MXL 2003A Schematics / Modding anyone?

Ok, not finished with the first Project but allready anxious to do the next one.. I looked at the MXL 2003A today..pretty nice looking mic and Body.. i checked the Guts and i thought about why not mod it.. wanne replace the Capsule with an RK-87 , maybe replace some caps too, you guys got any schematics or ideas what i could do..bare with me I'm still a noob ok 

I can also take some high quality photos on the Guts if "we" can figure it out this way.. Appreciate your time, Thanks

Check out the vintage U-87 thread started by poctop. He has PCB's and a Bill of Materials that would fit in that mic. It might be a little over your experience level, but there might be U-67 boards floating around soon, as well. Check it out...

-James-

ok but, i just thought about to get rid of all the ceramic caps inside this mic (C8, C9, C10 and C6), maybe try to replace the Elecrolytes too (C13), cause i heard Ceramic and Elkos are the worst for Audio, i guess they use it so much cause they are small and probably the cheapest, can somebody confirm that statement?

not sure if its possible to replace the Big elkos on C2 on C7, seems like they are the Output.. like i sayed i just wanne upgrade that mic dont want to build a new one

Why do you want to change anything in the microphone?  What don't you like?

If you change things with out understanding the design of a microphone you can/will make it worse. 

Examples of things I have done, changing the parts in a Oktava MC012 sometimes the stock parts sound better than the "improved" parts when recording certain things.  Changing the tube and caps in a Rode K2 or NTK the stock electronic parts are fine. 

Where did you hear the caps are the worst for audio?

yes GUS you absolutely right about this, i just want it to be more Mid rangy, will only use it for Rap Vocals, so the mic is pretty dark, which is good but still there is something sizzling in the highs going on what makes me crazy when i use this mic. There must be something that impoves the sound, mids of this microphone, i guess a capsule change is most important.

There was a guy in a different forum talkin alot of stuff, i'm not sure but he posted this (i found it randomly on the net)

Polyester, or mylar (Polyesterfilm): Bare minimum for audio applications. Pretty good sound and a definite improvement over electrolytic, ceramic and tantalium as far as non-linear distortions.
Polypropylene (das Polypropylen ): Better than mylar but also slightly larger per value.
Polycarbonate (das Polykarbonat) : Better than polypropylene. Again, usual larger.
Polystyrene or Teflon ( das Polystyren): Probably the best you can get, but larger values typically won't fit in any mic. .01uF would be a large cap.
Paper in Oil: Good sound. Not useful in small bodied mics.

  My older 2003 is one of the really nice vocal mics I have in my personal studio. After changing 3 capacitors (recommended originally by Gus on this site , I believe) that mic has become my favorite for my own voice.
  I understand if you are looking for a donor mic for a project, and just don't like the microphone, but since you admit to being a newbie, I will humbly suggest that you don't ruin something that might actually be a good piece of gear.
  It's my understanding the the 2003a is the same mic, already upgraded to the new caps. Not much to improve there, unless you spend a few hundred on a really good capsule.
  If you want a donor mic, use something with one of the brass-ringed capsules (U-67 style), and not the white-ringed ones (RK-47 style). At the very least, save the capsule from this mic and put it in something else. It's not great, but better than the ones found it the 2001, V67g, 9000, etc, to my ears.
  Just my 2 cents worth.
  After seeing your new post-- what kind of mic pre are you using with it? Maybe turn it slightly from facing directly at the source to lower the highs that bother you.

What preamp are you using?
If you want more mids you can try an EQ.
Are you overdriving/clipping the preamp or A/D?  What other microphones have you used with the preamp?

I have not heard a 2003a  From the picture it looks like a cap coupled transformerless output microphone, pin 2 driven R4 100 ohm ?uf cap and pin 3 to ground R11 100 ohm ?uf cap.  Transformerless microphones can have a large output levels.
http://www.mxlmics.com/microphones/studio/2003/

Shows it draws 6.6ma can your preamp phantom power, supply this current?

I think my point is, I start to get curious.

for Example, those Ceramic Caps, how much (lets call it Voltage), or uf hf pf?! is going through them, I just want to understand for the Future, if I replace them with something else, does it need to have the same specifications (for example 16V 220uf) or could i also replace it with a lets say 50V 220uf Cap? or would it damage the whole mic.. i try to understand how that works, cause right now, when i think about to replace something, I always look for exactly the same specifications of that Cap. the Uf's, and Voltage, and even the Heat (example 105°)

the only thing that is printed on those Ceramic Caps are number, 27, 10 and 102, and 2 of them seems to have a half black dot, what the hell does that mean??

you guys know what i mean, sorry i dont wanne bother you but i try to understand that stuff a lil bit more. Maybe i need to figure out how a multi meter works to get all the data of a Cap

I use a SPL 9844 Class A Goldmike Pre with different tubes

yap there are 2 big bombers Output caps, yea R4 and R11 to 100 uF 50V 85° (M)  each , so there are 2 of those big Elco caps, can i ge rid of them  ;D ;D

tchgtr said:

 
  If you want a donor mic, use something with one of the brass-ringed capsules (U-67 style), and not the white-ringed ones (RK-47 style). At the very least, save the capsule from this mic and put it in something else. It's not great, but better than the ones found it the 2001, V67g, 9000, etc, to my ears.
 

Click to expand...

The RK-87 from microphone parts is white-ringed and a dual isolated backplate version of the U-67 capsule specifically for vintage U-87 style mods (it is needed for proper polar pattern switching in the old U-87 cicuit). In other circuits, the backplates can be connected together, so it will work with any K-67 friendly circuit.

Maliq,
    What the cap does, and how it affects the sound, depends on where it is in the circuit, and what role it plays.
Some questions to ask yourself:
Is it in the path the signal takes from the capsule to the output pin on the XLR jack?
Is it in the path of the 48V power line coming into the mic? (or the B+ from the PSU)
Is it part of an EQ circuit inside the mic?

If the cap is part of the EQ circuit, changing it's (microfarads) value will change the EQ curve.
If it's in the signal path, changing the type of cap might make it sound better (or worse). Changing the value might cut the lows/highs at a different frequency.
If it's in the power rail, you might change the voltage the capsules needs for polarization.

I know there are lots of threads out there that say improving the quality of all the caps in mic might make it sound better, but you also might ruin the circuit board with too much solder heat, for a change that is hardly noticeable.

You are smart to ask for schematics. If you look at them long enough (and read all the great info here) you will eventually be able to recognize the different parts of the circuits, and have a better idea of what (if anything) to do.

I would personally say that the most important caps are the ones in the signal path. These make the largest audible difference when changed.
The design of most mics are taken from time-tested circuits (as the 2003 circuit is). Just try to figure out where the factory tried to save money on parts. Electrolytics in the signal path are one place, but sometimes replacing them just shows the other weak spots in a mic, like a cheap capsule.

Electrolytics are fine if the cap is there to bolster the B+ voltage, and changing them won't make much difference in the sound.

thanx tchgtr, yes i try to figure it out, its a lil bit difficult cause even when i unscrew the boards you can't see much because of the wires.

There are 2 wires coming out of the Capsule, one is Red, and there is a + sign on the board where its soldered, does that mean this is the path where the Capsule gets feeded with Power?

the other one is Black (- sign on the Board), is this the actual signal path then?

Thanks that you bare with a newbie :

Maliq
What you are asking takes time to learn.  I don't see anything wrong with the parts in the pictures.  Some of the caps are for the DC to DC converter that generates the voltage to charge the capsule.  The electros look fine in the the output stage. 

Any EQ in this microphone is most likely under the white block.  If there is EQ it most likely was designed for the capsule used if you change the capsule the EQ might be wrong for the new capsule

I was trying to help you.
what preamp?
Can the preamp supply 48VDC at 6.6ma?
Can you try this microphone with another preamp?

right sorry GUS...I just try to understand things better, yes i hear you, my preamp is an SPL Goldmike, I don't know bout that 6.6ma??

its the only preamp i got right now, the other would be the pres from the Focusrite Saffire itself..

Maybe this Helps but I don't think so http://spl.info/?id=146

I also removed the white Cap..here are both sides of the MXL 2003a Microphone, so you would say changing the Capsule would not be a good idea?!

There's a lot of liquid BS talked about caps.  I won't go into the gory details but for the real goss.  Look up Cyril Batemans' stuff.

Most cap mods just make the mike more expensive and prone to EMI but usually don't make the sound worse.

However, the most critical cap is the one between the capsule & the FET/tube.  The BEST cap for this is a COG/NPO CERAMIC.

If you want a noisier mike, change it for a Silver Mica
If you want a more microphonic mike, change it for a polystyrene.

Scott Wurcer, will provide chapter & verse in his Linear Audio series on low noise mike amps.

And if you change anything in this most critical position, you'd better know how to clean the PCB & parts properly.

Your post makes me a lil bit scary about this whole thing here Ricardo...now i feel like if i change a cap or a Capsule then i'm in trouble.. sure i don't spit on the boards or capsules, but i touch them, and also some of them seemed allready a lil "dirty" when i opened some mics the first time, maybe just trying out is the only thing that i can do.. my solder joints are clean at least, need to get some shrink tube to make sure the leads are not exposed.

I tryed to look up Cyril Batemans but its seems like his page or yahoo blog is down..

I think i was a lil bit to fast and hyped about the idea that if i change a cap and capsule here and there that i will end up having a full rich and crisp microphone  : must be a reason that a u87 cost more then 2000$..

Maliq said:

I tryed to look up Cyril Batemans but its seems like his page or yahoo blog is down..

Click to expand...

http://www.proaudiodesignforum.com/forum/php/viewtopic.php?f=6&t=153&p=4574&hilit=cyril+bateman#p4574

You do need to be very careful with every/anything near the capsule and grid/gate of the tube/FET.  The impedance there may be several Gigaohms.  Breathing on it will change the noise.

Electrets are less fussy than proper capacitor capsules which need a polarizing voltage but you still need to take care.

Another problem with polystyrenes is they don't take kindly to poor soldering technque.

Thanks Ricardo, i will try to read it when i find some time.. and thanks, wit every sentence i'm learning a lil bit more..

I talked to a electronic engineer from mouser, he also told me some interesting stuff, but no matter what: THERE IS NOTHING YOU CAN DO WITHOUT A DATASHEET

also, there is noway to meassure the specifications of a Cap..uf's, temperature and so on.. and without this data, there is noway to replace those caps with high quality caps

and as a bussy Artist, i can't get to deep into electronics, changing a Capsule, a Cap and soldering ok.. but when i see all that uF, pF etc..it just scares me off.

so back to my basic Question, is there a DATASHEET for the MXL 2003a, at least, i can learn from it.. Thank you guys

Maliq said:

Thanks Ricardo, i will try to read it when i find some time.. and thanks, wit every sentence i'm learning a lil bit more..

I talked to a electronic engineer from mouser, he also told me some interesting stuff, but no matter what: THERE IS NOTHING YOU CAN DO WITHOUT A DATASHEET

also, there is noway to meassure the specifications of a Cap..uf's, temperature and so on.. and without this data, there is noway to replace those caps with high quality caps

and as a bussy Artist, i can't get to deep into electronics, changing a Capsule, a Cap and soldering ok.. but when i see all that uF, pF etc..it just scares me off.

so back to my basic Question, is there a DATASHEET for the MXL 2003a, at least, i can learn from it.. Thank you guys

Click to expand...

Just to be clear, you CAN test for uF, pF, nF etc. with some multimeters, or a dedicated capcitance tester. Hell, most caps have their value written right on them. It may be in "code" though, so you will have to research what the codes for that cap style may be. Also, there is no datasheet for a mic. You might find specifications for the 2003a, but those usually refer to the mic's noise figures, max spl, etc. If you plan on modding the circuit (instead of gutting the mic), you will need a schematic. Also, the datasheets for the internal electronic components you intend to change and the new parts you intend to put in will be all that is necessary to make sure the "upgraded" parts are compatible (cross reference the datasheets).  I hope this helps.

-James-

yes, see i'm learning each day a lil bit more haha..i make the whole world allready mad about it.. i figured something out about those codes, but they don't tell me the whole thing about a Cap. Many Questions are left. A code might tell me about how much microfarad or picofarad a cap has, the letter might tell me about the Tolerance of the Cap.

But what about the AC voltage and nominal voltage, cause i think that should be the same if i replace a cap with a higher quality Cap.. Is there somebody i can ask all that stuff??

cause i think i cannot use anykind of AC Voltage or yes??  :-\ :-\

Can somebody tell me what the Code 51M means??