Official C12 Clone - Build and Support Thread

[saxmonster]

its there in the build

"The CT12 capsule has isolated backplates which we will bridge together at the solder terminals on the capsule.  With this capsule being scavenged from a previous prototype, Matador already soldered in wires for the front diaphragm, rear diaphragm, front/rear backplates, as well as bridge the front and rear backplates together."

http://studio939.zenfolio.com/img/s8/v75/p1456848224-4.jpg

 

[icemanaman]

Thanks saxmonster, that explains a lot! Really appreciate you showing me with picture and all!
I bought the Heiserman capsules from chunger.
I don't have the capsules in front of my right now.. but as I can remember, this is what came with the capsule:
Capsule, 4 leads with solderpads, 2 screws, 1 capsule mount.

So, I can just remove one of the screws from the rim of the front capsule, put in on lead, and then screw that screw back in??

I would double check with Eric on taking out the screw,  I wouldn't want to change the tension on the membrane but if it has to be done then kind of feel how tight it is when you first take out the screw so you can get it somewhat close to the original tension that the screw originally had.  I never had to do this so not too sure about it yet, on another mic I have one of tim's capsules and he had the solder tabs already installed on the rims of the capsule so all I had to do with solder my connections to that.

Can someone guide me with this?
Just noticed, looking at the Heiserman capsule, one side has more screws than the other, so there must be a front and read?

 

[Tim Campbell]

I can't speak for Eric (and really any questions about his capsules should be directed towards him). I set up my capsules with the side with extra screws as the front. This is also the way AKG did it. Really though listen to both sides and pick the one you like most as the front.

 

[icemanaman]

I can't speak for Eric (and really any questions about his capsules should be directed towards him). I set up my capsules with the side with extra screws as the front. This is also the way AKG did it. Really though listen to both sides and pick the one you like most as the front.

Thank you Tim! But will removing one screw loosen the tension of the mylar? or is it safe to remove a screw and reinstall it?

 

[Tim Campbell]

Really any questions about his capsules should be directed towards Eric.

 

[kidvybes]

I have reached out to Eric for response...

 

[icemanaman]

Thanks guys. I heard back from Eric.
Here's what he said:

So the two of the wires go on each backplate edge in a hole with an existing screw in it, the empty holes are for mounting the capsule. Do not use any holes with screws in it for mounting. The other two wires you remove one of the face screws but be mindful one side has three extra screws don't use those....(they hold the capsule sides together)

 

[dipfrik]

Hey C-12 folks,

i got my hands dirty on a Alctron HST-11A.
After reading this thread i have a 1st question regarding the possible capsule.
Because this is my 1st mic project, i want to start with a "budget type" capsule from Chunger's web store.

From what i see, i can choose from a 34MM edge terminated capsule and a 35MM K67 type center terminated capsule. What confuses me is the description on the store webseite. It sounds that the last one, the 35MM capsule is "better" based on the description but only costs $39? copy: "...the sound quality is excellent.".
For the 34MM priced at $70 i read only: "...these capsules are quite good...".

So which one is better?

Thanks, Sven

 

[Matador]

Hey C-12 folks,

i got my hands dirty on a Alctron HST-11A.
After reading this thread i have a 1st question regarding the possible capsule.
Because this is my 1st mic project, i want to start with a "budget type" capsule from Chunger's web store.

From what i see, i can choose from a 34MM edge terminated capsule and a 35MM K67 type center terminated capsule. What confuses me is the description on the store webseite. It sounds that the last one, the 35MM capsule is "better" based on the description but only costs $39? copy: "...the sound quality is excellent.".
For the 34MM priced at $70 i read only: "...these capsules are quite good...".

So which one is better?

Thanks, Sven

It's 'better' in the same way that 'blue' is 'better' than orange.

In general, the K67 center-terminated capsule types aim to get additional midrange detail (in the 1K to 4K range), at the expense of possibly "hyped" highs - this means the response tends to have a significant peak in the 8K-10K range.  Whether or not this is 'bad' is completely up to you.  Some mike designs specifically try to bring down the high peak to give an overall band response that leaves the mids forward while taming down the bass and the very high stuff.  The C12 does *not* do this:  all other things being equal, what the capsule gives is what you'll hear.

The edge-terminated capsule tends to flatten the midrange response, and pushes the "peak" upwards into the 10K+ range.  So you get less midrange emphasis, and more overall flat sound with the "airiness" emphasized.

Again, nobody can tell you what you would want to hear:  I've heard both on this design and I think both sound 'good' in different ways.

 

[dipfrik]

It's 'better' in the same way that 'blue' is 'better' than orange.

Yeah, sorry...i thought the minute ago i posted this reply: "...what a stupid one!"
In other words, i was only confused, why one product feels better "promoted" and still cost only the half of the other one.

But you give me the exact the right answer i was searching for! I think i 'am more a "midrange detail guy".
At this price point i should order both and make a final decision later.

Thanks for your answer, Sven

 

[vinylwall]

Matador, I just wanted to throw my name in here as another who has built this amazing kit.  I had no problems at all with the build and the mic fired up perfectly.  I am currently half way through burn-in and will give a shout out once I use it in a session.  Take care and thanks so much.  Jimi Ray

 

[micaddict]

Dipfrik wrote:

I think i 'am more a "midrange detail guy

Then look into the K47 (and M7) capsule, too. Especially with a flat (no de-emphasis) circuit.

 

[chunger]

Dipfrik wrote:

I think i 'am more a "midrange detail guy

Then look into the K47 (and M7) capsule, too. Especially with a flat (no de-emphasis) circuit.

I am about to build a C12 clone utilizing either a Thiersch Blue Line M7 capsule or Eric Heiserman HK47 capsule because our studio also favors the center terminated capsules for general use microphone, and the C12 is a nice flat-response circuit I feel is conducive to this application.  I have very much liked how both of these capsules sound in MK47 application and want try them in another "clean" circuit with the 9 pattern functionality like C12 and pair it with a larger core transformer.  Cinemag is sending a prototype to me with the appropriate winding soon

 

[dipfrik]

Dipfrik wrote:

I think i 'am more a "midrange detail guy

Then look into the K47 (and M7) capsule, too. Especially with a flat (no de-emphasis) circuit.

I will definitely do that!

Thanks for the advice, Sven

 

[Matador]

I know I've posted it here before, but it bears repeating.

You can get a 'poor mans' de-emphasis by using the ELA M251 plate cap, just picking one of higher value.  If you place a small ceramic cap right where the transformer coupling cap connects to the tube plate (the other end grounded), you can make a simple low-pass filter.  Standard ELA M251 value is 100pF (about 19kHz rolloff), but 470pF will give a 10-12kHz roll-off, and a 1nF will give a 7-8K rolloff.

Picture of where cap goes is here:

So if you find the K67 type a bit too shrill, try this cap as a very cheap alternative/remedy.  I put a 470pF on a switch in one of my prototypes and it was useful on certain sources.

 

[flatresponse]

Thanks guys. I heard back from Eric.
Here's what he said:

So the two of the wires go on each backplate edge in a hole with an existing screw in it, the empty holes are for mounting the capsule. Do not use any holes with screws in it for mounting. The other two wires you remove one of the face screws but be mindful one side has three extra screws don't use those....(they hold the capsule sides together)

Hi icemanaman,

did you finally have the Heiserman capsules working?
I got a pair of C12s from Chung as well with 2 HK12 and I can´t get them to work.
I think I did what you got as advice by Eric - hopefully ...
Good result with another capsule ( Equinox Q-D47 I still had at hand), but no go for the HK12.

Best
Manfred.

 

[icemanaman]

Thanks guys. I heard back from Eric.
Here's what he said:

So the two of the wires go on each backplate edge in a hole with an existing screw in it, the empty holes are for mounting the capsule. Do not use any holes with screws in it for mounting. The other two wires you remove one of the face screws but be mindful one side has three extra screws don't use those....(they hold the capsule sides together)

Hi icemanaman,

did you finally have the Heiserman capsules working?
I got a pair of C12s from Chung as well with 2 HK12 and I can´t get them to work.
I think I did what you got as advice by Eric - hopefully ...
Good result with another capsule ( Equinox Q-D47 I still had at hand), but no go for the HK12.

Best
Manfred.

Hi Flat,
Did you remember to bridge the backplates?
Yeah, the HK12 capsules are working!


BUT, I am having a problem. There is a deviation in high end respons between the two microphones I built.
I built them both step-by-step and they are identical besides the fact that they use different sides of the tube.

So, one of the microphones is sounding noticable darker than the other.
I have never heard a C12, but have read that it is a "bright sounding" mic, so my guess is that the dark sounding mic is the culprit. I put both mics up as close as possible and did some quick recordings, and on of the mic sounds darker. I tried swapping powersupplies, and the same problem. So the problem is defintely in the mic. Haven't tried changing tubes yet. The sound is kind of less present and like it has a eq with perhaps a -5db shelf from 10khz (just guessing here, I haven't confirmed this)

Can someone advise on how to perform troubleshooting for this kind of fault?
Start by switching capsules??

 

[Tim Campbell]

This doesn't sound like a tube problem. Try cleaning everything and check for solder bridges.
If it's easy enough to swap capsules do so. The you'll know. As has been said here many times, capsules can easily sound dissimilar.

 

[Category 5]

This doesn't sound like a tube problem. Try cleaning everything and check for solder bridges.
If it's easy enough to swap capsules do so. The you'll know. As has been said here many times, capsules can easily sound dissimilar.

Not only that though.  You need to clean clean clean the hi-z parts.  And then clean them again and once again.  This makes all the difference in my experience.  This design does not like the faintest but of flux residue. 

 

[kidvybes]

I am about to build a C12 clone utilizing either a Thiersch Blue Line M7 capsule or Eric Heiserman HK47 capsule because our studio also favors the center terminated capsules for general use microphone, and the C12 is a nice flat-response circuit I feel is conducive to this application.  I have very much liked how both of these capsules sound in MK47 application and want try them in another "clean" circuit with the 9 pattern functionality like C12 and pair it with a larger core transformer.  Cinemag is sending a prototype to me with the appropriate winding soon

Yes, I'm looking forward to your thoughts on this...I too have been considering trying an M7 or K47 in the C12 build...why not think outside the box...