標題: MHZS CD33 distorted and clipped heavily [打印本頁] 作者: him27hk 時間: 2009-7-1 22:37 標題: MHZS CD33 distorted and clipped heavily hi everyone
I hv owned cd33 for a few years. And i hv moded some caps before. After intalled a pair of NOS GE5670 to it today. it played normally at first.
Then after some hours, i turned it on again and it started to distort and clip
heavily.
I am sure that the tubes are normal cause i trace back the distortion to the output pin of the opamp. And i assume the opamp should be normal because i measure the rail it was 30v.
What would be the source of the distortion? :?
Where should i test?
Last resort would be bring it to the dealer and the warranty was ended.......gonna cost me some....
many thanks~~作者: alfcat 時間: 2009-7-2 16:13
Hi,
Can you read Chinese?
There is a thread right above by K.K. Ho on the distortion of the CD 66 Player.
K K suggested changing the Zener diode on the Power Supply board. I have checked the voltage at that point as well; it exceeds the tolerence of the default Zener diode. This MAY be one cause of your distortion
CAT作者: him27hk 時間: 2009-7-2 20:09
yep. i can read it~~ XP
I hv measured the plate voltage ~80v should be fine. But thx anyway~~
I suspect there is bad soldering in the DAC board, cause i trace back and found the distortion came from the dac out put . (before 2 100uf coupling cap)
I was fustrated and gave up yesterday. Today morning, i opened the case and it played normally. Then i just closed the case and the distortion came back. (damn it)
So i suspect there was some bad soldering point.作者: alfcat 時間: 2009-7-2 20:30
Hi,
So the distortion comes in when the CD gets hot?
I re-soldered many parts of the DAC board and I even changed the tube sockets of my CD 33. You may as well consider that.
I guess there is NO dealer of CD 33 in HK .....
CAT作者: him27hk 時間: 2009-7-2 21:03
thx for ur kind reply,
i think the distortion is independent of the temperature. I think the vibration caused by sliding the top plate back will make the weak soldering point fall apart.
Anyway, i will get all the joint on dac board re-solder on this weekend. (and mod it as well : )
If i still cant get it fixed, can i take it to hifi fever to ask some experienced hifi-er to help me?
thx~~作者: alfcat 時間: 2009-7-2 23:12
Good luck.
I recall I changed most of the caps that lies on the signal path after the DAC to RMG and DALE. The sound quality improved a lot.
You can check the threads here at HiFiFever. We have posted a lot of discussions here. Maybe some will interest you.
You better send a message to K.K.Ho if you want assistance with HiFiFever. K.K. Sir is kind of busy. You will be lucky if he is around ....作者: mhifi508 時間: 2009-7-8 20:53
him27hk, I think you have the same problem as we have over here.
: )