[FEELER] C12 Clone Project

[JessJackson]

Cheers!

I received my kits today... I really appreciate fast shipping and the amount of time and work you've put into this, its an amazing kit you've put together. I'm going to start putting it together asap. I just need a Tim capsule.

The head basket does look amazing thought regardless of the bends. I cant wait to finish these and compare them to my vintage c12s. make a few records with them first... asthetics can be changed later down the line.

Best,

Jess

Hi Jess,

Perfection comes with a price. . . we are operating in the real world here.

Low Cost
Perfect Quality
Fast Production

Choose any 2. 

Can I make a headbasket myself to a higher level of fit/finish?  Yes. . . it would take forever.  You are welcome to buy a Flea body kit and I'm sure you will find a better specification and manufacture tolerance there.  What I'm trying to do here is strike a balance and give proper priority to the non-negotiable tone elements (capsule, tube, transformer), and for the rest of it, keep things reasonably priced and functional.  Your priorities are probably different, and your mic locker undoubtedly reflects these differing priorities.

If I'm building an heirloom firearm or race car engine the standards would be set to a completely different standard.  Looking at this headbasket from those standards, I can certainly pick it apart point by point. . . slight mis-alignment here, a nick or scratch in the metal surface there, a corner that has not been perfectly beveled, the radius of the hoop not exact, the straight portions of the brass bar not exact.  Is it fair for me to demand all of these issues be resolved to perfection at the price point the factory is producing these at?  No.

I did not start this headbasket project by saying to myself, "I want to make the highest quality headbasket I can have".  I started by creating a general look and function that I am after and finding a factory that would build it for me to a slightly better standard on average than the bodies I import at a price that would allow everyone that wants one to have one.

Sorry to disappoint you, and you are correct.  None of the sample headbaskets are perfect, and I did not photograph the best copy.  That was on purpose.  I do not want to mis-lead anybody, but chose a "mid-level" sample to accurately represent what I feel will be a representative of the final product that I will be shipping to people.  This is why I requested 6 headbaskets for sample verification instead of the usual 1.  I wanted to see the slight variations between them to get a better understanding of what to expect in a large run.

Hi chunger, i'm a bit of perfectionist when it comes to these things... so apologies for nit picking.

In terms of the basket shape, it does look more bent in your other image from your build thread. although i'm sure i can have it aligned and soldered from the inside.

Best,

Jess

 

[micaddict]

John Willett, over at the Gearslutz forum, directed me to this 1954 BBC review of the AKG C12:
http://downloads.bbc.co.uk/rd/pubs/reports/1954-41.pdf

Great stuff.

One bit that hit me was this:

"Mechanical protection and electrical 'screening are afforded by an outer
case of fine wire gauze sandwiched between two layers of coarse gauze."

 

[tonycamp]

Addict!

What an awesome find!

thanx
T

 

[mulletchuck]

lol geez, those guys weren't very kind talking about that mic..

The effect of "spikiness" noticed in speech transmitted from a non-reverberaitlt room was probably due to the fall in the 5 to 7 kc/s region followed by the "sharp recovery at 9 kc/so

 

[micaddict]

lol geez, those guys weren't very kind talking about that mic..

It's quite positive compared to their U47 report, actually. 

http://downloads.bbc.co.uk/rd/pubs/reports/1954-23.pdf

 

[Biasrocks]

It's quite positive compared to their U47 report, actually. 

I dunno, read the review of the U47 for orchestral recording, it handily beat out the M49!

Regards.
Mark

 

[Telefunken_Guy]

I would to order a C12 pcb set, please.  Thanks.

 

[Pip]

Go to these web sites.

http://store.studio939.com/
http://www.groupdiy.com/microphones/official-c12-clone-build-and-support-thread/
http://www.carvinguitars.com/group/studio_microphones

Its an awesome build enjoy!

 

[Cgaines]

I read in an earlier post that there was contemplation of a 251 clone as well. Is this still in the plans?

 

[chunger]

I read in an earlier post that there was contemplation of a 251 clone as well. Is this still in the plans?

The plan right now is to build a hybrid 251 microphone on the same PCB and see how it performs.  As I understand it, with simple component changes, we can get the preamp circuit very close to the original ELA configuration with the only major change being the way the capsule is polarized.  Matador feels this difference in polarizing setup should not effect sonics.  The ela utilizes isolated backplate capsule and switches pattern on the microphone.  Tim Campbell's capsule can accomodate this original configuration, but I prefer to retain the 9 pattern setup switching pattern at the psu.

This is the plan right now.  Matador will likely build the first prototype to iron out the technical kinks and I will follow up with another complete build tutorial building the microphone in this configuration.

 

[JessJackson]

I read in an earlier post that there was contemplation of a 251 clone as well. Is this still in the plans?

The plan right now is to build a hybrid 251 microphone on the same PCB and see how it performs.  As I understand it, with simple component changes, we can get the preamp circuit very close to the original ELA configuration with the only major change being the way the capsule is polarized.  Matador feels this difference in polarizing setup should not effect sonics.  The ela utilizes isolated backplate capsule and switches pattern on the microphone.  Tim Campbell's capsule can accomodate this original configuration, but I prefer to retain the 9 pattern setup switching pattern at the psu.

This is the plan right now.  Matador will likely build the first prototype to iron out the technical kinks and I will follow up with another complete build tutorial building the microphone in this configuration.

looking foward to it!

RE: keeping pattern selector on PS, the m49 had a cardioid only switch for 4db better s/n avoiding PS polar pattern switch. Matador seems to think it wont effect the 251 circuit but will it? We should try and keep it as true to schematic as possible.

J

 

[mulletchuck]

anyone shot this guy out with a real C12 using a Tim Campbell capsule or similar hi-end capsule?

 

[chunger]

RE: keeping pattern selector on PS, the m49 had a cardioid only switch for 4db better s/n avoiding PS polar pattern switch. Matador seems to think it wont effect the 251 circuit but will it? We should try and keep it as true to schematic as possible.

J

It's hard to know if something is effecting sonics in an unanticipated way without building 2 with the only change being the feature in question.  My personal preference is to retain the 9 pattern setup for 2 reasons:

1.  Flexibility in mic use
2.  ease of build (a pattern switch would need to be hacked in to the HT-11A body to be true to the ELA's polarizing scheme)

The PCB layout is essentially a turret board and Matador made provisions on it to utilizethe isolated backplates on Tim's capsule so I believe it would be possible to build very close to if not exact to the ELA M251 original circuit.  . . but I should let Matador confirm or see if any PCB hacking is required.  As I discovered building one of the early prototypes, hacking the first prototype PCB was actually quite fun.

 

[micaddict]

Chunger wrote:

My personal preference is to retain the 9 pattern setup

Yes, but the thing is you don't have to lose that. Comparing pattern switching on the body (Ela M251) to remote (C12) is one thing. However, the cardioid only switch is and extra feature, added to the remote setup. Here's an example:

Poctop wrote:

All M49 models after 1957 had a “cardioid only” switch built in, to achieve a 4dB s/n improvement [as compared to setting the pattern] remotely, from the power supply.

More info in his build thread, e.g. reply #132.

And here's another example:
http://www.wunderaudio.com/cm7-gt.html

 

[Treelady]

From a May 2013 perspective, is there a timeframe update on the next run of head baskets?  Thanks.

 

[chunger]

From a May 2013 perspective, is there a timeframe update on the next run of head baskets?  Thanks.

They arrive on Monday according to my Fedex tracking.

 

[mulletchuck]

What about mic bodies?

 

[Matador]

What about mic bodies?

Check Chunger's White Market thread:  he keeps updating it with the latest lead times as far as I can tell.

 

[Reverend]

I'm doing the C12 project and I'm stuck on the power supply. Everything is in, but my DMM isn't reading any voltage. I'm thinking that I have a problem with the stock transformer in the Apex 460 power supply box. Any suggestions? Re-solder? Is there a replacement transformer that will fit? Thanks.

 

[Pip]

I'm doing the C12 project and I'm stuck on the power supply. Everything is in, but my DMM isn't reading any voltage. I'm thinking that I have a problem with the stock transformer in the Apex 460 power supply box. Any suggestions? Re-solder? Is there a replacement transformer that will fit? Thanks.

Which Donor are you using and have you checked to make sure that the fuse and the voltage selector switch are working and are on the correct voltage for your country. Not all the donors that are out there have the same output wires in the same place check that you have the 200VAC side and the 9VAC side correct.