opa 627bp in MHZS cd33

[quote:57f0b07e77="WINDWSS"]T, VIEWER,

U got any idea on the nipon chimi con oil cap in the picture (black)?
it is a film cap or electrolytic cap?

anyone kno0w the sound quality of this cap?[/quote]

I'm not 100% sure but the black capacitor looks like a PIO  ( I maybe wrong)
Also notice it has a silver stripe on the right?   this is normally the side where the internal foil is connected.

Please be careful with the old PIO,  sometimes they can leak DC voltage if used as a signal coupling capacitor

[quote:0e81a2a876="alfcat"]Dear Friends,

To avoid confusion of which pin is which one, I drew an ugly diagram to show my final findings.

I TRIPLE check this time before I take down the readings. The readings in PURPLE are mine. The readings in RED are my friend's CD 33. The main difference is his Zener is the Original One while I changed mine to 100V.

What do you guys think?

Can anyone explain why the two TUBES got different readings? The most amazing part is one has FIVE readings but the one closer to the DAC only got THREE! Aren't they doing the SAME job for EACH channel?

CAT[/quote]

See my above post, if it makes no sense I'll try and explain better,  the bottom tube supplies left and right signal which goes to the top tube, the top tube also supplies left and right signal to the coupling capacitors

Your voltages do not look right,  we need to find the problem.
You seem to have some voltages missing,  
your filament voltages are ok
Your cathode voltages are missing
Your Grid voltages on top tube look too high and the Grid voltages on bottom tube are missing
Your Anode voltages look fine

[quote:eb98bdbed6="WINDWSS"]
Dear T,
then your CD33 circuit is a lot diferent from my BADA HD21. wehen my voltatge at zener =100v, my anode is the same =100v, grid & cothode will increase to ~45+.

ur cd33 is using 2 tube, is they use 1 tube for 1 channel?
my bada using only 1 tube (use for 2 channel)

when it zener =75v, gtid & cathode~28+v,

so the differential voltage is ~ 54-10.3 = 43.7v

my different voltage is ~47V[/quote]

Theres 2 x tubes in the CD33,  I have had a closer look and it seems that one tube is for the first stage supplying both Left and Right and the second tube is for the second stage Left and Right.
My measurements was for the tube in the first stage,  it has dropper resistors before the Anode.
Here is the measurements for the second tube

Anode 99/99V
Cathode 52/54.6V
Grid  51.8/54.3V
Filament 5.8v

Basically  each half of the triode is for Left channel  and other half of triode for the right channel,  this second tube has different voltages compared to the other tube in the first stage

Dear Blair,

I followed your advice and checked all the power cables going from the PS PCB onto the Analog one. They checked OKAY; closely matched the readings on the PCB.

I also took a very carefully reading of the tubes right now [see my ugly drawing of the tubes]. When examing the PS PCB, I realised that some of the OS-CON were not well soldered. I re-solder them before I took the tubes readings.

Are the readings normal? If they are normal, I don't need to go through all the trouble ... ha..ha... :

Tossing the CD out of the window? It should be okay if you do it in TEXAS, ha..ha... In Hong Kong, if I do that, I will be quite certain that someone will got killed down the road ..... That is why in Hong Kong we use a different term --- dump it into the sea.

CAT

Dear Friends,

To avoid confusion of which pin is which one, I drew an ugly diagram to show my final findings.

I TRIPLE check this time before I take down the readings. The readings in PURPLE are mine. The readings in RED are my friend's CD 33. The main difference is his Zener is the Original One while I changed mine to 100V.

What do you guys think?

Can anyone explain why the two TUBES got different readings? The most amazing part is one has FIVE readings but the one closer to the DAC only got THREE! Aren't they doing the SAME job for EACH channel?

CAT

Dear Viewer,

That is strange. You have the readings > 100VDC. I just have pin 4 close to 100V. Pin 2 & 3 is just around HALF of what you got.

Another strange thing. You have 3 readings (> 0V) for one tube and 4 readings for another. I have 4 readings for both tubes.


CAT

Hi alfcat.
revised reading as follows:
For the tube closer to the dac:
1. 5.9v
2. 0v
3. 0v
4. 101.5v
5. 0v
6. 101.5v
7. 0v
8. 0v
9. 0v

For the tube closer to the RCA socket
1. 5.9v
2. 0v
3. 101.5v
4. 102.4v
5. 0v
6. 102.4v
7. 101.8v
8. 0v
9. 0v.

thanks,

Hi alfcat,

reading as follows:
For the tube closer to the RCA socket:
1. 5.9v
2. 0v
3. 0v
4. 101.5v
5. 0v
6. 101.5v
7. 0v
8. 0v
9. 0v

For the tube closer to the DAC
1. 5.9v
2. 0v
3. 101.5v
4. 102.4v
5. 0v
6. 102.4v
7. 101.8v
8. 0v
9. 0v.

thanks,

Cat,

I think that there is some good advice coming in from other members, but lets take a few minutes and breathe. One thing I can tell you from working on tube gear all this time is that troubleshooting on the tube end is not always a good idea.

Try this. Take all associated signal wires off your new board so as the tubes are the only thing still connected. Not because you are damaging anything, but it removes several different possibilities. Now you simply have the jumper between the PS board and the audio signal board. Remove the jumper from the audio board end of the jumper and take your meter set to DC and test all the pins on the cable. Write them down in order of what you get. If the holes are too small for your meter, take a push pin and put it in there and use a alligator clip to clip your meter to the push pin. Now that you have established the voltages are good from your PS, take three different colored markers (preferably fine tipped). Begin by tracing the path of your high voltage trace all the way to the tube. Then do the same for your filament voltages. If I remember correctly, this should be around 6.3v on this tube. Note that the 6.3v should be AC, so you may need to adjust your meter to establish the correct pin for these voltages. Do not start at the tube as it is much easier to make a mistake this way because you are viewing the tube upside down when you look at it.

Now that you have your traces marked for the 6.3v and the 80-100v depending on how you modded the player, trace each path with your fingers and examine each component on the board. I know this will take time, but there is probably nothing but resistors in the voltage paths. If you are not certain about the values, remove one end of the resistor carefully as not to lift the contact pads. The value is clearly marked underneath each resistor. If you ohm the entire voltage path out and the values are all correct then you will need to either change tubes to see if they are the culprit, or begin to examine the signal path for bad components. Take your time, and have fun with this

If you are anything like me, you are about to toss the player out the window!

I hope this advice helps you to take a step back and learn instead of troubleshooting by changing parts. Not that resistors are expensive, but you can sometimes do more damage than good by swapping parts out.

Blair

Hi alfcat,

I will be take  measurement again.

thanks.

Cat,

Your testing shld be correct as you reading make sense, but viewer's measurement may be wrong for chathod & grid voltage (it look weird), his reading on plate & filamet shld be correct.

We are now measure the idle volatge, if u play the CD then the voltage will change (flatuate acording to audio signal if not mistaken)

Blair,

This is what's been troubling me since I got the new PCB. The factory practically de-solder everything on my old pcb and put them onto the new one. My worry is that some of the components may already be burned or malfunctioned because of my terrible mistake.

I have the CD turned on but NOT playing. Will it be different if I let it plays and take the readings?

It looks like WINDWSS, t, Viewer and I all got different readings for our CD players.

WINDWSS post the diagram of the 5670 / 2C51 tubes somewhere. I followed the diagram and took the measurement. Will try to re-take the readings again later today.

My CD player doesn't sound right after it returns; especially the high frequency part ... sort of like distorted. I won't say that is a "clean" sound. That is why I keep checking on the S/N ratio.

CAT

Cat,

I'm not there to observe, but how does your player sound? I hate to sound discriminating, but your measurements make no sense if you are getting failry clean sound. The circuit incorporated here in your output stage is called a cathode follower. I can't find a scematic, but if I were to guess, only one tube is used per channel like a buffer.

Viewer's measurements are dead on.

Please look up Duncan's Amp Pages, and you can query the 5670 tube and see a visual of the pinout and figure out if you are hitting all the right point and then give us new measurements. Unless you have a resistor that has drastically changed, your plates and filament voltages should stay the same between the two tubes.

Hope this helps some,

Blair

alfcat,
reading as follows:
For the tube closer to the RCA socket:
Cathode -- 0V
Grid -- 102V
Plate -- 102.7V
Heater -- 5.9V

For the tube closer to the DAC
Cathode -- 0V
Grid --0V
Plate -- 102.7V
Heater -- 5.9V

thanks.

alfcat.

ok!!! i will  measure it soon and revert you.

thanks.

Dear Viewer,

Would you please measure your tubes' readings as well? In that case, I can have a reference.

Many thanks.

ALF

hi alfcat,

I agree with windwss said that :
Since u said u had change a new board, in case they put in wrong resistor at teh cathode side then it will change the cathode voltage....


try to take the reading of the said resistors for both tubes.
you can see the reading of the resistors which marked on the pcb.

thanks.

Cat,

Since i don't have the schematic of your CDP as i'm using bada not cd33 so i'm not sure your 2 tube is for 2 channel or for 2 stage( stage 1 & 2).

If 2 tube for 2 channel then the reading for both tube should be similar but if is is for 2 stage then it can be very different.

cathode resistor is the resistor connected to the cathode the give the voltage on the cathode (they use voltage drop theory). V=IR

For e.g,

if the the cathode resistor is 10R and create cathode voltage say 5V at plate voltage 70V. When u accidently replace with 100R then, it will created higher voltage drop, then ur cathode voltage will read >5V.

Since u said u had change a new board, in case they put in wrong resistor at teh cathode side then it will change the cathode voltage....

Dear WINDWSS,

What I don't understand is the CATHODE part of tube 1 & 2. Tube one says 63.4V but tube 2 is only 11.3V. Shouldn't they be equal as each tube governs each channel?

Second, I use the same trick for measuring Voltage for measureing resistance value? Just switch the Multi-meter to measure resistance?
Sorry, I got a bit confused as you said Cathode RESISTOR.

CAT

Dear cat,
ur measurement when cd not playing right?

since your zener use 100v thus your plate getting 96.7V is normal (i'm wonder how come T getting only 54v?, may be he refer to another tube?))

But the diffential voltage is ~33.7V for tube 1 which is quite low, maybe this is 1 of the reason your dB may read low. Try check your cathod resistor value, is it correct when u change it back as u had cahnge the whole board or compare the resitor value with the original and see....

your 2nd tube differntial is ~50V which is normally use.... when we compare T, n my cdp which using this 2c51/6N3 tube normally they use ~40-50v voltage differences.

So i suggest u check your cathod resistor value  (compare with original, n measure the value see it fall in the tolerance range not?)

or if your other friend got the same cd u do the measurement then compare n look at the cathode resistor wheter same value?

Dear friends,

I measured the readings by placing the RED probe on the base pin of the tube and the Black one on the ground screw located at the analog pcb.

I got very interesting but worrying readings.

For the tube closer to the RCA socket:
Cathode -- 63.4V
Grid       -- 62.6V
Plate      -- 96.7V
Heater    -- 5.4V

For the tube closer to the DAC
Cathode  -- 11.3V
Grid        -- 2.3V
Plate       -- 62.8V
Heater    -- 5.4V

What could be wrong with my CD?

CAT

T, VIEWER,

U got any idea on the nipon chimi con oil cap in the picture (black)?
it is a film cap or electrolytic cap?

anyone kno0w the sound quality of this cap?

Dear Cat & viewer,

T is right, just place the black pin on the ground, & red pin on the the place u need to make measurement.

No need remove vacum tube, your red pin from multimeter just touch at the 9pin socket's lead on the pcb.

Dear T,
then your CD33 circuit is a lot diferent from my BADA HD21. wehen my voltatge at zener =100v, my anode is the same =100v, grid & cothode will increase to ~45+.

ur cd33 is using 2 tube, is they use 1 tube for 1 channel?
my bada using only 1 tube (use for 2 channel)

when it zener =75v, gtid & cathode~28+v,

so the differential voltage is ~ 54-10.3 = 43.7v

my different voltage is ~47V

Hi WINDWSS,

My voltages are below with 100v zener,  remember there is dropper resistors on the Anode supply before the Anode pins, I also have adjusted the resistor on cathodes because the op-amps have been bypassed

Grid 8.5v
Cathode 10.3v
Anodes 54v
filament 5.8v

[quote:6bd60c2e58="alfcat"]Dear WINDWSS,

You mentioned about a "probe". Is it something that looks like a "hook"? I just have a very cheap multi-meter and it comes with two pins only. Can I use those? Will it be a bit dangerous if I just use those?

I have to make something clear first before I can go ahead and check the voltage for you. I need to turn the CD 33 on but no need to play any CD, right? But then do I have to remove the vacuum tubes from their sockets?

Please advise this amatuer. Thanks.

CAT[/quote]

Yes,  all you need to do is measure the voltage across those pins using your multimeter,  your cheap multimeter is fine.
Your probes/hook  should have a plastic handle which you hold, one black and one red?
use the black one going to a ground connection  and the red one to each of those pins,  simply write down what each of those pins measure.
Set your multimeter to read DC

[quote:6f822bafd0="WINDWSS"]Hi T,

Here's some brief info on the 6N3/2C51/5670 tube which i had try in my system. (Bada 6N3 CDP, audiolab 8000A (mod with BG cap & jensen big tank, AE AEGIS1 speaker (mod with vishay mkp &mkt + damping)

Tube tested:
1) Eclipse pioneer 2c51 (later known as bendix) - neutral, good detail & good bass - suit instrument lover. suit bookshelf speaker who need more bass. sound not as fast/crispy as tungsol.

2) Bendix 2c51 - characteristic similar as clipse pioneer but more dull/dark, slightly less musical & detail

3) Tungsol 2c51- very good detail & cripspy at HF & MID but bass is slightly less
4) WE 396A - more emphasis on mid (vocal), very musical, suit vocal lover but may not suit instrument lover like me

5) GE5670 - Soft, less detail, nice sweet vocal - suit vocal lover too but less detail than 396A

6) united electronic - dark, not musical...can't impress me so far...
5) GE 5670[/quote]

Thank you WINDWSS, thats a big help 8)   
Nice write up too

good questions.

Dear WINDWSS,

You mentioned about a "probe". Is it something that looks like a "hook"? I just have a very cheap multi-meter and it comes with two pins only. Can I use those? Will it be a bit dangerous if I just use those?

I have to make something clear first before I can go ahead and check the voltage for you. I need to turn the CD 33 on but no need to play any CD, right? But then do I have to remove the vacuum tubes from their sockets?

Please advise this amatuer. Thanks.

CAT

Hi T,

Here's some brief info on the 6N3/2C51/5670 tube which i had try in my system. (Bada 6N3 CDP, audiolab 8000A (mod with BG cap & jensen big tank, AE AEGIS1 speaker (mod with vishay mkp &mkt + damping)

Tube tested:
1) Eclipse pioneer 2c51 (later known as bendix) - neutral, good detail & good bass - suit instrument lover. suit bookshelf speaker who need more bass. sound not as fast/crispy as tungsol.

2) Bendix 2c51 - characteristic similar as clipse pioneer but more dull/dark, slightly less musical & detail

3) Tungsol 2c51- very good detail & cripspy at HF & MID but bass is slightly less
4) WE 396A - more emphasis on mid (vocal), very musical, suit vocal lover but may not suit instrument lover like me

5) GE5670 - Soft, less detail, nice sweet vocal - suit vocal lover too but less detail than 396A

6) united electronic - dark, not musical...can't impress me so far...
5) GE 5670

Dear Cat,

Refer the attachedment, pin 2&8 is the cathode, pin 3&7 is the grid, 1&9 is the filament, pin 4&6 is the anode.

So you just put 1 probe on the ground and 1 probe on either pi which you which to test.

e.g: if you put 1 probe on the ground, another probe on the pin 6, u r measuring the one of your anode voltage, if you put the probe on pin 4 you are measure another anode voltage.

Hi T,

i did post some tetsing on the tube but not include rusia tube, anyway in mandarin.

[quote:524276e859="WINDWSS"]Hi T,

How the epcos cap sound characteristic compare to Vishay mkp & BC mkp??

the yellow colour film cap you use is what brand?

ss[/quote]

Hi WINDWSS,

I also like Vishay mkp and BC mkp caps too,  the guy who owned the Cd33 before me fitted the 2.2uf Epcos,  I feel these are good caps so will keep them.
I did compare them against Audionote copper PIO, Auricap.   I liked the Epcos better,  just my opinion though :wink:   

Those yellow capacitors are 10uf Arcotronic MKP C.4G ,  these was the only type I had in my spares box in 10uf

I now have a favour to ask you guys   I still have the original 6N3 tubes fitted, has anybody tried those Russian 2C51 or 6N3P-E?  I will change the tubes after most of the mods for the electronics and was wondering what types make a worthwhile sound upgrade over the Chinese 6N3's

You guys should try bypassing the op-amp,  it saves having to worry about  what op-amps to use

Dear WINDWSS,

I don't mind doing you a favour but you have to do me one first .... WHERE do I measure those? Ha..ha.. I am not an expert like you guys.  :

If you please, take a close up photo and mark the position where I should measure the Voltage. I can then give you the results.  

CAT

CAT SIR,

can do me a favour? since u had change zener to 100V, your anode voltage of the tube should be about 100v now, can use measure the chatode & grid voltage when CD is not playing? is it ~45v??

if not mistaken when anode voltage is ~75v, the cathode voltage ~26-28v.


Dear KK sir,

from your experience for 2c51/6n3 tube what the best voltage different between anode & cathode? 50v?

Hi T,

How the epcos cap sound characteristic compare to Vishay mkp & BC mkp??

the yellow colour film cap you use is what brand?

ss

No wonder when i plug the 627 in the CD player, i actually can't heard much imporvement compare to plug into my amp.

Anyway i'm now using AD825....it suit my taste as i found 627AP's bass is fat is not so control compare AD825 and also not as detail as AD825 in my system.

OPA627 is NOT suitable to be used in the CD33 without modification, the op-amp decoupling is not good,  have you looked at the supply rails on a scope when using OPA627?  

I've now fitted a VBE modified ALW super regulator to supply the dac.
Op-amp and op-amp regulation removed

Dear WINDWSS,

That is why I feel strange. If I use back the Chinese Tubes + OPA2604, the S/N ratio is close to 90db!!

It is only with the Bendix Tubes or Chinese Tubes + OPA627AM the S/N ratio dropped.

Dear Cat,

let your player warm up for ~30hr then only proceed for other action.....all the circuit in your new board is not run in yet. So it is like a new player now....

[quote:aed370592b="viewer"]HI, t.,

i buy a zener in4764a 100v 1w today.
the data sheet is enclosed for your reference.
can i use this replace the 75v zener of cd33's power supply part.

many thanks.[/quote]

Those should be ok,  measure the voltage going to the pair of 100v rubycon ZL capacitors, make sure the voltage across these caps does not exceed their rating,   mine measured 97v,  a little under the max rating,  notice the tolerance  in the Zeners datasheet states they can range from 95v to 105v .

Please be careful,  remember we are dealing with highish voltage :wink:

[quote:4e901741be="alfcat"]Dear t.,

I followed your link to the Regulator page ... but I have some difficulties understanding it.  The thing comes as a DIY project? So how can we order the parts? I was in kind of hurry today when I visited the link and as I can't get much out of it, I lost my patience.

You can take a look at the last photo I posted. I changed all the large caps in the PS part to Black Gate already. That is how I boosted the S/N ratio from 65db to 75db or so.

I haven't got any Zener at home. Viewer had promised to send me one tomorrow to try out.

All the original caps I used in the wrecked PCB are now in their original places. However, I realised that my CD33 is not performing as good as it used to be. Really strange and disappointing.

BTW, is that your cat you are using as the avatar?[/quote]

Hi Cat,

Yes, the Flea regulator is a diy type, I ordered all the parts for mine from Farnell.
Now the CD33 op-amp stage has been bypassed its psu regulator circuit is not needed so I may try removing the 15v regs and run the clock circuit from there, I'll post pictures once I've tried it.

You will notice I do not use Blackgate caps, the reason being I do not like them, they sound too Euphonic/fake  to my ears,   I've tried all the grades from standard to NX Hi-Q,  even after weeks of burn in they are not to my taste.
If you improve the regulation etc that will give far better results than BG caps  :wink:   

Give your CD33 a few days to run in, it should improve,  did you apply lots of heat using your soldering iron when you replaced the capacitors?
Capacitors internal chemicals can change when the legs are heated, it can take a while for them to settle down.
Also be careful with using lots of Sanyo Oscon capacitors, their ultra low esr can make the output of regulators go unstable causing oscillation

BTW yes, that is my cat in the Avatar

HI, t.,

i buy a zener in4764a 100v 1w today.
the data sheet is enclosed for your reference.
can i use this replace the 75v zener of cd33's power supply part.

many thanks.

Dear t.,

I followed your link to the Regulator page ... but I have some difficulties understanding it.  The thing comes as a DIY project? So how can we order the parts? I was in kind of hurry today when I visited the link and as I can't get much out of it, I lost my patience.

You can take a look at the last photo I posted. I changed all the large caps in the PS part to Black Gate already. That is how I boosted the S/N ratio from 65db to 75db or so.

I haven't got any Zener at home. Viewer had promised to send me one tomorrow to try out.

All the original caps I used in the wrecked PCB are now in their original places. However, I realised that my CD33 is not performing as good as it used to be. Really strange and disappointing.

BTW, is that your cat you are using as the avatar?

Hi Cat,

Yes I live in the UK, this is the only forum I've found that has a modding thread for the CD33.

The clocks supply is DC, I fitted a rectifier and smoothing cap on the same bit of vero board for the small transformer.
The PFM XO low noise regulator is very good!  

I have two diy dacs I use as a reference
http://pic20.picturetrail.com/VOL1293/4634025/12749957/271121637.jpg
http://pic20.picturetrail.com/VOL1293/4634025/12749957/225303858.jpg
http://pic20.picturetrail.com/VOL1293/4634025/12749957/245458821.jpg

Sorry, I forgot to post the relevant photo.

You are station in UK? Your clock is an interesting one. It uses DC instead of AC?

CAT

Dear t.,

Thanks for the photos. Now it is very clear for me what you are referring to. I have similar modifications with my CD 33. I think I posted the photos in another thread.

http://www.hififever.com/forum/viewtopic.php?t=1619&sid=d85768dc9df9825a1f5585aaa527bf7d

Heres the PSU showing Zener and a few other bits,  I have a lot more planned to do on this cdp,  I'll add more when I have the time

I don't have a picture of the bypassed op-amp yet but heres a picture with notes, only do these mods if you are confident

Clock circuit etc

Are these any better Alfcat :wink:

I have modded a Cayin CDT-17a,   its not my cdp but I modded it for a friend,  the sound is quite good
I fitted Burson discrete op-amps and low noise Clock circuit,  tubes was changed to Mullard ECC88