Topic: Simple hack to increase SPL on AT853

[poorlyconditioned]

I finally did a simple (and obvious) hack on AT853's to prevent overloading.

Normally they are connected like this:
- red wire: + battery box, and audio
- yellow wire and shield: ground for battery and audio
The standard (two-wire) battery box supplies power to the mics through a 10k resistor.

What I did was put a 4.7k resistor between yellow and ground.  (Actually, I put a *tiny* surface mount part right at the capsule, but you could do this anywhere on the cable.)  Now I power the mics with the standard (two-wire) battery box.  This will reduce gain a bit, but it *should* prevent overloading.

I think this idea originates with Dick Campbell, where he used it for WM60A mics for speaker response measurement.

Anyway, I modified a pair of my mics and sold them to Bobcat.  He's going to torture test them at some Tool shows...

  Richard

[Church-Audio]

Thats actually my mod but its ok you do not have to give me credit
I have measured the distortion before and after the before 8% at 114db @1k after 0.5% at 114db @1k net loss of output 5.6 dB
Chris Church
ps....

Dick Might have come up with it at the same time as me,  But I have been doing that mod for 10 years now. I have just recently done it to the 3 wire in the last 2 years It does work great.

And do not use a surface mount use a 1/8th watt resistor via NTE you have to order them they are metal film 2% I have to hand match them all because if you deviate from the 4.7k by as much as 100 ohms your distortion goes right up again.

I finally did a simple (and obvious) hack on AT853's to prevent overloading.

Normally they are connected like this:
- red wire: + battery box, and audio
- yellow wire and shield: ground for battery and audio
The standard (two-wire) battery box supplies power to the mics through a 10k resistor.

What I did was put a 4.7k resistor between yellow and ground.  (Actually, I put a *tiny* surface mount part right at the capsule, but you could do this anywhere on the cable.)  Now I power the mics with the standard (two-wire) battery box.  This will reduce gain a bit, but it *should* prevent overloading.

I think this idea originates with Dick Campbell, where he used it for WM60A mics for speaker response measurement.

Anyway, I modified a pair of my mics and sold them to Bobcat.  He's going to torture test them at some Tool shows...

  Richard

[poorlyconditioned]

Thats actually my mod but its ok you do not have to give me credit
I have measured the distortion before and after the before 8% at 114db @1k after 0.5% at 114db @1k net loss of output 5.6 dB
Chris Church
ps....

Dick Might have come up with it at the same time as me,  But I have been doing that mod for 10 years now. I have just recently done it to the 3 wire in the last 2 years It does work great.

And do not use a surface mouu have to order them they are metal film 2% I have to hand match them all because if you deviate from the 4.7k by as much as nt use a 1/8th watt resistor via NTE yo100 ohms your distortion goes right up again.

I finally did a simple (and obvious) hack on AT853's to prevent overloading.

Normally they are connected like this:
- red wire: + battery box, and audio
- yellow wire and shield: ground for battery and audio
The standard (two-wire) battery box supplies power to the mics through a 10k resistor.

What I did was put a 4.7k resistor between yellow and ground.  (Actually, I put a *tiny* surface mount part right at the capsule, but you could do this anywhere on the cable.)  Now I power the mics with the standard (two-wire) battery box.  This will reduce gain a bit, but it *should* prevent overloading.

I think this idea originates with Dick Campbell, where he used it for WM60A mics for speaker response measurement.

Anyway, I modified a pair of my mics and sold them to Bobcat.  He's going to torture test them at some Tool shows...

  Richard

Cool.  I thought that might be what you were doing, but I didn't want to make any claims or disclose any of your proprietary methods.

I'm still going to use three wire for my own stuff.  One thing is I love those locking miniXLR connectors (instead of the unreliable stereo 1/8" miniplugs).  Another thing is with 3-wire, you can get "all" the voltage, instead of losing 1/2 or 1/3 of it on that 5k resistor.  All of my stuff (AKG CK91/2/3, AT853, Naks, etc) use the same three-wire configuration.

  Richard

[Church-Audio]

Electronics is like music there are no proprietary methods/ideas anymore just good ideas that we all come up with sooner or later I guess I will refund the shipping on the mics since you already know one of my little secrets. And I don't feel like having them all exposed.

Chris Church

Thats actually my mod but its ok you do not have to give me credit
I have measured the distortion before and after the before 8% at 114db @1k after 0.5% at 114db @1k net loss of output 5.6 dB
Chris Church
ps....

Dick Might have come up with it at the same time as me,  But I have been doing that mod for 10 years now. I have just recently done it to the 3 wire in the last 2 years It does work great.

And do not use a surface mouu have to order them they are metal film 2% I have to hand match them all because if you deviate from the 4.7k by as much as nt use a 1/8th watt resistor via NTE yo100 ohms your distortion goes right up again.

I finally did a simple (and obvious) hack on AT853's to prevent overloading.

Normally they are connected like this:
- red wire: + battery box, and audio
- yellow wire and shield: ground for battery and audio
The standard (two-wire) battery box supplies power to the mics through a 10k resistor.

What I did was put a 4.7k resistor between yellow and ground.  (Actually, I put a *tiny* surface mount part right at the capsule, but you could do this anywhere on the cable.)  Now I power the mics with the standard (two-wire) battery box.  This will reduce gain a bit, but it *should* prevent overloading.

I think this idea originates with Dick Campbell, where he used it for WM60A mics for speaker response measurement.

Anyway, I modified a pair of my mics and sold them to Bobcat.  He's going to torture test them at some Tool shows...

  Richard

Cool.  I thought that might be what you were doing, but I didn't want to make any claims or disclose any of your proprietary methods.

I'm still going to use three wire for my own stuff.  One thing is I love those locking miniXLR connectors (instead of the unreliable stereo 1/8" miniplugs).  Another thing is with 3-wire, you can get "all" the voltage, instead of losing 1/2 or 1/3 of it on that 5k resistor.  All of my stuff (AKG CK91/2/3, AT853, Naks, etc) use the same three-wire configuration.

  Richard

[poorlyconditioned]

Electronics is like music there are no proprietary methods/ideas anymore just good ideas that we all come up with sooner or later I guess I will refund the shipping on the mics since you already know one of my little secrets. And I don't feel like having them all exposed.

Chris Church

Thats actually my mod but its ok you do not have to give me credit
I have measured the distortion before and after the before 8% at 114db @1k after 0.5% at 114db @1k net loss of output 5.6 dB
Chris Church
ps....

Dick Might have come up with it at the same time as me,  But I have been doing that mod for 10 years now. I have just recently done it to the 3 wire in the last 2 years It does work great.

And do not use a surface mouu have to order them they are metal film 2% I have to hand match them all because if you deviate from the 4.7k by as much as nt use a 1/8th watt resistor via NTE yo100 ohms your distortion goes right up again.

I finally did a simple (and obvious) hack on AT853's to prevent overloading.

Normally they are connected like this:
- red wire: + battery box, and audio
- yellow wire and shield: ground for battery and audio
The standard (two-wire) battery box supplies power to the mics through a 10k resistor.

What I did was put a 4.7k resistor between yellow and ground.  (Actually, I put a *tiny* surface mount part right at the capsule, but you could do this anywhere on the cable.)  Now I power the mics with the standard (two-wire) battery box.  This will reduce gain a bit, but it *should* prevent overloading.

I think this idea originates with Dick Campbell, where he used it for WM60A mics for speaker response measurement.

Anyway, I modified a pair of my mics and sold them to Bobcat.  He's going to torture test them at some Tool shows...

  Richard

Cool.  I thought that might be what you were doing, but I didn't want to make any claims or disclose any of your proprietary methods.

I'm still going to use three wire for my own stuff.  One thing is I love those locking miniXLR connectors (instead of the unreliable stereo 1/8" miniplugs).  Another thing is with 3-wire, you can get "all" the voltage, instead of losing 1/2 or 1/3 of it on that 5k resistor.  All of my stuff (AKG CK91/2/3, AT853, Naks, etc) use the same three-wire configuration.

  Richard

Hey Chris,

I wouldn't worry about people finding out this stuff.  Unlike others who rely on secret methods (eg., Core-audio) we are paying you for honest disclosure of your product, quality work, and great prices.  It is not like one of us is going to start buying hundreds of capsules or opamps and start competing with you.

You've already told us what is inside your some of your gear (preamps, etc).  Hell, if somone wants to really bust you, they will buy your stuff under an assumed name, take it apart, and try to copy it.  No way you're going to prevent that.

Oh yeah, the other thing is most other competitors are incompetant as well, so they couldn't even do this handiwork, even if they wanted to.

So, please send me your stuff.  I'm not out to bust your methods or sources.  I'm just out to give them a fair shake.  My *guess* at this point is that they will sound close to, but not quite as good as the AT853.  I'd like to try them out though.  Well, if I don't someone else will.  I think you've got a good product at $100 or whatever.  Aside from a few used pairs of AT853 I'm selling, new pairs are going to cost $200 at Soundpros.  Oh yeah, I've sold just three pairs *total* of AT853 over the last year.  I think I'll sell one more and that will probably be it.

  Richard

[poorlyconditioned]

Dear Chris:

Hmm.  OK, maybe don't bother sending me those mics after all.  Just refund the shipping.

I wanted to compare to AT853, but someone else can do that with the "loaner" pair.

I also don't want to be blamed for disclosing anything more about them...

Well, I guess my opinion is that things should be open, and you will make more sales in the long run just based on the workmanship and service.  But I don't want to start an argument about that.  I just want to keep tweaking gear and recording.

  Richard

[Church-Audio]

Hey relax I am sending you the mics I would value your opinion I think your very talented with electronics design I have seen some of your handy work you just have to get better with a dremel tool but hell when I started hacking things together well lets just say I am glad that I have not seen any for sale I would be too embarrassed to say I made them. I have sold over 2000 preamps world wide after about 100 you get pretty good at putting them together lol. I would like to chat with you about preamp design some day I have a few challenges in the next few weeks and it would be nice to bounce some ideas off you. I am sorry for my first post it was immature and brash. I was upset about one of my mods being exposed but you know what who cares. People will figure things out on there own sooner or later like I said about music with electronics its all been done before. Just a different package same result.

Chris Church

Dear Chris:

Hmm.  OK, maybe don't bother sending me those mics after all.  Just refund the shipping.

I wanted to compare to AT853, but someone else can do that with the "loaner" pair.

I also don't want to be blamed for disclosing anything more about them...

Well, I guess my opinion is that things should be open, and you will make more sales in the long run just based on the workmanship and service.  But I don't want to start an argument about that.  I just want to keep tweaking gear and recording.

  Richard

[Church-Audio]

T+ for figuring out the 4.7k thing with out a distortion analyser ( I have one so it makes it easy)

Dear Chris:

Hmm.  OK, maybe don't bother sending me those mics after all.  Just refund the shipping.

I wanted to compare to AT853, but someone else can do that with the "loaner" pair.

I also don't want to be blamed for disclosing anything more about them...

Well, I guess my opinion is that things should be open, and you will make more sales in the long run just based on the workmanship and service.  But I don't want to start an argument about that.  I just want to keep tweaking gear and recording.

  Richard

[Patrick]

I was upset about one of my mods being exposed but you know what who cares. People will figure things out on there own sooner or later like I said about music with electronics its all been done before. Just a different package same result.

Chris, not to sound like a dick, but you are the one who exposed the mod.  While Richard put it out for all to see, you came along and claimed that it was yours.  You could have just not said anything, and you would still have a secret.

[Church-Audio]

Pat it’s not the only mod I do, so it’s all cool I don’t mind me and Richard talked about It I apologized and its over
Chris Church

I was upset about one of my mods being exposed but you know what who cares. People will figure things out on there own sooner or later like I said about music with electronics its all been done before. Just a different package same result.

Chris, not to sound like a dick, but you are the one who exposed the mod.  While Richard put it out for all to see, you came along and claimed that it was yours.  You could have just not said anything, and you would still have a secret.

[RebelRebel]

I was upset about one of my mods being exposed but you know what who cares. People will figure things out on there own sooner or later like I said about music with electronics its all been done before. Just a different package same result.

Chris, not to sound like a dick

Thats one of the big issues here...people just pile on. Nothing against you Patrick, you were nice about it..but it was Chris and Poorly's discussion..no need for any other folks to jump in. That is the biggest problem with this site. Gang-ups.

[Josephine]

Would the AT933's benefit from a similar modification?
Used them a couple weeks ago and had a huge overload problem . . . they just couldn't handle it.
Recording is distorted in many places. 

[poorlyconditioned]

Would the AT933's benefit from a similar modification?
Used them a couple weeks ago and had a huge overload problem . . . they just couldn't handle it.
Recording is distorted in many places. 

Yep.  They're pretty similar.  AT831 are also very close.

For my stuff I use a (hard-wired) 3-wire battery box.  But if you have an existing battery box and mic set (eg., from Soundprofessionals), then you should be able to do the "4.7k mod".  Let's call it the "Church" mod, since I think no other retailer is doing this.  (Soundpros don't do any mods, while CoreSound does the Linkwitz mod.)

By the way, please don't ask me to do this.  I don't want to get into doing mods for others.  I sell a few mic sets, etc, when I get overloaded, but I don't want to do mods.

Hmm.  Maybe Chris would do this for you (or others?).  It might be a useful service for those with existing mic sets.  On reflection, this is probably nicer than the 3-wire battery box, especially for those that already have a "standard" 2-wire one...

Can you solder?  If so, take apart the miniplug.  You'll probably see yellow wire (*) shorted to ground (shield), and a red wire for each of channels (L: tip, R: ring).  Seperate the yellow wire and insert a 4.7k resistor between yellow and shield, and try it out.  You may not be able to do this inside the connector, but you could probably hack at the cable and do it somehow ().  Remember to use lots of shrinkwrap and hot melt glue

(*) Some AT mics have a white wire instead of yellow.  So they are either shield/yellow/red or shield/white/red.  Also, some mics have a pair of each yellow and red (star quad cable) and others just have a single wire for each.

  Richard

[Josephine]

Would the AT933's benefit from a similar modification?
Used them a couple weeks ago and had a huge overload problem . . . they just couldn't handle it.
Recording is distorted in many places. 

Yep.  They're pretty similar.  AT831 are also very close.

For my stuff I use a (hard-wired) 3-wire battery box.  But if you have an existing battery box and mic set (eg., from Soundprofessionals), then you should be able to do the "4.7k mod".  Let's call it the "Church" mod, since I think no other retailer is doing this.  (Soundpros don't do any mods, while CoreSound does the Linkwitz mod.)

By the way, please don't ask me to do this.  I don't want to get into doing mods for others.  I sell a few mic sets, etc, when I get overloaded, but I don't want to do mods.

Hmm.  Maybe Chris would do this for you (or others?).  It might be a useful service for those with existing mic sets.  On reflection, this is probably nicer than the 3-wire battery box, especially for those that already have a "standard" 2-wire one...

Can you solder?  If so, take apart the miniplug.  You'll probably see yellow wire (*) shorted to ground (shield), and a red wire for each of channels (L: tip, R: ring).  Seperate the yellow wire and insert a 4.7k resistor between yellow and shield, and try it out.  You may not be able to do this inside the connector, but you could probably hack at the cable and do it somehow ().  Remember to use lots of shrinkwrap and hot melt glue

(*) Some AT mics have a white wire instead of yellow.  So they are either shield/yellow/red or shield/white/red.  Also, some mics have a pair of each yellow and red (star quad cable) and others just have a single wire for each.

  Richard

I can totally appreciate your not wanting to get started doing modifications, Richard, I have no issue with that . . . . and I thank you for enlightening me about the possibility of modifying my 933s.  I'd be afraid to plug in a solder gun, let alone use it.  lol  I guess there's a first time for everything, but I'm not about to learn on a set of mics . . . . so maybe Chris can chime in, let me know whether this is a mod that he would consider doing.

These are not my main mics and I'd really be in no particular hurry to get this done.  I just read the thread and thought, "Hmm,   I wonder if that would work with my AT933's?"  Now I know.  Thanks, Richard. 

[Church-Audio]

If you need the small resistors to do this I have 1/8th watt I can send you for free they are metal film and very hard to find in a 2% value the you can also build a battery box 3 wire and do this mod inside the battery box you can have it so it can be switched in and out of the circuit for shows that do not require it sort of like a pad..... Well exactly like a pad for your mics but way before the signal ever gets to your second gain stage. Richard has plans for a good battery box if your interested. Or you can purchase one from me if you dont like to build.


Chris Church

Would the AT933's benefit from a similar modification?
Used them a couple weeks ago and had a huge overload problem . . . they just couldn't handle it.
Recording is distorted in many places.