標題: Interesting S/N Ratio of CD33! [打印本頁] 作者: alfcat 時間: 2007-10-15 19:10 標題: Interesting S/N Ratio of CD33! Suddenly I have the thought of putting ALL the Chinese stuffs back into my CD 33 and see what the S/N ratio comes out.
1. Original Beijing 2C51 Tubes
2. Original BB 2604
See what will I get.作者: alfcat 時間: 2007-10-15 20:16
So dear Brothers, what do you think? I need not do the combination of Bendix + OPA627AM. It is definitely worse than the ORIGINAL Chinese combination.
The Question is, WHY? Is it because of the Circuit Design? Any comments?
thanks作者: viewer 時間: 2007-10-15 21:01
alfcat,
the original cdt-15a photo作者: alfcat 時間: 2007-10-15 21:59
Dear Viewer,
So you changed the WIMA to Auricaps + Jensens. How much did you pay for this modification?
I haven't try comparing the Chinese Tubes + 6204 with Bendix + 627AM. Will try that later.
Very exhausting after a day's work and my work still haven't finish. Still need to mark exercises and set test papers ..... sigh作者: alfcat 時間: 2007-10-15 22:27
Dear Viewer,
I have changed the Zener to 100V already. Just listened to the THREE combinations I have used in the above experiment.
There is NO SIGNIFICANT better one. I would say it depends on your taste. The music sense for all three are pretty good.
Ha..ha.. I think I may be able to sell my Bendix and OPA627AM ... ha..ha..作者: alfcat 時間: 2007-10-15 22:28
Oh, I forgot to ask. How is your Cayin compared with your CD 33?作者: viewer 時間: 2007-10-15 23:43
hi alfcat,
I changed the WIMA to Auricaps + Jensens the costs as follow:
jensen and musiccaps are stored one year old.
modified cdt15a is better than our upgraded cd33 a little bit on 3D an bass !!!!!!!!!
if both no modification I very sure that cdt15a is better than cd33 much.
You said have changed zener to 100v it is IN4764A ????
thanks,作者: alfcat 時間: 2007-10-16 08:58
Dear Viewer,
Yes, I have changed the Zener to 100V one; the one on the PSupply board next to my five BlackGates.
I asked my wife to listen for comparison as well. We concluded the following:
1. Pure Chinese Stuffs --- Beijing 2C51 + BB 2604 ==> Piano in 陳潔麗 really stands out. However, the vocal part is not that 3D ... but still good and clear.
2. Bendix / OPA 627AM changed ==> High Pitch Instruments not that "sharp". Vocals more natural, more details than the Chinese Stuffs.
It is obvious that without touching the Capacitors, the replacement of the OPAM and the TUBES really makes a difference. However, after changing the PS and the Analog part capacitors (and let them run in), the difference is not that significant.
CD33 的分享
發覺在原裝的CD 33上, 換了OPAM 和胆的分別是顯著的. 但當換了電容之後, 這個分別便在收細. 大胆講句, 電容 run in 之後, 可以說是口味之分. 大陸料, 高音樂器似乎較為特出, 但人聱相對比了下去. 用了 Bendix 胆, 人聱較為暖和, 為真.
以上只是小貓心德, 非金科玉律, 請勿見笑.作者: viewer 時間: 2007-10-16 11:58
Hi alfcat,
I found the web site as following
http://www.threesixty.hk/products.asp?bmenu=178&jb=00720074
they have cable for sell.
thanks.作者: SSWONG 時間: 2007-10-16 13:59
Dear Alfcat,
As hifi fans i personally think that the quality of sound is more important than the measured reading. In audio, if you compare measure reading between tube equipment and the solid states equipment, very frequently SS equipment will give you better reading but the sound may not sound better.
I agree that after changing the good cap, the impact of other part like tube, power code may reduce. Before i cahnge to BG cap, my DIY power cord give a long difference/impact but after changing good cap, the power cord like not much doifferences already....作者: viewer 時間: 2007-10-16 16:58
Hi alfcat,
I 100% agreed with windwss said that :
"As hifi fans i personally think that the quality of sound is more important than the measured reading. In audio, if you compare measure reading between tube equipment and the solid states equipment, very frequently SS equipment will give you better reading but the sound may not sound better."
I have replace the zener of cd33 from 75v to 100v. the sound is more stable ,detail and high notes on great volume.
no much different on lower volume.
Thanks for sharing.作者: alfcat 時間: 2007-10-16 18:54
True. That is why I think we come to a stage that "ersonal Taste" is far more important than just readings.
I am not saying readings / measurements are not important. Yet, getting the sound from our CD actually takes more steps than getting it just from the Headphone. All the stages that follow will exert additional factor on the sound of the CD.
Frankly, I am pretty happy with BOTH settings. It is a bit of surprise to me the Beijing tubes now are more "compatible" with the Bendix. When I first got the CD 33, you really can't stop me from replacing the Beijing tubes.作者: kk_ho 時間: 2007-10-16 21:02
Cat and all,
Pay attention on the measurement, to get the basic requirement first.
Like S/N ratio. Frequency response, FFT analysis, and channel seperation.
Comment on original setting.
Do you know the GAIN in the circuit when you apply OPA627?
I will attach a important application note about opamp at another thread.
You get the good sound but you did not have good S/N, i.e. some of the "original small signal" must not be presented.
CAT, remember what I say in the class ?
KK.HO作者: alfcat 時間: 2007-10-16 23:15
Dear KK Sir,
What I don't understand are:
1. I used to have 75db after using the BG in the PSupply part. Now, with the same materials, the db dropped to only 65 or less.
2. The Chinese 2C51 + OPA2604 gave a reading of 89db. I just changed the TUBES to Bendix 2C51. Readings dropped to 65db already. I HAVEN'T change the OPAM.
Really want to know the possibilities of what went wrong with my CD.作者: DUALXEON 時間: 2007-10-17 11:09
我都話有90dB.如果部機得60幾dB我第一個吾買.
Can't type Chinese on this machine. Thanks for the advice. Will continue to run the CD33 for another 100 hrs and see what will happen to the S/N ratio.