Official C12 Clone - Build and Support Thread

[Matador]

Guys, quick question.
I'm trying to understand what Chunger is trying to achieve when he wired 2 cables to one of the backplates and then to FB and RB on the PCB.
I may have misunderstood the drawing.

He also says it's optional.

right now, I have the front "back" plate wired to FB. do I need to jump FB to RB or do I need to run a second cable from RB (capsule) to RB (PCB)?

.... am I making sense?

It's an either/or thing.  You can bridge the FB and RB right at the capsule (the preferred way), or you can bridge them at the PCB.  Bridging in both places neither helps nor hurts.  If you have a capsule with a single backplate you don't have to run two wires, and you can bridge them right at the PCB.

I debated making them a single PCB connection but figured people wanted the connections as close to the original as possible.

 

[Phrazemaster]

Does anybody know where I could acquire one of Tim's CK12 capsules? I've tried several emails with no response

Thanks!
Aaron

Hey Aaron/Phraze,

I thought the same also, but if you haven't received a response confirming you are on the list, then you are not on the list. At least this is what Tim told me about 6 weeks ago. Good luck!

Cheers,

Matt

Thanks Matt. I guess I'm not on the list then. I may get a Sneesby C12 then; his work looks top notch.

Mike

 

[jplebre]

Guys, quick question.
I'm trying to understand what Chunger is trying to achieve when he wired 2 cables to one of the backplates and then to FB and RB on the PCB.
I may have misunderstood the drawing.

He also says it's optional.

right now, I have the front "back" plate wired to FB. do I need to jump FB to RB or do I need to run a second cable from RB (capsule) to RB (PCB)?

.... am I making sense?

It's an either/or thing.  You can bridge the FB and RB right at the capsule (the preferred way), or you can bridge them at the PCB.  Bridging in both places neither helps nor hurts.  If you have a capsule with a single backplate you don't have to run two wires, and you can bridge them right at the PCB.

I debated making them a single PCB connection but figured people wanted the connections as close to the original as possible.

Thank you!
Would this also matter for capsules like the stock Alctron with 2 separate backplates (no continuity between the 2 backplate screw holes)?
Is the objective to bridge them both?
What would happen if one of them is not?

Just trying to understand a bit better what I'm about to do. I don't like it when it becomes to simple as I learn less

 

[Matador]

Thank you!
Would this also matter for capsules like the stock Alctron with 2 separate backplates (no continuity between the 2 backplate screw holes)?
Is the objective to bridge them both?
What would happen if one of them is not?

Just trying to understand a bit better what I'm about to do. I don't like it when it becomes to simple as I learn less

The net-net is that you need to convert any 2 backplate capsule into a single backplate capsule with a wire bridge.  The single-backplate scheme is implicit in the design of the C12.

Here is my preference (and it really is just a preference: the electrons don't care ):  run the FB wire from the FB turret to the FB of the capsule.  So the same with a second wire from RB to RB of the capsule.  Then run a jumper wire across the two terminals on the capsule itself.  That is also what is documented in Chunger's build pics.

For those with a single backplate capsule:  run a single wire from FB to the capsule backplate.  Then run a jumper from the FB turret to the RB turret right on the PCB itself.

 

[Matador]

Here's another way to conceptualize what is going on.

The node/turret labelled "RB" is connected to the junction of the two 499K resistors to B+.  These form a 50% voltage divider and provide a 60V reference to polarize the backplate.  Put a little piece of tape over the PCB "RB" label in your mind, and write "Backplate Polarization Send".

The node/turret labelled "FB" is connected to the gate coupling capacitor that goes to the grid.  Put another little piece of tape over the "FB" label in your mind that says "Backplate signal tap".  So a wire from RB to the capsule sends the "power", and the wire back to FB taps the signal and allows it to be amplified.

Because the capsule is supposed to be a single metal piece (from an electrical point of view), this all works.  If you have a capsule with isolated backplates, they need to be jumpered together to make them "a single metal piece".

 

[chunger]

Does anybody know where I could acquire one of Tim's CK12 capsules? I've tried several emails with no response

Thanks!
Aaron

From what I hear this is normal...you probably will get an email in x number of weeks saying your capsule is done...at least that's what I read from another guy. I also sent Tim a request for a CK12 but did not get a response; but again I think this is because he is so incredibly backlogged...guy is in high demand.

This is NOT the case. . . you are only on the build list if you receive a confirmation email from Tim.  He may or may not be accepting new orders at this time from the DIY community.  Right now, it would be very difficult to get into the build queue as Tim does not seem to respond to all email requests when he has a full backlog of orders that need to be filled.

 

[Phrazemaster]

OK...thanks for clarifying that 'Chung. Would be nice from a customer standpoint to know such things, as now I will look for other sources, but I understand he is a world class capsule maker, a one-man shop, and he is crazy busy.

Thanks,

Mike

 

[Woot]

[/quote]
Thanks Matt. I guess I'm not on the list then. I may get a Sneesby C12 then; his work looks top notch.

Mike
[/quote]

Ill be receiving a pair of Bens C12'sin a couple of weeks which I will drop into these c12's. I was intending on posting some samples soon after.

 

[jplebre]

Thank you Mat now it makes perfect sense!

 

[Tim Campbell]

This is one of the few forums that I actually consider myself a member of and so I'm so sorry to have inconvenienced any of you.
Contrary to what some of you may imagine that I'm lying under a palm tree, waited on by bikini clad women building a capsule or two when the mood strikes me I actually work round the clock and produce a steady and growing amount of capsules every month.
I have been hesitant to contact inquirers for my capsules because I am currently swamped with orders and have no way of giving a realistic time frame for when I could deliver. Some of my private customers have waited months and still are unsure when they'll receive their capsule.
My OEM customer accounts must always be serviced first because their business' rely on having a product in time. Those OEM orders have been growing exponentially of late, slowing down delivery to private customers.
I'm am honestly doing all I can to increase my output and hope to have a solution soon.
I am honestly sorry about the delays. If you're still interested please contact me in a month or two.
Kind regards,
Tim

 

[tonycamp]

This is one of the few forums that I actually consider myself a member of and so I'm so sorry to have inconvenienced any of you.
Contrary to what some of you may imagine that I'm lying under a palm tree, waited on by bikini clad women building a capsule or two when the mood strikes me I actually work round the clock and produce a steady and growing amount of capsules every month.
I have been hesitant to contact inquirers for my capsules because I am currently swamped with orders and have no way of giving a realistic time frame for when I could deliver. Some of my private customers have waited months and still are unsure when they'll receive their capsule.
My OEM customer accounts must always be serviced first because their business' rely on having a product in time. Those OEM orders have been growing exponentially of late, slowing down delivery to private customers.
I'm am honestly doing all I can to increase my output and hope to have a solution soon.
I am honestly sorry about the delays. If you're still interested please contact me in a month or two.
Kind regards,
Tim

Tim, it's all good man, don't compromise the way you do things, your capsules are things of beauty, i'm looking for 2 more, i'll contact you in a month or so, and be happy to get em when i get em.

thanx for building the best
T

 

[Phrazemaster]

This is one of the few forums that I actually consider myself a member of and so I'm so sorry to have inconvenienced any of you.
Contrary to what some of you may imagine that I'm lying under a palm tree, waited on by bikini clad women building a capsule or two when the mood strikes me I actually work round the clock and produce a steady and growing amount of capsules every month.
I have been hesitant to contact inquirers for my capsules because I am currently swamped with orders and have no way of giving a realistic time frame for when I could deliver. Some of my private customers have waited months and still are unsure when they'll receive their capsule.
My OEM customer accounts must always be serviced first because their business' rely on having a product in time. Those OEM orders have been growing exponentially of late, slowing down delivery to private customers.
I'm am honestly doing all I can to increase my output and hope to have a solution soon.
I am honestly sorry about the delays. If you're still interested please contact me in a month or two.
Kind regards,
Tim

Hi Tim, I have great respect for your situation, and looked at differently, this is the result of being absolutely phenomenal at what you do! So congrats are in order, although the day-to-day experience for you is currently mounting work and increasing delivery times. Time to increase prices/limit customers? Or perhaps take on some apprentices to help with the work? You have entered the world of the elite highly sought after, well done.

I feel no unkindness towards you for not responding; I understand and I will try contacting you in a month or two as I'd love to have one of your capsules too.

Thanks for your many contributions and we appreciate you here buddy.

Best,

Mike

 

[micaddict]

+1



Henk

 

[robomatique]

Hi,

Another one with a problem...

FInished my vuild yeaterday but have some porblems:

1. B+ only goes up to 115 or so, I will change R1 and R2 to 75k as suggested elsewhere. I have a lot of 0,1W resistors at hand, would that work or should I get 0,25W as in the kit?

2. The output is extremely low and does not have any bottom/bass at all. I can't hardly to get the microphone to distort with my simple yamaha soundcard preamp with 60db of gain. Everything seems to be wired correctly so I am worried that the (Campbell) capsule is dead (had problems when bridging the backplates so I heated more than I usually do) or... anything else? Where do you think I should start looking?

For the info I use a 6072a tube and the polar patterns seems to work correctly. The voktages seem ok except for B+ is 115V (which I will fix but I guess it is not the major problem here). The oputput transformer was measured and has been checked, it should be wired correctly. Just the low output/no bass problem that I have no clue about...

 

[pasarski]

...The output is extremely low and does not have any bottom/bass at all....

Could be transformer hooked up incorrectly.

...I am worried that the (Campbell) capsule is dead (had problems when bridging the backplates so I heated more than I usually do) or...

Not sure but doesn't seem like a capsule problem, because:

...polar patterns seems to work correctly...

...The oputput transformer was measured and has been checked, it should be wired correctly...

I would double check.

One thing to check for is if anything is touching the mic casing?  Is it buzzing as loud as your other condensers with out the body tube or is the buzz also reduced in level?

 

[Tim Campbell]

"2. The output is extremely low and does not have any bottom/bass at all. I can't hardly to get the microphone to distort with my simple yamaha soundcard preamp with 60db of gain. Everything seems to be wired correctly so I am worried that the (Campbell) capsule is dead (had problems when bridging the backplates so I heated more than I usually do) or... anything else? Where do you think I should start looking?"

You should never be heating the capsule. That's what the solder tags are for.  Turn on the mic without the headbasket and make sure the membranes aren't collapsing ( your description sounds like this). If they are, it could be caused by damage, incorrectly wiring the capsule, or incorrect polarization voltage (most likely). Too high a polarization voltage can over time cause permanent damage to the membranes.

 

[robomatique]

Thanks for your answers!

I guess it is not the capsule (phew) as the polar patterns work correctly and the membranes looks as they should when powered on!

So far so good!

I will try to hook up the T14 again, but I have already tripkle checked it, measuring the output at the pins I get the 20R as expected and I remember that I measured the primary before mounting it and that it was correct.

Assuming it is not the T14, anyone has any suggestions? I can also mention that it not onlly have lost the bass/bottom, the highs are very present, much more treble than expected...

Thanks agian for your help on this!!!

Robert

 

[robomatique]

One thing to check for is if anything is touching the mic casing?  Is it buzzing as loud as your other condensers with out the body tube or is the buzz also reduced in level?

I get a lot of hum without the body tube...?

THanks!!!

 

[pasarski]

One thing to check for is if anything is touching the mic casing?  Is it buzzing as loud as your other condensers with out the body tube or is the buzz also reduced in level?

I get a lot of hum without the body tube...?

THanks!!!

Not sure about my reasoning, but that could imply it's not the trafo, the hum would be low level also.

 

[RuudNL]

I have the intention to build a C12, but I still have one question:

The capsule boosts the higher frequencies (just like a K67 capsule).
In the schematic there is no de-emphasis or other frequency correction.
Won't this microphone sound 'over bright'?
Would it be an idea to add a capacitor between the anode and ground (just as in the ELA M251) to roll-off the HF a bit?

(Sorry, but I did not read all 247 posts...)