Hi,
I must use some caps in signal path (input) of a high end OP amp to
protect from DC.

What non expensive caps are recommand? I search good *inaudible* caps.

Solen or Axon 4,7 uF 250V - found on http://www.percyaudio.com/ or
RIFA 4,7uF 250V - PHE 426 or PHE 450? Or?
--
Greetings
Friedrich Stockhammer
http://www.stockhammer.at/

Friedrich Stockhammer wrote:

Hi,
I must use some caps in signal path (input) of a high end OP amp to
protect from DC.

What non expensive caps are recommand? I search good *inaudible* caps.

Solen or Axon 4,7 uF 250V - found on http://www.percyaudio.com/ or
RIFA 4,7uF 250V - PHE 426 or PHE 450? Or?
Depending on the op-amp being used and the feedback resistors, *any*
capacitor would do, even electrolytics.
One does not "hear" linear passive components.

Robert Baer wrote:

Depending on the op-amp being used and the feedback
resistors, *any* capacitor would do, even electrolytics.
One does not "hear" linear passive components.

For an electrolytic capacitor to constitute A linear component it has to
be biased with a dc voltage larger than the peak to peak amplitude of
the audio signal so that reverse polarisation voltage is avoided.


Kind regards

Peter Larsen




--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

"Robert Baer" wrote in message
k.net...
Friedrich Stockhammer wrote:

Hi,
I must use some caps in signal path (input) of a high end OP amp to
protect from DC.

What non expensive caps are recommand? I search good *inaudible* caps.

Solen or Axon 4,7 uF 250V - found on http://www.percyaudio.com/ or
RIFA 4,7uF 250V - PHE 426 or PHE 450? Or?
Depending on the op-amp being used and the feedback resistors, *any*
capacitor would do, even electrolytics.
One does not "hear" linear passive components.

Some capacitors are not linear passive components.

geoff

Peter Larsen wrote:

Robert Baer wrote:


Depending on the op-amp being used and the feedback
resistors, *any* capacitor would do, even electrolytics.
One does not "hear" linear passive components.


For an electrolytic capacitor to constitute A linear component it has to
be biased with a dc voltage larger than the peak to peak amplitude of
the audio signal so that reverse polarisation voltage is avoided.


Kind regards

Peter Larsen




Not true.
Good electrolytics work without regard to polarity ws long as the
reverse polarity is not more than 30 percent of rating (very good brand
& types) to not more than 10 percent of rating (decent brand & types).

Geoff@home wrote:

"Robert Baer" wrote in message
k.net...

Friedrich Stockhammer wrote:


Hi,
I must use some caps in signal path (input) of a high end OP amp to
protect from DC.

What non expensive caps are recommand? I search good *inaudible* caps.

Solen or Axon 4,7 uF 250V - found on http://www.percyaudio.com/ or
RIFA 4,7uF 250V - PHE 426 or PHE 450? Or?

Depending on the op-amp being used and the feedback resistors, *any*
capacitor would do, even electrolytics.
One does not "hear" linear passive components.


Some capacitors are not linear passive components.

geoff


True, depending on type (tantalum and aluminum electrolytics) and
amount of bias (eg: excessive reverse or excessive forward bias).

Robert Baer wrote:

Peter Larsen wrote:

For an electrolytic capacitor to constitute A linear component
it has to be biased with a dc voltage larger than the peak to
peak amplitude of the audio signal so that reverse polarisation
voltage is avoided.

Not true. Good electrolytics work without regard to polarity
ws long as the reverse polarity is not more than 30 percent
of rating (very good brand & types) to not more than 10 percent
of rating (decent brand & types).

Interesting, thank you, this explains WHY it sometimes appear to be more
required to replace them or bypass them than some other times.

Mostly however I let that choice depend on serviceability and expected G
load in case I modify stuff. Generally I tend to leave them or replace
them in inputs and bypass if easy in outputs.


Kind regards

Peter Larsen


--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************