AKG Perception P220 to Neumann u87 5 min mod ( p200, p100, p400, p420? )

[Khron]

My first time ever dealing with smd and yup rip off the pads off the circuit board trying to remove the 220smd so i cant solder in a 680pf film capacitor….

Post a good close up picture. I'm wondering how you ripped the pads off, if you actually did--did you actually pry the capacitor off the board without liquefying the solder at even one end?

Still a bit confused why removing the stock capacitor is even necessary, instead of just ADDING a 470pF in parallel with it...

 

[joulupukki]

Still a bit confused why removing the stock capacitor is even necessary, instead of just ADDING a 470pF in parallel with it...

I’m confused too. I just added on and the mod was simple and effective.

 

[narcolepzzz]

I’m confused too. I just added on and the mod was simple and effective.

would you mind posting a picture? I'm very new to this but would like to give it a try

 

[micolas]

Well ive been soldering and repairing studio equipment for years,
So decide to give my old perception 420 a shot on this mod….
My first time ever dealing with smd and yup rip off the pads off the circuit board trying to remove the 220smd so i cant solder in a 680pf film capacitor….

But am i losing my mind- the mic still works fine and sounds the same????

Don't buy another microphone just yet
Post some clear, high-resolution, good-definition close-up pictures of the affected area (probably you overheated and/or held the temperature too long on the PCB)
Circuit paths can be redone with thin wires, components can be soldered at other points, the capacitor for de-emphasis is connected in parallel to the 1M resistor even with the de-emphasis circuit affected, the mic continues to work, with a different frequency response.

 

[spiro.sekulovski]

220 is cardioid, 420 is multipattern. The modification applies to both.

I understand that the mod applies to both. But I also realize that they have different capsules, so even with the 420 set to cardioid, they'll still have subtle differences between them. I was wondering if you can remember what was the exact model that you modded for the "high-end production facility" 6 years ago.

I'm probably going to go with the Perception 220 since I can find it for sale a lot cheaper.

 

[kingkorg]

I understand that the mod applies to both. But I also realize that they have different capsules, so even with the 420 set to cardioid, they'll still have subtle differences between them. I was wondering if you can remember what was the exact model that you modded for the "high-end production facility" 6 years ago.

I'm probably going to go with the Perception 220 since I can find it for sale a lot cheaper.

The answer is literally in the first passage of the original post, p220.

 

[spiro.sekulovski]

The answer is literally in the first passage of the original post, p220.

Sorry man, I didn't make the connection between the first post and the update. I thought you were referring to two different clients. Thanks for the answer.

 

[cholmes777]

The answer is literally in the first passage of the original post, p220.

Don't buy another microphone just yet
Post some clear, high-resolution, good-definition close-up pictures of the affected area (probably you overheated and/or held the temperature too long on the PCB)
Circuit paths can be redone with thin wires, components can be soldered at other points, the capacitor for de-emphasis is connected in parallel to the 1M resistor even with the de-emphasis circuit affected, the mic continues to work, with a different frequency response.

I thought about trying to repair it. Its just there NO room to do anything.
Ill try to send pics tonight

 

[cholmes777]

Still a bit confused why removing the stock capacitor is even necessary, instead of just ADDING a 470pF in parallel with it...

Are you sure this will work??

So much easier to just solder 680pf
onto the 220pf!! A brand new p420
Is on sale for $159 currently.

 

[Khron]

Are you sure this will work??

So much easier to just solder 680pf
onto the 220pf!

https://www.electronics-tutorials.ws/capacitor/cap_6.html

Pretty sure

 

[micolas]

I thought about trying to repair it. Its just there NO room to do anything.
Ill try to send pics tonight

Are you sure this will work??

So much easier to just solder 680pf
onto the 220pf!! A brand new p420
Is on sale for $159 currently.

It is counterproductive to start modifying before thoroughly documenting yourself, it would be beneficial to read the entire thread. The subject has been debated several times.

 

[micolas]

Are you sure this will work??

So much easier to just solder 680pf
onto the 220pf!! A brand new p420
Is on sale for $159 currently.

https://groupdiy.com/threads/akg-pe...in-mod-p200-p100-p400-p420.67473/post-1149891

 

[joulupukki]

Here’s how I added a 470pF cap on to the existing 220pF cap (total of 690pF). This is on the AKG P420 but obviously it’d be similar for the P220.

 

[Khron]

Here’s how I added a 470pF cap on to the existing 220pF cap (total of 690pF).

Might wanna consider laying it flat across the board, and perhaps even tack it down with a drop of glue, "just in case", if that through-hole cap is the only option. If only for the longevity of the copper-to-board adhesion...

 

[micolas]

Here’s how I added a 470pF cap on to the existing 220pF cap (total of 690pF). This is on the AKG P420 but obviously it’d be similar for the P220.

View attachment 129621View attachment 129622

Very well! Keeping the stock capacitor on the PCB - everything is more robust and the risks of destroying something are lower.
It's a negative feedback circuit, not a direct audio path, so it doesn't matter that there are different capacitors in parallel, even different types, it will work fine.
And @Khron 's advice on stiffening with some glue is very good for increasing the resistance to shocks, vibrations, etc., it does not affect the operation of the circuit.

 

[cholmes777]

Thanks everyone. If i do decide to do it in parallel, I see i need to get a 470pf instead of 680pf. Much easier this way

 

[micolas]

Thanks everyone. If i do decide to do it in parallel, I see i need to get a 470pf instead of 680pf. Much easier this way

Yup
Or even bigger if you want something flatter in the U67 style.

 

[joulupukki]

Might wanna consider laying it flat across the board, and perhaps even tack it down with a drop of glue, "just in case", if that through-hole cap is the only option. If only for the longevity of the copper-to-board adhesion...

I could add in some superglue around the solder joints. I didn't want to lay it flat because it'd obscure the screw right there. But, I'm sure one could get a much smaller cap. This is just what I happened to have on hand (a 1KV cap).

 

[Khron]

I didn't want to lay it flat because it'd obscure the screw right there.

And doesn't fit folded down in the other direction?

 

[joulupukki]

And doesn't fit folded down in the other direction?

I don't think so, but I'll double-check it again today. I would think it'd take considerable multiple violent drops to break it free in its current position, even with no glue. It hardly has any mass.