Topic: Audio Technica U853 Sensitivity Issue?

[Sunday Driver]

I purchased two Audio Technica U853-C capsules new a little over three years ago. I've probably used them about 30 or so times since then. When I first got them, one cap was only about -2db off in sensitivity from the other. However, I noticed the last time I used them that one cap seems to have decreased drastically in sensitivity....it's now between -6db to -8db off from the other capsule. My question is if this is a common problem with AT caps and if this may be a sign that the FET in the capsule is going? I know these aren't exactly high end mic capsules, so I'm wondering if that may be the case and they have a short life span. Thanks.

[Church-Audio]

I purchased two Audio Technica U853-C capsules new a little over three years ago. I've probably used them about 30 or so times since then. When I first got them, one cap was only about -2db off in sensitivity from the other. However, I noticed the last time I used them that one cap seems to have decreased drastically in sensitivity....it's now between -6db to -8db off from the other capsule. My question is if this is a common problem with AT caps and if this may be a sign that the FET in the capsule is going? I know these aren't exactly high end mic capsules, so I'm wondering if that may be the case and they have a short life span. Thanks.

How are you measuring that?

[Sunday Driver]

I purchased two Audio Technica U853-C capsules new a little over three years ago. I've probably used them about 30 or so times since then. When I first got them, one cap was only about -2db off in sensitivity from the other. However, I noticed the last time I used them that one cap seems to have decreased drastically in sensitivity....it's now between -6db to -8db off from the other capsule. My question is if this is a common problem with AT caps and if this may be a sign that the FET in the capsule is going? I know these aren't exactly high end mic capsules, so I'm wondering if that may be the case and they have a short life span. Thanks.

How are you measuring that?

Probably not the right way. Adobe Audition has a feature that provides amplitude statistics for a wave form. One piece of data this provides is average RMS power. So if you subtract Left from Right or Right from Left, that's what I'm using to find the difference.

[SmokinJoe]

I've never had a problem with AT853 caps degrading, and I've had several pairs (still own 3 pair at the moment), with various caps.

I have seen what might be the same problem.  I have one which I assume a dirty connection where the cap screws onto the body.  Every once in a while I fire them up before a show and the Left/Right channels disagree by a large amount, which I'm guessing is what you are seeing.  I just unscrew the caps, screw them back on, and everything is fine.  In my case it is tied to a particular body, I can swap caps, switch from cards to omnis, etc, and when it happens it's always this left body which actually feels kind of funny when I screw it back on.  This particular set of mics are mongrels... I bought 2 different mics cheap off ebay, cut the phantom adapters off and had Chris do the 4.7K mod to a miniplug.  It's never started happening during a show, and I've always been able to "fix it", so I don't get too excited.

[Church-Audio]

I purchased two Audio Technica U853-C capsules new a little over three years ago. I've probably used them about 30 or so times since then. When I first got them, one cap was only about -2db off in sensitivity from the other. However, I noticed the last time I used them that one cap seems to have decreased drastically in sensitivity....it's now between -6db to -8db off from the other capsule. My question is if this is a common problem with AT caps and if this may be a sign that the FET in the capsule is going? I know these aren't exactly high end mic capsules, so I'm wondering if that may be the case and they have a short life span. Thanks.

How are you measuring that?

Probably not the right way. Adobe Audition has a feature that provides amplitude statistics for a wave form. One piece of data this provides is average RMS power. So if you subtract Left from Right or Right from Left, that's what I'm using to find the difference.

Thats not how you want to do it. For argument sake the best way to do it is take a 1 k tone put both mics as close together as possible then use a good level meter to see if there are differences. Also make sure the metal tab is bent up towards the capsule pin. And that the nut is tight on the capsule pin. But you dont want to use any tools on it just your fingers to make sure its tight. Or a small pair of pliers. But you do not want to use any force.

[Sunday Driver]

I have seen what might be the same problem.  I have one which I assume a dirty connection where the cap screws onto the body.  Every once in a while I fire them up before a show and the Left/Right channels disagree by a large amount, which I'm guessing is what you are seeing.  I just unscrew the caps, screw them back on, and everything is fine.  In my case it is tied to a particular body, I can swap caps, switch from cards to omnis, etc, and when it happens it's always this left body which actually feels kind of funny when I screw it back on.  This particular set of mics are mongrels... I bought 2 different mics cheap off ebay, cut the phantom adapters off and had Chris do the 4.7K mod to a miniplug.  It's never started happening during a show, and I've always been able to "fix it", so I don't get too excited.

I think it's the same issue. Back in July at a show I noticed the severe mismatch in sensitivity between channels and unscrewing/screwing the cap fixed the problem. That made me think it was a connection issue, but it happened again and unscrewing/screwing didn't seem to fix it. I haven't been able to produce the issue at home though since. I'll probably just clean the connection tips between the capsule and body and leave it as is.

The U853s are great though. I've had mine now for more than three years, and I like them. Every time I think about upgrading, I circle back to them because they get the job done. I just got my Naiant PFAs in the mail to replace my old Nady adapters and I can't wait to use those too for improved sound quality. 

[Sunday Driver]

I purchased two Audio Technica U853-C capsules new a little over three years ago. I've probably used them about 30 or so times since then. When I first got them, one cap was only about -2db off in sensitivity from the other. However, I noticed the last time I used them that one cap seems to have decreased drastically in sensitivity....it's now between -6db to -8db off from the other capsule. My question is if this is a common problem with AT caps and if this may be a sign that the FET in the capsule is going? I know these aren't exactly high end mic capsules, so I'm wondering if that may be the case and they have a short life span. Thanks.

How are you measuring that?

Probably not the right way. Adobe Audition has a feature that provides amplitude statistics for a wave form. One piece of data this provides is average RMS power. So if you subtract Left from Right or Right from Left, that's what I'm using to find the difference.

Thats not how you want to do it. For argument sake the best way to do it is take a 1 k tone put both mics as close together as possible then use a good level meter to see if there are differences. Also make sure the metal tab is bent up towards the capsule pin. And that the nut is tight on the capsule pin. But you dont want to use any tools on it just your fingers to make sure its tight. Or a small pair of pliers. But you do not want to use any force.

OK, thanks for the advice, Chris. I'll give it a try. Hopefully it just ends up being a connection issue.

[Church-Audio]

I purchased two Audio Technica U853-C capsules new a little over three years ago. I've probably used them about 30 or so times since then. When I first got them, one cap was only about -2db off in sensitivity from the other. However, I noticed the last time I used them that one cap seems to have decreased drastically in sensitivity....it's now between -6db to -8db off from the other capsule. My question is if this is a common problem with AT caps and if this may be a sign that the FET in the capsule is going? I know these aren't exactly high end mic capsules, so I'm wondering if that may be the case and they have a short life span. Thanks.

How are you measuring that?

Probably not the right way. Adobe Audition has a feature that provides amplitude statistics for a wave form. One piece of data this provides is average RMS power. So if you subtract Left from Right or Right from Left, that's what I'm using to find the difference.

Thats not how you want to do it. For argument sake the best way to do it is take a 1 k tone put both mics as close together as possible then use a good level meter to see if there are differences. Also make sure the metal tab is bent up towards the capsule pin. And that the nut is tight on the capsule pin. But you dont want to use any tools on it just your fingers to make sure its tight. Or a small pair of pliers. But you do not want to use any force.

OK, thanks for the advice, Chris. I'll give it a try. Hopefully it just ends up being a connection issue.

ALSO!! try switching the caps. When I match my mics I mach the mic body and the capsule as one unit. So if you were to switch capsules on my ca-11 left for right you might find them mismatched. Why because the Fets are not all the same and the capsules are not all the same. By matching the capsule / body as one unit you get a better match because you are also taking into consideration the differences between fets and capsules. So that would also be a good place to look.

Hope that made sense lol.