Official C12 Clone - Build and Support Thread

[Mikael-ange]

Villemoisson sur Orge (Essonne, 91)

Ok cool
Je suis pas loin de toulouse (dans une petite ville qui vient d'etre connu pour ca defaite contre une equipe de foot parisienne)

 

[Matador]

Sorry, was traveling for the holidays. Glad you got it sorted.

 

[Matador]

For like a 120B+, self Bias should have a 220K plate resistor& 3.8K for cathode for around -4 grid voltage for class A.

-1 at the grid would be for more like a 12AX7 or a 12AU7 on self bias.

Should? That is one operating point out of countless others: the 120v, 100k loadline at a -1V quiescent point is perfectly valid. Also note that 220K with a 120V supply will have little output headroom running near 1mA static. The C12 operating point is a good compromise between noise, input single swing, output headroom, and output impedance.

Class A? What other class can you have with a single tube?

Keep in mind, the more current you pull from the tube, the less series R you can have in the power supply, so all other things being equal, filtering is worse.

 

[HyprDrivr]

Any chance that these boards will be avalible again?

 

[JeffKall]

Any chance that these boards will be avalible again?

+1 on PSU PCB’s …

I miss these boards !!!

 

[geekmacdaddy]

Is there a mic body that fits Dany's D12 boards? I have been searching the forum and understand there are modifications to the board (not quite clear on what they are) to make them fit donor bodies.There are currently 151 pages to this thread so forgive if I missed the info. Any links are helpful, thank you

 

[cariocaman85]

Hello,

I'm having trouble with one of my C12 clones

It's been in service for 8 years and sounding great, but last week I decided to upgrade to AMI T14 transformer. I installed it, and it worked fine.
Then I decided to fine tune bias and B+ has it's been I long time I didn't. Tried to get to 110V because this is a Tim Campbell Capsule and I read they sound better at this voltage, couldn't get any lower than 116V.

Then I plugged it, still monitoring B+, ran a few tests, very good.

After 10 min or so I lost signal, B+ was increasing at fast rate, I stopped PSU at 145V.
I waited, tried again, and the same, fine for 5 mins, then B+ is increasing suddently.

What do you think could cause this ? I think failling tube, but maybe not...

 

[cariocaman85]

With no load, minimum B+ is at 174V.
Now with the mic plugged, B+ minimum, voltage rise. I cut power when it passes 125V. It shouldn't be near this at B+ minimum.

 

[cariocaman85]

Tried with a 200k resistor between ground and B+, could trim fine to 90V, so it must be something wrong in the mic...

 

[tonycamp]

I ordered another pcb and parts kit from Chung, got an initial 939 site generated conformation email, haven't heard anything back for 8 days now, is Chung still in the game?

 

[tonycamp]

Tried with a 200k resistor between ground and B+, could trim fine to 90V, so it must be something wrong in the mic...

I had a similar problem back in the day at the very beginning of this thread, it was one of the polystyrene's had burned up, might want to take a look back in the thread to then, good luck

 

[cariocaman85]

I had a similar problem back in the day at the very beginning of this thread, it was one of the polystyrene's had burned up, might want to take a look back in the thread to then, good luck

Thank you,
I read your story. I will order new styrenes and see if there's a change.
All the best

 

[tonycamp]

Thank you,
I read your story. I will order new styrenes and see if there's a change.
All the best

You probably already know this, but for anyone inquiring, I found the safe way to install styrene is to pre tin the turret and then clip a heat sink(alligator clip) to the styrene lead, get your iron very hot, touch and go quickly as to not hang around and run the heat up into the styrene, i'm positive that is how i burned my first one

 

[tonycamp]

I ordered another pcb and parts kit from Chung, got an initial 939 site generated conformation email, haven't heard anything back for 8 days now, is Chung still in the game?

bump...

 

[geekmacdaddy]

bump...

Took about 6 weeks and a few days for me to get my order (received about 2 weeks ago) which is consistent with other orders from chunger. I have recently made another order with him, so his "system" is functioning. I don't think you'll receive further communications from him, but, I can't speak for the man.

 

[JeffKall]

bump...

Hey, Tony …
I just placed an order with Chunger … and I am happy to report we had a brief email exchange …

After resolving some life priorities … he has refocused and is working to get Studio 939 restocked on its most popular items …

Chunger has always come through … and he has always credited me for items that have become unavailable (particularly during the pandemic) …

I am always happy to offer him my patience and support … because I know he will ultimately deliver …

He is one of the truly good guys in our DIY community !!!

 

[tonycamp]

thanx guys, yeah Chung has always been tops, he emailed me and said he was restocking some things, so all's good

 

[Matador]

Part of it was my fault: work has been crazy the last 6 months, and I've been going through the process of moving designs from Eagle to KiCAD, which takes some time.

 

[Nick6691]

Hi
Does anyboby know where to buy the:

TPS100 Tube Microphone Power Supply?​

Used in Danys D-12 build
Tried Studio 939 but they seems to be sold out
Nick

 

[mjmajilton]

Hi
Does anyboby know where to buy the:

TPS100 Tube Microphone Power Supply?​

View attachment 136774
Used in Danys D-12 build
Tried Studio 939 but they seems to be sold out
Nick