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

[kingkorg]

2023 Update:
Just got a image from the producer I modified first two ever for. High end production facility. 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 6 years later.

 

[LevinGuitar]

Could you jump the interstage capacitor (and rewire the second pnp) in order to reduce a cap?

I followed Matador's schematic
https://groupdiy.com/threads/mxl-microphone-circuit-simulation-how-to-simulate-the-capsule.58727/
And also the input one? The input is easy in the cardioid mics changing the polarization to backplate but the pnp mod gives me some low noise and 2-3db more gain, I wonder how to solve it.
Also changing the fet cap 22uf to a better esr one makes a difference and the output one to a polyester of same value gives a little more clarity.

 

[AUDIO FREQ]

I just tried this with my Perception 200. I didn't have a 680pf on hand, but I did have a 470pf FKC wima. And I have to admit, this mic sounds absolutely fantastic now. The high end is tamed, and the mic sounds JUST RIGHT for my voice. I think I will buy a 680pf capacitor and try it out! Thank you

 

[mikes425]

Excellent, thanks very much to you both - that's great advice. I'll keep my powder dry on the Arienne capsules until doing something with the right shape headbasket.

Cheers!

Not really, the whole body construction is actually great, but the headbasket type is not ideal for exact u87 clone. Not that it makes a world of difference, but since we are talking about differences in couple of db at max, i would spare Ari's capsule for exact replica with right headbasket type. The capsule in the perceprion is maybe a couple of db brighter than Ari's, but has the right shape. With this cap mod we get the right response anyways, so as @Khron suggested Ari's capsule would be an overkill.

I have modified the headbasket on it, by making a new one, fully transparent, but it turned to be the ugliest mic i have. Great sounding though. Maybe easiest mod would be to transplant the whole thing into accurate u87 body?

This should not affect sensitivity in any way. It could be you perceive it as less sensitive as it's less bright. Unless you messed something up along the way.

Regarding the polystyrene cap recommended by MP it won't do much, maybe in theory reduce microphonics of the stock cap, but this is highly speculative, and it doesn't mean the stock one is microphonic to begin with. I would leave it alone. Polystyrene caps are also sensitive to heat, so if your soldering technique is less than ideal you could do more harm than good.

Reviving a thread here as a group newcomer, and a longtime voice actor. I'm very much intrigued with the mod that you describe on the P220, having at least one that I'd love to do this on, but alas, I am not a DIY guy and would be interested in sending one out to have it performed. If you have any recommendations feel free to advise! Thanks!

 

[kingkorg]

Reviving a thread here as a group newcomer, and a longtime voice actor. I'm very much intrigued with the mod that you describe on the P220, having at least one that I'd love to do this on, but alas, I am not a DIY guy and would be interested in sending one out to have it performed. If you have any recommendations feel free to advise! Thanks!

Hello. Idk if it would be worth the hassle, i live in Norway. I believe there are many here whom could easily do it, and are located in the US.

 

[mikes425]

Hello. Idk if it would be worth the hassle, i live in Norway. I believe there are many here whom could easily do it, and are located in the US.

Thanks! Are you familiar with the mod offered by Matt at microphone-parts? I was considering that but, they appear to want to include a new K87 capsule along with their capacitor swap. I'm hoping to replicate a genuine 87Ai as closely as possible (and may just buy one) but since I've got these AKGs sitting around, figured it'd be worth a small investment to upgrade one of them and see how it compares... I just wondered if the mod they offer is fairly equivalent to yours in terms of the end result. And otherwise, yes, if I could locate someone in the US - perhaps someone on this forum who could just do your mod, I'd be happy to hear from them if they happen upon this thread : )

 

[kingkorg]

Thanks! Are you familiar with the mod offered by Matt at microphone-parts? I was considering that but, they appear to want to include a new K87 capsule along with their capacitor swap. I'm hoping to replicate a genuine 87Ai as closely as possible (and may just buy one) but since I've got these AKGs sitting around, figured it'd be worth a small investment to upgrade one of them and see how it compares... I just wondered if the mod they offer is fairly equivalent to yours in terms of the end result. And otherwise, yes, if I could locate someone in the US - perhaps someone on this forum who could just do your mod, I'd be happy to hear from them if they happen upon this thread : )

Replacing the capsule would be downgrading this mic, it just needs capacitor change as described in the original post.

 

[mikes425]

Replacing the capsule would be downgrading this mic, it just needs capacitor change as described in the original post.

Good to know! Just the capacitor change it is then! Thanks! Well, if any US-based folks would be interested in working with me on this, feel free to let let me know!

 

[kingkorg]

Good to know! Just the capacitor change it is then! Thanks! Well, if any US-based folks would be interested in working with me on this, feel free to let let me know!

Also nice to note different values will give you different results. 820pf would give more like u67 response, 470pf- 680pf, would be more in line with u87ai. You can also make it switchable.

 

[mikes425]

470pf- 680pf, would be more in line with u87ai.

Interesting. So of that choice range, if your preference was to match the 87Ai specifically which size would you go with?

 

[kingkorg]

Interesting. So of that choice range, if your preference was to match the 87Ai specifically which size would you go with?

I would have to measure the mic i try to model. For the vintage one i had and mentioned in the OP it was 680pf i believe. It was a darker sounding vintage 70's u87.

 

[mikes425]

I would have to measure the mic i try to model. For the vintage one i had and mentioned in the OP it was 680pf i believe. It was a darker sounding vintage 70's u87.

Ok. I'd be looking to replicate the character of the current 87Ai, circa 2015 and beyond...on an AKG P 220.

 

[mikes425]

680pF for what? The capacitor that rolls off the high end? That would give you something like a classic U87. Don't bother changing the original capsule, with the correct roll off you're getting something really close to a vintage U87. At that point the difference is probably just the acoustics of the body.

So I'm just looking to clarify as I've given a mic to a tech to perform the OP's mod. My mic is a Perception 220. The question is which capacitor value. I'm looking at strictly changing out the stock cap. My desire would be a character more in line with the modern U87Ai than the classic 87i. That said, which capacitor would be recommended. And, I presume nothing else needs to be modified, just keeing stock AKG 200 capsule. Specifically, would the 470pf be more in line with the 87Ai (vs vintage 87) than say, the 680pF cap? ((or is there somehing in between 470-680pF for that matter).

Thanks for any help!

 

[micolas]

In AKG P420 over the stock capacitor I added different values outside the microphone to avoid hum noise
For a pleasant, musical sound, between U87ai and U87i, I used 560pF+100pF+Stock capacitor
Or a multi-position switch with different capacitor values can be used

 

[mikes425]

Nice. So of the spectrum, from the 470pf to a 680pf, if you had to go with just one cap, as i’m asking a tech to do for me..what size would you say would most closely replicate the current U87Ai - keeping all else ‘stock on the Perception 220? Thanks!

 

[micolas]

For the U87ai sound, in P420, I found a total value of 470pF...510pF, but to further reduce the sibilance, I would use 560pF.

 

[cyrano]

680 pF is just the size you could still fit a trimmer...

 

[dj_jormi]

Do you have a link to buy a wilma 680pf or a photo of the trainer with one? I am good at soldering because I did some repair work in class with tin, but I have no idea about electronics, and I don't know what shape it is... I'm going crazy looking on Google... thanks!!

 

[micolas]

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!

 

[kingkorg]

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.