Hi
This is my first post in this forum so I'll start with I saying hi to everybody
Reading a lot of the old messages in this forum and looking at all your wonderful builds I think I will enjoy this forum a lot
Well now onto my issue...
I am contemplating building a two channel green pre (the one designed by Peter C) as a project but have a small question regarding the circuit design, specifically the use of polar electrolytic caps in the signal pathway.
I searched old posts somewhat but could not find anything about it.
Long ago I learned that the use of polar electrolytic caps in audio signal pathways is often a thing of evil (sound wise) and should only be used if there is some properly oriented DC applied over them.
At the input of the green pre there is some large polar electrolytics to block the phantom power. All things is well as long as you use the phantom power but what if you suddenly work with a passive dynamic microphone such as the SM57 and turn the phantom off ?
As I see it, Peter has made a good thing here and also bypassed the polar caps with small plastic caps which will help but will this be enough to rule out the known nonlinear operation of these large polar caps (when there is no DC)?
I do not know how important this is and if I will really hear a difference but though I would ask about it anyway.
Here someone will probably step in and say that they used a lot of polar electrolytics in the signal pathway of old super-classy recording consoles :grin:
Well, I do not think they were put there because of particularly good audio performance but rather because of the very limited space available (in these always component packed consoles) and for a somewhat reasonable cost effectiveness with so many channels.
Long ago you could almost only use this type of cap when there was a requirement for large values, small space/footprint and a reasonable cost at the same time.
However, for my application I have a lot of space (two channels in a large rack) and today there is more alternatives. The cost difference going with large poly caps instead when there is only two channels required will not make a devastating difference.
Am I totally wrong about all this and should I perhaps use the polar electrolytic caps (such as intended in the design) anyway?
All thoughts are welcome :grin: Perhaps Peter C has given the input caps some consideration and will comment?
Best regards / Bo
This is my first post in this forum so I'll start with I saying hi to everybody
Reading a lot of the old messages in this forum and looking at all your wonderful builds I think I will enjoy this forum a lot
Well now onto my issue...
I am contemplating building a two channel green pre (the one designed by Peter C) as a project but have a small question regarding the circuit design, specifically the use of polar electrolytic caps in the signal pathway.
I searched old posts somewhat but could not find anything about it.
Long ago I learned that the use of polar electrolytic caps in audio signal pathways is often a thing of evil (sound wise) and should only be used if there is some properly oriented DC applied over them.
At the input of the green pre there is some large polar electrolytics to block the phantom power. All things is well as long as you use the phantom power but what if you suddenly work with a passive dynamic microphone such as the SM57 and turn the phantom off ?
As I see it, Peter has made a good thing here and also bypassed the polar caps with small plastic caps which will help but will this be enough to rule out the known nonlinear operation of these large polar caps (when there is no DC)?
I do not know how important this is and if I will really hear a difference but though I would ask about it anyway.
Here someone will probably step in and say that they used a lot of polar electrolytics in the signal pathway of old super-classy recording consoles
:grin: Well, I do not think they were put there because of particularly good audio performance but rather because of the very limited space available (in these always component packed consoles) and for a somewhat reasonable cost effectiveness with so many channels.
Long ago you could almost only use this type of cap when there was a requirement for large values, small space/footprint and a reasonable cost at the same time.
However, for my application I have a lot of space (two channels in a large rack) and today there is more alternatives. The cost difference going with large poly caps instead when there is only two channels required will not make a devastating difference.
Am I totally wrong about all this and should I perhaps use the polar electrolytic caps (such as intended in the design) anyway?
All thoughts are welcome :grin: Perhaps Peter C has given the input caps some consideration and will comment?
Best regards / Bo
