我部 CD 33 的 S/N Ratio 讀數

alfcat,

i have no that machine to 度部機個 Signal to Noise Ratio .
can you teach me how to 度部機個 Signal to Noise Ratio, if i get it.

thanks.

Hi Viewer,

Where do you live or work? I have the AC voltmeter to measure the S/N Ratio. Maybe you call me later today to arrange for it ....

hi alfcat,

I am very enjoy its muscial no need to 度部機個 Signal to Noise Ratio.
becuase i have other project may consider to do (pre and power amp).

i can say it is better my other cd system :

1. Transport Audio Alchemly  Digital System Pro HK$14k
2. Diyeden o1-plus duly modification (10 pieces 627bp).


thank you.

Viewer 兄,

No problem. Just wonder whether you would like to "play" with those toys. These toys are useful to determine whether any audio equipment got "bugs" or not.

Where did you get those Elna? Hoi Wan at Hamilton Street or Wai Wai at Ap Liu Street?

alfcat,

buy it from 宝寶樹電子 at central the dealer of those brands.

thanks.

Viewer 兄,

Just back from school today and borrowed a Oscilloscope for testing out our CD 33.

I tested BOTH my CD 33 and my colleague 秋官's one. Lucky for us, there is no serious distortion. But when it comes to 1KHz at -60 db, our CD 33 just can present the signal.

The second set of photo shows Mine with Power Supply part modified giving a S/N ratio of 78dB. 秋官's one hasn't yet modified, gives only a S/N ratio of barely 70dB.

These numbers are just for FUN. I can say my CD gives more "details" than 秋官's one .... but why do we keep our CD player ..... just because we like the sound it produces ... or else we would have sold it out.

秋官 's CD 33 OUTPUT part modified similar to ours and he is also using the Bendix 2c51 tubes which are VERY good. If not, I think the S/N ratio will even be lower!

As you have said, as long as we feel happy about our CD, need not put too much emphasis on how many dB it makes.

Sorry, post the wrong photo!  :

Forgot to attach the photo ... sigh ... I am really tired.

I can share with you HOW to measure the S/N ratio of your Hi Fi equipment. It is easier to tell you on the phone than type it out here. If you want to know more about it, you can give me a call while you are in front of the computer.

hi cat cat,

I am jack, i also want to learn how to measure S/N ratio?
can u pls teach me too??
millions thx........

Dear Jack,

No problem. Leave me your mobile / contact phone number at my email address: alfchan@netvigator.com

I will call you up in the coming week or so.

[quote:7023a58f16="viewer"]hi windwss,

long time no hearing form you. How are you ???
any new toy

You comy problem just the working votagle, because 9v not enough for IC2132. You can try use two 9v battery in series content = 18v. this  can solve its problem.
otherwise check the solder point with grounding. and all material solder point is fixed well.
I have used IC2132 there (two 9v batterys power supply) no problem. very good sound.
try to use volume part.
your problem i have touch  before.
replaced 470uf is no problem. bass is more.
can you post for comy headphone amp front and base  for sharing???

thanks[/quote]

hi attached is the photo, not so organize. the input/output jack is not good quality 1...give noise so need to change it...

had try using 2 battery but seems no differences.

Hi viewer,

I starting a new project....the SP-27, but will shot the 6N3 tube to be use as tube rectifier...

refer diagram...

Dear WindWss,

You order this from China or ...

Alfcat,

initially i order a board from china but never received it, so now use direct connection n purchase parts locally....
since i got many spare 2C51 tube so no harm to try try... only headache is that a lot info not in the diagram so need to try & error...


By the way, u said you just change the several e-cap & diode in the power side already increase your S/N ratio? without cahnging any circuit right?

Dear WINDWSS,

I always lack confidence in ordering stuffs from China. I have the feeling that I won't be able to get them at all.

Right. I am an Economics Professional, never an Electronic guy. I can't even read the Schematics, therefore I don't know how to change the circuit at all.

I replaced the Power Supply Rubycon caps to Black Gate. Actually I think Elna Cerafine or so will already do the job right. Black Gate is just tooooo expensive.

Then I changed some diodes to Rectifier Diodes Schottky PBYR 1060. Finally, I used some BYV96E to replace the original diodes.

I am VERY positive about the change in S/N as I measure the S/N ratio before the modification. Two days after the modification, I measured the S/N ratio again using the same equipment and Testing CD. I feel shock myself as the improvement is so great.  :wink:

To make sure my speculation is correct, I use my friend's CD 33 (Power Supply NOT modified) for a second test. The result confirms my findings. These are fully reflected by early postings in this thread.

If u use elna at power section, the the S/N ratio may not increase so much compare to BG as BG should has lower noise level compare to elna.

u r right, this my 1st time buy part direct from china...really disappointed...USA is much much better, so far all parts i purchase from USA received with good condition, i think China businessman need to improve a lot in their service.....

Dear WINDWSS,

Maybe I should bring my Voltmeter to Viewer's place and test his CD 33 as I think he used Elna caps for that part. He helped me a lot and gave me a lot of valuable advice during my modification.

Many of these Chinese man just aim at making as much money as they could. It is not surprising as all of a sudden, having money means you can get whatever you want; compare with the past only those in position can do that.

I am spending some time to do self study in electronics. I hope I can at least understand all those components and their functions in the first place. I am sure it is a long road to become experts like you people.  :?

alfcat,

I also not from electronics background....and only start modification last year, so we all are new......the most important thing is the keen to learn n has gut to try out but must do some study as well lah......

initially i also very blur....but now getting more familiar and can read diagram already.... during learning we may make some mistake but don't give up....  :

u in HK is better as got a many expert there which u can learn & sharing.....

Dear WINDWSS,

To my surprise indeed. So what occupation are you in?

I am a teacher here in Hong Kong and I myself like to learn new things all the time. It is sad to see my boys here have no interests in electronics stuffs like this anymore. All they care is their NDS, PSP, etc.

You like Diving too, right? I recall my last visit to 沙巴 ... what is that place called in English? I think we went to Kota Kinabula or so. Although I don't know diving, I like the weather, the sand and the water very much.

The ONLY problem is ... CATs are afraid of getting wet .... ha..ha.. I think I WILL like diving but I need to overcome the fear of learning swimming first.  :

i,m a Physicist, my company is doing servicing for medical equipment. I'm more on management side like licensing issue, operation and so on.

Anyway since i'm science student, during form 5 &6 had learn some basic electronic component la.

But for sure cannot compare with those from electronics background...la....

So still keep learning.... i'm now taking up a electronic short training (2 weeks) organized by my company... huh a lot to learn...but the knowledge really useful......at least now can understand the schematic more and has confident to change some simple circuit.....

Hmm Sabah is a nice place, nice sea food......

If you dont know swimming it is not advise to do diving..u will feel unsafe & uncomfortable.... unluckily u r not in malaysia, if not i can teach u swimming...i use to be a part time swimming instructor.....

ok take care!

Dear WINDWSS,

Since you mentioned Form 5 and 6, you are from Hong Kong as well?

As starting from the first place I've learned that you are in Malaysia, I am not sure whether you are just staying there 'cos your company sent you there or you are born there instead.

I like Sabah VERY much. The only problem with my last stay is the Hotel is too far from the Downtown. It costs us M$ 150 for a round trip each time and 45 mins or so.

Which part of Malaysia are you in right now?

I would VERY much like to go to Malaysia again, especially where there are nice sea view. Although I am a cat, I like the sea and sunshine ....

:  :
i'm not from HK.....

I'm Malaysian chinese..... my grand father is from hainan island......

My home town in Pahang but work in PJ (petaling Jaya) near Kuala Lumpur (Malaysia capital).

Oh, I see. So you are located in East Malaya instead. Am I right?

The last time I visited Sabah, the people there are very friendly. They said people in E. Malaysia won't be that friendly. I don't know whether it is true or not.

I brought my CD 33 PCB back to Mainland this afternoon. They said they will try to fix it for me and they can also sell me one without the Capacitors on it. This saved my trouble of removing them .. ha..ha..

: ) Sabah & Sarawak is consider as East Malaysia, Peninsular is west malaysia, so i'm from west malaysia.

Generally i will people in big town like KL, Pj is too busy, trafic n working environment make people look not that friendly. Sabah is not so develope, tourism is 1 of their main income thus generally u will feel people there more friendly. For e.g the people in Thailand is more friendly than in malaysia as tourism is their main income.

for a general comparison, west malaysian people is still more friendly than China, Singapore and maybe HK. A lot of friend hate to do shopping in HK as they said the sale's peoson's attitude is terrible. Much more terrible than in petaling staright.

How much they will charge u for the blank board?

Dear WINDWSS,

My Goodness, how come I have my Directions all mixed up? East is on the Right and West is on the LEFT .... right, I mean EAST Malaya.

It is a bit tricky in China. I went with my boss (the Principal) on several Study Trip back to Mainland China. He went shopping for souvenirs each time. No matter where he goes, he is always welcome by the sellers ... and they treat him very nice. Maybe he looks like a big spender.

Have you been to Hong Kong? The alienation effect here is quite strong. Most of those sales person don't like Mainlanders; unless in big money making business like Jewelery, AV equipment, etc. Sometimes I feel upset in seeing their attitudes towards foreigners.

I don't know HOW MUCH they are going to charge me for the PCB. I just give the green light on getting it for me. The sales said NORMALLY the factory won't sell a blank board (just without capacitors). The situation now is the sales will tell the friend he knows that this is a board for his friend who does DIY ... and try to get one at a bargain. There is NO guarantee that we will succeed .. just give it a try. For the damaged board, they will see what can be "recycled" and then give me a new one, deducting the cost of the "re-usable" items. All will be clear / settled next week after the National Holiday or so.

Alfcat,

I never been to HK.... if 3 yrs ago u ask me which place i will put as the last place to visit in world, I may tell u is HK as there is nothing attract me that time.... for scenary a lot other place is better, for shopping china and a lot other place is cheaper...., living cost is high, congested, poor air....But until recently after i fall in love with DIY audio equipment... then i had change mind, HK got a lot DIYER and can get cheaper parts, componentt, 2nd hand equipment.... If got chance i will go to have a visit.... : )

for your pcb, worse case if they can't get u a new 1, u just take back, bring it to Hififever sure got people there can help u lah.... solder pad lost is not serious damage.....

WINDWSS,

We do have some DIYers here and lots of shops selling all kinds of different things. The price varies and you can always make a comparison among them to get the best deal.

I think the sales in China can do something for me. Last Thurs when I got up there, he already fetched me a new PCB. The only point is, he said I don't need a new one with everything on; especially when I will replace all the caps anyway. So he is trying to get me another one without the caps.

Another good point about Hong Kong is you can go anywhere in within almost an hour. You don't want to get your merchandise here, take the subway or so and go to another shopping arcade ... always nearby

Viewer,

Need favour from u!!!

U had a CMOY right? u use it with your headphone right? Has u try it on the normal ear phone like sony ear phone?

Can u try is on a normally walkman ear phone and see whtehr got any hiss/shii sound?

After i rearrange it in a pcb board.. the hiss sound still there when use ear phone but when use on low quality head phone no hiss sound at all.... so i guess it is due to impedance matching??


Dear Alfcat,
Every place got its pro n cons.....HK & Malaysia got a lot similarity as both is conquer by British for quite some time.....that's 1 of the reason HK & malaysia chinese got some advantage as we can speak english & mandarin. HK is more freedom n less restriction....no racial issue...


In Malaysia, non-malay (chinese, indian & so on) has a lot of limitation/restriction in many field. Anyway under such tough situation most chinese can speak at least 4 language...so it become a advantage...

hi, windwss,

you sd condition also appear in my cmoy headphone amp. I think its current is hight so low quality got hiss/shii sound. you can try to change the gain over 6.

thanks.

viewer,

i had tray use different gain.
gain 11 --> louder hiss
gain 6 - middle hiss
gain 4.3 - similar hiss as gain 6.

change the cap still the same.

change wire still the same.

place 150R at R5--> more noise. (may need to try out using variable resistor)

use 2 battery -->18v still the same.
change opa 627, AD825 --> even worse...

so i suspect is the impedance matching as our normaly earphone is 16ohm, normall head phone is 32ohm above....


u mean your CMOY use at normal walkman ear phone also got the hiss sound right?? then it mean i has to look for a suitable headphone and it is not the cmoy prolem right?
ss

Dear friends,

I put back all the caps I used to have; the Jensens, the Elna, etc. Strangely, the S/N ratio dropped back to 65db or so.

I turned the CD 33 back on and it is for sure inferior with my colleague's one. At first I thought it was the connecting cable as I connect them to the pre-amp using different input channels and cable. Then I take the measure of the S/N ratio and it is just 65db ...

Really disappointing. Can't figure what is wrong ....

Cat,

Let your player warm up for 30 hour and measure again see any differences....
Relax..... rush will spoil the work.....

did u change the 75V zener to 100v as recomended by KK?

viwer,
attached is the cmoy after reconstruction....

by the way anybody here know for the 2 pcs 0.22uF/630V cap athe the AC power of CD33, if we change to 1mF, any effect? it should be able to give better smoothing but slightly slower response right?

HI WINDWSS,

I BUY A ZENER INE764A 100V 1W
THE DATA SHEET IS ENCLOSED FOR YOU EASY REFERENCE.

CAN I USE THIS ZENER REPLACE THE 75V ONE ON POWER SUPPLY OF CD33.

I WILL GIVE IT ONE TO ALFCAT TOMM.

THANKS.

this zener can be used.
But may need to slim down the zener pin ( normally the lead pin diameter is larger than the hold on PCB at this reading)

Besides, after replace it, you need to measured the voltage reading at the acthode side of the zener (1 probe at ground, 1 probe at cathode of zener). Some loudsy manufacture make loudsy zener, where a 82V zener give 107V output.