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

[micolas]

dj_jormi

as always, kingkorg is absolutely right, inexperience can lead to thermal destruction of styroflex capacitors. But also some small-capacity ceramic capacitors with through-hole terminals can be fragile and can be destroyed thermally or mechanically.Excessive heating may cause the terminals to peel off.
The circuit is mounted in smd technology, maybe it would be better to ask for the help of an experienced friend.
The good thing is that any type of capacitor can be used, it's a feedback network not a direct audio signal path.

 

[dj_jormi]

Hombre, You don't have to use expensive Wima capacitor, you can find a cheap 470...680pF styroflex capacitor from a friend who repairs electronic devices.
¡buena suerte!

Actually i'd stay away from styroflex if he is a beginner, exposing it tiny bit too long to solder heat will change the value of the cap. Any ceramic cap will do, and it will not cause any trouble with available space. Agree it doesn't have to be a fancy cap.

dj_jormi

as always, kingkorg is absolutely right, inexperience can lead to thermal destruction of styroflex capacitors. But also some small-capacity ceramic capacitors with through-hole terminals can be fragile and can be destroyed thermally or mechanically.Excessive heating may cause the terminals to peel off.
The circuit is mounted in smd technology, maybe it would be better to ask for the help of an experienced friend.
The good thing is that any type of capacitor can be used, it's a feedback network not a direct audio signal path.

thanks so much!!

I present to you my microphone. It's a perception 200.

and I have 3 questions:

1. In the photo below, does the SMD have to be removed or is it soldered on top?
2. Does it have polarity when soldering?
3. I understand that the micparts mod (AKG Perception Mod Kit) is not necessary making this mod. You do not have to change the capsule for an rk-87 or put in the capacitor that they indicate. I had a capsule that I bought on Aliexpress rk87 from a while ago and I was thinking of making a mic parts mod but I see that the guy's mod is simpler.

The use I am going to give it is for voices in general.

attached phtos from my mic!

 

[kingkorg]

thanks so much!!

I present to you my microphone. It's a perception 200.

and I have 3 questions:

1. In the photo below, does the SMD have to be removed or is it soldered on top?
2. Does it have polarity when soldering?
3. I understand that the micparts mod (AKG Perception Mod Kit) is not necessary making this mod. You do not have to change the capsule for an rk-87 or put in the capacitor that they indicate. I had a capsule that I bought on Aliexpress rk87 from a while ago and I was thinking of making a mic parts mod but I see that the guy's mod is simpler.

The use I am going to give it is for voices in general.

attached phtos from my mic!

Capacitors added in parallel increase in value. So you don't have to remove it. If you have 220pf stock, adding another 220pf will give you 440pf and so on... Don't replace the capsule, the stock one is exceptional. MicParts have to make some money... Try several values, listen, see what you like the most. I wouldn't go above 820pF in total, 820pF would probably give you vintage, dark u67 kind of sound.

 

[micolas]

dj_jormi


Kingkorg, Khron, and others have answered all your questions very explicitly in their previous posts. You have all the information you need to make this simple and brilliant mod.
Just be careful to not exfoliate the PCB by overheating or cause other damage.
This capacitor has no polarity, you can mount it as you like.
Good Luck!

 

[dj_jormi]

Capacitors added in parallel increase in value. So you don't have to remove it. If you have 220pf stock, adding another 220pf will give you 440pf and so on... Don't replace the capsule, the stock one is exceptional. MicParts have to make some money... Try several values, listen, see what you like the most. I wouldn't go above 820pF in total, 820pF would probably give you vintage, dark u67 kind of sound.

dj_jormi


Kingkorg, Khron, and others have answered all your questions very explicitly in their previous posts. You have all the information you need to make this simple and brilliant mod.
Just be careful to not exfoliate the PCB by overheating or cause other damage.
This capacitor has no polarity, you can mount it as you like.
Good Luck!

I just understood it, that is to say that being stock if I add a 220 to the 220 I have they would give me 440, if I add another 220 it would give me 660pf etc etc. It then occurred to me that I could put a switch to change it and thus get a different sound in the same microphone. Thank you very much, now I understand it.

Finally, what preamp for home studio do you recommend using with this microphone? I am currently using it directly with a focusrite 2i4 sound card that comes with Phantom output.

you are awesome!! I never thought I would find a forum like this and learn so much in so little!!

 

[kingkorg]

I just understood it, that is to say that being stock if I add a 220 to the 220 I have they would give me 440, if I add another 220 it would give me 660pf etc etc. It then occurred to me that I could put a switch to change it and thus get a different sound in the same microphone. Thank you very much, now I understand it.

Finally, what preamp for home studio do you recommend using with this microphone? I am currently using it directly with a focusrite 2i4 sound card that comes with Phantom output.

you are awesome!! I never thought I would find a forum like this and learn so much in so little!!

You are right. And switching different voicings is a nice feat, eventually you will end up using a favorite value and it's a nice way to experiment before you land on the "best" value. 2i4 has nice, clean pres, they won't limit you in any way. Vibey, colorful preamps are wholenother can of worms, it's mostly about personal preference.

 

[dj_jormi]

You are right. And switching different voicings is a nice feat, eventually you will end up using a favorite value and it's a nice way to experiment before you land on the "best" value. 2i4 has nice, clean pres, they won't limit you in any way. Vibey, colorful preamps are wholenother can of worms, it's mostly about personal preference.

Thanskkkk frienddd.

 

[AUDIO FREQ]

Between this:

http://cdn.recordinghacks.com/images//mic_extras/akg/perception-420-circuit.jpg
and what i've seen in my own Perception 200's, it's gonna be on that horizontal board that also carries the switches.

I've also annotated Henry Spragens' Perception 220 schematic with the values i measured on my 200's (i didn't bother measuring the pad cap on mine - that's the only difference between the _00's and the _20's) - see attachment.

It'll be an 0805 ceramic capacitor, on the bottom of the input/switch board. It may very well be easily accessible even without removing the board(s) from the chassis, i think it's near the edge.

Sorry im a bit confused. It says here that it's a PNP BJT? But on my board the K30A is a N type JFET?

 

[Khron]

Sorry im a bit confused. It says here that it's a PNP BJT? But on my board the K30A is a N type JFET?

"On your board", i'm sure, is the switch-carrying board, where the capsule wires connect to.

The PNP is on the board carrying the transformer - the little SOT-23 packaged component, partially drowned in the glue fastening the transformer down, and next to that big block of a tantalum capacitor.

 

[AUDIO FREQ]

"On your board", i'm sure, is the switch-carrying board, where the capsule wires connect to.

The PNP is on the board carrying the transformer - the little SOT-23 packaged component, partially drowned in the glue fastening the transformer down, and next to that big block of a tantalum capacitor.

Ahhhhhhhhhh!!!! Makes sense.

 

[callgrlmusic]

I guess i am done with this one. I sent bunch of files to the owner, side by side comparison, blind test, he picked AKG every time to be Neumann. AKG being flat in low end made him believe it had to be Neumann as it was ''more fluent in the low end'' translated from Norwegian. Now that characteristic high end from AKG disappeared, he couldn't pick it easily out. And he is full time mastering engineer

Now i am not pretending i turned this AKG into Neumann, as he managed to follow AKG in every example there is obviously a difference, and we can hear it. But to achieve this by changing that little bugger without spending 2 x 164 dollars for something like this and still not reach that curve, i'd say it's pretty cool.

AKG Perception Mod Kit

hey kingkorg, i know i’m replying to a really old thread but: i tried this mod and lifted one of the SMD pads when attempting to put the new cap on!! do you have any tips on what to do? (i know this is a very stupid thing i’ve done, but it was my first time dealing with SMD boards/components and i knew the risks)

 

[Khron]

hey kingkorg, i know i’m replying to a really old thread but: i tried this mod and lifted one of the SMD pads when attempting to put the new cap on!! do you have any tips on what to do? (i know this is a very stupid thing i’ve done, but it was my first time dealing with SMD boards/components and i knew the risks)

You could "extend" to whatever that pad connects to, with a thin piece of wire. Although some well-lit, well-focused photos of the affected area would help a lot.

 

[kingkorg]

That cap should be parallel to a 1Meg resistor. You can check to what resistor leads the good pad, and solder the capacitor across that resistor.

 

[micolas]

I know this is a very stupid thing i’ve done, but it was my first time dealing with SMD boards/components and i knew the risks

As Khron and Kingkorg say, post some clear pictures of the crime scene.
Instead of smds, if they are destroyed, through-hole parts can be used, the tracks on the pcb, pads, connectors, etc. can be repaired with thin flexible wires. You need calmness, patience and trust. We're just on a DIY group.
Any circuit can be restored.
What model is the microphone exactly?

 

[AUDIO FREQ]

You guys are a bunch of helpful library of knowledge. Just wanna say thanks for everything. Finally got all the broken mics I bought off ebay/reverb working perfectly. Now to make the bodies less ugly, one had rust on it! YIKES!

 

[s wave]

Hi people,

As we all know Perception circuits are pure ripoff of u87, but don't sound like one because of the capsule. A fellow musician sent me vintage u87 to clean super dirty capsule, and two AKG P220 to try to match the sound to Neumann.

I found out by comparing and measuring the two, for some reason AKG has weaker HF attenuation, and brighter capsule. I just wanted to report that Neumann u87's C6 capacitor responsible for HF de emphasis network is super easy to reach and change.

By measuring frequency responses of u87 and P220 i came to conclusion that it needs to be changed to an 680pF capacitor, instead of original 220pF. You get incredible replica in minutes. It's just that Perception has better bass response , because i t's bass roll off is weaker as well. I didn't want to touch that. I sent files of the shootout to the owner, he picked wrong one to be Neumann. Probably due to AKG's better bass response. Akg is louder, and has less noise. Modded even less due to more HF attenuation. By googling i found that people report this cap to have up to 870pF in some Neumanns. This value gave me u67 kind of response.

No need to disassemble any boards, it's right in front of you when you open the mic. This should work for other Perception mics as well. Might be tricky for newbies to remove smd cap.

One thing to add, AKG is built like a tank!

I'll upload audio files and frequency response graphs tomorrow.
Here is the cap we are talking about.

2023 Update:
Just got a image from the producer I modified first two ever for. These guys can choose any mic they'd like, including original, vintage u87 these were moded after, but seem to keep coming back to these.
View attachment 114744

So you switched out the cap indicated by the red marker on the PCB photo? Anything else - would be appreciated! Thanks pioneer on ~

 

[rodmang]

I would save Ari's capsule for a better, more accurate project. Perception has another limiting factor - the headbasket.

Newbie here and sorry about this but I'd like to know why is the headbasket a limiting factor and also where can I get a good headbasket

 

[kingkorg]

Newbie here and sorry about this but I'd like to know why is the headbasket a limiting factor and also where can I get a good headbasket

Here's the effect of a headgrille. U87 is designed to have a transparent one.

https://groupdiy.com/threads/wa-47.79979/post-1047689

There's also this, position of the capsule is also important.

Post in thread 'Effect of capsule height in head basket' https://groupdiy.com/threads/effect-of-capsule-height-in-head-basket.84530/post-1097866

 

[Paul W]

Newbie here and sorry about this but I'd like to know why is the headbasket a limiting factor and also where can I get a good headbasket

I wonder that, too. If there's no easy headbasket swap, is there an inexpensive body the boards etc. would fit in (without too much trouble) that has a better headbasket?

Also, would simply removing the HF capacitor make the circuit flat? I have an Arienne Audio Flat 47 capsule looking for a home and am wondering if this circuit would be good for that.

 

[micolas]

I wonder that, too. If there's no easy headbasket swap, is there an inexpensive body the boards etc. would fit in (without too much trouble) that has a better headbasket?

Also, would simply removing the HF capacitor make the circuit flat? I have an Arienne Audio Flat 47 capsule looking for a home and am wondering if this circuit would be good for that.

Can modify the headbasket to be close to the U87.
Everything from the inside can be transplanted into another body, like HL-95
Removing the de-emphasis capacitor can increase noise and distortion
(it is a negative feedback circuit) and still retain low-frequency attenuation.