Capacitor Values

[tazzo]

Hello all, diy novice here,

I have bought a cheap chinese preamp from eBay but need some help with the following...

I am needing 8 capacitors of the following value;

8 X 220uf @ 50v

Is it possible to replace the values above with the following?

4 X 100uf @ 50v (Black gates)
4 X 330uf @ 50v (Elna Silmic II)

I understand that the value is 40uf less than required, but does that really matter and can I implement the above in the preamp? I can't get Black Gates at the required capacitence (uf).

I think the preamp uses two channels, so it would be 2 silmics and 2 black gates for each.

The preamp I bought is below;

HiFi Tube valve Stereo Buffer Preamp preamplifier amplifier amp 110 or 220V UK | eBay

I am also replacing the bog standard transformer with a toroidal type, the input voltage is AC12V/1A, will this transformer do the job? I'm not sure what the "1A" stands for.

P042C 50VA Toroidal Transformer 0-12, 0-12 Vac Outputs | eBay

Any help would be much appreciated,

cheers.

 

[12E1]

If the pairs of capacitors are in parallel, then Yes, it will work. The missing 40uF is not significant. It's less than 5% of the total, and electrolytic capacitors normally have a tolerance on the capacitance value of at least 20%. Often the tolerances are more like -20% to +80%, so you can easily end up with more capacitance than intended. That is not likely to be an issue either in this case.

If the caps are not in parallel, then please let us know how they are connected.

 

[DF96]

Why replace the transformer?

What you have appears to be a cathode follower 'buffer', not a preamp. If designed properly it will, in most systems, do nothing to the music signal. Given the likely low supply rail voltage it may not be as good as this. Have you tried running without it?

 

[AndrewT]

Test the "customer support" of the retailer.

Try asking a a schematic.
Try asking for a Bill of Materials (BoM).
Try asking if the supplied 220Vac transformer is suitable for a UK 240Vac, which can rise to 253Vac.

 

[TonyTecson]

here we go again.....another capacitor thread....did you search the forum for other similar threads?

 

[tazzo]

Yes, I have been searching the forums, so eventually posted a thread.

I am still awaiting the preamp to be delivered, previously I modded a Yaquin SD-CD3 with Mundorf Evo in oil capacitors and Shuguang 50th Anniversarry treasure tubes, it made a significant difference to the sound, clearer, stronger signal, better bass etc etc.

I am replacing the transformer DF96 because at the price I am getting the preamp, I assume it will be of really shitty quality and I want a good bass response, if I am going to have top quality capacitors fitted, why not go all the way?

The eight capacitors will be replaced as follows;

There are two rows of four of the 220uf below is how I intend them to be installed.

BG ES BG ES
ES BG ES BG

BG = Black gates
ES= Elna Silmics

Is this what you mean 12E1?

AndrewT, the guy is just an eBay seller, he probably does not even know what a schematic is.

 

[tazzo]

Look forward to your replies, as I said, I am just a novice at this with one tube buffer upgrade under my belt.

Thanks for the replies so far.

 

[TonyTecson]

Yes, I have been searching the forums, so eventually posted a thread.

I am still awaiting the preamp to be delivered, previously I modded a Yaquin SD-CD3 with Mundorf Evo in oil capacitors and Shuguang 50th Anniversarry treasure tubes, it made a significant difference to the sound, clearer, stronger signal, better bass etc etc.

I am replacing the transformer DF96 because at the price I am getting the preamp, I assume it will be of really shitty quality and I want a good bass response, if I am going to have top quality capacitors fitted, why not go all the way?

The eight capacitors will be replaced as follows;

There are two rows of four of the 220uf below is how I intend them to be installed.

BG ES BG ES
ES BG ES BG

BG = Black gates
ES= Elna Silmics

Is this what you mean 12E1?

AndrewT, the guy is just an eBay seller, he probably does not even know what a schematic is.

if you already convinced yourself that changing caps/transformer even before you heard the amp is your cup of tea, then nothing we can say here will mean much to you....so good luck to you then....😉

 

[tazzo]

I'm going by experience from a mod that I have done in the past which made a significant difference to my set up.You cant deny the quality of Elna and BG caps compared to stock ones, and thanks for the good luck, hopefully it will come in handy...

 

[12E1]

The eight capacitors will be replaced as follows;

There are two rows of four of the 220uf below is how I intend them to be installed.

BG ES BG ES
ES BG ES BG

BG = Black gates
ES= Elna Silmics

Is this what you mean 12E1?

No.

I meant that if the capacitors are electrically in parallel then the capacitances will add up to be sufficiently close as to make no difference. That is something that you will need to determine from the schematic and / or PCB connections.

I'm going by experience from a mod that I have done in the past which made a significant difference to my set up.You cant deny the quality of Elna and BG caps compared to stock ones, and thanks for the good luck, hopefully it will come in handy...

However, since you are apparently looking at changing the capacitors (in the power supply of a pre-amp) with the expectation that this will somehow improve the sound, this becomes a matter of religion rather than a simple technical matter.

I had thought that the question of the "missing" 40uF was just due to inexperience. I know quite a bit about the properties of capacitors in power supply circuits. I know plenty about how to connect them up. I was giving advice on that basis.

I know nothing about why one would replace perfectly satisfactory capacitors with other perfectly satisfactory capacitors that cost a great deal more, when the power supply conditions in a pre-amp dictate that the former would be just as good. Of course, religion may give you a warm, fuzzy feeling that the sound is "better" after the change compared to before, but that is all it is. It is a personal choice for you to make. If it works for you, then great. It would not work for me.

 

[tazzo]

Thanks for your advice, I will take in on board and think about this. I have had Elna Silmic II capacitors replace previous ones in my Yamaha A-S500, and again I noticed a difference, smoother, warmer with a more open top end, but this came unexpected to me after 120+ hours of running on.

 

[TonyTecson]

I know nothing about why one would replace perfectly satisfactory capacitors with other perfectly satisfactory capacitors that cost a great deal more, when the power supply conditions in a pre-amp dictate that the former would be just as good. Of course, religion may give you a warm, fuzzy feeling that the sound is "better" after the change compared to before, but that is all it is. It is a personal choice for you to make. If it works for you, then great. It would not work for me.

and to think that that amp is a cathode follower.....

btw, i am getting that amp like for U$12 from china...

here is a thread by the one and only.... http://www.diyaudio.com/forums/parts/151392-best-electrolytic-capacitors.html

 

[tazzo]

What is a cathode follower?

I can see that DF96 is very skeptical of such upgrades, and he has shown that on other threads such as the one for the Yaqin SD-CD3, however as mentioned I noticed a strong amplification and difference from tube and cap rolling even if that is a "cathode follower" also, I wonder if I am missing something?

AJT, are you planning to tube/cap roll this amp yourself, and can I ask your source for the purchase? I paid £24.95 for mine. I am interested in hearing your views...

 

[tazzo]

No.

However, since you are apparently looking at changing the capacitors (in the power supply of a pre-amp) with the expectation that this will somehow improve the sound, this becomes a matter of religion rather than a simple technical matter.

If the upgrades genuinely give me more than a "warm fuzzy feeling" as I have experienced through cap rolling, I don't see how "effects" of religion come into this. In fact I'm sure you are aware that many people have seen the benefits of cap rolling, the Elna Silmic II caps in the power supply of my Yamaha certainly improved the sound of my amplifier.

Also, looking at the matter at a technical point of view, is this not where datasheets come in to show different aspects of different capacitors?

 

[TonyTecson]

What is a cathode follower?

The Valve Wizard -Cathode Follower

AJT, are you planning to tube/cap roll this amp yourself, and can I ask your source for the purchase? I paid £24.95 for mine. I am interested in hearing your views...

no, i am building it to gift a friend....🙂
my friend who works in China hand carried the amp kit...😉

 

[tazzo]

Ok, and thanks for the links.

Are you replacing the caps, and can you get hold of a schematic?

I've e-mailed a few sources to try and get a copy, the black gate and elna capacitors will be replacing the "bunch" of eight (2 bunches of 4) in the middle of the preamp and I'm not sure how I should position them, any advice for me?

Theoretically I would be using four each of the two types.

 

[12E1]

If the upgrades genuinely give me more than a "warm fuzzy feeling" as I have experienced through cap rolling, I don't see how "effects" of religion come into this. In fact I'm sure you are aware that many people have seen the benefits of cap rolling, the Elna Silmic II caps in the power supply of my Yamaha certainly improved the sound of my amplifier.

Also, looking at the matter at a technical point of view, is this not where datasheets come in to show different aspects of different capacitors?

I didn't say anything about the ""effects" of religion". I simply used the word religion to describe the belief that changing electrolytics in the power supply of a small signal amplifier (as opposed to a power amplifier) would improve the sound in some way. Your subsequent approach and comments seem to confirm that you will do this because it is something that you believe will work, rather than something that can be proven to work based on mathematics, data sheets, etc.

As I said it's your choice. I have nothing further to add.

 

[tazzo]

Ok, that's cool. But if datasheets say that one capacitor is better than another, would that not work on the small signal amplifier?

My approach is based on the fact that people say that according to datasheets that certain capacitors are better than others. However I understand now that the small signal amp may not be powerful enough to make a noticeable difference.

I mentioned that I am also replacing the transformer to one of better quality, it will be 50 VA, do you think that think will help bring out the sound better as opposed the the cheap
(I think it is like 12 VA) one that you get with the preamp?

As I said before,I am just a novice, you guys are the experts, if at the end of the day it would not make very much difference then that is something I have to seriously consider as opposed to wasting my time and money.

Is there any cheap (tube or SS) preamp that I can maybe buy to implement changes that I have mentioned? 12E1, I hope that you add more to this thread, because I find your input valuable.

 

[TonyTecson]

if only you learned about what cathode followers were
before you learned about changing caps....
or how circuits worked.....
it looks to me you have been reading a lot of snake oil articles...

 

[godfrey]

I am also replacing the bog standard transformer with a toroidal type,

I mentioned that I am also replacing the transformer to one of better quality

Isn't that a condradiction, or is the supplied transformer also a toroid?

John Curl's opinion from here:

Rcore or the equivalent transformers are better than toroid, by far, and even preferred in some ways over a good E-I transformer,

There's someinteresting discussion of transformers in the ollowing couple of pages.