Akg c451e what’s the difference between these bodies

[earlfsmith]

What’s the difference between these two? One on the right seems to not work and I’m thinking maybe standard 48v isn’t what powers it.

 

[Matt Nolan]

They should both work with anything from 9 to 52V.

IIRC, the difference between the bodies is that the one on the right is considerably easier to get into

 

[cyrano]

What device did you use to test?

My C451s tend to draw too much current for a typical USB powered interface, resulting in stuttering, sometimes needing more than a minute to start working, or even not working at all.

They all work with classic mixers, or interfaces that are externally powered. And the Sound Devices USB powered interface I used to own worked with nearly all other phantom powered mics.

 

[earlfsmith]

What device did you use to test?

My C451s tend to draw too much current for a typical USB powered interface, resulting in stuttering, sometimes needing more than a minute to start working, or even not working at all.

They all work with classic mixers, or interfaces that are externally powered. And the Sound Devices USB powered interface I used to own worked with nearly all other phantom powered mics.

I used a Behringer 1202 small mixer with same ck1 capsule.

Maybe it need to be recapped? I tap on the body and can hear tapping in the headphones

 

[ubxf]

yes probably the tantalum capacitor

 

[cyrano]

Could you test with something else as a phantom power source?

I fear ubxf is right. But I've never found schematics for the C451 family, so I never got the courage to open them up and replace caps. I mean, mine work, with the exception of some USB powered thingies...

The Behringer should provide ample power, but it's a small budget mixer that's known to have a PSU problem every now and then. That's why I keep a separate phantom power box around for testing. Also from Behringer, BTW.

 

[abbey road d enfer]

Could you test with something else as a phantom power source?

+1. Also measure the voltage at pins 2 and 3. that would give a definite indication that your phantom source is correct (or not).

I've never found schematics for the C451 family,

You haven't looked hard enough 
Those are commonly available. Just google "schematic AKG 451" and you get about 190 000 hits.

The Behringer should provide ample power, but it's a small budget mixer that's known to have a PSU problem every now and then.

Many small mixers and USB interfaces are definitely failing in the phantom department. Some deliberately deliver P15 (derived from the opamps rail) and many deliver anything from 38 to 44V.

Don't get me started on API preamps that deliver their rightful 48V through a 10k resistor before the 6.8k, limiting the available current to 3.5mA.

 

[cyrano]

Those are commonly available. Just google "schematic AKG 451" and you get about 190 000 hits.

I suppose you meant I didn't search enough?

You're right, Abbey. Just found some. Thanks.

Keep in mind I searched for that schematic over ten years ago. In my notes, I was confused about the naming of the different releases of the C451, as nobody seems to have the definite knowledge and info is conflicting.

EDIT: Also, I'm a fool. Already had both C451E and EB, from Gyraf's website. Just missed it while looking in the "AKG" folder, as the name of the files is spelled with an underscore in stead of a space. It wasn't until I changed the sort method, I noticed both gifs.

 

[earlfsmith]

I have plenty of other stuff with phantom power like my neve 1290’s with JLM power supply.

I just figured if it works for the one on the left it’ll work for the one on the right. I thought it was odd that I bought it on ebay that the capsule works but body doesn’t.

 

[abbey road d enfer]

I suppose you meant I didn't search enough?

Yes, typo. I've corrected my post.