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From: Joerg on 21 Feb 2010 17:08
Fred Abse wrote:
> On Sat, 20 Feb 2010 18:08:52 -0800, Joerg wrote:
>
>> John Larkin wrote:
>>> On Sat, 20 Feb 2010 21:07:48 +0000, Nemo
>>> <zzz(a)nospam.nospam.nospam.nospam.co.uk> wrote:
>>>
>>>> I am trying to evaluate whether to use tantalum versus OS-CON aluminium
>>>> electrolytics as the output decouplers for some linear postregulators
>>>> after a (relatively low noise) switcher. This is for a high gain
>>>> amplifier that will be operating down to audio frequencies. I've come
>>>> across references to aluminium electrolytics being noisy, but no firm
>>>> details (kind of odd as there are lots of details about ceramics'
>>>> problems under bias, wet vs dry tantalums etc). There's also some
>>>> references to "low noise" aluminium electrolytics for audio work, but I
>>>> don't know whether to take them seriously as audiophools believe all
>>>> kinds of weird stuff. So, can anyone advise if aluminium electrolytics -
>>>> specifically low ESR solid electrolyte types - have some kind of noise
>>>> problem? I know tants are NOT microphonic but I've not come across any
>>>> info about electrolytics and microphony one way or another.
>>>>
>>>> Assuming they do not, I favour them over tants because their ESR is
>>>> lower, I get the impression that tants' ESR is poorer at low
>>>> frequencies, and I can get electrolytics at higher voltages (I like to
>>>> run caps at about double their rated voltage under the impression this
>>>> improves their reliability). The load on these linear regs will be
>>>> fairly constant, so ripple current will be low.
>>>>
>>>> Thank you,
>>> I've never encountered noise from electrolytics. ...
>>
>> Oh, I sure did: pheeeooou ... *BOOM*
>
> I once got the can off one in the crotch, from across the lab. Makes yer
> eyes water ;-)
>

Ouch, ouch ...

As a kid I was blissfully unaware of ESR and all those secondary
"non-essentials". Fluorescents dimmed ... wait, there's no dimmer on
that circuit ... *KABLOUIE* ... phsssooosh ... *POCK* ... phssss

Followed by some plaster raining down on me and a hissing and smoldering
can on the carpet. It had sailed mere inches past my right eye and I sat
there all shaking.

Had to spackle the crater in the ceiling, easy. Also had to get new
carpet, from a discount store five miles away, using my bicycle to
transport the large and heavy roll. Not so easy.

This was a serious capacitor, several hundred uF and a few hundred
volts, directly fed by a 230V/16A mains line. In a Cockcroft-Walton
tripler with numerous other caps feeding a kilowatt-size amplifier. In
hindsight it's all pretty amazing that I survived my childhood.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
From: Ban on 22 Feb 2010 02:12
Joerg wrote:
> Fred Abse wrote:
>> On Sat, 20 Feb 2010 18:08:52 -0800, Joerg wrote:
>>
>>> John Larkin wrote:
>>>> On Sat, 20 Feb 2010 21:07:48 +0000, Nemo
>>>> <zzz(a)nospam.nospam.nospam.nospam.co.uk> wrote:
>>>>
>>>>> I am trying to evaluate whether to use tantalum versus OS-CON
>>>>> aluminium electrolytics as the output decouplers for some linear
>>>>> postregulators after a (relatively low noise) switcher. This is
>>>>> for a high gain amplifier that will be operating down to audio
>>>>> frequencies. I've come across references to aluminium
>>>>> electrolytics being noisy, but no firm details (kind of odd as
>>>>> there are lots of details about ceramics' problems under bias,
>>>>> wet vs dry tantalums etc). There's also some references to "low
>>>>> noise" aluminium electrolytics for audio work, but I don't know
>>>>> whether to take them seriously as audiophools believe all kinds
>>>>> of weird stuff. So, can anyone advise if aluminium electrolytics
>>>>> - specifically low ESR solid electrolyte types - have some kind
>>>>> of noise problem? I know tants are NOT microphonic but I've not
>>>>> come across any info about electrolytics and microphony one way
>>>>> or another. Assuming they do not, I favour them over tants because
>>>>> their ESR
>>>>> is lower, I get the impression that tants' ESR is poorer at low
>>>>> frequencies, and I can get electrolytics at higher voltages (I
>>>>> like to run caps at about double their rated voltage under the
>>>>> impression this improves their reliability). The load on these
>>>>> linear regs will be fairly constant, so ripple current will be
>>>>> low. Thank you,
>>>> I've never encountered noise from electrolytics. ...
>>>
>>> Oh, I sure did: pheeeooou ... *BOOM*
>>
>> I once got the can off one in the crotch, from across the lab. Makes
>> yer eyes water ;-)
>>
>
> Ouch, ouch ...
>
> As a kid I was blissfully unaware of ESR and all those secondary
> "non-essentials". Fluorescents dimmed ... wait, there's no dimmer on
> that circuit ... *KABLOUIE* ... phsssooosh ... *POCK* ... phssss
>
> Followed by some plaster raining down on me and a hissing and
> smoldering can on the carpet. It had sailed mere inches past my right
> eye and I sat there all shaking.
>
> Had to spackle the crater in the ceiling, easy. Also had to get new
> carpet, from a discount store five miles away, using my bicycle to
> transport the large and heavy roll. Not so easy.
>
> This was a serious capacitor, several hundred uF and a few hundred
> volts, directly fed by a 230V/16A mains line. In a Cockcroft-Walton
> tripler with numerous other caps feeding a kilowatt-size amplifier. In
> hindsight it's all pretty amazing that I survived my childhood.

What a vivid imagination!

Ban


From: Joerg on 22 Feb 2010 12:06
Ban wrote:
> Joerg wrote:
>> Fred Abse wrote:
>>> On Sat, 20 Feb 2010 18:08:52 -0800, Joerg wrote:
>>>
>>>> John Larkin wrote:
>>>>> On Sat, 20 Feb 2010 21:07:48 +0000, Nemo
>>>>> <zzz(a)nospam.nospam.nospam.nospam.co.uk> wrote:
>>>>>
>>>>>> I am trying to evaluate whether to use tantalum versus OS-CON
>>>>>> aluminium electrolytics as the output decouplers for some linear
>>>>>> postregulators after a (relatively low noise) switcher. This is
>>>>>> for a high gain amplifier that will be operating down to audio
>>>>>> frequencies. I've come across references to aluminium
>>>>>> electrolytics being noisy, but no firm details (kind of odd as
>>>>>> there are lots of details about ceramics' problems under bias,
>>>>>> wet vs dry tantalums etc). There's also some references to "low
>>>>>> noise" aluminium electrolytics for audio work, but I don't know
>>>>>> whether to take them seriously as audiophools believe all kinds
>>>>>> of weird stuff. So, can anyone advise if aluminium electrolytics
>>>>>> - specifically low ESR solid electrolyte types - have some kind
>>>>>> of noise problem? I know tants are NOT microphonic but I've not
>>>>>> come across any info about electrolytics and microphony one way
>>>>>> or another. Assuming they do not, I favour them over tants because
>>>>>> their ESR
>>>>>> is lower, I get the impression that tants' ESR is poorer at low
>>>>>> frequencies, and I can get electrolytics at higher voltages (I
>>>>>> like to run caps at about double their rated voltage under the
>>>>>> impression this improves their reliability). The load on these
>>>>>> linear regs will be fairly constant, so ripple current will be
>>>>>> low. Thank you,
>>>>> I've never encountered noise from electrolytics. ...
>>>> Oh, I sure did: pheeeooou ... *BOOM*
>>> I once got the can off one in the crotch, from across the lab. Makes
>>> yer eyes water ;-)
>>>
>> Ouch, ouch ...
>>
>> As a kid I was blissfully unaware of ESR and all those secondary
>> "non-essentials". Fluorescents dimmed ... wait, there's no dimmer on
>> that circuit ... *KABLOUIE* ... phsssooosh ... *POCK* ... phssss
>>
>> Followed by some plaster raining down on me and a hissing and
>> smoldering can on the carpet. It had sailed mere inches past my right
>> eye and I sat there all shaking.
>>
>> Had to spackle the crater in the ceiling, easy. Also had to get new
>> carpet, from a discount store five miles away, using my bicycle to
>> transport the large and heavy roll. Not so easy.
>>
>> This was a serious capacitor, several hundred uF and a few hundred
>> volts, directly fed by a 230V/16A mains line. In a Cockcroft-Walton
>> tripler with numerous other caps feeding a kilowatt-size amplifier. In
>> hindsight it's all pretty amazing that I survived my childhood.
>
> What a vivid imagination!
>

Sorry but your telepathic crystal ball let you down, like before.

It happened with a Siemens electrolytic no less. Amplifier with PL509
tubes, tripler from 230VAC to about 900VDC. To be exact, this one, made
by yours truly:

http://www.analogconsultants.com/ng/images/PL509amp2.jpg

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
From: Ban on 22 Feb 2010 13:02
Joerg wrote:
> Ban wrote:
>> Joerg wrote:
>>> Fred Abse wrote:
>>>> On Sat, 20 Feb 2010 18:08:52 -0800, Joerg wrote:
>>>>
>>>>> John Larkin wrote:
>>>>>> On Sat, 20 Feb 2010 21:07:48 +0000, Nemo
>>>>>> <zzz(a)nospam.nospam.nospam.nospam.co.uk> wrote:
>>>>>>
>>>>>>> I am trying to evaluate whether to use tantalum versus OS-CON
>>>>>>> aluminium electrolytics as the output decouplers for some linear
>>>>>>> postregulators after a (relatively low noise) switcher. This is
>>>>>>> for a high gain amplifier that will be operating down to audio
>>>>>>> frequencies. I've come across references to aluminium
>>>>>>> electrolytics being noisy, but no firm details (kind of odd as
>>>>>>> there are lots of details about ceramics' problems under bias,
>>>>>>> wet vs dry tantalums etc). There's also some references to "low
>>>>>>> noise" aluminium electrolytics for audio work, but I don't know
>>>>>>> whether to take them seriously as audiophools believe all kinds
>>>>>>> of weird stuff. So, can anyone advise if aluminium electrolytics
>>>>>>> - specifically low ESR solid electrolyte types - have some kind
>>>>>>> of noise problem? I know tants are NOT microphonic but I've not
>>>>>>> come across any info about electrolytics and microphony one way
>>>>>>> or another. Assuming they do not, I favour them over tants
>>>>>>> because their ESR
>>>>>>> is lower, I get the impression that tants' ESR is poorer at low
>>>>>>> frequencies, and I can get electrolytics at higher voltages (I
>>>>>>> like to run caps at about double their rated voltage under the
>>>>>>> impression this improves their reliability). The load on these
>>>>>>> linear regs will be fairly constant, so ripple current will be
>>>>>>> low. Thank you,
>>>>>> I've never encountered noise from electrolytics. ...
>>>>> Oh, I sure did: pheeeooou ... *BOOM*
>>>> I once got the can off one in the crotch, from across the lab.
>>>> Makes yer eyes water ;-)
>>>>
>>> Ouch, ouch ...
>>>
>>> As a kid I was blissfully unaware of ESR and all those secondary
>>> "non-essentials". Fluorescents dimmed ... wait, there's no dimmer on
>>> that circuit ... *KABLOUIE* ... phsssooosh ... *POCK* ... phssss
>>>
>>> Followed by some plaster raining down on me and a hissing and
>>> smoldering can on the carpet. It had sailed mere inches past my
>>> right eye and I sat there all shaking.
>>>
>>> Had to spackle the crater in the ceiling, easy. Also had to get new
>>> carpet, from a discount store five miles away, using my bicycle to
>>> transport the large and heavy roll. Not so easy.
>>>
>>> This was a serious capacitor, several hundred uF and a few hundred
>>> volts, directly fed by a 230V/16A mains line. In a Cockcroft-Walton
>>> tripler with numerous other caps feeding a kilowatt-size amplifier.
>>> In hindsight it's all pretty amazing that I survived my childhood.
>>
>> What a vivid imagination!

I meant the vivid desciption of your exploding components, you really can
differ between a failing MOSFET and passive parts, but nothing seems to beat
a tantal.
and by imagination was meant to be a special creative talent, unfortunately
I worded it ambivalent. ;)

>>
>
> Sorry but your telepathic crystal ball let you down, like before.
>
> It happened with a Siemens electrolytic no less. Amplifier with PL509
> tubes, tripler from 230VAC to about 900VDC. To be exact, this one,
> made by yours truly:
>
> http://www.analogconsultants.com/ng/images/PL509amp2.jpg

I was waiting for the crater in the ceiling tho.
ciao Ban


From: Joerg on 22 Feb 2010 13:40
Ban wrote:
> Joerg wrote:
>> Ban wrote:
>>> Joerg wrote:
>>>> Fred Abse wrote:
>>>>> On Sat, 20 Feb 2010 18:08:52 -0800, Joerg wrote:
>>>>>
>>>>>> John Larkin wrote:
>>>>>>> On Sat, 20 Feb 2010 21:07:48 +0000, Nemo
>>>>>>> <zzz(a)nospam.nospam.nospam.nospam.co.uk> wrote:
>>>>>>>
>>>>>>>> I am trying to evaluate whether to use tantalum versus OS-CON
>>>>>>>> aluminium electrolytics as the output decouplers for some linear
>>>>>>>> postregulators after a (relatively low noise) switcher. This is
>>>>>>>> for a high gain amplifier that will be operating down to audio
>>>>>>>> frequencies. I've come across references to aluminium
>>>>>>>> electrolytics being noisy, but no firm details (kind of odd as
>>>>>>>> there are lots of details about ceramics' problems under bias,
>>>>>>>> wet vs dry tantalums etc). There's also some references to "low
>>>>>>>> noise" aluminium electrolytics for audio work, but I don't know
>>>>>>>> whether to take them seriously as audiophools believe all kinds
>>>>>>>> of weird stuff. So, can anyone advise if aluminium electrolytics
>>>>>>>> - specifically low ESR solid electrolyte types - have some kind
>>>>>>>> of noise problem? I know tants are NOT microphonic but I've not
>>>>>>>> come across any info about electrolytics and microphony one way
>>>>>>>> or another. Assuming they do not, I favour them over tants
>>>>>>>> because their ESR
>>>>>>>> is lower, I get the impression that tants' ESR is poorer at low
>>>>>>>> frequencies, and I can get electrolytics at higher voltages (I
>>>>>>>> like to run caps at about double their rated voltage under the
>>>>>>>> impression this improves their reliability). The load on these
>>>>>>>> linear regs will be fairly constant, so ripple current will be
>>>>>>>> low. Thank you,
>>>>>>> I've never encountered noise from electrolytics. ...
>>>>>> Oh, I sure did: pheeeooou ... *BOOM*
>>>>> I once got the can off one in the crotch, from across the lab.
>>>>> Makes yer eyes water ;-)
>>>>>
>>>> Ouch, ouch ...
>>>>
>>>> As a kid I was blissfully unaware of ESR and all those secondary
>>>> "non-essentials". Fluorescents dimmed ... wait, there's no dimmer on
>>>> that circuit ... *KABLOUIE* ... phsssooosh ... *POCK* ... phssss
>>>>
>>>> Followed by some plaster raining down on me and a hissing and
>>>> smoldering can on the carpet. It had sailed mere inches past my
>>>> right eye and I sat there all shaking.
>>>>
>>>> Had to spackle the crater in the ceiling, easy. Also had to get new
>>>> carpet, from a discount store five miles away, using my bicycle to
>>>> transport the large and heavy roll. Not so easy.
>>>>
>>>> This was a serious capacitor, several hundred uF and a few hundred
>>>> volts, directly fed by a 230V/16A mains line. In a Cockcroft-Walton
>>>> tripler with numerous other caps feeding a kilowatt-size amplifier.
>>>> In hindsight it's all pretty amazing that I survived my childhood.
>>> What a vivid imagination!
>
> I meant the vivid desciption of your exploding components, you really can
> differ between a failing MOSFET and passive parts, but nothing seems to beat
> a tantal.


The biggest tantalums I have ever encountered were the size of a
thimble. Their (frequent) explosions set off some nice and dazzling
greenish-orange clouds but the bang was quite modest. This one was a
serious beker type electrolytic cap, about 8cm long and maybe 4cm
diameter. Its aluminum tube including innards decided to become a
spacecraft. Went off like a champagne cork. I could have lost an eye in
that incident, scary.


> and by imagination was meant to be a special creative talent, unfortunately
> I worded it ambivalent. ;)
>

:-)

>> Sorry but your telepathic crystal ball let you down, like before.
>>
>> It happened with a Siemens electrolytic no less. Amplifier with PL509
>> tubes, tripler from 230VAC to about 900VDC. To be exact, this one,
>> made by yours truly:
>>
>> http://www.analogconsultants.com/ng/images/PL509amp2.jpg
>
> I was waiting for the crater in the ceiling tho.


I was too shaken to take a photo back then. Plus after the loud bang my
dad came running down the stairs, expressed some rather immediate
ractions of disgust and that it should be fixed, and pronto. Then, he
saw the smoldering hole in the carpet ...

The only camera I had was a 6cm*6cm children's camera but even B&W film
was very expensive and I spent all my money on electronics. I wouldn't
have dared to ask dad for his Agfa 35mm camera at that moment. In
hindsight I understand his reaction. Back in the 60's it was financially
hard to build a house when your family had lots of kids and he didn't
want to see his dream burn down just because I had to have the biggest
honking amplifier in town.

For US readers: Homes in Germany have concrete ceilings (I wish they
also did here). There is a roughly 1/2" thick layer of gypsum-based
plaster applied to that ceiling which is either used as the base to
apply wallpaper or like in our case it was painted.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
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