Official C12 Clone - Build and Support Thread

[Reverend]

Hey Everyone!
does anyone know what is the best way to assemble Gotham GAC-7 cable? (for the C12 Clone)

Thanks a lot !

I built one. I thought is was a Chunger instruction thread, but I just looked and could not find it. I need it again too. Hope we find it.

 

[chunger]

Hey Everyone!
does anyone know what is the best way to assemble Gotham GAC-7 cable? (for the C12 Clone)

Thanks a lot !

The most important point is to use the 2 large conductors for heater and ground connections.  These are higher current and benefit from the larger conductors provided in specialty cable like the GAC-7 or Mogami products. 

Whether you should tie the shield into the ground connection at the cable is a matter of debate.  I have done so with no apparent ill effects although keeping all connections separate at the pins may be more "correct".

 

[Reverend]

The tube isn't drawing current if the plate voltage is that high:  TP2 should be reading 50(ish) volts.

Assuming the heater is working correctly, and it is indeed heating the "#2" side, please confirm (WITH THE MIKE UNPLUGGED):

1) you have 0 ohms between TK2 and ground.
2) you measure 100K between TP2 and B+ node (this is the plate resistance)

1)With the mic unplugged, with the DMM black lead clipped to the rail of the mic, when I touch TK2, I'm not getting a reading at all, but I may be doing it wrong?
2)I'm measuring 99.5K between TP2 and B+ node...that looks good.

Matador - I've got to get ready for a tour and so I'm going to shut down this project for about two weeks. Thank you for your help. It may seem redundant, but I'm going to be back after the tour to ask some more of the same questions. Thanks again so much, the first one I built (after a screw up on my part and some troubleshooting) sounds amazing.

 

[Reverend]

Hey Everyone!
does anyone know what is the best way to assemble Gotham GAC-7 cable? (for the C12 Clone)

Thanks a lot !

The most important point is to use the 2 large conductors for heater and ground connections.  These are higher current and benefit from the larger conductors provided in specialty cable like the GAC-7 or Mogami products. 

Whether you should tie the shield into the ground connection at the cable is a matter of debate.  I have done so with no apparent ill effects although keeping all connections separate at the pins may be more "correct".

Chunger, I would love to see that thread you did about the GAC-7 cable build again. Did you take it down? Thanks - the cable works great.

 

[dmnieto]

The most important point is to use the 2 large conductors for heater and ground connections.  These are higher current and benefit from the larger conductors provided in specialty cable like the GAC-7 or Mogami products. 
Whether you should tie the shield into the ground connection at the cable is a matter of debate.  I have done so with no apparent ill effects although keeping all connections separate at the pins may be more "correct".

I agree with that, on my first "crappy" cable it was dissipating 300mV... at the 350mA drain of the heater... do your math 100mW of dissipation on the cable.

 

[dmnieto]

1)With the mic unplugged, with the DMM black lead clipped to the rail of the mic, when I touch TK2, I'm not getting a reading at all, but I may be doing it wrong?
2)I'm measuring 99.5K between TP2 and B+ node...that looks good.

Matador - I've got to get ready for a tour and so I'm going to shut down this project for about two weeks. Thank you for your help. It may seem redundant, but I'm going to be back after the tour to ask some more of the same questions. Thanks again so much, the first one I built (after a screw up on my part and some troubleshooting) sounds amazing.

Floating cathode then... no wonder you are not draining anything.

You should get 0 ohm there

 

[omribgr]

Hey Everyone!
does anyone know what is the best way to assemble Gotham GAC-7 cable? (for the C12 Clone)

Thanks a lot !

The most important point is to use the 2 large conductors for heater and ground connections.  These are higher current and benefit from the larger conductors provided in specialty cable like the GAC-7 or Mogami products. 

Whether you should tie the shield into the ground connection at the cable is a matter of debate.  I have done so with no apparent ill effects although keeping all connections separate at the pins may be more "correct".

Thanks a lot for the help i appreciate it !
so just tell me please if this is correct:
Pin 1 = B+
Pin 2 = heater      - red large cable
Pin 3 = pattern
pin 4 = bias
pin 5 = audio -
pin 6 = audio +
pin 7 = ground      - blue large cable

nothing happens between pins, i can choose if i want to connect the the shield to the G pin and the 7 pin or only to the G pin, and that's all?

 

[Reverend]

1)With the mic unplugged, with the DMM black lead clipped to the rail of the mic, when I touch TK2, I'm not getting a reading at all, but I may be doing it wrong?
2)I'm measuring 99.5K between TP2 and B+ node...that looks good.

Matador - I've got to get ready for a tour and so I'm going to shut down this project for about two weeks. Thank you for your help. It may seem redundant, but I'm going to be back after the tour to ask some more of the same questions. Thanks again so much, the first one I built (after a screw up on my part and some troubleshooting) sounds amazing.

Floating cathode then... no wonder you are not draining anything.

You should get 0 ohm there

What should I do?

 

[chunger]

The shield should be connected to the little ground tab for the connector's casing.  Thus, the shield is maintained throughout.

 

[Matador]

What should I do?

There needs to be a ground wire from the main PCB (any ground point is fine) to the cathode (either TK1 or TK2).

 

[Reverend]

I've got TK2 going straight down to C11. Should it go to C10? I'm not really understanding what to do.

 

[dmnieto]

I've got TK2 going straight down to C11. Should it go to C10? I'm not really understanding what to do.

Which side of C11? you must connect the cable from TK2 to the side of C11 that measures 0 ohm between ground and itself.

 

[Reverend]

What should I do?

There needs to be a ground wire from the main PCB (any ground point is fine) to the cathode (either TK1 or TK2).

Ok. Making some progress maybe, I'm working with the TK2 side as you know, but I soldered a wire from TK1 down to the turret below it marked C10 (on the front side of the pcb) (Since I first wrote this, I took this wire to one of the reinforcement leads instead of the turret). Suddenly, I'm getting close to proper readings, I can hear sound and there's mainly not any hum. This is all with a tester tube and the stock Alcatron capsule. HOWEVER, when I speak into the mic, it sounds ok kind of for a second, then starts to pull back like some kind of really, really slow compressor. If I set it down on the table, I can actually kind of hear it come and go like the ocean. Progress, but not quite right yet. Any ideas? (After changing the ground point from TK1, I'm getting the same thing...as soon as I start talking, the sound goes away, then when I stop I can hear it come back and so forth? Thanks for all the troubleshooting.

 

[Matador]

Ok. Making some progress maybe, I'm working with the TK2 side as you know, but I soldered a wire from TK1 down to the turret below it marked C10 (on the front side of the pcb) (Since I first wrote this, I took this wire to one of the reinforcement leads instead of the turret).

Just to be clear:  if you are using side "2", then TK2 needs to be grounded, not TK1.

Just a typo?

What is the plate voltage and B+ measuring now with the cathode grounded?  Can you confirm the bias voltage (measuring in the PSU is fine for now). 

 

[Reverend]

Attached is a photo before I ran the ground wire from TK1. I just tried to do the opposite of what would be done on side 1.

 

[JessJackson]

you can run all the other pins of the other side of the tube to ground too.

 

[Tim Campbell]

These just arrived on my bench.

 

[mica]

Just got a CK12 beesneez capsule in mine, but i only seem to be able to get cadiod no matter how I turn the pattern switch? Did I miss something. I have wired it FC,FB,RC, RB exactly like my old capsule..

EDIT:
Ahh i just left the wires as they were when i recieved it. Thats not right is it? I need to move some of them right?



/M

 

[Category 5]

Just got a CK12 beesneez capsule in mine, but i only seem to be able to get cadiod no matter how I turn the pattern switch? Did I miss something. I have wired it FC,FB,RC, RB exactly like my old capsule..

EDIT:
Ahh i just left the wires as they were when i recieved it. Thats not right is it? I need to move some of them right?



/M

Looks right, as long as you bridged the backplates.

 

[mica]

Ohh so i need to run a new wire between FB and RB on the capsule?