Recommended output caps?

[nad]

Hello,

Can anyone out there recommend any output caps?
I'm using LME49720HA opamps and replaced the 'stock' caps with 25v 47uf Rubycon ZA's, then after a while bypassed them.

Theres nothing wrong but it just seems to have lost something. I doubt the Rubys are ideal for the job so any help??

My purchase would probably be from Farnell, I know Black Gates and Mundorfs aren't available there but if there's anything on their site which could be good, a part number would be great.


Ta.....

[amc184]

It depends of a few things. One of the main things is how much capacitance you actually need. A lot of the time electrolytic coupling capacitors are specified with ten times the capacitance needed. Have a look at wikipedia's article on high pass filters, and chose a value of capacitance so that fc is between 1 and 3Hz.

If you want to stick with electrolytics, your be bet is a Blackgate. Take a look at the Parts Connexion store, Farnell doesn't stock many 'audio specific' brands.

The best thing to do however is to replace it with a plastic film cap. However, space restrictions may not allow this.

[Joachim Gerhard]

try pannasonic fm back to back (minus poles together)
that gives a bipolar capacitor with half value and much lower distortion.
i would bypass it with a 0.01 - 0.1uF Vishey-Röderstein MKP they make 1% tolerance parts that are awailable from Farnell
the best grade of black gate bipolar is good too but i think modern electrolytics are so good that you can safe the money without ill effect

[Joachim Gerhard]

if you use an electrolytic the value has to be much bigger then a foil cap because they tend to distort in the deeper ranges esr is also lower in bigger elcaps so is leakeage current so a compromise has to be struck pannasonic fm have low leakeage but there is a part from elna (i forgot the name maybe rhe) that has even lower leakeage and is made for audio as the blurb says

[Mooly]

Panasonic ECA range are good,
Your Search Results | CPC

I suspect you may be expecting to much and that the sound hasn't really deteriorated, more your expectation are so high Was it better before you replaced the opamps ?

[nad]

Originally Posted by amc184

It depends of a few things. One of the main things is how much capacitance you actually need. A lot of the time electrolytic coupling capacitors are specified with ten times the capacitance needed. Have a look at wikipedia's article on high pass filters, and chose a value of capacitance so that fc is between 1 and 3Hz.

If you want to stick with electrolytics, your be bet is a Blackgate. Take a look at the Parts Connexion store, Farnell doesn't stock many 'audio specific' brands.

The best thing to do however is to replace it with a plastic film cap. However, space restrictions may not allow this.

Thank you, I think plastic caps are the way. I've started an ammended/new thread with a diagram here: Help to 'better' output schematic??

[nad]

Originally Posted by Mooly

Panasonic ECA range are good,
Your Search Results | CPC

I suspect you may be expecting to much and that the sound hasn't really deteriorated, more your expectation are so high Was it better before you replaced the opamps ?

Thank you, I may be expecting too much and no, the ouput wasn't better before the replacement opamps. I've started an ammended/new thread with a diagram here: Help to 'better' output schematic??

[nad]

Originally Posted by Joachim Gerhard

if you use an electrolytic the value has to be much bigger then a foil cap because they tend to distort in the deeper ranges esr is also lower in bigger elcaps so is leakeage current so a compromise has to be struck pannasonic fm have low leakeage but there is a part from elna (i forgot the name maybe rhe) that has even lower leakeage and is made for audio as the blurb says

Thank you for your reply, I think plastic caps are possibly the way. I've started an ammended/new thread with a diagram here: Help to 'better' output schematic??