Topic: SP-CMC-4U and other SP mics with new "low-sensitivity-mod" for very high SPL

[nameloc01]

thanks for the info, and kudos for your brainstorm/creation.thats about the only downfall with mine, its not quite as stealthy as i'd like it to be.

[Alchemy]

Interesting, considering when I was in the market for microphones a month or two ago, Chris C claimed they had no interest in offering this famous 4.7k mod. Now this all of a sudden.

I've still yet to have clipping issues with the 831s.  An upgrade is imminent though...

[Church-Audio]

Interesting, considering when I was in the market for microphones a month or two ago, Chris C claimed they had no interest in offering this famous 4.7k mod. Now this all of a sudden.

I've still yet to have clipping issues with the 831s.  An upgrade is imminent though...

You sent me an email on March 03, 2007 You said Hey Chris I think I can do the mod my self can you supply me with the resistors lol.. You never asked me if I could do the mod for you. I would have said yes. I get at least 10 customers a month that pay me $10 each to do MY 4.7k MOD.

 

Chris

[Alchemy]

Interesting, considering when I was in the market for microphones a month or two ago, Chris C claimed they had no interest in offering this famous 4.7k mod. Now this all of a sudden.

I've still yet to have clipping issues with the 831s.  An upgrade is imminent though...

You sent me an email on March 03, 2007 You said Hey Chris I think I can do the mod my self can you supply me with the resistors lol.. You never asked me if I could do the mod for you. I would have said yes. I get at least 10 customers a month that pay me $10 each to do MY 4.7k MOD.

 

Chris

No, I was talking abou Sound Pro Chris in my last post. I forgot you guys both have the same initials (CC).

[illconditioned]

Its nice to know someone is making some money off my 4.7k mod but just to let you know I do the mod MY MOD for $10 + return shipping.

Hey Chris,

It sucks to see noone crediting your mod, but I'm sure you'll continue to do a good business here.
Unlike random websites and Ebay, here is where the rubber hits the road and people get to hear real feedback about all kinds of products.
Your (modded) cardioids are a solid product and great value as far as I'm concerned.
Just keep adding new stuff, like omni caps, "ultrastealth" preamps, etc, and we'll keep buying them...

  Richard

[Church-Audio]

Interesting, considering when I was in the market for microphones a month or two ago, Chris C claimed they had no interest in offering this famous 4.7k mod. Now this all of a sudden.

I've still yet to have clipping issues with the 831s.  An upgrade is imminent though...

You sent me an email on March 03, 2007 You said Hey Chris I think I can do the mod my self can you supply me with the resistors lol.. You never asked me if I could do the mod for you. I would have said yes. I get at least 10 customers a month that pay me $10 each to do MY 4.7k MOD.

 

Chris

No, I was talking abou Sound Pro Chris in my last post. I forgot you guys both have the same initials (CC).

Sorry

[Church-Audio]

Its nice to know someone is making some money off my 4.7k mod but just to let you know I do the mod MY MOD for $10 + return shipping.

Hey Chris,

It sucks to see noone crediting your mod, but I'm sure you'll continue to do a good business here.
Unlike random websites and Ebay, here is where the rubber hits the road and people get to hear real feedback about all kinds of products.
Your (modded) cardioids are a solid product and great value as far as I'm concerned.
Just keep adding new stuff, like omni caps, "ultrastealth" preamps, etc, and we'll keep buying them...

  Richard

Well you have done a lot more for the community then I have. Your words mean a lot to me thanks..

Chris

[Roving Sign]

Not sure if this is fair to call this "your mod" - I think this info was bandied about USENET back in the day...

Originally published: http://sound.westhost.com/project58.htm
Siegfried Linkwitz, Shaped Tone-Burst Testing, JAES, Vol. 28,  No. 4, April 1980

http://sound.westhost.com/project93.htm

[Church-Audio]

Not sure if this is fair to call this "your mod" - I think this info was bandied about USENET back in the day...

Originally published: http://sound.westhost.com/project58.htm
Siegfried Linkwitz, Shaped Tone-Burst Testing, JAES, Vol. 28,  No. 4, April 1980

http://sound.westhost.com/project93.htm

That's actually not my mod... This shows a two wire capsule that is converted to three wire. My mod converts a three wire capsule to two wire and gives you the same performance as this mod except my mod is backwards to this one. And for the record I have never seen this mod but like most things in electronics. I am sure its been done before, I was the first one to figure out why some AT capsules were distorting. I found a way that is similar to this mod except that my resistor goes from the negative side of the capsule to ground and you only connect the ground side of the resistor + the output of the capsule. So I guess I can say that the 4.7k mod I do is in fact still my mod..


I am not someone that takes other peoples ideas and says they are my own. To my knowledge no one has done a mod exactly like the one I have done.. Linkwitz actually ended up with a better mod then the original one shown here. But its much more complicated then my mod.



If you take a three wire capsule and take the Negative side of the capsule connect it to ground then take the ground side and connect it to audio ground and the positive side for output you have done my mod. The problem has always been that 2 wire mics always distort, when I started building mics I needed a way to use the cheaper cable lol because I could not afford mogami. I needed a mod that would work on two wires so that's why I came up with it.. I wanted to not have to use three wire mics with three wire battery boxes but still get three wire performance.. No big mystery.

What Linkwitz did was convert a two wire capsule into three wires. I wanted to go the other way round. But I did not copy his design I came up with this all by my self. Using a low distortion source @1k @114db and changing resistors until I found the right value that allowed for maximum output and minimum distortion 4.7k happened to be the right choice. I dont understand why I only know that I tried every other value I could and nothing worked better then 4.7k I did not read about linkwitz and copy his idea..




PS.. The mod below is the only 2 wire Linkwitz mod I have ever seen.. And its nothing like my mod.. Even the mod you posted is not exactly like my mod.

Chris

[sjoe]

And for the record I have never seen this mod but like most things in electronics. I am sure its been done before

It has been done before if you consider it in the context of FET amplifier design, which is what this is really about.   (The fact that there's a microphone capsule involved is mostly irrelevant; the important bit is the proper biasing of the FET circuit.)

The "4.7k mod" is a form of common-drain or source-follower circuit.   These things have been around since the 1960's, and the design methodology is very well known and extensively documented.    Here's a couple of links:

http://www.rason.org/Projects/jfetamp/jfetamp.htm

http://www2.eng.cam.ac.uk/~dmh/ptialcd/spice/simulation.htm#SelfBiasJFET

http://ist-socrates.berkeley.edu/~phylabs/bsc/PDFFiles/bsc5.pdf

There's several very interesting bits of information in there, including the explanation for the decrease in distortion, and a possible work-around for the loss of gain.

Joe

[Roving Sign]

And for the record I have never seen this mod but like most things in electronics. I am sure its been done before

It has been done before if you consider it in the context of FET amplifier design, which is what this is really about.   (The fact that there's a microphone capsule involved is mostly irrelevant; the important bit is the proper biasing of the FET circuit.)

The "4.7k mod" is a form of common-drain or source-follower circuit.   These things have been around since the 1960's, and the design methodology is very well known and extensively documented.    Here's a couple of links:

http://www.rason.org/Projects/jfetamp/jfetamp.htm

http://www2.eng.cam.ac.uk/~dmh/ptialcd/spice/simulation.htm#SelfBiasJFET

http://ist-socrates.berkeley.edu/~phylabs/bsc/PDFFiles/bsc5.pdf

There's several very interesting bits of information in there, including the explanation for the decrease in distortion, and a possible work-around for the loss of gain.

Joe

Ahhh - thats a good explanation. I suspected the theory in play wasn't a secret. (although I leave it to the experts to determine if your info here is relevant)

I'll disagree somewhat here:

The fact that there's a microphone capsule involved is mostly irrelevant

Well it's relevant as to who first applied this theory to a electret microphone. (which is what is being debated) Chris seems to have a solid claim on that aspect.

[kfrinkle]

I had such a pain in the ass time recording high SPL shows (heavy metal stealth taping of course) that I ended up getting a three wire mod with my CMC-8s... Definitely improves the sound.  Seems like many of the mics that SP.com offers really do have this issue (at least going into JB3s and MT 24/96s etc...).  I wish I had known about a fix earlier, so I think it is awesome that a few people on the board do the mods.  It beats sending them back to SP.com where I already explicitly asked them what to get to ensure all worked fine at heavy metal shows.

*sigh*...

[Church-Audio]

And for the record I have never seen this mod but like most things in electronics. I am sure its been done before

It has been done before if you consider it in the context of FET amplifier design, which is what this is really about.   (The fact that there's a microphone capsule involved is mostly irrelevant; the important bit is the proper biasing of the FET circuit.)

The "4.7k mod" is a form of common-drain or source-follower circuit.   These things have been around since the 1960's, and the design methodology is very well known and extensively documented.    Here's a couple of links:

http://www.rason.org/Projects/jfetamp/jfetamp.htm

http://www2.eng.cam.ac.uk/~dmh/ptialcd/spice/simulation.htm#SelfBiasJFET

http://ist-socrates.berkeley.edu/~phylabs/bsc/PDFFiles/bsc5.pdf

There's several very interesting bits of information in there, including the explanation for the decrease in distortion, and a possible work-around for the loss of gain.

Joe

What you say is true, but again I was the first one to use it in a mic capsule... I came up with the value by using a distortion meter and a 1k test tone. And I am the one that figured a workaround for existing microphones. I know that everything in electronics has been done before. But no one to my knowledge has ever applied this to a electret fet on a capsule with a resistor that is 4.7k and I would have to strongly disagree that the context of the applied method has no relevance.. This mod had come about not because of my knowledge of the technique you describe but purely because of experimentation. And there for its still valid that I came up with a method to reduce distortion in electret mics that has not been done before. And one last thing none of the schematics you show actually show my method although there are similarities none of the methods exactly describes my modification. Not that I have come up with some revolutionary electronics theory. But I did come up with a method to reduce distortion in a microphone capsule. I guess there will always be theory's that are close to describing someone else's work that's the part of science that makes things interesting, please show me the circuit on the Internet or anywhere that describes using my method on a mic capsule. You cant because I am the inventor of it. None of your methods are exactly like the mod that I do...

Chris

[GDfan]

patent that mod and get paid for it 

[Church-Audio]

patent that mod and get paid for it 

No that was never my intention.. I only got pissed when another company was doing the mod and charging for it and not giving me proper credit... I also got pissed when a few people were saying I was lying and did not come up with this.. So I defended my self. I never had any intention of making money from this..