AKG C414 Problem

[Jellybelly]

All in all, I'm ready for my journey of fixing this microphone. Hopefully it will be a good one!

 

[Whoops]

Can anyone recommend a decent multimeter that's reasonably priced, with a link to ebay in private message because I can't seem to find my one. Thank you so much!

sure,
Uni-T has a variety of really good multimeters for an amazing price.
This one is pretty good:

https://eleshop.eu/uni-t-ut133a-multimeter.html
You can easily get them off EBay

 

[Tubetec]

I got a Uni-T 171b a few years back , its great in the dark but not very visible in full daylight. It does have a handful of minor but anoying quirks.
I went away and got a used Fluke 187 afterwards , I doubt I'll ever need a better meter than that in my lifetime , the dbu /dbv scales are handy for audio . Its an old meter now but unlike its brother the Fluke 189 it doesnt have a memory back up battery that leaks and can destroy the PCB. I used a Wavetek meter for many years , and even though it doesnt provide the resolution of the Fluke or UNI-t its still rock solid .

 

[Whoops]

I have a Fluke 179, it's an incredible DMM, I'm really happy with it's performance and it always served me well.
I also have an Unit-T UT133, and I have to be honest it does everything the Fluke 179 does not worse or better, but for 1/5 of the price.

So my only recommendation for a DMM will be an UNI-T model and not a Fluke

 

[mrgrooves666]

Mastertech MS8268, very affordable, and has auto-range, wich imho simplfies things. You can get in amazon.
Yes do check that the basket assembly, has good, proper ground contact all around the mesh, or you will be prone of all sort of EMI/RFI interference. Body removed while checking also can induce hum. Old switch can be sourced in fullcompass.com, as well as the 1st gen CK12 teflon capsule, and the second.
Per Piotr suggestion, I upgraded my pair of darker BULS to the 2nd generation CK12 teflon and top end improved.

 

[Jellybelly]

Mastertech MS8268, very affordable, and has auto-range, wich imho simplfies things. You can get in amazon.
Yes do check that the basket assembly, has good, proper ground contact all around the mesh, or you will be prone of all sort of EMI/RFI interference. Body removed while checking also can induce hum. Old switch can be sourced in fullcompass.com, as well as the 1st gen CK12 teflon capsule, as well as the second.
Per Piotr suggestion, I upgraded my pair of darker BULS to the 2nd generation CK12 teflon and top end improved.

Thanks all for your help and advice.

I have seen posts where people have mixed glue with copper dust to try to keep a connection when repairing a broken headbasket, I will bear it in mind.

I think definitely, capsules would be interesting to swap out on this type of microphone.

 

[chops]

Aside from a vocal test, when I move the polar pattern switch it cancels the buzzing and bumping sounds and seems OK again. However it sometimes sustains a 14dB drop for a while at times.

I don't think this conclusively rules out the capsule. (Switching polar pattern sends different polarization voltages to the capsule which is still definitely capsule related.) I'd make sure before you go swapping out components on the board.

 

[Jellybelly]

That's definitely an idea. I have a second mic that works and can maybe solder the other capsule with some longer wire to see if the symptoms disappear.

 

[Jellybelly]

Just to confirm, there is a time when the mic works perfectly. Then the mic does loud rhythmic bass drum frequency bumps, sometimes it's high mid and softer interference. Sometimes the level drops by approx 20dB and becomes very faint. The behaviour cannot be altered in any discernable way by singing or speaking into the capsule.

Changing the polar patterns does seem to perform a reset for osme time until load is placed on the circuit once again by way of speaking or singing into the capsule.

This leads me to believe it is electronics related. But yes, it could be the capsule, it could also be a couple of things such as the switch and the caps!

I've got a good decent working c414 buls to swap parts and diagnose.

I would think wiring up the capsule in place on the other mic with longer wire would rule out the capsule if the behaviour persists in the faulty mic.

If there are any obvious cap tests with a multimeter and a test for the transformer please can you carefully explain, I have pictures of the circuit that I found here and on Google images.

 

[inkster]

Reverse the front/back capsule leads to test the capsule, recap the mic, the problem often lies in the dc-dc convertor so do the non polarized caps in that circuit.
Measuring voltages in a very high z circuit is not possible with a typical DMM no matter the quality, a special circuit or meter is required.

 

[inkster]

Full Compass sells frames for c414...much better than glue

 

[Jellybelly]

I'd love a frame but I wish AKG would stamp them with the original serial number on request or a picture of the mic! Thank you. Probably will be worth doing.

 

[ccaudle]

sourced in fullcompass.com, as well as the 1st gen CK12 teflon capsule

Thanks for pointing that out, I did not realize that Full Compass sold replacement capsules.

 

[Jellybelly]

Any hope of a decent brass capsule similar to the c12 that would fit right in?

 

[inkster]

I've installed Tim Campbell's CK12 with great results...be sure to order it with the mount and screws, be careful not to over tighten those tiny screws.

 

[mrgrooves666]

Thanks for pointing that out, I did not realize that Full Compass sold replacement capsules.

AKG 2072Z00050 Mic Element For C414BULS 1st Gen
AKG 2072Z00110 Silver Condenser Capsule For C414EB And CK12 2nd Gen
They currently do not have them in stock, I guess because of the pandemic, so waiting time can be long, but they did supplied me a pair in the end.

AKG 2148Z00110 3-Position Switch For C414 B-ULS 3 position switch. Somewhere in their store there's the front 4 position, I know I've seen it too, but couldn't find it now.

 

[Whoops]

AKG 2148Z00110 3-Position Switch For C414 B-ULS 3 position switch. Somewhere in their store there's the front 4 position, I know I've seen it too, but couldn't find it now.

Although pretty pricey it’s great that those switches are available, they break a lot. I stopped asking for 414 in my Live sound tech riders because all the 414 of PA companies have the switches broken which makes impossible sometimes to change the settings of the mic.
Even in most studios I find 414 with the switches broken.

I have the new 414 mics with the electronic (phantom powered) switching system, no more broken switches, although I’m not impressed with the sound of these newer mics

 

[mrgrooves666]

The switch was also a PITA to exchange too lol

 

[Jellybelly]

Uni t dmm on the way. Can't find my other one! I've got a nice Weller iron, fluxed solder and a sucker, clamps for hands free and a magnifying glass.

Can anyone help me with selecting microphone wire to buy from ebay that I can use to bridge to the second 414 to rule out if the first is capsule related issue?

Also a shopping list with parts from digikey rs or mouser for trafo DC filter caps and other caps?

Thank you so much!

 

[mrgrooves666]

10' teflon PTFE Silver Plated Copper wire 28 Awg Gauge Stranded black M16878/4 | eBay for capsule, you can use 22 gauge for other