2011-08-18 22:30:16
孟波
個人訊息 正式會員
218.xxx.xxx.240
2011-08-18 22:18
[#5] Luxman A3700II tube bias    
孟波 Hing,

Please don't call me 兄. You are my hi fi Ching.

Yes, A3700II should be good. I see one in Apliu Street selling $9.5k, of course not with Gold Lion KT88. Not counting Gold Lion, I still want to buy things from Hifido,they check things first and repair defective parts before sale. Japanese guy should be more honest. God knows wheather the Apliu Street A3700II is okay. Paying more for a reliable gear plus 4 used Gold Lion (hope they still have long live) may be a good decision.

I am looking for a preamp, but another Luxman preamp may give the sound too "Luxman". Perhaps an Accuphase preamp may give a balanced sound. I don't know. I like vocal, light jazz and chamber music. BTW, your advice is much welcome.
pizzalo
個人訊息 正式會員
121.xxx.xxx.132
2011-08-18 23:00
[#6] Luxman A3700II tube bias    
孟波 Hing,

I received A3700II from hifido.

Oh, there are 3 possible circuit connections for KT88: triode with NFB, triode without NFB, and pentode. Based on the manual, my A3700II should not be a pentode. I don't know yet if it is a with NFB triode or without NFB triode. I will look at the circuit diagram carefully to find out the answer. Anyway, that is good news. For triode (whether with or without NFB), its output is 30W/channel.

Said before, it comes with four Gold Lion KT88. Hope they still have long live.

Happy listening.
pizzalo
個人訊息 正式會員
220.xxx.xxx.132
2011-08-27 16:30
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