Official C12 Clone - Build and Support Thread

[JessJackson]

I don't see a problem with it:  most switches can be found in 120V flavors.  If its inside the body, one would have to unplug the mike to get at it in any case.

It's odd to think of a mike with a "high cut" switch, but with a C12 it might be just the ticket to a new sonic crayon.

My original intent was to apply this capsule switching design into a full DIY mic that has a 251 variant as its circuit (no smoothing cap). Implementing the switch in the apex 460 type of mic of mic might require the models with a pad and low cut switch.

-James-

Best idea

 

[Winetree]

There's a real Elam 251 on ebay for $14,200 with 15 hrs. to go.
Thank heavens for DIY.

 

[Ericbazaar]

Hello Again,

I'm really desperate. I built this micro-and it does not work. Unfortunately I have not the new capsule, I ordered a capsule of Microphone Parts. I live in Germany and the shipping takes a long time! All values ​​are good, B + on PSU = 120v, B + on Tube Pin 1 = 80V, 6.3 V Heater on Tube and on PSU bias - 1V. Tested with a Electro Harmonix 6072a Gold. The microphone is in an audio test totally quiet and thin. Can this be the stock capsule? Perhaps the T14 Transformer is broken? The red cable show 22Ohm, the blue cables show nothing (but should show about 900ohm, right?). What should I do to find the error? I would like this micro works, please! I'm really not an expert!

 

[Matador]

Primary should read 900, secondary 20-ish.  If the primary is open it's kaput.

 

[Ericbazaar]

The T14 can go wrong so quickly? $ 95 for nothing, really great): I have treated this thing really careful, I can fix it? I have checked through the blue wire, no pass! $ 95 again? I'm really tired.

 

[chunger]

The T14 can go wrong so quickly? $ 95 for nothing, really great): I have treated this thing really careful, I can fix it? I have checked through the blue wire, no pass! $ 95 again? I'm really tired.

Hi Eric,

Send your contact info to me and I'll get another T14 out to you ASAP!  I'll take the issue up with Oliver and sort it out.  This is assuming you purchased the T14 through me.

 

[Volume11]

hey guys, when I test the wire wound resistors with my fluke 175, I get a reading of 9.3ohms on both of them, instead of 4.7ohms. Is there a specific reason for this that I am unaware of? They are testing at twice the resistance. Would it have anything to do with the wattage? I am new to this DMM, so maybe it has something to do with it?

Also Chunger, can you tell me what gauge of the silver teflon wire you use is, and maybe a good source?

Thanks

 

[HellfireStudios]

You have to pull one leg of the resisitor off the pcb (or pull it completely out of the circuit) before you can test its resistance accurately.

-James-

 

[Matador]

Here is a short spoken-word (mine) test of a C12 I built for kidvybes.  He is using a GT-12 capsule, a GE 6072A, and an AMI T14 for his build.

C12 Test Mp3

It's not a great recording environment but it will give you an idea of what to expect.

 

[micaddict]

Mark and Matador, thanks for the samples.

Keep them coming, folks!



Henk

 

[kidvybes]

Here is a short spoken-word (mine) test of a C12 I built for kidvybes.  He is using a GT-12 capsule, a GE 6072A, and an AMI T14 for his build.

C12 Test Mp3

It's not a great recording environment but it will give you an idea of what to expect.

...I am eagerly awaiting the arrival of this mic for a project I am midway thru, with a very talented female vocalist (with a very dynamic voice)...I hope to provide additional samples once I have the opportunity to run some sessions with her...

BTW, the capsule I provided Matador for this build is the ADK Custom Shop (3-Zigma) GK12d (which appears to use a K67 drill pattern combined with an edge-terminated diaphragm):
http://www.adkmic.com/catalog/customshop/ModsAndParts.php

...I am interested in hearing how the voicing of this capsule compares with Tim Campbell's historically accurate C12 capsule in this C12 clone...based on Matador's short clip, it sounds nicely balanced...

...this is probably one of the finest quality capsules available from the Asian based microphone manufacturers...Larry Vilella at ADK maintains very high QC on these capsules and uses them in his new Z-MOD Series mics:
http://www.adkmic.com/catalog/customshop/Z-Mods.php

 

[Volume11]

You have to pull one leg of the resisitor off the pcb (or pull it completely out of the circuit) before you can test its resistance accurately.

-James-

Thanks for the response... I actually tested both of them completely out of the circuit. Weird, right?

 

[gary o]

Reading from the link to the ADK web site telling us they used a $6 resistor in their mics I guess thats the grid resistor........ will the $6 res make a difference than a cheaper res this or any mic build ?

I have a ADK Vienna its good for the money

 

[chunger]

hey guys, when I test the wire wound resistors with my fluke 175, I get a reading of 9.3ohms on both of them, instead of 4.7ohms. Is there a specific reason for this that I am unaware of? They are testing at twice the resistance. Would it have anything to do with the wattage? I am new to this DMM, so maybe it has something to do with it?

Also Chunger, can you tell me what gauge of the silver teflon wire you use is, and maybe a good source?

Thanks

Hi Volume 11,

I recall vaguely during my build that the 4.7ohm resistors measured a bit off (perhaps a wide tolerance part, but it shouldn't be almost 100% off).  I'll wait for Matador to chime in and see if that variance is still ok in the circuit.  I may seek a tighter tolerance resistor for future kits in that position.

For PTFE silver teflon wire, I am generally using 20 and 22 gauge stranded. . . and 28 gauge stranded for capsule connections.  I now have kits in hand with all of the original wire colors in the stock psu for $5.  Alternately, you can find various sources on Ebay and such for small quantities in various colors.  I need to clean a bit of my mess before I can take pictures and post to the webstore, but email me and I can send out a wire kit if you like.

 

[Matador]

It would be odd for both to be in error that much.  Are you using a high-impedance probe?

The tube draws about 300mA of heater current, and the voltage before filtering is about 12.7V.  10 ohms drops three volts a piece, which leaves nothing for the regulator to work on.

We need 6.3V, which means pre-regulator we need about 8.3V.  12.7 - 8.3 = 4.4V of drop at 300mA, which means total resistance (R7+R8) cannot be higher than about 14 ohms worst case.  I picked about 10 ohms to be safe.

I would install them, then measure the regulator output (or heater voltage).  If those really are 10 ohms a piece, you won't be able to dial the heater voltage up to the required 6.3V.  If you can dial it in, then somethings odd with the meter reading(s).

The 5W resistors are overkill:  dissipation in R7 and R8 is 0.3*0.3*4.7 = 0.423W each.  A half watt part would work, or a 1W to be conservative.  Should be easy to find 1% resistors in that value.

 

[Volume11]

Hi Volume 11,

I recall vaguely during my build that the 4.7ohm resistors measured a bit off (perhaps a wide tolerance part, but it shouldn't be almost 100% off).  I'll wait for Matador to chime in and see if that variance is still ok in the circuit.  I may seek a tighter tolerance resistor for future kits in that position.

For PTFE silver teflon wire, I am generally using 20 and 22 gauge stranded. . . and 28 gauge stranded for capsule connections.  I now have kits in hand with all of the original wire colors in the stock psu for $5.  Alternately, you can find various sources on Ebay and such for small quantities in various colors.  I need to clean a bit of my mess before I can take pictures and post to the webstore, but email me and I can send out a wire kit if you like.

Ah, I didn't see this in time! I just ordered some 20gauge from tube depot. At least I know that I picked the right size. As far as quality goes, I'll have to wait and see. Thanks for the info.

 

[Volume11]

Check your battery in the meter, low batteries can cause erratic behaviour.

Regards,
Mark

This could be the case, I did buy it used. Thanks

 

[Volume11]

It would be odd for both to be in error that much.  Are you using a high-impedance probe?

The tube draws about 300mA of heater current, and the voltage before filtering is about 12.7V.  10 ohms drops three volts a piece, which leaves nothing for the regulator to work on.

We need 6.3V, which means pre-regulator we need about 8.3V.  12.7 - 8.3 = 4.4V of drop at 300mA, which means total resistance (R7+R8) cannot be higher than about 14 ohms worst case.  I picked about 10 ohms to be safe.

I would install them, then measure the regulator output (or heater voltage).  If those really are 10 ohms a piece, you won't be able to dial the heater voltage up to the required 6.3V.  If you can dial it in, then somethings odd with the meter reading(s).

The 5W resistors are overkill:  dissipation in R7 and R8 is 0.3*0.3*4.7 = 0.423W each.  A half watt part would work, or a 1W to be conservative.  Should be easy to find 1% resistors in that value.

I'm not sure about the impedance of the probes but, I believe that they are the original ones that came with the dmm?

I went ahead and soldered them into place, as soon as I get some more wire and a few other parts I will fire it up and take measurements. Thanks for all of the help, I'll report back shortly.

Chad

 

[bobtheninja]

It's odd to think of a mike with a "high cut" switch, but with a C12 it might be just the ticket to a new sonic crayon.

This is an aside, but my Pearlman TM-1 has a high-cut switch on it that is actually really useful. Especially on vocals, but also for room duties, etc.

 

[JessJackson]

My readings across my Haufe T14