MXL 2003A Schematics / Modding anyone?

[HellfireStudios]

You'll need datasheets for the rest of the information. Does the schematic show the voltage rating on the caps and the wattage for the resistors (as well as their values)? This info should be enough to find compatible upgrades. A FET mic doesn't get too hot, so temperature tolerances are not gonna matter much with audiophile replacement parts.

-James-

 

[Maliq]

thats the problem Hellfire, there is no schematics outheir for the MXL 2003a,

see i figured something out, i took another photo of the Ceramics that i want to change, see the one with the 102 (C10), i figured out that it means 10-pF multiply to 100 (last number tells us about 2 =zeros=). So, the ceramic is a 1000-pF.

Good but if i wanne replace it for example with a wima film cap, then i need to know how much Voltage the Ceramic cap "got", cause a Wima cap got alot of info and many 1000pf Film Caps to choose from: for example they got film caps ranging from 63 to 630V AC Voltage, same goes for Norminal Voltage..and thats my major problem, i dont know which one to choose cause i'm scared if i take one with to high AC,norminal that it will blow the mic, and if i choose a cap to low, that it will not work, and nobody can give me an answer on that so far. Simple sayed i don't know what to buy cause the Cap cose provide not enough info..or i just dont know it..i found some tools that can easily identify infos of resistors and inductors but i guess that will not help me.. guess the voltage thing is killing me here

 

[Maliq]

One last intresting thing i found out right now, All Electrolytics in this mic are 50V (Output) , 16V (Signal chain), and 63V, maybe this means that I should stick with a maximum of 63V AC for the caps that i want to order..and dont risk to blow something apart  :

 

[HellfireStudios]

You can't really go too high in voltage rating, within reason, but size becomes an issue with increased voltage tolerance. Be sure to check the datasheet to make sure it will fit in your mic. Check out some other mic schematics in the same vein as your mic (2001 maybe?) to see what voltages they use, and use slightly higher rating, if it will fit.

-James-

 

[Gus]

I looked at a few pictures on the web that I could find of the insides of the 2003a and other MXL microphones like it. I also worked with a forum member to reverse the circuit. I have a guess of the circuit drawn up.

IMO  cap change(s) will not help.

Question is one of the transistors a 2N6426 in the 2003a?

 

[Gus]

Discuss and supply voltages if you have one and want to share.
I did not want to buy one to trace.
Some PNs are made up I could not read the printing on the PCB.
This was traced from pictures on the web and help of a forum member. The Aria measures as a nondarlington so maybe it is different than the part number I saw in  picture of the 2003a.
I was curious about this microphone because of what I read about it on the web.
DC to DC is the "standard" one you find D1 and R12 are what is changed in that part.

I see things I question.
What do you think I question.

 

[Gus]

No interest?

 

[volker]

• No gate capacitor, the positive bias reduces the effective polarization voltage
• R2 doesn't make much sense, only reduces headroom
• R1/R7 junction could use a cap
• R3/R9 could be lower
• 2SK170 wouldn't be my first choice for either input or CS JFET
• I like the impedance balanced output. Have built it like that too, works very well.

 

[Gus]

one could add a resistor from source to ground with the gate going to ground to adjust the CC to a lower current

I was thinking about why the input was done that way
R2 for follower stability
OR it worked in another circuit as a PI so they used it as SF
OR...

I don't like 170s in microphones look up long vs short channels in jfets

output section  the 1megs and C4
I agree the voltage divider should have a noise bypass cap
(volker noted the R3/R9 issue and divider cap)

There are more things I question

 

[Gus]

I am surprised that there are not more posts in this thread

In a picture at RecordingHacks it looks like the capsule construction  is changed (the rear backplate).

 

[Gus]

A bump

Funny I posted this to start a discussion
What is good about this microphone?
What can be improved?