Cap choices for Chinese Mic mod's

Hi,
I just removed one layer of mesh from the basket of my MXL2001, and it got me thirsty for more adventerous mods.
i've been looking through the Mic meta's, and it looks like one of the most common (and easy) things to do with the circuit is to change out the caps. My problem is that i don't know where to begin as far as replacement for the individual caps. Is it best to change them all? Which ones to use specifically (electrolytic, film, etc...). Does brand matter? Should all the values be the same as the original? Can anyone point me in the right direction based on what they've had success with?
I know that the "paint by numbers" approach is pretty lame, but i don't know where to begin with making replacement decisions. I've been reading the Art of Electronics to try to get a better grasp on all these concepts, but it's just confusing me more.
Thanks for any responses,
_Brian_

Hi Brian,

I've spent the last few days screwing around with MXL mics, having a lot of fun. I've pulled the inner mesh from my 2001's basket, but havent touched the circuitry in that one yet.

Based on the mods I've done to the 603s/990/991, I'd say definitely swap the ceramic capsule to gate cap (the one on the underside of the board, soldered to the PTFE mounts that the capsule connects to) with a 1000pf polystyrene cap. Mouser has them.

Aside from that, I dunno what to do with this circuit. I think most people rip the guts out of these entirely and do the royer mod. I may do that at some point. For now, I think I'm gonna stick a polystyrene in there for the hell of it

what about black gate, calrad (sp?), and the other super high end caps? is that a total different type than what can be used? or just overkill?

t

Black Gates are electrolytics - not something to use for replacing a ceramic cap. Try the polystyrene (styroflex), or another film type if you want to experiment.

Best regards,

Mikkel C. Simonsen

Look here... http://www.groupdiy.com/index.php?topic=217&highlight=mxl+2003

lots of info there that will hopefully help to point you in the right direction.... Look at how Gus's KM84 type circuit is set up as far as capsule polarisation... I have not been inside a 2001, but you may be able to remove the cap to gate (not in the 991/603s though). U47 circuit is another good one to look at for capsule polarisation (as suggested to me by gus). Some of the capsules in the MXL mics like a lower polarisation voltage... To my ears, I definetly like the 991 with a lower voltage on the capsule than stock, its worth playing with at any rate. Hope this is somewhat helpful.

The 2001 has more problems than poor caps... the transformer needs re-laminating too. This probably isn't the best mic for a first modification. A transformerless mic (1006, 2003, etc...) would be better.

Tim may be right... but for 50$ or so a lundahl xformer can be had.

The transformer looks like it's a part of the structural design of the mic, it's case is threaded and holds on the body tube. It doesn't look like there's any room to fit another one, maybe with a dremel and some luck i could cut the case in half and fit another transformer in it? Is this completely stupid?

I'm sure it would sound better with a Lundahl, but you would probably have trouble fitting it in there. I think most folks just breadboard a new circuit and fit the Lundahl on the board some where.

If it were me and my first mic mod and all, I'd order a pcb from Scott Dorsey and get a back issue of the Recording magazine January '02 issue that has this mod in it, along with Scott's explanation of how it works. The article is called "Making Mics Better: a Practical DIY Project". I did this to my Cascade M20 which is basically the same mic and it sounds great. Only difference is, use a 1000pf polystyrene where he says to use a 820pF ceramic.