How can I understand if it is time to replace capacitors?

[peranders]

My contribution to this is: If it ain't broken don't fix it.

If the amp works good, don't do anything. There are always a risk messing things up and impossible to repair later. Replace parts only if you have to.

A thirty years old cap might have many years left if it has not been put out for high temperatures.

 

[wintermute]

Very sage advice Peranders having been there done that, I wholeheartedly agree (though I did get it back to working properly in the end )

Tony.

 

[beppe61]

Dear Mr. Peranders,

thank you so much for your kind and very valuable reply.
Let me please ask you further opinions between the lines.

> My contribution to this is: If it ain't broken don't fix it.
If the amp works good, don't do anything.

The fact at Odyssey Audio, a well considered audio company, offers caps increase made me think about the possibility.
And it seems indeed that a lot of their customers pay for it.
Without having their amps broken anyway.

> There are always a risk messing things up and impossible to repair later.

that is indeed a risk and a point.
But it is a sort of experiment. and what if the outcome would be remarkable?
It costs about 20 USD of surplus Sprague, Mallory ...

> Replace parts only if you have to.

I read that just replacing an electrolytic caps in series with the signal with a film one has a nice improvement in the sound.

> A thirty years old cap might have many years left if it has not been put out for high temperatures.

Nice to hear this. Sprague make great caps indeed.
My amp should be of the 1978 and they seem to work just fine.
But i don't know about their ESR now.

Thank you so much.
Kind regards,

beppe61

 

[wintermute]

But i don't know about their ESR now.

Hi beppe61,

This may not be an issue. I tested (measured) with speaker workshop some 16 yo caps I took out of my amplifier.

Now I'm not sure if the resistance that speaker workshop reports is ESR ( I'm assuming it is) but the 16 YO generic brand caps actually had lower resistance than brand new panasonic FC caps of the same value and voltage!!! (I can't remember the exact figures but I think it was something like 6 ohms for the panasonic, 3 ohms for the old ones, and 1.5 ohms for rubycon ZA) All were 10uf 16V from memory. I wondered whether it had been wise to replace them!! having said that I only checked two, and the amp did sound better ( the bass improved) after changing the caps out (note these weren't the power supply caps).... It is of course possible that I only thought I could hear a difference, but that is a whole other kettle of fish

Tony.

 

[jacco vermeulen]

Beppe already made up his mind, i think.

Bartolomeo Aloia is the Nelson Pass of Italy.
I believe STEG is mainly in the car audio business nowadays.
If the amplifier you have is virtually the same as the one on Ebay it is a very fine looking amplifier, 30 years ago it must have been a luxury amplifier.

Even so, every commercial audio designer needs to monitor costs, the likes of Krell also.
Every dollar spent on parts raises the price tag by 5 to 6 dollars of the end product for high grade equipment.
The multiplication factor for consumer electronics is likely to be in the order of 10.
For an integrated amplifier choosing between a 7200uF or 15.000 uF capacitor will also be cost driven.
imo, replacing capacitors that were produced in the 52th week of 1975 is not a bad option.

Replacing them by bigger ones could be an improvement, but you'd have to check the rest of the powersupply, and see what the output stage is like.
But the looks, the choice of capacitors, and the name of the designer this must be a high quality design.
There is no point comparing an integrated class AB amplifier with a US high bias class A amplifier.
Putting 160.000uF in a vintage integrated amplifier is a waste of money and asking for problems.
Turning a classic Lancia Fulvia into a thoroughbred Ford Mustang is bad taste.
Maybe such a goodlooking Aloia design should be kept original.
No doubt there is room for upgrading, i have had very good results replacing and adding parts in amplifiers, such as; capacitors, resistors, transistors,opamps and different wiring.
Do you have the possibility of making/showing us a picture of the interior, Beppe ?

 

[beppe61]

Hi beppe61,
This may not be an issue.
I tested (measured) with speaker workshop some 16 yo caps I took out of my amplifier.
Now I'm not sure if the resistance that speaker workshop reports is ESR ( I'm assuming it is) but the 16 YO generic brand caps actually had lower resistance than brand new panasonic FC caps of the same value and voltage!!! (I can't remember the exact figures but I think it was something like 6 ohms for the panasonic, 3 ohms for the old ones, and 1.5 ohms for rubycon ZA) All were 10uf 16V from memory. I wondered whether it had been wise to replace them!! having said that I only checked two, and the amp did sound better ( the bass improved) after changing the caps out (note these weren't the power supply caps).... It is of course possible that I only thought I could hear a difference, but that is a whole other kettle of fish
Tony.

Hello Tony,

very interesting experience of yours.
I am already sold on the idea of replacing them.
Now I have only to find 2 nice 15 or 20.000 uF.

Thank you very much again.
kind regards,

beppe61

 

[Tweeker]

The Krell is a class A amp, such amps demand very large capacitances in the power supply to reduce ripple as they are always drawing heavy continuous curents. Id probably replace the 30 year old caps with somewhat larger ones too. Dramatically increasing thier size may lead to problems with inrush currents and stress the rectifiers and transformer.

 

[beppe61]

Hello Jacco,

nice to hear that Aloia is also known in The Netherlands.

>

Beppe already made up his mind, i think.
Bartolomeo Aloia is the Nelson Pass of Italy.

He is indeed one of the most famous (maybe the most) of italian audio designers.
This is a quite old (but still nice) design. Low global feedback, few parts, powerful power supply, nice components for its time.
I think they were hand-made and tested one by one.

> I believe STEG is mainly in the car audio business nowadays.
If the amplifier you have is virtually the same as the one on Ebay it is a very fine looking amplifier, 30 years ago it must have been a luxury amplifier.

Yes, same model. May be just a little more used.
It was about the equivalent of about 400 euro in the 1978.

> Even so, every commercial audio designer needs to monitor costs, the likes of Krell also.
Every dollar spent on parts raises the price tag by 5 to 6 dollars of the end product for high grade equipment.
The multiplication factor for consumer electronics is likely to be in the order of 10.
For an integrated amplifier choosing between a 7200uF or 15.000 uF capacitor will also be cost driven.
imo, replacing capacitors that were produced in the 52th week of 1975 is not a bad option.

Thank you jacco. So you approve the idea of the replacement ?
If only I could get a drop more in the bass.
I have compared this amp with a pair of Albarry monos and honestly there is no comparison in favour of the english amps.
Through the red front panel anyway I can see a 500 VA transformer and two huge caps.
Nice amps these Albarry.

> Replacing them by bigger ones could be an improvement,

I really hope so.

> but you'd have to check the rest of the powersupply

600 VA transformer. discrete diodes bridge. all in all nice.

> and see what the output stage is like.

a single pair of BJT in metallic case. I have to read the model.
the amp is specified at 70 W/channel with 8 ohm and about 100 W with 4 ohm loads.

> But the looks, the choice of capacitors, and the name of the designer this must be a high quality design.

I agree completely here. Actually I like its clean and punchy sound.

> There is no point comparing an integrated class AB amplifier with a US high bias class A amplifier.
Putting 160.000uF in a vintage integrated amplifier is a waste of money and asking for problems.

What do you think of 2 nice blue high-grade americans of about 15.000 or 20.000 uF?
Could you suggest any particular brand and model?

> Turning a classic Lancia Fulvia into a thoroughbred Ford Mustang is bad taste.

I cannot agree more. different cars for different tastes.

> Maybe such a goodlooking Aloia design should be kept original.

This amp will be like a test bench. As I said I am trying to get just some bass out of it.

> No doubt there is room for upgrading, i have had very good results replacing and adding parts in amplifiers, such as; capacitors, resistors, transistors,opamps and different wiring.

very interesting. I would like to have time to do the same.
I like very much the idea of restore audio things.

> Do you have the possibility of making/showing us a picture of the interior, Beppe ?

I will try to get a digital camera, that I do not own myself and shot some photos.
The power amp has a nice modular structure. Very interesting and possibility to extract these modules for any purpose.
Dear Jacco, as I understand you have a great experience on audio equipment mods, would you mind if I contact you privately?

Thank you very much again for your kind and very valuable reply.

Kind regards,

beppe61

 

[beppe61]

Thank you Mr. Tweeker for your kind and precious advice.

> The Krell is a class A amp, such amps demand very large capacitances in the power supply to reduce ripple as they are always drawing heavy continuous curents.

Of course, but in AB design there is the need to cope with impulsive high demands of current during musical peaks.
I think that a fast and big capacitance reservoir is always a nice plus.

> Id probably replace the 30 year old caps with somewhat larger ones too. Dramatically increasing thier size may lead to problems with inrush currents and stress the rectifiers and transformer.

Do you think that just doubling the total capacitance could cause some problems like those you mention ?
After all 30 years are always 30 years.
If one reads the lifetime value of caps I think that time has arrived.

Thank you very much again and kind regards,

beppe61

 

[maxlorenz]

Dear Beppe:
I am probably the least indicated to advice you but I value your interest in renewing your amp's life

My (limited) experience comes from building Hypex' UCD180 ClassD amp: an easy and rewarding experience. As these are modules one only has to put together the PS and connections. Believe me the sound is first class and the bass is excellent, not floor shaking but deep, expansive and articulated.

I'm sure you will notice an improvement in sound when you upgrade but first check rectifier's current capacity (they are cheap) and soft start (for your 600VA Tx).
Well, I have tried these caps:
1)BHC ALS40 (RS nº 381-9908 ) which are very good sounding, with excellent bass and a bit dark presentation.
2) Epcos Sikorel(RS nº 190-8955 ): great sounding, more transparent-detailed.
Those caps are NOT cheap! And probably overkill on your project, but in mine they were terrific. Note that this is a very personal opinion of caps that I found at RS components (search the site for better options).
You may consider these RIFA (RS nº189-793 ) wich are said to be very good and cheaper.

You may also consider changing the stock power cord and speaker/RCA connectors and internal wiring.

Appart that, I must say that I think you are a very kind and polite person and that your posts are a delice to read

I hope this helps

Mauricio

 

[Tweeker]

Doubling it will probably be ok, increasing it to 160,000 uF might be another matter. As Mauricio said rectifiers are cheap, check them. I dont know what it looks like in there, but if its easy to do so, you may do better to use say a 7,200uF cap + a 12,000uF cap per rail than one 20,000 uF cap.

 

[beppe61]

Dear Beppe:
I am probably the least indicated to advice you but I value your interest in renewing your amp's life
My (limited) experience comes from building Hypex' UCD180 ClassD amp: an easy and rewarding experience. As these are modules one only has to put together the PS and connections. Believe me the sound is first class and the bass is excellent, not floor shaking but deep, expansive and articulated.
I'm sure you will notice an improvement in sound when you upgrade but first check rectifier's current capacity (they are cheap) and soft start (for your 600VA Tx).
Well, I have tried these caps:
1)BHC ALS40 (RS nº 381-9908 ) which are very good sounding, with excellent bass and a bit dark presentation.
2) Epcos Sikorel(RS nº 190-8955 ): great sounding, more transparent-detailed.
Those caps are NOT cheap! And probably overkill on your project, but in mine they were terrific. Note that this is a very personal opinion of caps that I found at RS components (search the site for better options).
You may consider these RIFA (RS nº189-793 ) wich are said to be very good and cheaper.
You may also consider changing the stock power cord and speaker/RCA connectors and internal wiring.
Appart that, I must say that I think you are a very kind and polite person and that your posts are a delice to read
I hope this helps
Mauricio

Dear Mr. Mauricio,

thank you very much for your extremely kind compliments and valuable advice.
Anyway I must confess you that my politeness is not natural at all.
Instead it is a sneaky strategy to steal precious schematics and information to generous audio experts as you.
Now you can better understand what kind person am I.
Knowledge is a precious thing and I must admit that I am here to take profit of the knowledge of other persons.
I am a RS Components customer as well and I read great things about the brands you mention. Really good products.
That said, I think that the costs of just two new caps of the brands you mention is higher than the residual value of my amp.
I think that the Sikorel are 10.000 uF/63 VDC, if I am not mistaking.
I would like to try before two surplus caps of about 15.000 uF.
I have a wonderful opinion of those blue american caps of brands like Mallory, Sprague Powerlyitc (in teh name there is all the programm), Cornell Dubillier, Sangamo, United ChemiCon.
The fact that brands like Mark Levinson, Krell use them speaks for itself I think.
On the basis of your very kind and friendly reply I would like to ask you which kind of preamp do you use to drive your Hypex' UCD180 modules.
As you can see from my other threads I am also obsessive in my search for a minimalist line preamp to use along with the digital source to drive this amp I am trying to power up.

Thank you very much again for your extremely nice and kind words.

Kind regards,

beppe61
ITALY

 

[beppe61]

Dear Mr. Tweeker,
thank you very much again for your kind and helpful advice.

>

Doubling it will probably be ok,

Thank you. This is the value I will try. I do not expect much but I will not be satisfied until I try.
Well to be perfectly honest I expect a nice improvement in the bass region of the audio spectrum. Maybe I am too optimistic.

> increasing it to 160,000 uF might be another matter.

It would mean more than ten times the present value of capacitance. I understand very well your point.

> As Mauricio said rectifiers are cheap, check them.

All right.

> I dont know what it looks like in there, but if its easy to do so, you may do better to use say a 7,200uF cap + a 12,000uF cap per rail than one 20,000 uF cap.

I record your valuable suggestion.
Thank you very much again.

Kind regards,

beppe61

 

[RetroAudio]

going crazy!

beppe61 - you sure got all sorts of advice here, just hope you can make sense of it all. or,....are you sorry you asked??..

 

[wintermute]

hehehe @ Retro

I have had Nichicon KG caps highly recommended if you can't get them in Italy, Percy Audio http://www.percyaudio.com/ has them at reasonable prices

Tony.

 

[maxlorenz]

Dear Beppe:

Instead it is a sneaky strategy to steal precious schematics and information to generous audio experts as you.

Ha, ha, ha sonno morto di tanto ridere...
Your strategy (the same that I use) works.
I have never being called an audio expert and I'm very flatted, although without ANY fundament.

No, I consider myself an "ethernal beginner" (I read this description somewhere and I found it genial). In fact we could form here an ethernal beginners' guild.

I think that the Sikorel are 10.000 uF/63 VDC, if I am not mistaking.

And and insane beginner I must admit Once I heard that Halcro amps used sikorel and was irremediably lost!

On the basis of your very kind and friendly reply I would like to ask you which kind of preamp do you use to drive your Hypex' UCD180 modules.

For now I use the UCD's amps on my second rig, an active speaker setup with cheap analog Behringer crossover as preamp wich has "servobalanced" outs. The DDDAC1543 with a 16*TDA1543 chips tower is the source.
My plan is substituting my ClassA amps in my main system with a pair of UCD400 monos when I get the money to buy more "cans".

Projected system:
CDPRO-2M->Monarchy Audio DIP upsampler->heavily moded M-audio superDAC through balanced outs->balanced transformer based volume control with Stevens&Billingtons trannies->UCD400
All balanced...
What the ***, it's only money.
I like very much the TVC approach both sonically and phylosophically. And they match the UCD's wonderfully.

Arrivederci, mio caro...
Maurizio

 

[beppe61]

Re: going crazy!

beppe61 - you sure got all sorts of advice here,
just hope you can make sense of it all. or,....
are you sorry you asked??..

Dear Sir,

I am very happy indeed I asked.
I got a lot of very kind, friendly and above all extremely valuable advice from you and the other participants to the discussion.

Thank you so much.

Kind regards,

beppe61

 

[beppe61]

hehehe @ Retro
I have had Nichicon KG caps highly recommended if you can't get them in Italy, Percy Audio http://www.percyaudio.com/ has them at reasonable prices
Tony.

Hello Tony,

thank you so much for your kind and extremely valuable suggestion.
Yesterday I actually saw 4x10.000 uF Nichicon caps (don't remember the exact series) in the power supply of the BAT integrated.
This confirms in some way your great suggestion.

Thank you so much.

Kind regards,

beppe61

 

[beppe61]

Dear Maurizio,
thank you again for your kind and very helpful reply.
I would like to quote you and reply between the lines.

Dear Beppe:
Ha, ha, ha sonno morto di tanto ridere...

Your italian is really good. Congratulations!
I would like my spanish were good like your italian.

> Your strategy (the same that I use) works.
I have never being called an audio expert and I'm very flatted, although without ANY fundament.
No, I consider myself an "ethernal beginner" (I read this description somewhere and I found it genial).
In fact we could form here an ethernal beginners' guild.
And and insane beginner I must admit

I really think that you are much more than a simple beginner and your experience is evident from your replies.
On the other hand I am very inexperienced instead.

> Once I heard that Halcro amps used sikorel and was irremediably lost!

That is a very good method: looking at the parts used in high-end amps is a good way to select them.

> For now I use the UCD's amps on my second rig, an active speaker setup with cheap analog Behringer crossover as preamp wich has "servobalanced" outs.
The DDDAC1543 with a 16*TDA1543 chips tower is the source.
My plan is substituting my ClassA amps in my main system with a pair of UCD400 monos when I get the money to buy more "cans".
Projected system:
CDPRO-2M->Monarchy Audio DIP upsampler->heavily moded M-audio superDAC through balanced outs->balanced transformer based volume control with Stevens&Billingtons trannies->UCD400
All balanced...
What the ***, it's only money.
I like very much the TVC approach both sonically and phylosophically.
And they match the UCD's wonderfully.

Your set up is much more complex than mine.
My system is very basic and I am trying to imporve it just a little in the bass department.
Anyway thank you for your interesting suggestion of the UCD modules.

Arrivederci, mio caro...
Maurizio

Hasta la vista, Maurizio !

 

[maxlorenz]

Caro Beppe:
Allow me to quote you.

Your italian is really good. Congratulations!

When one is a longtime opera fan one finally ends by learning something

"Oh rustici, Oh rustici,
attenti! non fiatate!
Io giá suppongo é immagino,
que al par di me sapiate
qu'io sonno quel gran medico,
dottore enciclopédico,
chiamatto Dulcamara,
la cui virtú preclara
e il portenti infiniti,
son noti a l' universo
e...e a d'altri siti..."

... from Dulcamara's presentation aria, L'Elisir d'Amore", G Donizetti. (sorry for the mistakes )

My system is very basic and I am trying to improve it just a little in the bass department.

May I suggest that you address your source first?

Good luck
Mauricio