MXL 2003 Mod?

  • Thread starter Thread starter radzikk
  • Start date Start date
R

radzikk

New member
In the post about the MXL 2001, someone mentioned a mod for the MXL 2003 that involved changing a few caps inside. Does anyone have the info or schematics for this. It would be cool to try on my 2003.
Thanks,
-k
 
Mouser is the only place to get polystyrene caps so you may as well get the rest of them there too:
One 1uF CDE Polyester cap
One 1000pF polystyrene
Two .33uF Xicon’s (mine are 250V)

Replace C9 with the 1uF

Replace C10 with the 1000pF

Replace C8 and the unmarked cap across from it with the .33uFs. These are large and you have to remove the board and put them on the bottom. Mount them so they can be folded down beside each other to fit between the boards. I used these because a friend gave them to me to try, but I plan to try some with lower voltage ratings and larger values in hopes of more low end (not that I need more lows, but hey, it's fun to experiment!).

Be sure and record before and after clips, same source, distance, etc…
 
Any other mics this might work on??? (Of the cheap "What have I got to lose") MXL variety?? :)
 
turnitdown said:
Any other mics this might work on??? (Of the cheap "What have I got to lose") MXL variety?? :)
Click to expand...
Like I said in the other thread, the 1006 is the same circuit and the mod will work there. The 603S is also basically the same circuit, but of course you have to use smaller sized caps for the 1uF and the .22uFs. Almost any Chinese and Russian condenser mic will sound better if you swap the 680pF monolithic for a 1000pF polystyrene between the capsule and the FET.
 
In what sense 'beter'? I have a couple of 2003's that I am satisfied with but better is, well, better.

Have you done this before? Would you suggest it for a newbie? I am hardly a technophobe but most of my experience is at the build-one's-own-computer rather than at the circuit board level.
 
Well, you absolutely have to be able to desolder and solder to do this. It helps to be able to screw and unscrew screws too.:) Otherwise, it's not rocket science. The capacitors are relatively heat tolerant, compared to active devices.
 
crazydoc said:
Well, you absolutely have to be able to desolder and solder to do this. It helps to be able to screw and unscrew screws too.:) Otherwise, it's not rocket science. The capacitors are relatively heat tolerant, compared to active devices.
Click to expand...

Just make sure you don't overheat PCB traces, otherwise it is very easy to lift them. Also, use braded solder remover--you can get it even in RShack.

>Any other mics this might work on??? (Of the cheap "What have I got to lose") MXL variety??<

Most of cheaper Chinese transformerless mics use exactly the same "Schoeps" type schematics (input FET serves as a phase splitter and there are two bipolar buffer transistors) and would benefit from parts (mainly caps) upgrades.
 
But in what way would it be 'better'. If I recall from high school physics a capacitor is a fairly simply device that holds and releases electrical charges. It is rated by the quantity of charge it can hold and the release is near instantaneous. Excuse me if this statement is kind of naieve, but either it does that (holds and releases its rated charge) or it doesn't. What constitutes 'better' and how would that effect the quality of the signal that comes down the wire?

Or to put it another way, should I expect 'brighter', 'darker', 'more detailed', 'smoother', 'hotter' or what? Would the frequency response curve be changed?
 
Unfortunately for dummies like me, there doesn't seem to be a simple answer to your question. Here's an excerpt from the link below, which is excellent, and which I suggest you peruse at your leisure.

http://www.capacitors.com/picking_capacitors/pickcap.htm

For those readers unfamiliar with the "sound" of capacitors or this general subject area, much of the above might sound like mad ravings to some degree or another. We'd like to leave some implication of what we feel the magnitude of this problem really is.

After we had gone through all of the above exercises and exorcised our complete system of unnecessary or poor-quality capacitors, the total degree of improvement was greater than any other improvement measure ever employed. With no capacitors (or clean capacitors), you begin to hear the music in a new light, one which is much more like the sound of the real thing. In fact, you will be able to differentiate subtleties you never before even realized existed. Your system simply becomes a new system, in terms of resolution and definition. The "solid-state sound" we've all heard discussed may be largely due to lousy electrolytics—which by and large never got used in the signal path in the tube days
 
Here's a before and after sample. The extra noise in the "after" clip is because the door to my computer cabinet was left cracked open. I didn't realize it until later and was too lazy to do another take. The modified version became a little more sensitive, too.

V93/2003 Before Mod

V93/2003 After Mod
 
wow, that's quite a noticable difference in the sound. I think i'll go ahead and get the caps just for shits and giggles. I was looking on the Mouse page as you had suggested and was having trouble finding the last 2 you had listed. Is there another place that sells them or do you have the links to the ones you used??

Craig
 
CDE 1uF/100V Polypropylene: Mouser # 5989-100V1.0
Xicon 1000pF Polystyrene: Mouser # 23PS210
Xicon .33uF Polypropylene: 1431-2334K

Total cost is around $2.50. (Why doesen’t MXL do this to begin with?!?! :confused: )

You could also try CDE/Mouser #s 5989-100V.56, 5989-100V.68, or 5989-100V.82 in place of the .33 Xicon if they’ll fit. The larger values may open up the lows a little more, but who knows.
 
Marik said:
Just make sure you don't overheat PCB traces, otherwise it is very easy to lift them. Also, use braded solder remover--you can get it even in RShack.
Click to expand...
Right.

Soldering is not rocket science, but it does take a little skill. Use a soldering iron, not a soldering gun. Use braided solder-wick to remove the solder by placing it over the joint and heating it with the iron. Don’t use anymore heat than is necessary and practice on an old junk radio or something first.

On big secret to this as that you need to always “tin” the tip of your iron with a little bit of solder before either soldering or removing solder. This improves heat transfer between the iron and the joint.
 
You said the 1006 schematic is the same as the 2003, but cap c9 on my 1006 is 6.3 pf, not 1uf. Is the c9 on the 2001 being upgraded from 6.3 pf to 1uf? and my c9 is a ceramic labled 27, which isn't on the cap code chart I have, is it 27 or 2.7pf? Those codes are weird. And there is no unlabled cap. And the electrolytics are 2x 16v 220uf and a 50v 47uf, no .33uf 250v caps. C1, 2, 12 and 11 are all .022uf ceramics. C14 and 15 are both marked 8 <BR> 102K. Would I be correct in assuming those are .02ufs? Would it be beneficial to replace all those ceramics with polystyrenes or polyesters? And I'm sure the balancing resistors would benefit from being replaced with more closely matched resistors. The ones that come in pairs on the symetrical side of the board, if they are more closely matched, if you get a bunch of 1% resistors and use the most closely matched pairs as found with a multimeter, then I believe the balancing would reject more noise on the output. That might just be on the input side on a preamp though? Maybe metal film resistors should be used? I might replace the electrolytics with Nichicon UPWs. Does that sound good? And what do people mean when they talk about bypassing electrolytics? Does that mean parralleling them with a polystyrene? What value? Maybe upgrading the diodes and transisters would help too? They are 2x 5401 and a 5551 both headed with 2N. Maybe the diodes could be replace with schottkys? What values? And what are those two rectangular thin paper resistors sandwiching the balancing fet? And what are the L1 and L2s? They look like resistors. Any ideas about all this would be very helpful for my constant tweaking curiosities! Thanks.
 
amzavareei said:
You said the 1006 schematic is the same as the 2003...
Click to expand...
I once had pics of the 1006 circuit board (can't find them now) and it looked just like the 2003. Here's a picture of a modified 2003. Does it look like your 1006?
 
No, it looks pretty different. Here, I scanned it in.
I don't know how this picture thing works...
 

Attachments

  • MXL1006.webp
    MXL1006.webp
    83.1 KB · Views: 427
Different board, but probably similar circuit. Actually from looking at the board, the 1006 looks just like the 603s circuit. If you take the top board off, there should be a cap on the back of it on the end closest to the capsule. That's the most important one to change. Can you post a pic of the back of the board so I can be sure?
 
Flatpicker said:
Different board, but probably similar circuit. Actually from looking at the board, the 1006 looks just like the 603s circuit. If you take the top board off, there should be a cap on the back of it on the end closest to the capsule. That's the most important one to change. Can you post a pic of the back of the board so I can be sure?
Click to expand...

I did this too. It's the same board as the MXL v63 and the MCA SP1. Change the one on the back of the board to a 1000pF polystyrene. Change the two little ones on the outer edges (marked 224) for .22uF Mylars and the two bottom ones (by the white red and black wires - marked 223) for.022uF Mylars. The .22uF are big, so you may want to put 'em on the backside. I left alot of the leads out so I could move them to a position that would tilt so I could get the body on. On the MCAs I wanted a little more low end, so I changed the .022uF to .047uF. It seemed to make the bottom a little bigger.
 
That cap is marked 102, so I guess it's 1000pf.
 

Attachments

  • mxl1006inside.webp
    mxl1006inside.webp
    67.2 KB · Views: 387
You must log in or register to reply here.
Back
Top