AKG Perception 420 Mod

[AUDIO FREQ]

It seems to be just surplus solder material

Like, flux? Should I just spray some 99% isopropyl alcohol on it and rinse it off?

 

[micolas]

Like, flux? Should I just spray some 99% isopropyl alcohol on it and rinse it off?

Absolutely NOT!

 

[AUDIO FREQ]

Absolutely NOT!

How do i clean it then?

 

[micolas]

How do i clean it then?

You don't need to clean it now.
After a period of use, the capsule will be much dirtier, with dust, splashes of saliva, other particles, oxides, etc.

 

[AUDIO FREQ]

You don't need to clean it now.
After a period of use, the capsule will be much dirtier, with dust, splashes of saliva, other particles, oxides, etc.

Hollllly moly, does that still work? Is that yours?

 

[micolas]

Audio Freq,
When the front side no longer works properly, you swap it with the back side which is less often used (as a quick, emergency fix), then ask for the help of someone experienced in cleaning capsules. I have seen very dirty capsules that were still working. Indeed, dirt increases the mass of the diaphragm and slows down the speed of response to transients, so in many situations SDCs are preferred. But for now your capsule should be working properly.

 

[AUDIO FREQ]

Audio Freq,
When the front side no longer works properly, you swap it with the back side which is less often used (as a quick, emergency fix), then ask for the help of someone experienced in cleaning capsules. I have seen very dirty capsules that were still working. Indeed, dirt increases the mass of the diaphragm and slows down the speed of response to transients, so in many situations SDCs are preferred. But for now your capsule should be working properly.

That is wild. I always just sank my capsules very lightly inside alcohol and distilled water mixed solution, let the stuff dissolve and fall off the capsule, and then air dry it. I haven't had any bad luck or anything. I seen some people use q tips or light brushes, but i never been comfortable rubbing anything on the mylar. I always just let the water and alcohol work its magic.

 

[kingkorg]

I know we were all being sarcastic just recently, but are you being serious or sarcastic? Wouldn't the smudge, especially if its some sort of chemical or adhesive, be a detriment to the mobility/function?

No, im serious. But are you talking just about the part i marked with red, or is the part marked with yellow some dirt, or just reflection? Yes, i would also move that termination a bit away from the diaphragm, that solder seems too close.

 

[micolas]

I always just sank my capsules very lightly inside alcohol and distilled water mixed solution, let the stuff dissolve and fall off the capsule, and then air dry it. I haven't had any bad luck or anything. I seen some people use q tips or light brushes, but i never been comfortable rubbing anything on the mylar. I always just let the water and alcohol work its magic.

Some capsules have a very small hole (the size of a needle tip) in the diaphragm, hardly visible, in the area not covered with gold, to release the pressure. If liquid enters between the diaphragm and the backplate, at this high impedance, you compromise the capsule.

 

[Khron]

Some capsules have a very small hole (the size of a needle tip) in the diaphragm, hardly visible, in the area not covered with gold,

Or some have a gap in the spacer between the two halves of the backplate.

 

[AUDIO FREQ]

No, im serious. But are you talking just about the part i marked with red, or is the part marked with yellow some dirt, or just reflection? Yes, i would also move that termination a bit away from the diaphragm, that solder seems too close.

The yellow mark, its like a smudge of something. Im not sure what it is. I don't think its a finger print, it looks more like flux or glue or something? Idk.

 

[AUDIO FREQ]

Some capsules have a very small hole (the size of a needle tip) in the diaphragm, hardly visible, in the area not covered with gold, to release the pressure. If liquid enters between the diaphragm and the backplate, at this high impedance, you compromise the capsule.

I always let it dry inside and out before I re-install the capsule. I disassemble the two halfs, to let the water vapors escape.

 

[AUDIO FREQ]

I was looking for a good alternative for the K30A, and stumbled apon this. What do you guys think? It looks like it has the same noise figures.

https://www.mouser.com/datasheet/2/1442/LSK189DSRevA20-3179887.pdf

 

[kingkorg]

The yellow mark, its like a smudge of something. Im not sure what it is. I don't think its a finger print, it looks more like flux or glue or something? Idk.

I don't think it's a big deal, but since it's a new capsule it shouldn't have any of these issues. I'd either ask for a refund or replacement.

 

[micolas]

I was looking for a good alternative for the K30A, and stumbled apon this. What do you guys think? It looks like it has the same noise figures.

https://www.mouser.com/datasheet/2/1442/LSK189DSRevA20-3179887.pdf

It has been said before. LSK189 is good but more expensive. A larger quantity should be purchased to select the best specimens for the respective application, jFETs have a notable dispersion of parameters.

 

[micolas]

Audio Freq

Try to buy some 2SK30A through the Black Market on our group, maybe someone kind enough has some suitable parts available.
There are members who even bought 1000's of jFETs to choose the best ones.

 

[AUDIO FREQ]

Audio Freq

Try to buy some 2SK30A through the Black Market on our group, maybe someone kind enough has some suitable parts available.
There are members who even bought 1000's of jFETs to choose the best ones.

I think this is a great learning opportunity for me. When selecting the best JFETS, what measurements should I learn how to take? I have a multimeter, and a beginner oscilloscope. Would these be good enough?

 

[micolas]

Audio Freq,
Try studying the many threads on the group related to selecting jFETs.

https://groupdiy.com/threads/neumann-vintage-u87-clone-build-thread.48030/page-89#post-669392

 

[AUDIO FREQ]

Audio Freq,
Try studying the many threads on the group related to selecting jFETs.

https://groupdiy.com/threads/neumann-vintage-u87-clone-build-thread.48030/page-89#post-669392

Thank you I will be checking it out now!

 

[AUDIO FREQ]

No, im serious. But are you talking just about the part i marked with red, or is the part marked with yellow some dirt, or just reflection? Yes, i would also move that termination a bit away from the diaphragm, that solder seems too close.

I don't think it's a big deal, but since it's a new capsule it shouldn't have any of these issues. I'd either ask for a refund or replacement.

Well I think its too late now, since I already installed it into the mic, but thank you.