Official C12 Clone - Build and Support Thread

[Mikael-ange]

yea
I've built 2 of the c12 with gutting the 460, I would open them up, but they are both in use elsewhere.
I was hoping to build another with a more robust looking p/s case.
I was just needing the model# of the xformer it uses, I have all the other parts.
I looked in mouser and digikey but I couldn't find a dual 200v/9v secondary.
I'll get a 460 from one of the vendors here.
thanks

Others option is the t.bone psu (cheaper in europe), or go for a custom toroidal transformer.
But I don't know any adress in the us for that, and total cost between xformer/shipping/import tax would probably be the same as an apex psu.

 

[donivan]

thanks M
460 is the practical way to go

 

[Delta Sigma]

yea
I've built 2 of the c12 with gutting the 460, I would open them up, but they are both in use elsewhere.
I was hoping to build another with a more robust looking p/s case.
I was just needing the model# of the xformer it uses, I have all the other parts.
I looked in mouser and digikey but I couldn't find a dual 200v/9v secondary.
I'll get a 460 from one of the vendors here.
thanks

Collective cases tube mic PS case is reasonably priced. Look at the Mouser carts from Dany's projects. You should be able to find the Hammond part numbers (like 187B36) for heater supply and Triad part numbers for B+. This would more than double the PS cost, but they do look a lot nicer. It also gives you more room for filtered AC input, ground switches, cardioid only relay circuits, etc.

 

[donivan]

thank you
that helps

 

[donivan]

I got the c-12 kit from chunger
but the silk screen/schem. calls for a 5mm 4700uf 25v elect. cap at c10
what was sent with the package was a 15mm
mouser or digikey doesn't carry a small 4700
this is the new vrs. pcb from matador
I contacted chunger about this but no reply yet
anyone else with this issue?

 

[donivan]

c10 in the p/s

 

[Mikael-ange]

I got the c-12 kit from chunger
but the silk screen/schem. calls for a 5mm 4700uf 25v elect. cap at c10
what was sent with the package was a 15mm
mouser or digikey doesn't carry a small 4700
this is the new vrs. pcb from matador
I contacted chunger about this but no reply yet
anyone else with this issue?

Hello
I just opened mine for a quick check and cap are 15mm and no problem.
Btw the new psu build thread is here :Official Universal Passive Tube PSU Thread

Hope that help

 

[donivan]

Thanks Mikael
I'll move this over there
this is the p/s PCB that came from chunger

 

[donivan]

I'm hoping Chunger or Matador would have an answer

 

[Mikael-ange]

Thanks Mikael
I'll move this over there
this is the p/s PCB that came from chunger

Mine is a v1.4 purchased on december 2022. So a revision below yours

 

[donivan]

according to Matador , c-10 is not needed

also(off topic) I've read in a couple of places that you should seal the h-iz part of the pcb with a comformal coating
is that necessary and if so what would be the procedure, before the components are populated or after
and if after ,you wouldn't coat the components right?

 

[Matador]

I've read in a couple of places that you should seal the h-iz part of the pcb with a comformal coating

Not needed. The board itself is made of a composite ceramic substrate, with a polymerized soldermask over top. Provided it's clean, it's far better than even teflon.

 

[donivan]

thanks

 

[DuBmastah]

Happy new year everyone

I'm definatly stuck with this build.
There was no problem builind the PSU, but for the mic itself its another story
After spending numerous hours trying anything i could to make it work, my last option is to gather help from the community...

- First, the mic itself was previously working perfectly (microphone-parts "Fox 460" kit + peluso capsule + GE 6072A NOS tube).
- After building the Matador PSU kit, it was still working perfectly with it.
- Then i removed the Fox 460 stuff and keeped the capsule and transformer.
- I populated the Matador V1.4 PCB from 2021 with the provided components
- I putted everything together and... Get NO sound at all !

I then tested everything i could like : exchanging the capsule for a chinese Apex 460, exchanging the tube for a EA 6072A, Exchanging the power supply, cables... all for "known as working" ones...
Still no sound.

I checked the voltages at the mic and got (with modded PSU) :
- Pin 1 -> P5 (B+) = 120V
- Pin 2 -> P8 (heater) = 6,3V (6,6V with other PSU)
- Pin 3 -> P3 (polar pattern) = 0V to 96V (about 44V at cardioid position)
- Pin 4 -> P4 (bias) = -1.03V (0V with other PSU)
- Pin 5 and 6 are the audio from the transformer secondary, i could read 50,3Ω beetween them
- XP1 and XP2 are linked to the transformer primary, i could read 714Ω beetween them

From what i understand, those values might be correct, right ?
So what am i doing wrong? I'm not absolutly sure about the tube socket wiring, so i attached detailled pics of the build, maybe you could see something wrong somewhere ?

Many thanks in advance.

 

[Delta Sigma]

Is the cable pinout the same? From the Fox PSU to the Matador.

 

[DuBmastah]

Is the cable pinout the same? From the Fox PSU to the Matador.

I'm not pretty sure i understand the question.
But since i removed all the Fox stuff (that is basically a DIY kit for the Apex460), my guess is that the pinout is more or less the same. At least, the modded PSU by matador was working fine with the Fox 460 mod by MicParts.
One thing i could say is that the actual pinout is as stated above :
Pin 1 : B+
Pin 2 : heater
Pin 3 : polar pattern
Pin 4 : bias
Pin 5 : audio-
Pin 6 : audio+
Pin 7 : ground
I also use another PSU that i got from a shop and the pinout is the same (at least i'm not sure you can tweak the voltages to your needs as the Matador version does).

 

[DuBmastah]

At this point, i checked everything back an excessive amount of times, spending days on it.
I just don't get where the problem might be.

I have doubts on :
- Is the wiring of the tube correct ? (the PCB is rev 1.4 and i can't see nowhere a detailled pic of this zone)
- Could the transformer be a problem ? (like not suitable for this build, or improperly wired ?
- Is there a faulty component somewhere ? (then what components could it be and how to test them ?)

I doubt there could be a bad soldier joint somewhere as i traced the whole thing with my multimeter without finding any.

 

[Mikael-ange]

Hello
First I will resolder the connection between k1 and turret on the main board (if you zoom in on your pic, you can see the wire solder on the turret isn't pretty at all).

Second do you check your heater at the tube socket?
If that not the case do it and report back please.

Good luck

 

[DuBmastah]

Hello
First I will resolder the connection between k1 and turret on the main board (if you zoom in on your pic, you can see the wire solder on the turret isn't pretty at all).
Second do you check your heater at the tube socket?
If that not the case do it and report back please.

Good luck

Thanks for helping

Will resolder that point.
I had 6.3V at the tube socket (hoping this is the correct pin of the socket) ?

 

[DuBmastah]

Solder joint at the turret has been updated (at least it was OK at first, showing continuity on the multimeter).

Now, as i have exactly no clue how a tube works, i'm not 100% sure of the pinout.
But this is what i got at the tube sockets pins :
- Pin 1 (P1) : 110V (B+ was 120, unloaded at the PSU)
- Pin 2 (hole) : -67mV (bias was -1V at the PSU)
- Pin 3 (K1) : grounded
- Pin 4 : 6.30V (heater was 6.30V at the PSU)
- Pin 5 : not used (should be ground if zero ohm resistor present on this side)
- Pin 6 (P2) : not used
- Pin 7 (hole) : not used
- Pin 8 (K2) : not used
- Pin 9 : going to ground (but i'm not sure if it should be isolated or not, that's not pretty clear seing the traces on the PCB).
If someone could comfirm the pinout is correct ?

... And another newbie question :
XP1 and XP2 are the transformer primary connections, right ?
Assuming XP2 goes to ground i guess this one is "audio-" and XP1 is "Audio+" ?
Any chance the transformer could have a polarity and i have to invert cables from one side or another to get audio ?
I know this might sound like a total dumb question for most of you, sorry