My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out, they are 10000uF 80V. Lots around for
about 20quid each, or some ebay ones which I try to avoid if possible.
Does this look OK ?
http://connect-audio.co.uk/proddetai...000U80&cat=219
Does the life seem a bit short (I know this is at the max temp) ?

Also saw this but the lead spacing and layout is wrong:
http://parts.digikey.co.uk/1/1/91787...t1ka103fa.html

I did not realise the life was so limited though. I've left the amp on
24 hours a day on standby for years !

Also a couple of smaller 3300uF 50V jobs, I guess for a 5V or similar
supply for the ICs, DSP chips etc.
Probably worth changing those as well.

OR ..
Is this really worth my time and up to 50 quid fixing ???
A new replacement would cost 350 quid but would support blue ray
audio, HDMI etc.

Simon.

At that price I'd want to be certain it was those caps. Can you isolate
the main amps or perhaps short the inputs to be certain it isn't coming
from elsewhere?

I've got several amps here a lot older than that on the original smoothing
caps.

--
*When I'm not in my right mind, my left mind gets pretty crowded *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
At that price I'd want to be certain it was those caps. Can you isolate
the main amps or perhaps short the inputs to be certain it isn't coming
from elsewhere?


Just solder a new 80v cap of almost any flavour over 1000uf across whats
there.


Identical issue in 50 year old valve radio. Fixed it.

I've got several amps here a lot older than that on the original smoothing
caps.


Bad caps abounded 7-10 years ago.

They all dried out..

The Natural Philosopher wrote:
Dave Plowman (News) wrote:
At that price I'd want to be certain it was those caps. Can you
isolate the main amps or perhaps short the inputs to be certain it
isn't coming from elsewhere?


Just solder a new 80v cap of almost any flavour over 1000uf across
whats there.

Why would these need to be 80v out of interest? What sort of DC voltages do
these amps typically operate on? I know there's a margin for peaks, but 80v
across a nominal 8 ohm resistance would provide 800w. This is an amp, not a
room heater, surely?

On Mar 4, 11:09*am, "GB" wrote:
The Natural Philosopher wrote:
Dave Plowman (News) wrote:

Just solder a new 80v cap of almost any flavour over 1000uf across
whats there.

Why would these need to be 80v out of interest? What sort of DC voltages do
these amps typically operate on? I know there's a margin for peaks, but 80v
across a nominal *8 ohm resistance would provide 800w. This is an amp, not a
room heater, surely?

80 volts is the *peak* voltage, at the top of the waveform. The
wattage delivered to the speakers depends on the 'RMS' (root-mean-
square, a sort of average), which is 0.707, (for design purposes; it
varies with the waveform) of the peak.

alexander.keys1 wrote:
On Mar 4, 11:09 am, "GB" wrote:
The Natural Philosopher wrote:
Dave Plowman (News) wrote:

Just solder a new 80v cap of almost any flavour over 1000uf across
whats there.

Why would these need to be 80v out of interest? What sort of DC
voltages do these amps typically operate on? I know there's a margin
for peaks, but 80v across a nominal 8 ohm resistance would provide
800w. This is an amp, not a room heater, surely?

80 volts is the *peak* voltage, at the top of the waveform. The
wattage delivered to the speakers depends on the 'RMS' (root-mean-
square, a sort of average), which is 0.707, (for design purposes; it
varies with the waveform) of the peak.

That's still 400w average power.



--
Murphy's ultimate law is that if something that could go wrong doesn't,
it turns out that it would have been better if it had gone wrong.

On 04/03/2011 11:09, GB wrote:
The Natural Philosopher wrote:
Dave Plowman (News) wrote:
At that price I'd want to be certain it was those caps. Can you
isolate the main amps or perhaps short the inputs to be certain it
isn't coming from elsewhere?


Just solder a new 80v cap of almost any flavour over 1000uf across
whats there.

Why would these need to be 80v out of interest? What sort of DC voltages do
these amps typically operate on? I know there's a margin for peaks, but 80v
across a nominal 8 ohm resistance would provide 800w. This is an amp, not a
room heater, surely?



Fairly ordinary domestic power amps run with +/- 40 or 50 v rails.
80v rated caps would not be unreasonable.

The full rail voltage won't appear on the output ( unless the one of the
Output Devices have gone S/C ).


--
Ron

On Mar 3, 11:33*pm, sm_jamieson wrote:

My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out, they are 10000uF 80V. Lots around for
about 20quid each, or some ebay ones which I try to avoid if possible.
Does this look OK ?http://connect-audio.co.uk/proddetai...000U80&cat=219
Does the life seem a bit short (I know this is at the max temp) ?

Also saw this but the lead spacing and layout is wrong:http://parts.digikey.co.uk/1/1/91787...ect-tha-series...

I did not realise the life was so limited though. I've left the amp on
24 hours a day on standby for years !

Also a couple of smaller 3300uF 50V jobs, I guess for a 5V or similar
supply for the ICs, DSP chips etc.
Probably worth changing those as well.

OR ..
Is this really worth my time and up to 50 quid fixing ???
A new replacement would cost 350 quid but would support blue ray
audio, HDMI etc.

Simon.


Electronic equipment is complex in terms of the number of possible
faults. Guessing is a poor repair strategy, especially when it costs
£50 a guess. Lytics normally last many decades, though there have been
some duds on the market causing problems.

The simplest way to test the caps is to measure the ripple on them
with the power on. If you dont have the proper equipment, you can use
a mmultimeter on ac volts setting, connecting it to the big cap via a
small 1uF non-polarised cap (ie polyester, not electrolytic). Once the
meter reading settles down from 80v or so, you should get a steady
reading of the ripple.

Its more likely to be something else than the caps.

PS what sort of amp would/could fail to support blueray?


NT

Tabby wrote:
On Mar 3, 11:33 pm, sm_jamieson wrote:

My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out, they are 10000uF 80V. Lots around for
about 20quid each, or some ebay ones which I try to avoid if possible.
Does this look OK ?http://connect-audio.co.uk/proddetai...000U80&cat=219
Does the life seem a bit short (I know this is at the max temp) ?

Also saw this but the lead spacing and layout is wrong:http://parts.digikey.co.uk/1/1/91787...ect-tha-series...

I did not realise the life was so limited though. I've left the amp on
24 hours a day on standby for years !

Also a couple of smaller 3300uF 50V jobs, I guess for a 5V or similar
supply for the ICs, DSP chips etc.
Probably worth changing those as well.

OR ..
Is this really worth my time and up to 50 quid fixing ???
A new replacement would cost 350 quid but would support blue ray
audio, HDMI etc.

Simon.


Electronic equipment is complex in terms of the number of possible
faults. Guessing is a poor repair strategy, especially when it costs
£50 a guess. Lytics normally last many decades, though there have been
some duds on the market causing problems.

The simplest way to test the caps is to measure the ripple on them
with the power on. If you dont have the proper equipment, you can use
a mmultimeter on ac volts setting, connecting it to the big cap via a
small 1uF non-polarised cap (ie polyester, not electrolytic). Once the
meter reading settles down from 80v or so, you should get a steady
reading of the ripple.

Its more likely to be something else than the caps.


It isn't.

Either a bad solder joint to the cap or the cap itself has gone high
resistance..but the classic 'it slowly gets worse' is almost 100% sure
to be the cap.

Easily tested by temporarily connecting something of adequate volatge
rating across it.

Caps are just about the only components that fail gradually and non
catastrophically.

Those and valves/CRT tubes.

Everything else tends to be either so low stress it lasts almost
indefinitely, or so high stress that it goes bang and the set goes dead.

On Mar 4, 4:44*am, The Natural Philosopher
wrote:
Tabby wrote:
On Mar 3, 11:33 pm, sm_jamieson wrote:

My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out, they are 10000uF 80V. Lots around for
about 20quid each, or some ebay ones which I try to avoid if possible.
Does this look OK ?http://connect-audio.co.uk/proddetai...000U80&cat=219
Does the life seem a bit short (I know this is at the max temp) ?

Also saw this but the lead spacing and layout is wrong:http://parts.digikey.co.uk/1/1/91787...ect-tha-series...

I did not realise the life was so limited though. I've left the amp on
24 hours a day on standby for years !

Also a couple of smaller 3300uF 50V jobs, I guess for a 5V or similar
supply for the ICs, DSP chips etc.
Probably worth changing those as well.

OR ..
Is this really worth my time and up to 50 quid fixing ???
A new replacement would cost 350 quid but would support blue ray
audio, HDMI etc.

Simon.

Electronic equipment is complex in terms of the number of possible
faults. Guessing is a poor repair strategy, especially when it costs
£50 a guess. Lytics normally last many decades, though there have been
some duds on the market causing problems.

The simplest way to test the caps is to measure the ripple on them
with the power on. If you dont have the proper equipment, you can use
a mmultimeter on ac volts setting, connecting it to the big cap via a
small 1uF non-polarised cap (ie polyester, not electrolytic). Once the
meter reading settles down from 80v or so, you should get a steady
reading of the ripple.

Its more likely to be something else than the caps.

It isn't.

Either a bad solder joint to the cap or the *cap itself has gone high
resistance..but the classic 'it slowly gets worse' is almost 100% sure
to be the cap.

Easily tested by temporarily connecting something of adequate volatge
rating across it.

The way the circuit boards are layed out with various daughter boards,
ribbon cables etc,
its very hard to have the circuit working and out of the case. I would
really have to change
the caps and put the whole thing back together to test it.
Simon.

Easily tested by temporarily connecting something of adequate volatge
rating across it.

The way the circuit boards are layed out with various daughter boards,
ribbon cables etc,
its very hard to have the circuit working and out of the case. I would
really have to change
the caps and put the whole thing back together to test it.
Simon.

Extend the leads from the replacement cap to the one inside the case for
test?..
--
Tony Sayer

On Mar 4, 10:32*am, tony sayer wrote:
Easily tested by temporarily connecting something of adequate volatge
rating across it.

The way the circuit boards are layed out with various daughter boards,
ribbon cables etc,
its very hard to have the circuit working and out of the case. I would
really have to change
the caps and put the whole thing back together to test it.
Simon.

Extend the leads from the replacement cap to the one inside the case for
test?..
--
Tony Sayer

I thought about something like that.
I'll probably solder in some type of connector so I can replace the
capacitors
easily from the front of the board. Then I can stick the existing one
back in temporarily and see if a small cheapy cap in parallel reduces
the hum
Simon.

On Mar 4, 4:44*am, The Natural Philosopher
wrote:
Tabby wrote:
On Mar 3, 11:33 pm, sm_jamieson wrote:

My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out, they are 10000uF 80V. Lots around for
about 20quid each, or some ebay ones which I try to avoid if possible.
Does this look OK ?http://connect-audio.co.uk/proddetai...000U80&cat=219
Does the life seem a bit short (I know this is at the max temp) ?

Also saw this but the lead spacing and layout is wrong:http://parts.digikey.co.uk/1/1/91787...ect-tha-series...

I did not realise the life was so limited though. I've left the amp on
24 hours a day on standby for years !

Also a couple of smaller 3300uF 50V jobs, I guess for a 5V or similar
supply for the ICs, DSP chips etc.
Probably worth changing those as well.

OR ..
Is this really worth my time and up to 50 quid fixing ???
A new replacement would cost 350 quid but would support blue ray
audio, HDMI etc.

Simon.

Electronic equipment is complex in terms of the number of possible
faults. Guessing is a poor repair strategy, especially when it costs
£50 a guess. Lytics normally last many decades, though there have been
some duds on the market causing problems.

The simplest way to test the caps is to measure the ripple on them
with the power on. If you dont have the proper equipment, you can use
a mmultimeter on ac volts setting, connecting it to the big cap via a
small 1uF non-polarised cap (ie polyester, not electrolytic). Once the
meter reading settles down from 80v or so, you should get a steady
reading of the ripple.

Its more likely to be something else than the caps.

It isn't.

Either a bad solder joint to the cap or the *cap itself has gone high
resistance..but the classic 'it slowly gets worse' is almost 100% sure
to be the cap.

Easily tested by temporarily connecting something of adequate volatge
rating across it.

Caps are just about the only components that fail gradually and non
catastrophically.

Those and valves/CRT tubes.

Everything else tends to be either so low stress it lasts almost
indefinitely, or so high stress that it goes bang and the set goes dead.

foolish strategy.

Tabby wrote:
On Mar 4, 4:44 am, The Natural Philosopher
wrote:
Tabby wrote:
On Mar 3, 11:33 pm, sm_jamieson wrote:
My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out, they are 10000uF 80V. Lots around for
about 20quid each, or some ebay ones which I try to avoid if possible.
Does this look OK ?http://connect-audio.co.uk/proddetai...000U80&cat=219
Does the life seem a bit short (I know this is at the max temp) ?
Also saw this but the lead spacing and layout is wrong:http://parts.digikey.co.uk/1/1/91787...ect-tha-series...
I did not realise the life was so limited though. I've left the amp on
24 hours a day on standby for years !
Also a couple of smaller 3300uF 50V jobs, I guess for a 5V or similar
supply for the ICs, DSP chips etc.
Probably worth changing those as well.
OR ..
Is this really worth my time and up to 50 quid fixing ???
A new replacement would cost 350 quid but would support blue ray
audio, HDMI etc.
Simon.
Electronic equipment is complex in terms of the number of possible
faults. Guessing is a poor repair strategy, especially when it costs
£50 a guess. Lytics normally last many decades, though there have been
some duds on the market causing problems.
The simplest way to test the caps is to measure the ripple on them
with the power on. If you dont have the proper equipment, you can use
a mmultimeter on ac volts setting, connecting it to the big cap via a
small 1uF non-polarised cap (ie polyester, not electrolytic). Once the
meter reading settles down from 80v or so, you should get a steady
reading of the ripple.
Its more likely to be something else than the caps.
It isn't.

Either a bad solder joint to the cap or the cap itself has gone high
resistance..but the classic 'it slowly gets worse' is almost 100% sure
to be the cap.

Easily tested by temporarily connecting something of adequate volatge
rating across it.

Caps are just about the only components that fail gradually and non
catastrophically.

Those and valves/CRT tubes.

Everything else tends to be either so low stress it lasts almost
indefinitely, or so high stress that it goes bang and the set goes dead.

foolish strategy.


Oh dear. I guess the 16 years i spent designed audio power amps was
completely wasted?

On Mar 4, 3:22*pm, The Natural Philosopher
wrote:
Tabby wrote:
On Mar 4, 4:44 am, The Natural Philosopher
wrote:
Tabby wrote:
On Mar 3, 11:33 pm, sm_jamieson wrote:
My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out, they are 10000uF 80V. Lots around for
about 20quid each, or some ebay ones which I try to avoid if possible.
Does this look OK ?http://connect-audio.co.uk/proddetai...000U80&cat=219
Does the life seem a bit short (I know this is at the max temp) ?
Also saw this but the lead spacing and layout is wrong:http://parts.digikey.co.uk/1/1/91787...ect-tha-series...
I did not realise the life was so limited though. I've left the amp on
24 hours a day on standby for years !
Also a couple of smaller 3300uF 50V jobs, I guess for a 5V or similar
supply for the ICs, DSP chips etc.
Probably worth changing those as well.
OR ..
Is this really worth my time and up to 50 quid fixing ???
A new replacement would cost 350 quid but would support blue ray
audio, HDMI etc.
Simon.
Electronic equipment is complex in terms of the number of possible
faults. Guessing is a poor repair strategy, especially when it costs
£50 a guess. Lytics normally last many decades, though there have been
some duds on the market causing problems.
The simplest way to test the caps is to measure the ripple on them
with the power on. If you dont have the proper equipment, you can use
a mmultimeter on ac volts setting, connecting it to the big cap via a
small 1uF non-polarised cap (ie polyester, not electrolytic). Once the
meter reading settles down from 80v or so, you should get a steady
reading of the ripple.
Its more likely to be something else than the caps.
It isn't.

Either a bad solder joint to the cap or the *cap itself has gone high
resistance..but the classic 'it slowly gets worse' is almost 100% sure
to be the cap.

Easily tested by temporarily connecting something of adequate volatge
rating across it.

Caps are just about the only components that fail gradually and non
catastrophically.

Those and valves/CRT tubes.

Everything else tends to be either so low stress it lasts almost
indefinitely, or so high stress that it goes bang and the set goes dead.

foolish strategy.

Oh dear. I guess the 16 years i spent designed audio power amps was
completely wasted?

Youre fond of asuming too much

On Thu, 3 Mar 2011 17:06:56 -0800 (PST), Tabby wrote:

PS what sort of amp would/could fail to support blueray?

One that doesn't have HDMI... A nine year old AV amp just predates
HDMI 1.0 which came out in Dec 2002.

A graceful failure into hum is almost certainly down to dead or dying
reservior capacitors.

80v is a bit of a odd rating, 63v or 100v are the normal ones.

CPC have:
CA05298 10kuF 100v £17.03
CA05334 10kuF 100v £15.01 "computer grade" higher ripple current
capability than the above.

--
Cheers
Dave.

On Mar 4, 9:30*am, "Dave Liquorice"
wrote:
On Thu, 3 Mar 2011 17:06:56 -0800 (PST), Tabby wrote:
PS what sort of amp would/could fail to support blueray?

One that doesn't have HDMI... A nine year old AV amp just predates
HDMI 1.0 which came out in Dec 2002.

A graceful failure into hum is almost certainly down to dead or dying
reservior capacitors.

80v is a bit of a odd rating, 63v or 100v are the normal ones.

CPC have:
CA05298 10kuF 100v £17.03
CA05334 10kuF 100v £15.01 "computer grade" higher ripple current
capability than the above.

Ouch. Others posts were suggesting I should be paying about a fiver !
Anway, I like the units ! "kuF" !
You should have quoted the price in deci-mega-pennies ;-)
Simon.

On Mar 4, 9:30*am, "Dave Liquorice"
wrote:
On Thu, 3 Mar 2011 17:06:56 -0800 (PST), Tabby wrote:
PS what sort of amp would/could fail to support blueray?

One that doesn't have HDMI... A nine year old AV amp just predates
HDMI 1.0 which came out in Dec 2002.


I see HDMI doesnt contain analogue output :/ Trouble with using
hardware to keep up with digital standards is they keep changing.

NT

sm_jamieson wrote:
My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out, they are 10000uF 80V. Lots around for
about 20quid each, or some ebay ones which I try to avoid if possible.
Does this look OK ?
http://connect-audio.co.uk/proddetai...000U80&cat=219
Does the life seem a bit short (I know this is at the max temp) ?

Also saw this but the lead spacing and layout is wrong:
http://parts.digikey.co.uk/1/1/91787...t1ka103fa.html

I did not realise the life was so limited though. I've left the amp on
24 hours a day on standby for years !

Also a couple of smaller 3300uF 50V jobs, I guess for a 5V or similar
supply for the ICs, DSP chips etc.
Probably worth changing those as well.

OR ..
Is this really worth my time and up to 50 quid fixing ???
A new replacement would cost 350 quid but would support blue ray
audio, HDMI etc.

Simon.

Seems overly expensive for reservoir caps.

Definitely worth fixing tho.

But you shouldn't be paying much more than a fiver..try fleabay.

On Mar 4, 4:37*am, The Natural Philosopher
wrote:
sm_jamieson wrote:
My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out, they are 10000uF 80V. Lots around for
about 20quid each, or some ebay ones which I try to avoid if possible.
Does this look OK ?
http://connect-audio.co.uk/proddetai...000U80&cat=219
Does the life seem a bit short (I know this is at the max temp) ?

Also saw this but the lead spacing and layout is wrong:
http://parts.digikey.co.uk/1/1/91787...ect-tha-series...

I did not realise the life was so limited though. I've left the amp on
24 hours a day on standby for years !

Also a couple of smaller 3300uF 50V jobs, I guess for a 5V or similar
supply for the ICs, DSP chips etc.
Probably worth changing those as well.

OR ..
Is this really worth my time and up to 50 quid fixing ???
A new replacement would cost 350 quid but would support blue ray
audio, HDMI etc.

Simon.

Seems overly expensive *for reservoir caps.

Definitely worth fixing tho.

But you shouldn't be paying much more than a fiver..try fleabay.

There are some caps (more expensive) marked "for audio" etc.
Is this just marketing, or is there anything different ?
Surely in the power supply they cannot make much difference ?
I am sceptical myself.
Simon.

sm_jamieson wrote:
On Mar 4, 4:37 am, The Natural Philosopher
wrote:
sm_jamieson wrote:
My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out, they are 10000uF 80V. Lots around for
about 20quid each, or some ebay ones which I try to avoid if possible.
Does this look OK ?
http://connect-audio.co.uk/proddetai...000U80&cat=219
Does the life seem a bit short (I know this is at the max temp) ?
Also saw this but the lead spacing and layout is wrong:
http://parts.digikey.co.uk/1/1/91787...ect-tha-series...
I did not realise the life was so limited though. I've left the amp on
24 hours a day on standby for years !
Also a couple of smaller 3300uF 50V jobs, I guess for a 5V or similar
supply for the ICs, DSP chips etc.
Probably worth changing those as well.
OR ..
Is this really worth my time and up to 50 quid fixing ???
A new replacement would cost 350 quid but would support blue ray
audio, HDMI etc.
Simon.
Seems overly expensive for reservoir caps.

Definitely worth fixing tho.

But you shouldn't be paying much more than a fiver..try fleabay.

There are some caps (more expensive) marked "for audio" etc.
Is this just marketing, or is there anything different ?
Surely in the power supply they cannot make much difference ?
I am sceptical myself.

Because of the way they're made, electrolytics may have a significant
self inductance. I remember in the past buying low self inductance
versions for critical applications, which cost more.


--
Tciao for Now!

John.

John Williamson wrote:
sm_jamieson wrote:
On Mar 4, 4:37 am, The Natural Philosopher
wrote:
sm_jamieson wrote:
My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out, they are 10000uF 80V. Lots around for
about 20quid each, or some ebay ones which I try to avoid if possible.
Does this look OK ?
http://connect-audio.co.uk/proddetai...000U80&cat=219
Does the life seem a bit short (I know this is at the max temp) ?
Also saw this but the lead spacing and layout is wrong:
http://parts.digikey.co.uk/1/1/91787...ect-tha-series...

I did not realise the life was so limited though. I've left the amp on
24 hours a day on standby for years !
Also a couple of smaller 3300uF 50V jobs, I guess for a 5V or similar
supply for the ICs, DSP chips etc.
Probably worth changing those as well.
OR ..
Is this really worth my time and up to 50 quid fixing ???
A new replacement would cost 350 quid but would support blue ray
audio, HDMI etc.
Simon.
Seems overly expensive for reservoir caps.

Definitely worth fixing tho.

But you shouldn't be paying much more than a fiver..try fleabay.

There are some caps (more expensive) marked "for audio" etc.
Is this just marketing, or is there anything different ?
Surely in the power supply they cannot make much difference ?
I am sceptical myself.

Because of the way they're made, electrolytics may have a significant
self inductance. I remember in the past buying low self inductance
versions for critical applications, which cost more.


No, low series resistance. If inductance is an issue, you put a smaller
cap across them.

That takes care of HF impedances.

sm_jamieson wrote:
On Mar 4, 4:37 am, The Natural Philosopher
wrote:
sm_jamieson wrote:
My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out, they are 10000uF 80V. Lots around for
about 20quid each, or some ebay ones which I try to avoid if possible.
Does this look OK ?
http://connect-audio.co.uk/proddetai...000U80&cat=219
Does the life seem a bit short (I know this is at the max temp) ?
Also saw this but the lead spacing and layout is wrong:
http://parts.digikey.co.uk/1/1/91787...ect-tha-series...
I did not realise the life was so limited though. I've left the amp on
24 hours a day on standby for years !
Also a couple of smaller 3300uF 50V jobs, I guess for a 5V or similar
supply for the ICs, DSP chips etc.
Probably worth changing those as well.
OR ..
Is this really worth my time and up to 50 quid fixing ???
A new replacement would cost 350 quid but would support blue ray
audio, HDMI etc.
Simon.
Seems overly expensive for reservoir caps.

Definitely worth fixing tho.

But you shouldn't be paying much more than a fiver..try fleabay.

There are some caps (more expensive) marked "for audio" etc.
Is this just marketing, or is there anything different ?
Surely in the power supply they cannot make much difference ?
I am sceptical myself.
Simon.
generally able to handle high peak currents and maintain low resistance.

On 03/03/2011 23:33, sm_jamieson wrote:
My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out,

Is there the same racket coming out of the tape monitor output?

--
Adrian C

On Mar 5, 7:05*pm, Adrian C wrote:
On 03/03/2011 23:33, sm_jamieson wrote:

My approx 9 year old AV amp started buzzing / humming sounds like
100Hz, slowly got louder until drowning out the music ! PSU caps I
should think. They are labeled "kenwood for audio".
I've got the bigs caps out,

Is there the same racket coming out of the tape monitor output?


Good point. i.e. without the power output stages. Didn't think to
check that.
Well, I'm going to put trailing leads in the PCB where the caps were
and put the thing back together.
Then I can experiment to check it is the caps. Then I'll leave any new
caps on the
end of short trailing leads and wedge them in place somehow.
I'll let y'all know how it goes.
Simon.