General Discussions => The Lab => Topic started by: bushwick on July 09, 2005, 03:31:37 AM

Title: AKG C412 electronics...
Post by: bushwick on July 09, 2005, 03:31:37 AM
Has anyone come up with a super simple (not alot of parts) design for the AKG 412/414 mics that makes them sound better? They have fantastic capsules in them but they just don't sound that great. Klause Heyne mods them and talks them up to being quite amazing after the mod, sounding much closer to an ELAM after the mod. Curious what I can do these gems to liven them up.

Thanks mucho,
Title: AKG C412 electronics...
Post by: Marik on July 09, 2005, 04:12:58 AM

Welcome to the Lab!

I am not familiar with 412, but had some experience with all 414s.
I just don't see how either of them could possibly get close to ELAM.

Maybe some folks here will jump on me, but IMO, except of the old version (the simplest electronics), all others were just poorly designed--the newer, the worse.

Besides, the ELAM had an old brass version of the CK12 and acoustically transparent grill. The 414 has nothing like that. The teflon CK12 is much inferior, and I don't really like 414 grill. And last, but not least, ELAM is a tube design, which has completely different sonic signature.
Title: AKG C412 electronics...
Post by: jrmintz on July 09, 2005, 09:15:54 AM
The earliest version of the 414EB had the same brass CK12 capsule as the 251 and C12. AKG changed to the Teflon version midway through the run and all of the later 414s have the teflon capsule. I have a 414 with brass capsule that Klaus modified - it is excellent. I don't really think it sounds exactly like the 251s that I've used, but the 251s I've used don't all sound exactly the same anyway. The important thing is that Klaus takes a good, moderately usable mic and turns it into a really first rate, really useful mic in its own right.
Title: AKG C412 electronics...
Post by: Gus on July 09, 2005, 11:54:27 AM
I have not worked on a 412 but I have seen a schematic.

The circuit is simple a source follower into an emitter follower with a DC to DC converter for the capsule voltage

Not much to change to make it better(if it even can be made better with out changing alot of things and what is "better"?)The two caps C2, 470pf and C5?, 33uf look like OK values and I would GUESS are polystyrene and a tant

Is there something wrong with the microphone?

  The parts that I would check because of age are the 33uf cap and the electro in the DC to DC section.  What shape is the capsule in?

  FWIW the first dates on the 412 schematic are from 1970.
Title: AKG C412 electronics...
Post by: soundguy on July 09, 2005, 07:36:59 PM
I wish mic repair guys didnt compare their mods to other mics.  I have a c12a that tracy korby modified and its easily my best sounding mic yet it no longer is anything like a c12a nor is it really like anything else Ive ever used.  I could see someone slamming him for the mod not sounding like an elam even if the mic now sounds insanely good.

Anyhow, if I had a 414 with a good brass capsule, at this point, Id remove the capsule, use it in a mic from the ground up build, stick some cheap replacement in the 414 and sell it.  Then you can build any circuit onto that CK12 instead of trying to cram a bunch of stuff into the small housing of the 414.  Thats the best mod, probably, but also the most complicated as you are constructing a whole new mic...

Title: AKG C412 electronics...
Post by: NewYorkDave on July 09, 2005, 08:14:28 PM
Hey dude, welcome aboard. I like your user name... I was born on Wyckoff Avenue  :thumb:
Title: AKG C412 electronics...
Post by: jrmintz on July 09, 2005, 09:10:02 PM
Quote from: "NewYorkDave"
Hey dude, welcome aboard. I like your user name... I was born on Wyckoff Avenue  :thumb:

Right on the street?

 :green:  :thumb:
Title: AKG C412 electronics...
Post by: NewYorkDave on July 09, 2005, 09:39:53 PM
Yeah, and my mom tells me she would have kept right on walking, 'cept some stranger started chasing after her, yelling "hey, you forgot something!"

Title: AKG C412 electronics...
Post by: jrmintz on July 09, 2005, 09:45:39 PM
Damn, that was a tough neighborhood....

 :green:  :guinness:
Title: AKG C412 electronics...
Post by: NewYorkDave on July 09, 2005, 09:51:43 PM
You bet, Bushwick was tough. She had to make it back to Ridgewood before dark and she wasn't gonna stop for nothin'  :green:
Title: AKG C412 electronics...
Post by: soundguy on July 09, 2005, 10:26:28 PM
I think the baseball furies were from bushwick.

Title: AKG C412 electronics...
Post by: NewYorkDave on July 09, 2005, 10:59:56 PM
You almost made beer come out of my nose! I remember that movie!

"Warriors! Come out and plaaaaaay!"

In real life, I believe the main gang around Bushwick was called the Chaplains.
Title: Hi Guys...
Post by: bushwick on July 11, 2005, 06:06:43 PM
Thanks for the replies. NY Dave... My studio is in Bushwick, in fact and I live here too. Love the warriors reference. Its one of the movies I have here for people to watch when they are bored.

In reference to the C412 mics... They have the orig mics and the were just crappy sounding compared to most other lg dia mics I have and knew that oughtn't be the case. They both have CK12 capsules and yes the idea was to build elams using the capsules, putting teflons in the 412s and evilbaying them. I just didn't / don't have the funds right now. Klause wanted a sh*tload to do it - and yes I understand that for those who can make that kind of commitment it is money well spent. I opted to send them to Tracy Korby who has a pretty good rep. But I have to say, I have had nothing but bad luck with tracy.

First I bought an m49 through him that had his stamp on it. It was my first "big" mic in my studio and compared to other things sounded pretty nice. I started getting better mics in my place and it started to pale. I had some engineers through here and they didn't think that it was all that healthy. I sent it to someone else and they told me the capsule was not healthy and he cleaned it but it was too screwed up. We put a new K47 capsule in it and now it sounds quite impressive and I understand what is so special about it. ...first bad experience.

I sent Tracy my 412's and said he could go through em and make em amazing for a few hundred bucks... much cheaper than going with Klause. I know there isn't that much to them so I figured worth the gamble to perhaps save $4000 or so vs. the Heyne method. (Like I said, I just don't have it.)

So first they came back and they were super dull sounding. I mean realllly dull, lifeless. With those capsules I was shocked - they were borderline dead sounding and anyone familiar with that capsule knows that is should not be the case. I thought to myself, what is wrong with this dude? I can think of no one who would like these mics the way they are. We spoke about it. He said he didn't know what the story was and he asked for them back. I sent them, he worked on them and I got them back. I hooked em up and they had become about the brightest mic I have heard (I have an Elam 250 too) and again I was dissapointed.

So I am finished with Korby. Very dissapointed too javascript:emoticon(':cry:'). I am worried that he did something irreparable to the beautiful capsules, so I thought I would take matters into my own hands and with my tech put some new electronics in them to see what is what. Hopefully, he made his changes to the electronics and didn't futz with the capsules. So I thought I would post to some of the super talented folks here to see what folks had done with their mics coming up with cool circuitry.

I had mentioned simple desgin because it is my (and other too) that the fewer electronics the better the desgin. Perhaps a better transformer in there would be better?

Let me just say I have bee na observer here for sometime and really appreciate people sharing their intellect and experience. Y'all rock!

Semi-unrelated: I  have been engaged with some very eye opening AB testing of gear with my tech/friend who is also a designer. At some point he/I will share our experience...things like IC vs. Discrete and Transformer tests.

So, thanks for chiming in guys, have a great day

All the best,
Title: AKG C412 electronics...
Post by: Gus on July 11, 2005, 06:20:28 PM
look for the square microphone thread in the microphone meta.  That mirophone has a MBHO ck12 type capsule in it.

The circuit I used and that capsule type works well together.  Maybe Dave or Chris can post a little about what they thought.

If the capsule was not damaged and it was a circuit change I few pictures of the inside would help with your question.   You would want the circuit to be good even for the plastic ck12s

FWIW IMO the ELA m251 circuit is kind of boring the grill and the capsule must be the magic.
Title: AKG C412 electronics...
Post by: soundguy on July 11, 2005, 06:36:42 PM
I thought that was pretty much one of the best mics Ive ever heard in my life.

shame none of the commerical mic people arent making anything like that or something that sounds totally different but just as good.

Title: Cool...
Post by: bushwick on July 11, 2005, 07:11:32 PM
Thanks for the tip. I'll check for the square mic....I should have probably posted this over there.

Title: AKG C412 electronics...
Post by: Emperor Tomato Ketchup on July 12, 2005, 09:04:19 AM
Gus' square mic is really great.  It would make an excellent home for some brass CK12's.  I don't think that I heard it with the MBHO capsule yet though.  I'm sure it can only sound better than with the Chineese capsule though.  (Gus, I got your message.  I'll give you a buzz tonight.  Busy like mad...).

Just out of curiosity, I am wondering what the condition of your 414's are.  Have you compared them to any others?  I have some modern ULS and TLII's ("teflon" capsules) that I really like.  The TLII especially makes a great vocal mic.