Hi All ,Fellow Microphone Builders,

 just a little reminder that , it is strongly advised to use Gloves for HZ resistor installation in an Microphone Application
i would strongly recommend using gloves for this at least to 10Mohm and Up. It is very well know that peanut butter fingerinos does not mix well with this part of DIY Microphone world.  I also would like to recommend using gloves for any capsule installation as well for the exact same reason.  So the microphone shall not suffer any frequency response issues.
Using also No-Clean Solder for microphone application is recommended so the cleaning efforts is minimized to extreme if any needed, I also recommend using a very fine tip for precision work , always does a better job with those. I am using Weller St7 to St-6 Soldering tips

http://www.amazon.com/Weller-ST7-X0-79-Series-Conical/dp/B000B607OC

,
this is a reference to the best stuff I ever used

http://www.digikey.ca/product-detail/en/386876/82-121-ND/2498919



Best,
Dany,
Vintagemicrophonepcbkit.com



dmp

I used no-clean solder for quite awhile - but found that the flux I could see was harder to clean off (it is NOT flux free).
I use '44' now, and the flux can be cleaned off with alcohol.
I'm starting to think it might be important to have the High-Z off the PCB - or on a very high impedance board, as well as clean of flux.



I used no-clean solder for quite awhile - but found that the flux I could see was harder to clean off (it is NOT flux free).
I use '44' now, and the flux can be cleaned off with alcohol.
I'm starting to think it might be important to have the High-Z off the PCB - or on a very high impedance board, as well as clean of flux.

yep, when properly setup , the flux is not really an issue , but I looks much nicer,  ;)
all a matter of preference but there is no cleaning here, 
Best,
D


Patrick from Davis

Dany, when using the Multicore 386876, do you have a preferred cleaning routine?  I'm always curious about what little tricks people come up with.
Patrick

 

Dany, when using the Multicore 386876, do you have a preferred cleaning routine?  I'm always curious about what little tricks people come up with.
Patrick

the best tricks is to know what your rosin is made off and then choose appropriate solvent for it ,
I use HPLC grade solvent IPA and then hot distilled water with compressed N2 from the lab,
one thing is to always try to hold your iron as straight as possible almost vertically,
sometime you cook and spalsh the solder mask as well when not straight
and use really small core solder and one of the most important use the less solder as possible  ;),
Best,
Dan,



Patrick from Davis

Hah, HPLC grade.  Lab rats unite.
Patrick


Matador

Here's been my experience:

1) A good hand-washing goes a long way - but gloves also work
2) No-clean is intended to be left on the PCB - it's not the best formulation for this purpose.  Water clean has worked pretty well for me,  as does RA.  Both won't stand up to much IPA cleaning.  No clean can actually be harder to get off as it's meant to be non-reactive, whereas we want solvency.
3) Solvent loading in IPA can become an issue:  it's much better to use a tiny bit, scrub/rinse once, then use another fresh batch and repeat.  I have a small plastic cap just for this purpose that holds about 3-4 tablespoons of liquid.  You brush, rinse, then toss out, refill, and repeat.  After 2-3 times, the board is clean and not tacky.  Using a large container just redistributes the flux throughout the solution, and it can be impossible to remove the residues even after 10 such round trips.

Many PCB houses that do SMD assembly use water soluble flux, then immerse the boards in denatured water and clean them ultrasonically.

Patrick from Davis

Out of curiosity again, Matador, on the water soluble flux solders, does something like 70% IPA work better?  Or should you just stick to 100% IPA.  Or water for that matter.  Also, what is the solder (brand/number) that you prefer?  Thanks
Patrick


Why would gloves be necessary for cxapsule installation? Hopefully, one is not touching the diaphragm anyway

Can a build be sufficiently cleaned with IPA and cotton swabs, as long as one is careful to not get alcohol on any capacitors?


Tim Campbell

As I've mentioned before, contamination of capsules can cause switching noise as well as begin the process of building a short circuit. Alcohol and other solvents should be kept far away from capsules. With CK12 types they can cause cracking of the acrylic. With all types of capsules solvents can leech under the diaphragm.

Why would gloves be necessary for cxapsule installation? Hopefully, one is not touching the diaphragm anyway
It's not stuff on the diaphragm which is deadly .. its stuff on the insulators .. which you WILL be touching.

Oils & dirt from even the cleanest hands cause conductive paths on the insulators.  Remember the impedance of the amp is in the 1G region and the insulators MUST BE MUCH HIGHER.

As various people have said, not getting crap in the first place is MUCH better than trying to clean it off later.  If the solvents move crap under the diaphragm, the capsule will probably be forever noisy.  The only 'cure' is new diaphragms ... after ultrasonic cleaning of the metalwork.

Have a look at youTube for how the big makers assemble capsules in their 'clean rooms' for what you need to do.

Thanks for the info. If the issue is with the insulators, then does it matter less if you're bridging the backplates together of a dual backplate capsule, or using a single backplate capsule like a K47?

What should you do if you've already installed a capsule and didn't use gloves? Just curious... I haven't been having issues, and my mics sound excellent as they are.

What should you do if you've already installed a capsule and didn't use gloves? Just curious... I haven't been having issues, and my mics sound excellent as they are.
If you have no problems, just count yourself lucky and leave well alone.

If problems develop (especially in humid / hot / cold conditions) you have a problem ... for which only a capsule replacement by someone taking all the correct precautions is a a 'cure'.

Also the circuitry connected to the diaphragm and/or backplate, gate / grid etc.  (depending on the exact circuit) has to be treated with the same care ... hence teflon stand-offs etc. to get this stuff away from possibly contaminated PCBs.

If you build a few projects a year, a box of powderless nitrile gloves is a worthwhile investment. Here they're around $5 for 100, so $0.10 cost per capsule installed.

For the nuisance, after a while you really do forget you're wearing anything... It even starts to feel weird working on something without them ;).

What should you do if you've already installed a capsule and didn't use gloves? Just curious... I haven't been having issues, and my mics sound excellent as they are.

I am Glad this thread Picks up a bit ,
Thanks to everyone for you contribution ,
Best,
Dan,


Thanks for the suggestions. I will wear gloves in the future. I was simply unaware during my previous builds, and didn't know if there was something I should do to alleviate that mistake.

Phrazemaster

I just read a blurb off a high-z resistor company (ohm craft - nice stuff!).

They mentioned something I thought was good. They said fingerprints can cause an alternative pathway for current, which changes the resistance. They also said fingerprints can attract dust and moisture/dirt over time, also causing unwanted effects.

So...clean 'em up good gang!
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** * Kablooie!

I just read a blurb off a high-z resistor company (ohm craft - nice stuff!).

They mentioned something I thought was good. They said fingerprints can cause an alternative pathway for current, which changes the resistance. They also said fingerprints can attract dust and moisture/dirt over time, also causing unwanted effects.

So...clean 'em up good gang!

YEP
i always use powder less gloves using those, cleaning them with un pure solvent always leaves impurities,
you will notice that when mouser ship them to you they are specially packed in a carton sleeve so you dont have to mess with them to start with :) 

Best,
Dan,

Gain issues on D-87
« Reply #19 on: September 22, 2015, 05:43:42 PM »
Hi Gang
Love this site, great info. Thanks in advance for any help. My brother finished my D-87 project this weekend and the mic sounds very good. One issue I am having is I seem to have to use a LOT of gain with this mic. Far more than even a MXL 2001 or Samson C-01 mic. I have a Beesnees capsule and Cinemag transformer along with Chung's body and Dany's PCB.
Again, the mic sounds good but just having questions on why so much gain should have to be used on this. I'm talking 3/4 of max gain from my Grace M101 mic pre, whereas the MXL 2001 can sound same loudness with less than half of the gain input

Thanks all!
Bill