tube 414 revisited

pucho812 · Oct 18, 2008

Finally tearing into this thing

2 resistors in the mic are 1 X 22Mohms and 1X 1000Mohms
the cap in the mic is .1uf 400V

Schematic to follow

CJ · Oct 19, 2008

REV B - Note: This is a work in progress-not a real schematic.
Still needs a pwr. supply and other goodies.

pucho812 · Oct 19, 2008

Had the mic apart for a bit today. This was a rough schematic of just the mic

I am sure there are major errors.

Martin B. Kantola · Oct 19, 2008

Where is the cathode connected?

Martin

rodabod · Oct 19, 2008

[quote author="Martin B. Kantola"]Where is the cathode connected?[/quote]

I was wondering the same. I'd be guessing it should be connected directly to one of the XLR pins to find its way to a cathode resistor.

Gus · Oct 19, 2008

A 1 gig cathode to G1?

The cathode resistor, output cap and transformer can be in the power supply to save room inside the microphone.

http://twin-x.com/groupdiy/displayimage.php?pid=2680&fullsize=1
I would use a lin 1meg pot instead of a 5 way

connections
B+
cathode out
heater voltage
pattern control voltage
ground

Any shield connections in the microphone or power supply case?

pucho812 · Oct 19, 2008

gus is correct as the mic output transformer is in the PSU case. I suspect had he really wanted to, he could have put the mic transformer in the mic. hmmmm.

I'll make of a schematic of the psu today and maybe that will answer the rest of the questions.

I double checked the schematic today and it appears correct as that is what is in the mic and how it is wired.

Martin B. Kantola · Oct 19, 2008

[quote author="pucho812"]I double checked the schematic today and it appears correct as that is what is in the mic and how it is wired.[/quote]

Cathode has got to go somewhere, to ground if nothing else... But then the bias doesn't make sense... Hmm...

Martin

pucho812 · Oct 19, 2008

[quote author="Martin B. Kantola"][quote author="pucho812"]I double checked the schematic today and it appears correct as that is what is in the mic and how it is wired.[/quote]

Cathode has got to go somewhere, to ground if nothing else... But then the bias doesn't make sense... Hmm...

Martin[/quote]

you guys are good. Talk about missing something.

After a third glance. I saw it. Because things were so cramped inside it was hard for me to see what was connected and where. You can see that in the original photos. So I updated the schematic of the mic portion. The cathode goes out to pin2 on the 6 pin XLR

here is the updated schematic

CJ · Oct 19, 2008

Don't worry, we had your back like a Sealy Posterpedic.

OK, how does this look?
I have Gus' pot in there instead of the 5 position rotary sw.

pucho812 · Oct 19, 2008

CJ I have a photo for you. More clear the the ones I snapped 2 years ago... it's grown in size :shock:

CJ · Oct 21, 2008

check 1 chack 2...

I sat on the couch with Eve Anna and we were making out for a while.
Do you have a picture of that?

CJ · Oct 22, 2008

So is this right?

I looked at the Royer page and there's is different.

Marik · Oct 23, 2008

[quote author="CJ"]check 1 chack 2...

I sat on the couch with Eve Anna and we were making out for a while.
Do you have a picture of that?

http://vacuumbr.ipower.com//The_Lab/Microphone/AKG/414tube.jpg[/quote]

Didn't you find anything better to do with Eve Anna on the couch, you old fart? :razz:

It will take awile for the mic to think whether to change pattern, or not.
Why do you need the grid resistor? It seems that you need whether to omit it all together, or add one more resistor (going to cathode) for the proper tube bias.

Best, M

CJ · Oct 23, 2008

OK, thanks.

Pucho, have you opened up the pwr supply yet?

He must have gotten zapped while out behind the patch bay or somethin.

Hey Marik, don't knock it til you tried it.
:grin:

okgb · Oct 23, 2008

Some people will do anything for a mike
[ or mike if that's the way you are ]

Gus · Nov 5, 2008

Any news?

hitchhiker · Nov 10, 2008

A Fred Cameron 414 tube mod on ebay, with many clear pics.

http://cgi.ebay.com/2-Cameron-Lab-AKG-C414-C12-Conversion-Tube-Microphones_W0QQitemZ320317358133QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item320317358133&_trksid=p3286.c0.m14&_trkparms=66%3A2%7C65%3A3%7C39%3A1%7C240%3A1308

rodabod · Nov 10, 2008

[quote author="hitchhiker"]A Fred Cameron 414 tube mod on ebay, with many clear pics.

http://cgi.ebay.com/2-Cameron-Lab-AKG-C414-C12-Conversion-Tube-Microphones_W0QQitemZ320317358133QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item320317358133&_trksid=p3286.c0.m14&_trkparms=66%3A2%7C65%3A3%7C39%3A1%7C240%3A1308[/quote]

That's quite a long distance from capsule to grid, but I suppose you can't help that if you use an additional box like that.

I wonder what this CEK12-2 capsule is? Maybe a newer version of the CEK12.

Gus · Sep 25, 2018

did you ever record the cathode resistor value in the power supply? It looks like it would be the one next to the film cap.
If so was it 39k?

tube 414 revisited

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