Newbie - confused with voltage rating of capacitors ReVox B226

KanedaK

Member
2011-02-07 8:32 pm
Hello,

I'm about to recap my old ReVox B226 CD player.
I started ordering caps: Nippon Chemicon SXE - Nichicon VY (PSU), Elna Silmic II, there will most likely be some Panasonic FC as well

I am however confused with the voltage ratings.
I have been referring to the ReVox service manual for the caps values - sticking to the capacitance and voltage ratings I was reading in there, in the parts list.
For example, all Elna Silmic are going to be 100uF - 16v, as stated in the service manual.
Problem is, when I look at the board with the original caps in place, I see the 100uF that are supposed to be replaced with the Elna Silmic are Philips "blue" caps and are stated 100uF - 25v.
I didn't check yet the other caps, other than the PSU caps where the voltage rating on the cap matches the voltage rating indicated in the service manual.

Am I risking anything? What should I trust, the service manual, or the actual caps that are on the board? I understand caps should be 50% higher rating than the actual voltage that will go trough, for safety. So what is the rating in the service manual? Is it the voltage that goes trough ( in wich case I should order all new caps), or is it the recommanded voltage rating of the cap, and they just used a higher voltage rating because "they had them at hands"?

This is going to be my first serious recap, and I don't wanna mess things up...

thanks folks!
 
If you plan on changing the capacitors, use as described in the service manual as that is what has been designed. A good idea is to check the actual voltage on the cap that is going to be replaced, just in case. Maybe it has had a re cap in the past and all they had was at hand for their convenience.
No sense in fitting oversized over voltage capacitors.
Philips 'blue' caps are extremely good quality and even an aged capacitor will probably be within tolerance.
 
So what is the rating in the service manual?
The rating in the service manual is the rating specified by the original designer. It will be based on a combination of actual circuit requirements and component availability. Replacements need not be the same voltage rating, provided you can determine from the circuit what the rating needs to be. If in doubt, use the same or the next rating upwards.

In my view a "serious recap" may be a bad idea. More likely to introduce new faults than fix old ones. Replace faulty caps, if any. Do it one at a time, so you can check that it still works.
 

KanedaK

Member
2011-02-07 8:32 pm
The rating in the service manual is the rating specified by the original designer. It will be based on a combination of actual circuit requirements and component availability. Replacements need not be the same voltage rating, provided you can determine from the circuit what the rating needs to be. If in doubt, use the same or the next rating upwards.

In my view a "serious recap" may be a bad idea. More likely to introduce new faults than fix old ones. Replace faulty caps, if any. Do it one at a time, so you can check that it still works.

So even if the caps on the board are rated 25v, I can put some 16v caps in place if that's the service manual states... i'm still confused why the difference, all caps being originals...

As for recapping needed, it's a 1987 player, PSU caps are Frako (i heard those are potential bombs), and I had a total recap on a SAE preamp wich brought it from mediocre sounding to very good... I'm hjoping the same for the ReVox...
 
If the manual states 16V but the board has 25V then you can probably replace with 16V. I assume that the supply rail voltage is less than 16V, and the circuit does not do something unusual to create a local higher voltage. The voltage rating, provided it is sufficient, is not that important. The unit may have been built with some higher rated caps, or it may be the result of a later repair.

Be aware that we regularly get people popping up on here saying "I did a total recap on my XYZ123 to upgrade it, but now it doesn't work". If you must do a recap, at least do it a few at a time.
 

KanedaK

Member
2011-02-07 8:32 pm
I started soldering new caps yesterday, starting with what I already have - more caps are on their way.
So far I replaced three 2200uF 25v caps with Nippon Chemicon SXE, same values, in the PSU; the big 10000uF I couldn't replace yet, Nichicon FW is on its way. I replaced three small 1uF decoupling caps with Panasonic FC same value; and, as I will have to wait two more weeks for the Elna Silmic II to arrive, I couldn't resist replacing the 100uF output coupling caps with Panasonic FC same value, for the time being.
note: to replace the 4 legs Frako 2200uF, I had to solder some straps made of wire to reconnect tracks that were now left open (in the 4 legs Frakos, the central leg is (+) and the three external legs are (-). Had to look that up last night on the web to figure it out...)

All the other caps on the board I have to wait.

All I must say is I'm very, very satisfied with the result so far; with only a small number of caps replaced, the difference in sound is truly phenomenal! I guess the 30 years old caps had really badly drifted... The B226 is now much more dynamic, highs are clean and extended, bass seems to be faster and stronger, mids are much less harsh than they used to be. There was a roughness to the sound that is now completely gone. I can't wait to have the Elna Silmic and finish the recap, I have big big expectations!
 

Eldam

Banned
2012-09-13 12:25 am
France
There are only 4 reasons to replace caps on a DAC/CD players !

1- you want to secure it because you have nightmares about so said futur troubles !
2- you want to recover the genuine capacity of your beloved player
3- You want to improve Something
4- Wife became borring and you have more fun modding your music stuff!

Well :

- point 4 : can not be talked here, at worst in the swap met section (for instance : "I exchange wife for a dac")

- point 2 : impossible task but if you find NOS stock, and there is agging on the shelf too, so.... impossible task ! And the worst is you can not remember how it sounded when brand new, brain has poor memory of sound !

- point 1 : go for DF96 technic with the caps which feets exactly like the previous (size, pitch, values) . check twice !

- point 3 : go for DF96 : you can only know if the swap is good by hearing if it is not worst before : so component by component (or you are in fact totally in the point or point 2 territory). It is always a long task and it is never a guaranty if you have not the genuine stuff non modded to benchmark the genuine sound ! But it's a good way to adapt your source to your taste or adapt it to the others links of the hifi chain ! It's subjective, but sometimes real improvement can be waited. It can be also a hobby or a game and can beat into the point 4 territory ! A better cap like a better wife on the datasheet can be worst than the original, so you really need to try them one by one (the caps I mean) and listen what they have to said !

Hope that helps !
 

KanedaK

Member
2011-02-07 8:32 pm
You are sourcing capacitors in China it seems, will be a modern Revox.

China? Duh... I didn't buy any chinese cap. I don't really understand your comment.

Modern? well... if you wanna keep using that 1967 Ford Mustang and it needs new tires and maybe new gasket, even tho they will be made with modern materials, you will install them, right?

I don't know what the B226 sounded like when it was new. I was 9 years old in 1987 :) I guess nobody at this point remembers. Who cares? I guess if it sounds good, and is reliable, it's better than have it taking dust on a shelf. I can really hear a big difference in sound at this point, and for the better. I'm pretty sure it's more due to the facts that the original caps had drifted, rather than their quality; I'm pretty sure Revox used good parts all the way. I'm not derating any cap, to respect the original design as much as possible. I'm not even bypassing any. I'm using same type, same value, same voltage rating even in most cases, and just choose whatever brand I think will be best for this or that part of the circuit. They didn't have Elna Silmic iI in 1987, but I'm sure if they did, they would have used it or something similar. I guess my approach at "modding" is pretty safe, but the end result will tell; I'm confident it will be better than it was when I bought it two months ago, and that's already something.

Eldam, yes I'm using that method: I changed three big PSU caps then listened trough the headphone jack. as what I heard was a clear improvement over the (probably dying and close to shortcut) 30 years old Frako caps, i changed three 1uF (old electrolytics Philips Blue) with Pana FC, and the two output caps (also philips blue) with Pana FC, and now the player is back in the main system and i'm listening some music. There are 21 more caps that I wanna change.

Changing caps on a B226 requires taking the board out completely. I don't wanna put too much mechanical stress on it, as the plastic parts, connectors, ribbons, are old and become fragile with time; hence I won't do the " cap by cap" listening technique. I can do "all same type" but that's enough manipulation already.

Thanks for ur input!
 
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KanedaK

Member
2011-02-07 8:32 pm
Buying "Nippon Chemicon SXE" today and not some years ago and still two weeks for "SilmicII" to arrive is very chinese to me.

You mean they're from Chinese resellers. Well, the Silmic II are, indeed. The Panasonic FC came from France, and the Nippon Chemicon from UK. I'm aware of the fake caps plague on eBay; I'm trying my luck with the Silmic II. I bought some from two different resellers and will compare. I alo bought a bit more than needed so I can open one or two. I know buying from there is dangerous but I had no choice this time. if I have any doubt about what I receive from China, I won't install them, and will install Panasonic fC instead, or try to source Silmic II from another, European ebay reseller.
 

Eldam

Banned
2012-09-13 12:25 am
France
If you have some output caps after an old reg à la 78005 /7912 etc : it calls for some attention. For instance at the output of those regs an old Nichicon SE caps can be better than a new cap. Don't put here a cap with a too good ESR... sometimes there are exceptions but all dépends of layout and the last caps before the active device !

It's always a good method to check one by one all change with music after... of course (unluckilly it's borring) the same music to try to have a reference...

Have fun :)


(personaly I find Silmic 2 to be transparent but a little coldy : can be good at some place but worst on some other : experiments will give you the solution as always)
 

irribeo

Member
2013-04-01 2:46 pm
In a perfect world you bought bad Chemicons and real Panasonics and real Elnas. In this world you bought fake old Chemicons, fake Panasonics and fake Elnas. You take a chance with all capacitors you bought, for no good reason, you could have bought from official distributor.
 

KanedaK

Member
2011-02-07 8:32 pm
In a perfect world you bought bad Chemicons and real Panasonics and real Elnas. In this world you bought fake old Chemicons, fake Panasonics and fake Elnas. You take a chance with all capacitors you bought, for no good reason, you could have bought from official distributor.

I don't own a credit card. Might sound strange, but it's like that. My only payment method on internet is Paypal. Most online stores only accept credit cards.
Panasonic come from a French electronic ebay store. Nippon chems came from a UK ebay store.

I'm worried about the Silmic II; I am, however, quite confident on being able to tell a fake from a real. In any case, they are small values, so the investment in cash is reasonably low; it will make me waste some time, but it is not the end of the world. What else can I do? ;)
 
Revox service manuals are known to contain errors in schematics and text and were not updated after release with technical bulletins, like in the case of Studer.
As the rule of thumb, follow the schematics but the definitive component type/value/orientation is what you find on the PCB you work on, provided that it is in original state. Otherwise, you can look at the schematics which you have and check the effective voltage which the capacitor is connected to.