SP-CMC-4U Mics

[Church-Audio]

I don't understand the problem here.

The three-wire box (or Chris' 4.7k mod) loses a bit of gain, but not much.  I would guess something like -10dB or so.  But it is not a problem in practice (see below).

For any reasonable level of amplified music, a minidisc mic-in/low-sens will work great.  I've recorded a ton of shows with this.  FYI, mic-in/low-sens on MD is pretty much the same as mic-in/low-sens setting on the Edirol R09.  Both have moderate gain (around 20dB max) and a wide range of variation of input levels that will not overload (eg., from -20dBv to +10dBv).  At these moderate levels of amplification mic pre noise is not usually a problem.

Problem cases are:
- recording quieter stuff, like acoustic music.  You could run mic-in/hi-sens, but that is noisy.  An external pre will help.
- recording with certain low output mics, like Sony ECM-907.  These are  about -10dB lower than the AT stuff.
- trying to run into line input on crappy analog inputs, like iRivier, NJB3, etc.  These provide a little gain, but it is terrible quality,
   so all the gain should come from an external preamp.

I suspect a preamp may provide a bit nicer/cleaner gain than the MD/Edirol mic-in/low-sens inputs.  But it is not really needed per se.

  Richard

Its not needed. Until you need it I always suggest people buy this preamp instead of a battery box because I sell the preamp for $79 more then a three wire battery box $100 so your are better off having the best of both worlds my preamp allows you to get hotter levels with out the noise and to be able to normalize less. Not to mention the clip light that allows you to monitor distortion levels while your recording. Something a battery box does not have. I would say if your using the new HIMD recorders you don't need a preamp or if your using the Edirol R-09 with my mics or a pair of my modded mics you don't need a battery box never mind a preamp. But if you record all kinds of stuff from quiet to loud its better to spend the extra $79 and get a preamp and a battery box then to just spend $100 and get a battery box that will not help you much in quiet situations you "might" find your self in.

[poorlyconditioned]

I don't understand the problem here.

The three-wire box (or Chris' 4.7k mod) loses a bit of gain, but not much.  I would guess something like -10dB or so.  But it is not a problem in practice (see below).

For any reasonable level of amplified music, a minidisc mic-in/low-sens will work great.  I've recorded a ton of shows with this.  FYI, mic-in/low-sens on MD is pretty much the same as mic-in/low-sens setting on the Edirol R09.  Both have moderate gain (around 20dB max) and a wide range of variation of input levels that will not overload (eg., from -20dBv to +10dBv).  At these moderate levels of amplification mic pre noise is not usually a problem.

Problem cases are:
- recording quieter stuff, like acoustic music.  You could run mic-in/hi-sens, but that is noisy.  An external pre will help.
- recording with certain low output mics, like Sony ECM-907.  These are  about -10dB lower than the AT stuff.
- trying to run into line input on crappy analog inputs, like iRivier, NJB3, etc.  These provide a little gain, but it is terrible quality,
   so all the gain should come from an external preamp.

I suspect a preamp may provide a bit nicer/cleaner gain than the MD/Edirol mic-in/low-sens inputs.  But it is not really needed per se.

  Richard

Its not needed. Until you need it I always suggest people buy this preamp instead of a battery box because I sell the preamp for $79 more then a three wire battery box $100 so your are better off having the best of both worlds my preamp allows you to get hotter levels with out the noise and to be able to normalize less. Not to mention the clip light that allows you to monitor distortion levels while your recording. Something a battery box does not have. I would say if your using the new HIMD recorders you don't need a preamp or if your using the Edirol R-09 with my mics or a pair of my modded mics you don't need a battery box never mind a preamp. But if you record all kinds of stuff from quiet to loud its better to spend the extra $79 and get a preamp and a battery box then to just spend $100 and get a battery box that will not help you much in quiet situations you "might" find your self in.

Well said, Chris!  Exactly what I just rambled on about in the previous post.

Remember, you never know when you need a preamp.  You may use MD now and later on need to run into an iRiver/NJB3/etc that has no real gain stage, and then you will need it!

  Richard

[Church-Audio]

Here we go again...well for starters, the AT u853s with just battery power can only reproduce at most, 110 db's before they will start to distort.

Was this a loud show? Can you provide any samples?

Also, if you don't mind me asking, what other mics have you used in the past?

AT 114 db at 1k these mics have a distortion of 5% Pretty bad until you do my mod then its .5% much better.

[loul69]

Little question please.
For my u853 i m building a 3 wire bbox(will put schematics and pics when it will be ready). Is it necessary to put a bass roll-off or not for taping "pop" shows with a hi-md recorder?

Thanks

[Church-Audio]

Little question please.
For my u853 i m building a 3 wire bbox(will put schematics and pics when it will be ready). Is it necessary to put a bass roll-off or not for taping "pop" shows with a hi-md recorder?

Thanks

I would put a bass roll off simply because its just a matter of a switch dbdt and a extra set of caps I use 330nf or .33uf same thing. This gives me about 90hz at 10k input. If you don't want to do that make sure you use 10uf caps for your dc blocking caps so that you allow the maximum amount of bass to flow thru.

[hawghunter]

Here we go again...well for starters, the AT u853s with just battery power can only reproduce at most, 110 db's before they will start to distort.

Was this a loud show? Can you provide any samples?

Also, if you don't mind me asking, what other mics have you used in the past?

I have a mp3 sample if you would like

[loul69]

Little question please.
For my u853 i m building a 3 wire bbox(will put schematics and pics when it will be ready). Is it necessary to put a bass roll-off or not for taping "pop" shows with a hi-md recorder?

Thanks

I would put a bass roll off simply because its just a matter of a switch dbdt and a extra set of caps I use 330nf or .33uf same thing. This gives me about 90hz at 10k input. If you don't want to do that make sure you use 10uf caps for your dc blocking caps so that you allow the maximum amount of bass to flow thru.

Thanks for all, i ve just realised the thrid schematic of this page:
http://taperssection.com/index.php/topic,72994.0.html
Do u agree with the values of the resistance and capacitor?
If u have to put a bass roll off on it, which capacitors would you use?
Last question, i tape using a Hi MD. Is it better to plug the bbox in the mic or in the line in input?

Thanks
Bye

[Church-Audio]

Little question please.
For my u853 i m building a 3 wire bbox(will put schematics and pics when it will be ready). Is it necessary to put a bass roll-off or not for taping "pop" shows with a hi-md recorder?

Thanks

I would put a bass roll off simply because its just a matter of a switch dbdt and a extra set of caps I use 330nf or .33uf same thing. This gives me about 90hz at 10k input. If you don't want to do that make sure you use 10uf caps for your dc blocking caps so that you allow the maximum amount of bass to flow thru.

Thanks for all, i ve just realised the thrid schematic of this page:
http://taperssection.com/index.php/topic,72994.0.html
Do u agree with the values of the resistance and capacitor?
If u have to put a bass roll off on it, which capacitors would you use?
Last question, i tape using a Hi MD. Is it better to plug the bbox in the mic or in the line in input?

Thanks
Bye

If you do my modification you don't need to go to three wire. The two wire mod I have come up with is very easy.. When you wire AT mics to go two wire. You must use the Red wire as the signal wire and the Yellow wire must be shorted to ground... With my mod all you do is insert a 4.7k 1% metal film resistors between the Yellow wire and ground, and you now have a set of mics that can be plugged right into a Edirol R-09 with no battery box required that will handle the same SPL as a set of AT mics with a battery box. And you don't need the roll off to reduce distortion ether... Simple effective and last but not least cheap.. This is what I do to my microphones. Three wire has no advantage over this method when this modification is performed.. Now a battery box is needed if you plan on going into a MD line input.. But now most HIMD recorders have a built in mic pad so that you can in fact go  directly in with out the need for external battery boxes.

[loul69]

Little question please.
For my u853 i m building a 3 wire bbox(will put schematics and pics when it will be ready). Is it necessary to put a bass roll-off or not for taping "pop" shows with a hi-md recorder?

Thanks

I would put a bass roll off simply because its just a matter of a switch dbdt and a extra set of caps I use 330nf or .33uf same thing. This gives me about 90hz at 10k input. If you don't want to do that make sure you use 10uf caps for your dc blocking caps so that you allow the maximum amount of bass to flow thru.

Thanks for all, i ve just realised the thrid schematic of this page:
http://taperssection.com/index.php/topic,72994.0.html
Do u agree with the values of the resistance and capacitor?
If u have to put a bass roll off on it, which capacitors would you use?
Last question, i tape using a Hi MD. Is it better to plug the bbox in the mic or in the line in input?

Thanks
Bye

If you do my modification you don't need to go to three wire. The two wire mod I have come up with is very easy.. When you wire AT mics to go two wire. You must use the Red wire as the signal wire and the Yellow wire must be shorted to ground... With my mod all you do is insert a 4.7k 1% metal film resistors between the Yellow wire and ground, and you now have a set of mics that can be plugged right into a Edirol R-09 with no battery box required that will handle the same SPL as a set of AT mics with a battery box. And you don't need the roll off to reduce distortion ether... Simple effective and last but not least cheap.. This is what I do to my microphones. Three wire has no advantage over this method when this modification is performed.. Now a battery box is needed if you plan on going into a MD line input.. But now most HIMD recorders have a built in mic pad so that you can in fact go  directly in with out the need for external battery boxes.

I understand, but i have already build the 3 wire bbox. (third one of the link). My question is what to do if i need a bass roll off. May i have to only change the capacitor or do an external one?
I ve notice that with the 3 wire bbox, the sound is more muted when i record something (line in in Hi md recorder). I ve done a test recording my audio system. Is it normal? Will it be better for loud shows?

Thanks a lot

[poorlyconditioned]

Little question please.
For my u853 i m building a 3 wire bbox(will put schematics and pics when it will be ready). Is it necessary to put a bass roll-off or not for taping "pop" shows with a hi-md recorder?

Thanks

I would put a bass roll off simply because its just a matter of a switch dbdt and a extra set of caps I use 330nf or .33uf same thing. This gives me about 90hz at 10k input. If you don't want to do that make sure you use 10uf caps for your dc blocking caps so that you allow the maximum amount of bass to flow thru.

Thanks for all, i ve just realised the thrid schematic of this page:
http://taperssection.com/index.php/topic,72994.0.html
Do u agree with the values of the resistance and capacitor?
If u have to put a bass roll off on it, which capacitors would you use?
Last question, i tape using a Hi MD. Is it better to plug the bbox in the mic or in the line in input?

Thanks
Bye

If you do my modification you don't need to go to three wire. The two wire mod I have come up with is very easy.. When you wire AT mics to go two wire. You must use the Red wire as the signal wire and the Yellow wire must be shorted to ground... With my mod all you do is insert a 4.7k 1% metal film resistors between the Yellow wire and ground, and you now have a set of mics that can be plugged right into a Edirol R-09 with no battery box required that will handle the same SPL as a set of AT mics with a battery box. And you don't need the roll off to reduce distortion ether... Simple effective and last but not least cheap.. This is what I do to my microphones. Three wire has no advantage over this method when this modification is performed.. Now a battery box is needed if you plan on going into a MD line input.. But now most HIMD recorders have a built in mic pad so that you can in fact go  directly in with out the need for external battery boxes.

That is *almost* correct.  There is a slight loss of gain comparing 4.7k mod to 3-wire, but not much at all.  And it depends if that resistor is 4.7k or higher.

But, yes, this is the *simplest* solution.  The mics will work with both plug in power and "standard" two wire battery boxes.

Yep, time to do that mod, folks!  Note: you can do it right in the miniplug jack, or add a little extra "bump" in the cable that has the 4.7k resistors in it.  Cover with shrink wrap and you're off.

  Richard

[Church-Audio]

Little question please.
For my u853 i m building a 3 wire bbox(will put schematics and pics when it will be ready). Is it necessary to put a bass roll-off or not for taping "pop" shows with a hi-md recorder?

Thanks

I would put a bass roll off simply because its just a matter of a switch dbdt and a extra set of caps I use 330nf or .33uf same thing. This gives me about 90hz at 10k input. If you don't want to do that make sure you use 10uf caps for your dc blocking caps so that you allow the maximum amount of bass to flow thru.

Thanks for all, i ve just realised the thrid schematic of this page:
http://taperssection.com/index.php/topic,72994.0.html
Do u agree with the values of the resistance and capacitor?
If u have to put a bass roll off on it, which capacitors would you use?
Last question, i tape using a Hi MD. Is it better to plug the bbox in the mic or in the line in input?

Thanks
Bye

If you do my modification you don't need to go to three wire. The two wire mod I have come up with is very easy.. When you wire AT mics to go two wire. You must use the Red wire as the signal wire and the Yellow wire must be shorted to ground... With my mod all you do is insert a 4.7k 1% metal film resistors between the Yellow wire and ground, and you now have a set of mics that can be plugged right into a Edirol R-09 with no battery box required that will handle the same SPL as a set of AT mics with a battery box. And you don't need the roll off to reduce distortion ether... Simple effective and last but not least cheap.. This is what I do to my microphones. Three wire has no advantage over this method when this modification is performed.. Now a battery box is needed if you plan on going into a MD line input.. But now most HIMD recorders have a built in mic pad so that you can in fact go  directly in with out the need for external battery boxes.

That is *almost* correct.  There is a slight loss of gain comparing 4.7k mod to 3-wire, but not much at all.  And it depends if that resistor is 4.7k or higher.

But, yes, this is the *simplest* solution.  The mics will work with both plug in power and "standard" two wire battery boxes.

Yep, time to do that mod, folks!  Note: you can do it right in the miniplug jack, or add a little extra "bump" in the cable that has the 4.7k resistors in it.  Cover with shrink wrap and you're off.

  Richard

Hey I was hacking up a lung when I typed that... I am surprised anyone could make any sense out of it
Thanks for the correction Richard. I did find that 4.7 exactly produced the lowest distortion. I tried 5 k and it did not work very well. I also again highly recommend these be matched. And measured for precision 4.7k exactly gives the best results.

[Alchemy]

Here we go again...well for starters, the AT u853s with just battery power can only reproduce at most, 110 db's before they will start to distort.

Was this a loud show? Can you provide any samples?

Also, if you don't mind me asking, what other mics have you used in the past?

I have a mp3 sample if you would like

If you click on my username, you can find my e-mail address on my profile page. E-mail me the sample if you want to.

[loul69]

Hi everyone,

I ve a problem saturday night recording a show with my spcmc4u + 3wire bbox(third one of this page http://taperssection.com/index.php/topic,72994.0.html). The show was not too loud in a big concert hall (10000 people).
I used a line in input and a 20/30 manuel volume on the MD.

When i transfert the MD on my pc, the signal is very small...
So here is my question :

With the 3-wire bbox, is it better to put the bbox box in mic in to upper the signal?i know that it depend on the volume of the show, but generally what people do?

And what are the risk of distorsion in mic in?

Thanks a lot

Bye

[Javier Cinakowski]

regarding the 4.7k mod, [this is in regard to doing the mod at the mini-plug]

you can get away with just using 1 resistor.  In theory it is electrically identical to using 2 resistors, but I have heard some people get nervous about the cables being joined together.  maybe concerns over crosstalk or something.  Both yellow cables go to the same ground, so , using one resistor is the same as two.  Also by using one resistor, you don't have to worry about matching resistors, as it seems there is a problem using resistors that are slightly different values.

My mics were modded this way and work great....

[Church-Audio]

regarding the 4.7k mod,

you can get away with just using 1 resistor.  In theory it is electrically identical to using 2 resistors, but I have heard some people get nervous about the cables being joined together.  maybe concerns over crosstalk or something.  Both yellow cables go to the same ground, so , using one resistor is the same as two.  Also by using one resistor, you don't have to worry about matching resistors, as it seems there is a problem using resistors that are slightly different values.

My mics were modded this way and work great....

You need two I have 1/8th watt metal film resistors I can send you they are very small and I hand match them so your mics dont get unbalanced. I also use a switchcraft jack that is a bit bigger then the normal size 3.5 mm jack so you can put the resistors in with out any trouble. I will post some pictures in a day or so. Here is the only place I have found that has these jacks in stock BTX.COM  http://www.btx.com/ItemForm.aspx?item=CA-35HDBAU&Category=4348ad2f-1b43-47dc-83b3-5cee8464acbf   The picture of this connector might look similar to your regular jack but it has a jacket that is about 1x the size of a normal 3.5 mm jacket.