Ericbazaar

Re: Official C12 Clone - Build and Support Thread
« Reply #400 on: May 24, 2013, 05:56:07 AM »
I have make detailed Pictures of the CT 12 Capsule and the Connections. I think its all ok.


Ericbazaar

Re: Official C12 Clone - Build and Support Thread
« Reply #401 on: May 24, 2013, 06:00:42 AM »
and another…

Ericbazaar

Re: Official C12 Clone - Build and Support Thread
« Reply #402 on: May 24, 2013, 06:01:52 AM »
again

Ericbazaar

Re: Official C12 Clone - Build and Support Thread
« Reply #403 on: May 24, 2013, 06:04:05 AM »
I just want to make sure that the capsule is ok ...

Ericbazaar

Re: Official C12 Clone - Build and Support Thread
« Reply #404 on: May 24, 2013, 06:27:33 AM »
I have all connections checked, xlr, tube cable, i have build a new cable from Cable company "Sommer Cable" from Netherlands and Neutrix Connectors. Double checked, all ok! I think the best Option is order a new PCB and Part Set? The search makes me mad :'( I have build last Week a Lola Mic Pre, this thing works without problems. although this thing has 1000 parts…dammit
« Last Edit: May 24, 2013, 09:11:17 AM by Ericbazaar »

tonycamp

Re: Official C12 Clone - Build and Support Thread
« Reply #405 on: May 24, 2013, 12:57:44 PM »
I have all connections checked, xlr, tube cable, i have build a new cable from Cable company "Sommer Cable" from Netherlands and Neutrix Connectors. Double checked, all ok! I think the best Option is order a new PCB and Part Set? The search makes me mad :'( I have build last Week a Lola Mic Pre, this thing works without problems. although this thing has 1000 parts…dammit

right or wrong, i bridged my backplates AT THE CAPSULE?, working really great.

good luck
T

Ericbazaar

Re: Official C12 Clone - Build and Support Thread
« Reply #406 on: May 24, 2013, 01:06:12 PM »


right or wrong, i bridged my backplates AT THE CAPSULE?, working really great.

good luck
T

have you bridge the pins or on the capsule?

tonycamp

Re: Official C12 Clone - Build and Support Thread
« Reply #407 on: May 24, 2013, 01:27:31 PM »


right or wrong, i bridged my backplates AT THE CAPSULE?, working really great.

good luck
T

have you bridge the pins or on the capsule?

on the capsule, used a .25 watt resistor leg cut off.

strangeandbouncy

Re: Official C12 Clone - Build and Support Thread
« Reply #408 on: May 24, 2013, 01:50:34 PM »
HI,


   I didn't hear it at first, because I had a foam popshield over the headbasket. But I found a slight ring when I actually used it on a vocal "under fire". I put a thin sausage of BluTacK around the inside at the base.


    Sorted! It will probably still be there in 50 years. I probably won't!


      ANdyP
« Last Edit: May 24, 2013, 02:32:46 PM by strangeandbouncy »
. . . . RUH ROH . . . . .

Matador

Re: Official C12 Clone - Build and Support Thread
« Reply #409 on: May 24, 2013, 07:10:46 PM »

right or wrong, i bridged my backplates AT THE CAPSULE?, working really great.

good luck
T

This.

If you tie it together at the capsule, then you have separate wires from FB and RB.  If it's tied together at the PCB, then there should be a wire bridge between FB and RB right on the teflon turrets.


Matador

Re: Official C12 Clone - Build and Support Thread
« Reply #410 on: May 24, 2013, 07:14:59 PM »
This first page shows the bridging of the two backplates:



...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...

NTJEvan

Re: Official C12 Clone - Build and Support Thread
« Reply #411 on: May 24, 2013, 08:47:56 PM »
So i've got the mini-pot backed all the way out, but i cant seem to get the B+ voltage below ~124v This is while strictly function testing with the factory 12ax7 and capsule, but I dont want to put the good parts in and risk roasting them. Any ideas at what I could have done wrong?

Also, does anyone have a source for the 7 pin XLR plug that is inside the mic? I'm thinking about upgrading the factory jacks to neutrik or switchcraft parts, but I havent had any luck finding the raw in-mic parts?

JessJackson

Re: Official C12 Clone - Build and Support Thread
« Reply #412 on: May 24, 2013, 10:23:02 PM »
i have the same very low output problem yet i have bridged my backplates at the teflon pins.

I have checked continuity from the pins to the backplates etc.. and everything seems fine with no contamination. My transformer is wired correctly and my voltages seem fine.

This is seriously boggling me for the past week.

Matador

Re: Official C12 Clone - Build and Support Thread
« Reply #413 on: May 24, 2013, 10:54:22 PM »
i have the same very low output problem yet i have bridged my backplates at the teflon pins.

I have checked continuity from the pins to the backplates etc.. and everything seems fine with no contamination. My transformer is wired correctly and my voltages seem fine.

This is seriously boggling me for the past week.

What kind of diagnostic equipment do you have access to?

Can you confirm the printing on the plate load resistor R17?

JessJackson

Re: Official C12 Clone - Build and Support Thread
« Reply #414 on: May 25, 2013, 07:10:52 AM »
i have the same very low output problem yet i have bridged my backplates at the teflon pins.

I have checked continuity from the pins to the backplates etc.. and everything seems fine with no contamination. My transformer is wired correctly and my voltages seem fine.

This is seriously boggling me for the past week.

What kind of diagnostic equipment do you have access to?

Can you confirm the printing on the plate load resistor R17?

hi matador, i have the dale 100k resistor there

i have ddm oscilloscope and sine wave gen

i found this post on klaus forum with someone else who was down 20db a few years ago

Quote
Okay, here's where I'm at. The "cackle" was just a bad cable. For the life of me I couldn't trace the problem of the low output. So out of desperation I reversed the transformer connections, and viola - proper output.

I'm wondering if I can get an explanation. I assumed the secondary connected to the audio output. I assumed the 14/1 xformer was a step up xformer and measured the resistance of the leads and concluded the higher resistance would be the secondary.

So is the t14/1 actually a step down xformer for some sort of impedance matching function with the tube, or am I confused about something? Because as it stands now, the low resistance leads connect to the audio output and all seems working properly.

But my x-former does have the lower resistance value as secondary.

JessJackson

Re: Official C12 Clone - Build and Support Thread
« Reply #415 on: May 25, 2013, 07:14:44 AM »
could it be that the left primary and left secondary aren't wound that way? there is red and blue on left and red and blue on right side but  maybe they are swapped inside transformer?

Tim Campbell

Re: Official C12 Clone - Build and Support Thread
« Reply #416 on: May 25, 2013, 07:51:59 AM »
Eric, from looking at your pictures, Have you done something to the posts above the solder tags leading to the backplates? Perhaps soldered to them or filed them?

Ericbazaar

Re: Official C12 Clone - Build and Support Thread
« Reply #417 on: May 25, 2013, 08:11:22 AM »
Eric, from looking at your pictures, Have you done something to the posts above the solder tags leading to the backplates? Perhaps soldered to them or filed them?

i have solder with your Cover and i have double secure with tapes, i solder quick. and now i have brigde RB and FB, now the mic works with all pattern. your capsule works beautiful and i test the sound in the next few weeks. God damn…this was a strange projekt, I'll take the microphone with in grave ;D.

Tim, Matador and Chunger thanks for your help

ericbazaar
« Last Edit: May 25, 2013, 01:35:29 PM by Ericbazaar »

Matador

Re: Official C12 Clone - Build and Support Thread
« Reply #418 on: May 26, 2013, 10:37:12 PM »
hi matador, i have the dale 100k resistor there

i have ddm oscilloscope and sine wave gen

Ok, let's try this:  disconnect the capsule lead connected to FB (the one that leads to C13).  Inject a ground-referenced 1V peak-to-peak sine wave into this node (right at the teflon standoff labeled "FB").  Then read the peak-to-peak voltage coming out of the XLR jack that goes to your preamp.

You should be about 5-6dB of gain through the entire chain to the output jack.  If the signal is way low, move the injection point right to the tube grid (pin2 or pin7 depending on which half of the tube you picked).

Let's start there and we'll debug from there.

Re: Official C12 Clone - Build and Support Thread
« Reply #419 on: May 27, 2013, 09:13:22 PM »
Does anybody make nice boxes for these mics?
Seth

The definition of insanity: "Hey, this thing could be really cool - if I had the money to fix it up, which I don't, but if I did it could be really cool - if I had the time, which I don't, but


 

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