AKG C12 point to point build

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Coop

Well-known member
Joined
Apr 22, 2013
Messages
89
Location
Austria
Good evening everybody,

For a very long time I was looking at different DIY microphone projects I could do. There are many great kits out their but for me there is one thing besides the sound that is super important. I want not only the internal parts but also the outside to feel and look as original as possible. Living about 60km away from Vienna obviously makes me a big AKG fan. I always loved to use their mics, especially the old ones. I acquired a nice pair of C414B-ULS and C451E over the years and I have acmes to 4 more 414B-ULS and 2 414EB-P48. There is just something really nice about them and I love to work with mics that just sound great by going through a nice preamp.
A couple of months ago I did a little jazz trio session with 2 C414-B-ULS on the upright bass, 2 C414-EB-P48 on the grand piano and a D12, C451E and 2 M582 on the drum kit. It sounded awesome but something inside me has always wanted to have a pair of tube mics and 2 nice C12 would be the perfect match for my collection I think. So here we are, December 2021, the start of a probably very long journey to get (for now) one working C12 DIY clone.

I know that I will probably not reach the sound a original C12 has, but I think I can get really close and it makes more fun to build and test stuff than just go out an put 5000€ on the table and just buy a built FLEA 12.

Some facts about the build:

Body

As stated before I absolutely love it when it looks and feels original, so I will be using a FLEA body kit with the super expensive swivel mount connector. They seem to be the only ones who really get everything right. Headbasket, capsule mount, internals.... I know it's not the cheapest way, but who said that DIY is cheap.

Tube
I think there are a lot of choices here but to get it close to the original I need to look for a nice NOS GE6072 5 Star tube.

Electronics
For now I will be using modern parts. I do have ordered some soviet PIO caps to use as output caps and I am still looking for polystyrene caps to use in the build. Not easy to find some that are rated for more than 50V. I will probably be looking out to source a couple of NOS Siemens Karbowid resistors, just to try out and see if they change the sound in a good way. But this will probably take some time, cause these parts to get harder to find every day.

Capsule
I heard a lot of good things about Tim's CT12. But I think it will be really hard to get one these days. So right now I am looking for alternatives. I know that there are great ones out there and they are all in the same ballpark. It's just a very personal sound choice. I am looking to find one that is close to the original in terms of transient response, off axis response, mids, "3D sound". If actually don't really mind if one is a little brighter or the other a little darker. But I am still looking for the classic airy, but smooth sound.

Transformer
Another really personal choice I would say. Some have more low end, some less... I settled on the Haufe T14/1. Only need to find one for a reasonable price.

PSU

Ordered some PCBs already and 2 cases from Analogvibes. Will be using 7 pin Binder mic connectors and normal Neutrik 3 pin connectors. I think all those parts should be on the way or are at least ordered for 2 PSUs. Not a bad idea to have two I think.

If anyone has some ideas or knows where to get some of the parts I am still missing I am happy for any response. I hope I can share a lot of pics of the build over the next months (year?)

All the best,
Johannes
 

mihi_fuchs

Well-known member
Joined
Sep 21, 2019
Messages
89
Location
Austria / Europe
Hi,

just read through your thread. maybe for the polystyrene caps you can check with reichelt.at. they have at least some 160V DC caps. nevertheless, if you want bigger ones the omly source that worked for me was justradios.com. they had a good set of caps and my polystyrene 500V caps arrived fast and the contact was really nice.
maybe if you want to go for the justradios option we could share in on the shipping costs - i‘d be interested too in some caps and shipping within austria should be chaep and easy … :)

best regards,
michael
 

Coop

Well-known member
Joined
Apr 22, 2013
Messages
89
Location
Austria
@mihi_fuchs
Yeah, I was looking at the justradios.com page. They seem to have bigger ones. The only thing that bothers me is the 30$ minimum order. I think the 3 caps I need will come to 5$ or so. Original C12 schematic says 250V ones so justradios is my only change to get the right ones.

But we can definitely order together and then split the order up here in Austria. Sounds like a good plan :)
 

JerryPbury

Well-known member
Joined
Jun 6, 2004
Messages
141
Location
Charlotte, NC
I built two C12’s using Matador boards and Chunger bodies. I used Tim’s Capsules and ordered my transformers directly from Haufe. I believe Moby also makes a tranny. I used his transformers for a pair of U67’s and couldn’t be happier. Love my C12 clones! Good luck!
 

Coop

Well-known member
Joined
Apr 22, 2013
Messages
89
Location
Austria
@lampas Yeah, that sounds awesome. Did you use NOS resistors? Where did you get the MBHO capsule from. I heard they don't sell the capsules for DIY projects.

@JerryPbury Thanks, it's gonna be a nice journey I think.
Nice to hear that your clones turned out great. How much did you pay for the transformers? Was there a minimum order?
 

TillM

Well-known member
Joined
May 21, 2016
Messages
666
Location
Berlin - Germany
I don’t think, that NOS resistors will change anything.
For the “good” feeling use some Beyschlag or Vishay.
For my C12 builds I used first a GE 6072a Five Star tube. I tried also the 6072 tube from Tubeamp Doctor and have to say, I hear no difference!
As transformer I used Haufe T14 and in the other Mic Mobys T14 transformer.
Also there I hear no difference and I would go for Mobys T14 cause it’s much cheaper.
For the capsule go for Tim Campbell.
Haun don’t like to sell to private customers.
But If you want a Haun CK12 then better give them a call.
A friend of mine get my C12. He also have a original C12.
He told me, that he don’t hear a difference.
 

Coop

Well-known member
Joined
Apr 22, 2013
Messages
89
Location
Austria
@TillM
Yeah, I think it's not easy to tell a difference. Comparing mics is a tough thing. There are so many factors that come into play.
I will have a look into Mobys T14.
I would love to get a Tim Campbell capsule. But I read that he is not taking orders as he can't keep up with making all the orders he has.
 

JerryPbury

Well-known member
Joined
Jun 6, 2004
Messages
141
Location
Charlotte, NC
@lampas Yeah, that sounds awesome. Did you use NOS resistors? Where did you get the MBHO capsule from. I heard they don't sell the capsules for DIY projects.

@JerryPbury Thanks, it's gonna be a nice journey I think.
Nice to hear that your clones turned out great. How much did you pay for the transformers? Was there a minimum order?
They were not cheap but I don’t remember how much, check online. No minimum order. Don’t know how much the Moby are in comparison price wise but his quality is outstanding!
 

JerryPbury

Well-known member
Joined
Jun 6, 2004
Messages
141
Location
Charlotte, NC
@TillM
Yeah, I think it's not easy to tell a difference. Comparing mics is a tough thing. There are so many factors that come into play.
I will have a look into Mobys T14.
I would love to get a Tim Campbell capsule. But I read that he is not taking orders as he can't keep up with making all the orders he has.
I bought 3 capsules from Tim a little over a year ago. Quoted an 8 week wait (which would have been Christmas) they arrived mid January. It doesn’t hurt to ask.
 

Coop

Well-known member
Joined
Apr 22, 2013
Messages
89
Location
Austria
@e.oelberg That sounds interesting. Definitely want to try a more inexpensive tube first and see how I like the sound.

@JerryPbury Good to know. I will contact Haufe after the holidays. I did send Tim a mail a couple of days ago but I have not gotten a reply yet.

@mrgrooves666 Sent you a PM
 

Andresound

Active member
Joined
Feb 26, 2020
Messages
33
Good evening everybody,

For a very long time I was looking at different DIY microphone projects I could do. There are many great kits out their but for me there is one thing besides the sound that is super important. I want not only the internal parts but also the outside to feel and look as original as possible. Living about 60km away from Vienna obviously makes me a big AKG fan. I always loved to use their mics, especially the old ones. I acquired a nice pair of C414B-ULS and C451E over the years and I have acmes to 4 more 414B-ULS and 2 414EB-P48. There is just something really nice about them and I love to work with mics that just sound great by going through a nice preamp.
A couple of months ago I did a little jazz trio session with 2 C414-B-ULS on the upright bass, 2 C414-EB-P48 on the grand piano and a D12, C451E and 2 M582 on the drum kit. It sounded awesome but something inside me has always wanted to have a pair of tube mics and 2 nice C12 would be the perfect match for my collection I think. So here we are, December 2021, the start of a probably very long journey to get (for now) one working C12 DIY clone.

I know that I will probably not reach the sound a original C12 has, but I think I can get really close and it makes more fun to build and test stuff than just go out an put 5000€ on the table and just buy a built FLEA 12.

Some facts about the build:

Body

As stated before I absolutely love it when it looks and feels original, so I will be using a FLEA body kit with the super expensive swivel mount connector. They seem to be the only ones who really get everything right. Headbasket, capsule mount, internals.... I know it's not the cheapest way, but who said that DIY is cheap.

Tube
I think there are a lot of choices here but to get it close to the original I need to look for a nice NOS GE6072 5 Star tube.

Electronics
For now I will be using modern parts. I do have ordered some soviet PIO caps to use as output caps and I am still looking for polystyrene caps to use in the build. Not easy to find some that are rated for more than 50V. I will probably be looking out to source a couple of NOS Siemens Karbowid resistors, just to try out and see if they change the sound in a good way. But this will probably take some time, cause these parts to get harder to find every day.

Capsule
I heard a lot of good things about Tim's CT12. But I think it will be really hard to get one these days. So right now I am looking for alternatives. I know that there are great ones out there and they are all in the same ballpark. It's just a very personal sound choice. I am looking to find one that is close to the original in terms of transient response, off axis response, mids, "3D sound". If actually don't really mind if one is a little brighter or the other a little darker. But I am still looking for the classic airy, but smooth sound.

Transformer
Another really personal choice I would say. Some have more low end, some less... I settled on the Haufe T14/1. Only need to find one for a reasonable price.

PSU

Ordered some PCBs already and 2 cases from Analogvibes. Will be using 7 pin Binder mic connectors and normal Neutrik 3 pin connectors. I think all those parts should be on the way or are at least ordered for 2 PSUs. Not a bad idea to have two I think.

If anyone has some ideas or knows where to get some of the parts I am still missing I am happy for any response. I hope I can share a lot of pics of the build over the next months (year?)

All the best,
Johannes
Pulling up a chair 👍
 

Andresound

Active member
Joined
Feb 26, 2020
Messages
33
+1 on (Tim Campbell) TC12 capsule. I fitted A TC12 to a CK4 type head with adapter. Wired as cardioid and on an original AKG C28b (6072, T14/1 etc), it sounds fantastic. Originally purchased the TC12 for a RODE Classic 1, but it sounded so good on the C28b, I put the original Classic 1 capsule back. I am in the queue for another CT12 from Tim. He is VERY busy, but he did answer my request. Great person to deal with.
 

Coop

Well-known member
Joined
Apr 22, 2013
Messages
89
Location
Austria
@Andresound
Well I did send him a mail a couple of days ago. Not sure if it was the right address though. There are two on his website. Let's see if he does answer my request :)
 

Coop

Well-known member
Joined
Apr 22, 2013
Messages
89
Location
Austria
@TillM
Yes, I heard that the OPR ones should be pretty close to the original ones too. I think I will take whatever I can get my hands on more easily. Maybe even get a pair of both and try them out. Do have two C414 that could benefit from a brass capsule as well.
 

lampas

Well-known member
Joined
Nov 12, 2008
Messages
192
@lampas Yeah, that sounds awesome. Did you use NOS resistors? Where did you get the MBHO capsule from. I heard they don't sell the capsules for DIY projects.

No I did not. I did use resistor from Chunger shop.
 

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