DIY Mic Repairs, Mods (aka fixing Oktavas, SP,etc...)

[mindwave_21]

First of all, I'd like to say I'm new to the DIY recording world, and you've probably noticed my ignorance through my previous posts, but now I have a question that I feel is worthy of a post. I just purchased a JRRShop Oktava MK319, knowing full well that they do a pass fail check on their mics (aka the GC treatment). However, the price was good ($100), as ebayers keep pushing up the price of used oktavas to about $90. I figured why not get a newer Oktava and a chance of a good quality catch rather than get it from some ebayer who obviously doesn't want to keep his used mic (Defect or crappy mic? Who knows...).
Anyways, my main question is, for mics with known quality control problems (pretty much all low budget mics from China and Russia), are there any simple fixes to do to get them up to standard? Is it as easy as resoldering all the connections of components, or replacing electrolytic caps with metallized film (is this bad, good, or just different in terms or resulting sound quality?) If not, what are the main components to replace/inspect? I haven't recieved my mic yet, but I only have 30 days to decide if it's a good mic, otherwise I have to pay shipping and $15 restocking to send it back to JRRShop...something I REALLY don't want to do (it's like paying $30 for nothing). The first thing I'm going to do is run through Harvey's mic tests on this thread, and go from there. Thanks all for the great help in this forum!

PS, my electronics experience includes 2 DIY guitar pedals (TS clone and Ross compressor) which are in full working order, finally.

 

[mindwave_21]

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Anybody here a DIY man/woman? I know I've seen tech posts around here (I think it was Harvey who did all the schematic stuff, but I'm not sure...).

 

[chessrock]

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Anybody here a DIY man/woman? I know I've seen tech posts around here (I think it was Harvey who did all the schematic stuff, but I'm not sure...).

I think Han and Marik are the local tech heads.

 

[nat g.]

Marik has modified four mic's for me and fixed one. He's unreachable for a week or so, or I'm sure he'd reply.

I heard a single capacitor change (I can't remember if the value was changed or just the brand or type) on an MXL 603s make a small-but-worthwhile improvement. Capacitors do make a difference. Soldering on the PCB is difficult, though. I haven't tried it myself. A transformer upgrade is very noticeable. Grill modifications are noticeable. From my modest experience, a mic sounds mostly like its capsule, though, so it probably won't be totally unrecognizeable after mods, just usually cleaner and better-balanced.

 

[Treeline]

Let's keep the thread going.

I have an MXL 603s that is very sick; I expect it was damaged by a well intentioned harmonica player who thought it was almost as good as his NADY dynamic. I looked away for a just a moment and he decided that would be a good time to take apart the shock mount on the stage so he could change the mic for me. You know the rest of the story - mic slides down, suspended by the cable, whacks the stand a few times, hits the ground and then he gives up and asks me why I didn't use a NADY.

After I got all the blood off my hands, I tried the mic and it was kinda dead-like. Transmits a signal, but that's about it. This thing had less than twenty hours on it. So now what? It's sitting on the shelf. I can't hire a fix; it's cheaper to buy a new mic. I don't know what I'm doing with circuits, but there's very little to lose in trying to figure the thing out. Any ideas? Other than packing it with black powder for the next time I run into him?

 

[Flatpicker]

I have an MXL 603s that is very sick; I expect it was damaged ...Any ideas?

Send the 603S back to Marshall for repair and use cheap dynamics on stage. Trust me, the audience will never know the difference!