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Project Specific Discussions => Microphones => Topic started by: Gbout2 on September 03, 2016, 07:08:23 PM

Title: AKG Perception 420 Mod
Post by: Gbout2 on September 03, 2016, 07:08:23 PM
Rook mistake of desoldering backplate, front and back diaphragm wires without "clearly" marking where the new wires return for solder. Anybody perform this mod that can show pics of where to solder the new capsule wires? Thanks in advance!
Title: Re: AKG Perception 420 Mod
Post by: ln76d on September 03, 2016, 07:10:45 PM
Put the pic and i will mark on it.
There's few options to mod the circuit capsule is the last since it have deemphasis network and pretty good K67 copy.
Title: Re: AKG Perception 420 Mod
Post by: Gbout2 on September 03, 2016, 09:21:34 PM
Side A
Title: Re: AKG Perception 420 Mod
Post by: Gbout2 on September 03, 2016, 09:22:49 PM
Side B
Title: Re: AKG Perception 420 Mod
Post by: Khron on September 03, 2016, 09:32:43 PM
The wire from the rear diaphragm, goes through that little hole (between the 6-pin header and the 1G resistor, in the Side B view), and solders to the bottom of that white insulator (to which the middle leg of the pattern selector goes).

The wire from the front diaphragm goes through the little hole next to the JFET, and solders to the bottom of the white insulated pin between the pin header and the pad switch.

The backplate wire goes to that lone hole/pad right in the middle of the board, with a little solder blob sticking out of it, in-between the pad & high-pass filter switch, right next to the padding cap.
Title: Re: AKG Perception 420 Mod
Post by: Gbout2 on September 03, 2016, 09:36:48 PM
I appreciate it, about to try it out.
Title: Re: AKG Perception 420 Mod
Post by: Khron on September 03, 2016, 09:51:35 PM
Just going by the U87Ai schematic, and what i remember from modding my Perception 200's, plus a bit of logic / common sense :)
Title: Re: AKG Perception 420 Mod
Post by: mister b on September 04, 2016, 11:42:59 AM
Rook mistake of desoldering backplate, front and back diaphragm wires without "clearly" marking where the new wires return for solder. Anybody perform this mod that can show pics of where to solder the new capsule wires? Thanks in advance!

Maybe this post help ...

http://microphone-parts.com/pages/akg-perception-capsule-swap-tutorial

Regards
Title: Re: AKG Perception 420 Mod
Post by: Khron on September 04, 2016, 11:53:48 AM
Those photos are from a Perception 200/220, the cardioid-only version :) 420's the multipattern one.

Rook mistake of desoldering backplate, front and back diaphragm wires without "clearly" marking where the new wires return for solder. Anybody perform this mod that can show pics of where to solder the new capsule wires? Thanks in advance!

Maybe this post help ...

http://microphone-parts.com/pages/akg-perception-capsule-swap-tutorial

Regards
Title: Re: AKG Perception 420 Mod
Post by: ln76d on September 04, 2016, 02:40:05 PM
I followed mparts link and i wonder what's the sense of replacing original capsule to RK87...
Title: Re: AKG Perception 420 Mod
Post by: Khron on September 04, 2016, 02:43:10 PM
They've got capsules to sell ;D

I followed mparts link and i wonder what's the sense of replacing original capsule to RK87...
Title: Re: AKG Perception 420 Mod
Post by: JessJackson on September 05, 2016, 03:04:25 AM
If anyone has their original capsule from their 220 or 400 series i will gladly buy it from you. cheers

jess
Title: Re: AKG Perception 420 Mod
Post by: bxt403 on October 24, 2018, 11:37:35 AM
I'm wondering what the decoupling capacitor value is (the ceramic capacitor that's replaced with a polystyrene one in the Microphone Parts Perception mod kit).  The photo on the Micparts site shows a photo of a P220 and later photo of a ceramic marked 212 (so 2100pF).  Is that the same value found in the 420 and what's the capacitance used for a polystyrene? 

Also- there's another post about modding the Perception 220 to be like a U87 where a 220pF SMD capacitor's replaced to 680pF (found on the underside of the switch PCB) that's responsible for the circuit's de-emphasis EQ.  Would that imply I'd need anything from an open to 470pF for a CK12 type capsule and (for a K47 type) open to 220pF? 
Title: Re: AKG Perception 420 Mod
Post by: kingkorg on October 24, 2018, 05:59:19 PM
If you are going for c12 sound you don't need any cap there with rk12, maybe something like 100pf for elam-ish sound.

For k47 nothing as well.

However i would personally use original capsule with that 680pf as it is scary close to real u87.
I just did a shootout with some mics yesterday and p420 i modded on drum overhead. It's crazy good mic.
Title: Re: AKG Perception 420 Mod
Post by: bxt403 on November 02, 2018, 10:53:01 PM
So after getting a P420: I realized that it's not like the Perception 420.  The P420 I got ended up having all the parts that need to be replaced being surface mount.  There's little to no room to install a 470pF (or 1000pF)  polystyrene cap: the 470pF surface mount capacitor's on the underside of the switch board. 

The only mod I could do was replace the 220pF capacitor with a 680pF WIMA one I had leftover from building a MicParts S3-87.
The location is different than for the P220 but it's still easy to access.  I decided to keep the stock capsule installed but I'm  seriously impressed how great the mic sounds by simply changing out the 220pF capacitor with a 680pF one.

The only problem is that the capacitor I used needs to be desoldered if I ever need to disassemble the mic any further (like to access the top-side of the switchboard).  Considering how good mic sounds now: I doubt I ever will.
Title: Re: AKG Perception 420 Mod
Post by: Khron on November 03, 2018, 08:09:07 AM
I'm not 100% sure what the news / surprise is - i have three Perception 200's and they're (or rather, were) all surface-mount "already". Well, apart from the JFET and transformer.

Perception 220 inside shots  (identical to the 200 save one capacitor value) - http://audioimprov.com/AudioImprov/Mics/Entries/2013/2/26_AKG_Perception_220.html

So after getting a P420: I realized that it's not like the Perception 420.  The P420 I got ended up having all the parts that need to be replaced being surface mount. 
Title: Re: AKG Perception 420 Mod
Post by: kingkorg on November 03, 2018, 11:08:59 AM
So after getting a P420: I realized that it's not like the Perception 420.  The P420 I got ended up having all the parts that need to be replaced being surface mount.  There's little to no room to install a 470pF (or 1000pF)  polystyrene cap: the 470pF surface mount capacitor's on the underside of the switch board. 

The only mod I could do was replace the 220pF capacitor with a 680pF WIMA one I had leftover from building a MicParts S3-87.
The location is different than for the P220 but it's still easy to access.  I decided to keep the stock capsule installed but I'm  seriously impressed how great the mic sounds by simply changing out the 220pF capacitor with a 680pF one.

The only problem is that the capacitor I used needs to be desoldered if I ever need to disassemble the mic any further (like to access the top-side of the switchboard).  Considering how good mic sounds now: I doubt I ever will.

I find the capsule phenomenal. Coupling is just fine if you ask me. The only further mod i did, which made it realy shine, is custom headbasket which got rid of all internal reflections. I got crazy smooth response from the mic. Without random dips in the high end. I can post measurements later.  Sound samples as well. However it left me with very ugly mic. I use it as mono overhead on drums, so the looks are not that important.
Title: Re: AKG Perception 420 Mod
Post by: Khron on November 03, 2018, 11:26:14 AM
I made my Perception 200's into multipattern mics ;D The DC-DC converter was already made for that too, i just added the pattern switch.

On the other hand, the capsules were assembled from the "active" halves of sE 2200A capsules, put together. Haven't run any measurements on them yet, though.
Title: Re: AKG Perception 420 Mod
Post by: kingkorg on November 03, 2018, 06:16:49 PM
These are my replicas and modded Perception p420. Mics are placed over the shoulder of drummer. These are different takes, so there is some variation, but the sound difference is obvious. There is one Shure KSM44 which i like, just as a stock mic reference.

U67 with 797 capsule
https://app.box.com/s/pyxd2wpz4iodwoy2u2oiidtlv0uldjf3

U47 with Dale's M7 capsule
https://app.box.com/s/gp95jbg2sf542nyjx81z0qmoodeu5831

U47 with selected OEM k47 capsule
https://app.box.com/s/352xob1c0lv14s6oitdxbxm75q2eis3o

C12 with Tim Campbell's CT12
https://app.box.com/s/wlmx3bhgkqdxro9ndf004qcadlqvyiax

Shure ksm 44 stock
https://app.box.com/s/57nx0jdspe21wdfxq0dzpqphoet2tyim

Perception p420 with modded circuit and grille
https://app.box.com/s/2pljm7xvwrldru1792hj9wsm2thbmwx3

And just for the hell of it, as ''Chinese Mic'' sound reference - Stock Studio Projects C1
https://app.box.com/s/uxhrujd7y7wt6jdiidq74ksrtho3ekjg
Title: Re: AKG Perception 420 Mod
Post by: bxt403 on November 04, 2018, 09:25:24 AM
I find the capsule phenomenal. Coupling is just fine if you ask me. The only further mod i did, which made it realy shine, is custom headbasket which got rid of all internal reflections. I got crazy smooth response from the mic. Without random dips in the high end. I can post measurements later.  Sound samples as well. However it left me with very ugly mic. I use it as mono overhead on drums, so the looks are not that important.

Since I also have a MicParts S3-87 as a reference:  I decided to leave the head basket intact.

Comparing the two microphones: it looks like they both use two layer mesh but the S3 has wider gaps than the P420.  I'd rather have full EM shielding and physical protection from any contamination with the way the stock head basket is than risking anything by removing any of the mesh. 

Here's the video that initially made me want to install the RK-12 (or C12 type capsule):

https://www.youtube.com/watch?v=jsO4iJFAYjY

"Cuomo tragico..."
Title: Re: AKG Perception 420 Mod
Post by: joelgurule on December 01, 2018, 06:34:23 PM
I'm not 100% sure what the news / surprise is - i have three Perception 200's and they're (or rather, were) all surface-mount "already". Well, apart from the JFET and transformer.

Perception 220 inside shots  (identical to the 200 save one capacitor value) - http://audioimprov.com/AudioImprov/Mics/Entries/2013/2/26_AKG_Perception_220.html
Whats the part number for the 670pf smd cap, i orderdled some, but they are too small like half the size of all the smd caps,
Title: Re: AKG Perception 420 Mod
Post by: Khron on December 02, 2018, 08:54:02 AM
670pF is not a standard value - did you mean 680pF or 470pF?

And SMD ceramics have no markings whatsoever anyway. But you should be able to easily find loads of options at the major component distributors (Digikey, Mouser, Farnell etc).
Title: Re: AKG Perception 420 Mod
Post by: joelgurule on December 03, 2018, 11:55:48 AM
I'm sorry, I did mean 680pf, I have looked, but the ones I ordered are like micro, maybe 1mm long and the mic takes bigger capacitors, around 2mm or 2.5mm long.. I dont want to order more the wrong size,
Title: Re: AKG Perception 420 Mod
Post by: Khron on December 03, 2018, 12:21:06 PM
~1mm long (well, more like 1.6mm) sounds like 0603, 2mm long (which the ones in my Perception 200's are) are 0805.

https://en.wikipedia.org/wiki/Surface-mount_technology#Two-terminal_packages

If the capacitance value and the voltage ratings are the same, the physical package isn't all that critical.

You can easily solder 0603 components on to 0805 pads ;) The other way around may be a bit more interesting, but not impossible ;D

0402's (1mm x 0.5mm) could be a wee bit more... fiddly  :-X
Title: Re: AKG Perception 420 Mod
Post by: joelgurule on December 03, 2018, 12:31:18 PM
thank you, im new at this, I think i accidentally ordered and recieved the 0402's theyvare very small compared to the 0805's, I have the AKG perception 200, which is the mic im trying to mod. yhank you for replying and helping me out
Title: Re: AKG Perception 420 Mod
Post by: Khron on December 03, 2018, 12:51:38 PM
Well, with a steady hand, some willpower and perhaps a magnifying glass, even those can be usable. Hopefully :)

Just eyeballed some laptop boards (comparing 0402 components with 0805 pads) and yeah, should be workable.

When replacing SMD passives, i usually blob some fresh (leaded) solder onto the ends of the existing component, then heat both ends at the same time with my wide wedge-tip soldering iron. Then i clean the pads with some solder-wick, add a touch of fresh solder to one pad, tack down one end of the new component there, solder the other end, then re-melt and add solder to that first end.
Title: Re: AKG Perception 420 Mod
Post by: joelgurule on December 03, 2018, 01:20:32 PM
I was gonna attempt to try, but Im not that skilled for a cap that small, I might ruin it and the pcb, so Ill just return, and order the right size, anyway, Im in no hurry...
Title: Re: AKG Perception 420 Mod
Post by: Khron on December 03, 2018, 02:50:09 PM
I think the only way(s) you can ruin the PCB is if 1) your soldering iron's waaaaaay too hot and/or it's in contact with the pads for too long, or 2) you're being (excessively) "Neanderthal-ic" (or mechanically overly-aggressive) with it ;D

So unless you're using a "fire-stick" (ie. unregulated mains-powered soldering iron running at 400-450C), or the hammer-and-chisel (or pneumatic hammer) method, i'd imagine you should be safe :)
Title: Re: AKG Perception 420 Mod
Post by: JulesP on March 14, 2019, 01:07:48 PM
Hi, all. Just to make absolutely sure where the cap to be changed ( to a pf 680) is located  on the P420 ( i do not read circuits).
I did change the obviously visible cap on my perception 220 and am quite impressed by it.
And I have 2 p420 sitting here, way too sibilant  for my use on acoustic instruments.
Please, let me know if you can post a pic with an arrow clarifying where the cap is and would be located.
I think it could help a lot of electronic-illiterates  musicians like me.
Cheers.
Jules
Title: Re: AKG Perception 420 Mod
Post by: Khron on March 14, 2019, 01:14:21 PM
Any chance you could post a photo of the little "input board", and then we can (hopefully) point out the cap? ;)

Hi, all. Just to make absolutely sure where the cap to be changed ( to a pf 680) is located  on the P420 ( i do not read circuits).
I did change the obviously visible cap on my perception 220 and am quite impressed by it.
And I have 2 p420 sitting here, way too sibilant  for my use on acoustic instruments.
Please, let me know if you can post a pic with an arrow clarifying where the cap is and would be located.
I think it could help a lot of electronic-illiterates  musicians like me.
Cheers.
Jules
Title: Re: AKG Perception 420 Mod
Post by: Khron on March 14, 2019, 03:44:43 PM
You're in luck(?)...

https://groupdiy.com/index.php?action=dlattach;topic=63718.0;attach=44866;image
(one of the photos attached on the first page of this thread)

The right side of the board is really blurry, but the cap you want to replace is that light-grey little block, on the upper-right side.
It's in-between those two black-topped resistors saying "1004" on them.

The brown capacitor to the left of those is the 470nF cap coming from the JFET drain, and the trace then goes down to the 33-47nF cap (lower-right) in series with the 6.8k and 560 ohm resistors.

Hi, all. Just to make absolutely sure where the cap to be changed ( to a pf 680) is located  on the P420 ( i do not read circuits).
I did change the obviously visible cap on my perception 220 and am quite impressed by it.
And I have 2 p420 sitting here, way too sibilant  for my use on acoustic instruments.
Please, let me know if you can post a pic with an arrow clarifying where the cap is and would be located.
I think it could help a lot of electronic-illiterates  musicians like me.
Cheers.
Jules
Title: Re: AKG Perception 420 Mod
Post by: Icantthinkofaname on March 14, 2019, 06:00:07 PM
Even if you can't read a schematic, it's easy-ish to find the capacitor of you know the capacitance of it. Assuming it's a marked through hole cap.
Title: Re: AKG Perception 420 Mod
Post by: Khron on March 14, 2019, 06:46:00 PM
That's a biiiiiiig assumption, in this case :) Doesn't quite work in the case of 0805 (or 0603?) SMD ceramic caps though, sadly...

Even if you can't read a schematic, it's easy-ish to find the capacitor of you know the capacitance of it. Assuming it's a marked through hole cap.
Title: Re: AKG Perception 420 Mod
Post by: JulesP on March 16, 2019, 12:57:04 PM
Hi, all
This is the under view of the AKG  P420 switch box  There is nothing, out of the switches, and their contacts, on the upper level
I hope someone can help me ( I am circuit illiterate , I admit but quite precise at soldering when needed) to locate the cap to be changed to a pf 680.  The improvement on my 220 was very welcome.

Thanks if ever someone can locate this cap, Could help a lot of p420  owners.

Jules
Title: Re: AKG Perception 420 Mod
Post by: Khron on March 16, 2019, 01:14:11 PM
[sigh]

Did you even read my post above (Reply #30)?  :o

Here, i'll link directly to it:

https://groupdiy.com/index.php?topic=63718.msg912397#msg912397

How is your circuit board any different from the one in the Perception 420, the one i linked to in the post above (which points at one of the circuit photos that's on the first page of this thread)?  ???

[Edit]
Fine, it's a bit different, but it's IDENTICAL on the side that contains precisely the feedback network we're interested in.
So  what's your excuse?  :o

Hi, all
This is the under view of the AKG  P420 switch box  There is nothing, out of the switches, and their contacts, on the upper level
I hope someone can help me ( I am circuit illiterate , I admit but quite precise at soldering when needed) to locate the cap to be changed to a pf 680.  The improvement on my 220 was very welcome.

Thanks if ever someone can locate this cap, Could help a lot of p420  owners.

Jules
Title: Re: AKG Perception 420 Mod
Post by: JulesP on March 16, 2019, 05:05:41 PM
Hi, Krohn.
Sorry if the pictures did not post, at first.  It took three  times for me to be able to post them., here Image size limitation I sincerely thank you for all advice and clarification . My circuit seems a little different from the source you provided, but there is a grey cap between the two 1004  ones.  I did not want to trigger any impatience, and, yes, I saw your earlier post.
Thanks so much, again, for your patience I am a musician,  composer and arranger, but a true rookie at all circuitry.
I helped my dad with his shaky hands, as a teenager, soldering delicate operations, under his guidance, to help him at a Parkinson that left him without much control towards the end.
I wish I had the time and patience to learn to read electronics, back then...
J.
Title: Re: AKG Perception 420 Mod
Post by: Khron on March 16, 2019, 05:48:11 PM
You didn't so much trigger impatience, as much as frustration or annoyance, at seemingly ignoring my (i thought) quite obvious and detailed indications :D

But no harm done, all's well that ends well :)

For tips re: desoldering the stock part, see my earlier post on this page. Adding in a pair of tweezers to pick off the desoldered part while the solder is molten helps ;)
https://groupdiy.com/index.php?topic=63718.msg900825#msg900825
Title: Re: AKG Perception 420 Mod
Post by: JulesP on March 16, 2019, 06:13:40 PM
Thanks for your understanding, Khron!
As much as for this enlightening info.
Truly, I tried to open some images, including yours, here, and it did not work until recently.
Same as trying to upload mine, in the beginning.
Maybe a cookie issue, initially.

In any way, I thank you, as for all others, trying to squeeze-out the best from affordable tools.

Jules