Seeking a tech who can perform a mic mod for me.

[mikes425]

Hi! I'm a voiceover guy and do not do DIY work but do have what is said to be a fairly straightforward mod that I'd like to have performed on an AKG P 220 mic, per a thread referenced below, posted on the forum.

https://groupdiy.com/threads/akg-perception-p220-to-neumann-u87-5-min-mod-p200-p100-p400-p420.67473/
If there are any US-based freelancers who'd be available - or if you anyone can offer a referral to a person/place to do a 'one-off'project whereby I 'd send over the "donor mic" to have this capacitor changed out as described,
I'd love to hear from you! Thanks!

 

[dmp]

Hi,
This mod would literally take me 5 minutes. I'm in Wisconsin - send me a PM. (note, I'm not a professional, just DIYer)

 

[mikes425]

Hi,
This mod would literally take me 5 minutes. I'm in Wisconsin - send me a PM. (note, I'm not a professional, just DIYer)

Hi this is kinda out of the blue I realize but...i'm considering doing this mod - again - because...for some reason last year when i had an engineer friend do this, with a 540 pF ceramic capacitor ..cuz i was going for closer to a U87aI (somewhat brighter) flavor than the vintage 87.... I guess i spaced on the fact that my "donor mic" for the change-out - was an AKG Perception 200, not a 220. I am researching whether that matters. If the capsule and circuitry in the two models are identical i'm fine with it but...if there's some improvement possibly by modding a 220 (or 420-but they seem to be identical to the 220) - I might want to mod another one. If still interested, I'd be glad to try and work something out with you on it! Thanks! Mike (in Michigan)

 

[Khron]

I guess i spaced on the fact that my "donor mic" for the change-out - was an AKG Perception 200, not a 220. I am researching whether that matters. If the capsule and circuitry in the two models are identical i'm fine with it but...if there's some improvement possibly by modding a 220 (or 420-but they seem to be identical to the 220) - I might want to mod another one.

The only differences are some cosmetics of the outside of the body (x20's have a ring-groove where the switches are), and the JFET being surface mount in the x20's versus through-hole on the x00's.

The location of the high-frequency attenuation capacitor is the same, i believe, so no worries there. And it might be easier to just add another capacitor in parallel to the already-in-place 220pF, to get to whatever value you wish, no risky component-removal necessary.

If the "recommended" 680pF is desired, tack on a 470pF to get you to a total of 690pF - don't sweat the difference, it's less than 1.5%, and you'd be hard-pressed to find reasonably-priced ceramic capacitors with tighter tolerances than +/-5%.

560pF is a more standard (E12-series) value than 540pF, but adding a 330pF in parallel to the 220pF that's already there would get you to 550pF - plenty close enough.

 

[mikes425]

The only differences are some cosmetics of the outside of the body (x20's have a ring-groove where the switches are), and the JFET being surface mount in the x20's versus through-hole on the x00's.

The location of the high-frequency attenuation capacitor is the same, i believe, so no worries there. And it might be easier to just add another capacitor in parallel to the already-in-place 220pF, to get to whatever value you wish, no risky component-removal necessary.

If the "recommended" 680pF is desired, tack on a 470pF to get you to a total of 690pF - don't sweat the difference, it's less than 1.5%, and you'd be hard-pressed to find reasonably-priced ceramic capacitors with tighter tolerances than +/-5%.

560pF is a more standard (E12-series) value than 540pF, but adding a 330pF in parallel to the 220pF that's already there would get you to 550pF - plenty close enough.

Hi thanks for the note. Turns out I had it mistaken and in fact the mic i sent was in fact a 220. The engineer I sent it to used a 510 pF. I has suggested something in the 500 range because as I understood, if I wanted something closer in character to an 87Ai vs, the vintage 87, a lower value than the 680 pF was a better choice. So I gather that to accomplish the result I want, we would want to remove the old 220pF and replace with, in this case, the 510 pF. I've sent the mic back over to him because I could not see any indication that the mod was done...so i suppose i should be clear on all this if i speak to him about exactly what i want done. And, i also thought he was going to use
a 560 pF originally so, not sure why 510 pF was selected in this case, maybe just what he had available. Still i may want to specify at least the 560 pF if possible...given that i'd like to be closer to an Ai than vintage 87...tho not sure how much difference there would actually be.

 

[Paul W]

If the "recommended" 680pF is desired, tack on a 470pF to get you to a total of 690pF - don't sweat the difference, it's less than 1.5%, and you'd be hard-pressed to find reasonably-priced ceramic capacitors with tighter tolerances than +/-5%.

These Kyocera C0G (NP0) multilayer ceramic 0805 capacitors with 1% tolerance are $0.37 each, or 10 for $2.40. Would they be a good choice?

https://www.mouser.com/ProductDetail/KYOCERA-AVX/08051A471FAT2A?qs=wj/bfeEYr2cl1ER%2BQCVvnQ==

Shipping is 7.99, though; I've been assuming that's mostly per-order cost rather than per-item, and if I order some other stuff costing more, the total shipping will be not much higher. (I've never ordered from Mouser before.)

 

[Khron]

Looks about as good as anything, sure. And if you gather up to 50 bucks worth of stuff, you get free shipping too

 

[mikes425]

Hi, I returned the 220 to a an engineer in a nearby town, when I saw no evidence of a mod being performed and questioned whether it was done. I was sent this photo 'confirming' that it was performed. Does this look right? Where is this capacitor located? I do not know why the cap wouldn't be situated on the surface where I've seen the photos of others who performed this mod. I'm being charged a bench fee for reopening and checking it. Thanks for any feedback

 

[pucho812]

Hi, I returned the 220 to a an engineer in a nearby town, when I saw no evidence of a mod being performed and questioned whether it was done. I was sent this photo 'confirming' that it was performed. Does this look right? Where is this capacitor located? I do not know why the cap wouldn't be situated on the surface where I've seen the photos of others who performed this mod. I'm being charged a bench fee for reopening and checking it. Thanks for any feedback

That doesn’t look right.
But would need to probe it for sure.
I used a Wima cap on mine which soldered into a different place. But he may have done that because of that cap.

 

[mikes425]

That doesn’t look right.
But would need to probe it for sure.
I used a Wima cap on mine which soldered into a different place. But he may have done that because of that cap.

Ok, so is it conceivable that this is a functional mod has the same resulting effect as replacing the stock 220 pF as per korg's original post?

 

[pucho812]

Ok, so is it conceivable that this is a functional mod has the same resulting effect as replacing the stock 220 pF as per korg's original post?

Well the cap that gets replaced has the solder pads on the other side. When I did mine I didn’t go beyond that. So I can’t say what’s under that pcb and how it all connects in. I didn't search beyond that.

 

[Khron]

Ok, so is it conceivable that this is a functional mod has the same resulting effect as replacing the stock 220 pF as per korg's original post?

No, it is a completely different capacitor.