Just Picked up new Donor mic

[ricardo]

... I guess that's probably true for pro builders - we less than so,  have the discretion to do whatever the hell we wants to!

Double blind objectivity ??  vas is das?
..........

This is about making cheap mics into something else, generally cheaper than any other option one has! Whilst still using good parts.

I believe by and large, if you use good parts and are not too dim, then the end result should be very good.

Of course what you miss out on if you don't do Double Blind Listening Tests is finding the cheapo mikes which sound better than expensive mikes, modified or otherwise.

But if modding and stuff made by virgins takes precedence over better sound for you .. that's OK too.  8)

And I'm not dissing the modding & virgin stuff that's been discussed here    .. just suggesting it would be sensible to have a reality check on hand for comparison.

After all, the effect of any mod is either

• too small to be heard
• obvious and sounds better
• obvious & sounds worse

Determining THIS is the real importance of Double Blind Listening Tests.

 

[RuudNL]

I fully agree with ricardo...
There is a lot of psychology involved in DIY!
How come your last build usually sounds better than anything you made before?....
But is this also true after a longer period of time???
It may sound so good because you have put a lot of time, effort and money into the project you were working on.
So you simply want to hear that it is excellent!
A/B comparisons and blind tests are the only way to check the improvement. (If any...)

 

[chefducuisine]

  .. just suggesting it would be sensible to have a reality check on hand for comparison.

This is why I love DIY meetings!
It allows you to verify that the stuff you built compares to some commercial units you might never heard before... and of course discover some builts / projects from others that you should have in your rack, too.    :-\

The last one at Jens' place was awsome.
See here:
http://groupdiy.com/index.php?topic=56828.0
and here for some pictures:
http://www.energyrecording.de/viewtopic.php?f=11&t=2956&start=30
Many thanks to Jens for getting this happen!

 

[Gus]

Here is a photo of the back PCB with the tranny

What don't you like about the microphone?

 

[bnwitt]

Gus,
I haven't gotten to the point of testing and subsequently not liking the microphone.  I purchased this microphone with the intent of modifying it because my experience with cheap Chinese microphones to date, produces a preconceived notion of the quality of it's components (especially the capsule) due to it's price.  And, after working on audio equipment for almost 25 years I have learned that the quality of components affect the quality of the device most times.  Now of course there are some exceptions like Leo Fender's 1955 5E3 tweed deluxe cheapo practice amp.  That had cheap components but unbelievable tone.  There are a few other exceptions to the quality component rule in audio but I find these exceptions are in devices admired for their distortion not for their clean reproduction of sound.
All of that being said, before I modify any thing ( I build tube amps and am a luthier too) I always test the object in question in my home studio.  If this $129 microphone blows me away on one sound source or another, then it will go right into my Mic cabinet.  But, I have been recording since 1987 and so far no microphone under $500 has blown me away on anything so I don't have high hopes for this one any more than the ones in it's price class which came  before it.  But, who knows.  Miracles can always happen.

Barry

 

[kidvybes]

...just as a point of reference, that Recording Tools microphone originates from TongXin, the same factory that makes many of the CAD mics, AKG Perception mics, iSK mics and the respected KEL Audio microphones...my experience with their mics is that they are better quality than the typical cheap Chinese LDC mic...good build integrity, decent components (often red WIMA caps), and decent dual-bobbin transformers...they also make the capsules for companies like microphone-parts.com and micandmod.com...as Chinese mics go, they are a good value...there are better (cheaper!) candidates for gutting...just my .02c...

http://www.nbmic.com/products.asp

 

[bnwitt]

Of course what you miss out on if you don't do Double Blind Listening Tests is finding the cheapo mikes which sound better than expensive mikes, modified or otherwise.

I would love for someone to tell me which cheapo mics under $200 on the market sound better than the expensive ones rather than my randomly buying these things and being disappointed.  I would especially like someone to steer me to the cheap Chinese microphone that kicks the pristine original Neumann U47 tube microphone's butt on male vocals.  If there is a list of those exact Chinese under $200 microphones that replace all of the great studio mics costing thousands of dollars than please email it to me in secret so no one else starts buying them and drives the price up.  My email is bnwitt at hotmail dot com.  I would like a cheap Chinese mic under $200 which replaces  the U47, C12, C414, R121, 4038, KM84, MD421 and the list goes on.

 

[bnwitt]

...just as a point of reference, that Recording Tools microphone originates from TongXin, the same factory that makes many of the CAD mics, AKG Perception mics, iSK mics and the respected KEL Audio microphones...my experience with their mics is that they are better quality than the typical cheap Chinese LDC mic...good build integrity, decent components (often red WIMA caps), and decent dual-bobbin transformers...they also make the capsules for companies like microphone-parts.com and micandmod.com...as Chinese mics go, they are a good value...there are better (cheaper!) candidates for gutting...just my .02c...

http://www.nbmic.com/products.asp

Kidvybes,
Thanks for the information.  Maybe this will be a keeper.  The sputtering on the capsule looks extremely thing though.  We'll see.

Barry

 

[ricardo]

I would love for someone to tell me which cheapo mics under $200 on the market sound better than the expensive ones rather than my randomly buying these things and being disappointed.  I would especially like someone to steer me to the cheap Chinese microphone that kicks the pristine original Neumann U47 tube microphone's butt on male vocals.

If more people did what I recommend in my 15aug post ... and DBLTs ... we would get such a list very quickly.  Alas, the hand carved by virgins brigade never bother.

To kick U47s butt, a mike can't sound the same.  But if you like U47, you'll probably like this one made from Transound TSB2555A capsules.  Measurements under Zephyr.doc in
https://groups.yahoo.com/neo/groups/micbuilders/files/Mic%20Measurements/
Construction in
https://groups.yahoo.com/neo/groups/micbuilders/photos/albums/1818618464
You have to join.

It is an electret  , uses OPAs, has very low noise, doesn't look like vintage AKG or Neumann so can't be of interest to the hand carved by virgins brigade.  It just sounds good in the way U47 sounds good .. but not identical else it couldn't kick its butt.

Where am I coming from?
I used to design mikes for a living including probably the best mike of the 20th century.  Calrec's heritage is via Bernhard Weingartner (who did C12 for AKG) so we sneer at the centre terminated Neumann designs.  But I have friends who have been involved in some of the most famous recordings of the previous Millenium who use & like Neumanns (and C12s)[*]

I don't like designing mikes that make your girlfriend, wife, mother sound like Linda Ronstadt ... or you sound like Frank Sinatra ... but I do have some idea of how to do this.  The most important tool is DBLTs.  8)

[*] PS  One of them (a staunch Neumann fan) now records & makes mikes as a hobby and likes the microphone-parts stuff.

 

[bnwitt]

To kick U47s butt, a mike can't sound the same.

Ok well right off the top I have to throw the BS flag on that comment.  If you've got an under $200 Chinese Microphone that sounds exactly like a U47, it kicks the U47's butt simply by costing under $200 and by a huge margin.  I'll take ten of them right now. And the first thing I'll do with them is solder suck all of the ROHS lead free solder from every component and replace it with some good stuff that won't crack or whisker over time thereby rendering the device a boat anchor.

Look Ricardo, I've been building tube amplifiers since 1994 and I've heard all of the hand carved by virgins, this capacitor or that capacitor, holy grail horsesh*t there is out there and I'm here to tell you that I don't fall for any of it.  In my tube amp world those types of fools say things like you have to use CC resistors in any clone of a famous amp to get their mojo when I know (from servicing hundreds of these old amps) that CC resistors only give you value drift; and nothing magical comes from that by anything other than random luck.  In the microphone world those idiots say things like "..this cheap Chinese microphone sounds as good as a $10,000 Neumann"

I get where a double blind listening test would come in handy when modifying an already great sounding high quality circuit to a different circuit or with different component values or types, but this thread is about gutting a POS Chinese sub $200 microphone, and scavenging the body to make something that has a pretty high chance of far exceeding the original's performance.  One doesn't need to do a DBTT to determine if an identical wine bottle full of ripple will be improved by filling it with Staglin Family Cabernet Sauvignon any more than one needs to do a DBLT before gutting a POS cheap Chinese mic and replacing it's components with a known good circuit with quality components and a high quality capsule designed to work with the circuit.  I guarantee the odds are way in the favor of an improvement rather than downgrade under these circumstances.  On top of that the man hours needed to perform a DBLT on a mic this cheap far exceeds it's value.

While your point is valid and without dispute in other situations, it is nothing but a sidebar comment in this thread and when made in a discussion of this particular topic only serves to make you sound like an elitist cork sniffer (since we aren't talking about expensive donor mics anyway) and appears to insinuate that those of us engaged in the gutting of cheap a$$ microphones (because empty body prices are now approaching ridiculous costs) to use their bodies for the construction of what we danged well know will be a better microphone aimed at our particular needs are a bunch of dummies.

So in short let me just say..."Got it."  DBLT are a great preliminary first step before wasting money and labor trying to make an already really good or expensive thing better.  But, I don't need anything but a recording test on any microphone to determine if it suits my needs in the studio.  If it doesn't and it cost a lot of money then I sell it.  If it doesn't and it cost almost nothing then the little bugger is going to the surgery room to be dissected and rebuilt like the six million dollar man.  If it is a sub $200 Chinese unit, I buy it knowing it will probably not pass my studio tests and assume it is going to die so something better can live.  I would never mod a microphone that sounds pretty good already or that cost a lot of money.  So, I don't use DBLT.  I'll leave that for the manufacturers who are trying to improve their product.  I'd advise them to also use alpha and beta testers as well since many ears are a better representation of a market than just the R&D departments ears.  No offense to you, but your comment doesn't apply here.  Now if you've got some great design ideas for improving cheap Chinese mics, I'm all ears.

 

[bnwitt]

But if modding and stuff made by virgins takes precedence over better sound for you .. that's OK too.  8)

By the way, the comment above could be perceived as insulting.

Now I know you can do better than that Ricardo.  Come on, share some of your mic knowledge.  You didn't become a designer and not know your trade.  Here's something you can answer for me, Please recommend a good book which explains microphone circuits, how they work, how they are tuned etc etc.  Preferably one from after the introduction of the FET or JFET.

 

[alexc]

..  bfn

 

[ricardo]

Errh!  Some of you might have noticed, I've just posted some practical stuff that might help you make a mike sound like U47.

And I was answering bnwitt's question about how to find cheapo mikes that sound like U47.

In my book 'kick ***' means sounds better for a mike.  It's actually quite difficult to replicate U47 sound exactly.  An important problem is "What is the genuine U47 sound?"  I know for a fact that U47s differ.

But my micbuilders Files has good stuff about making cheapo Chinese U67 stuff sound like present U87.  It's pukka cos present Neumann stuff is quite consistent so this can be tested easily.

And I've also posted a recommendation for what I feel is the best source for replacement capsules.

The only accurate & practical book on mike design is the PDF one on the Neumann website by Peus.  Most of the classic texts are not very practical.

"Microphones Design Handbook" edited by Gayford, is good but unfortunately Unobtainium and fetching silly prices on eBay.  Snippets are available on the web.

Mike circuits are not so clear cut but you should go out and buy The Art of Electronics - Horowitz and Hill.  This is a very practical textbook and will start eg at "what is a JFET?" .. but you will still be referring to it when you are a guru in your old age.

I've got a small amount of useful stuff on FET type mike circuits on micbuilders which I will add to.

My recommendation to buy 2 donors and keep one intact until you make a better sounding one still stands.

If you can't do expensive DBLTs, at least do sighted ones.

But whatever rocks your boat.

 

[bnwitt]

Ricardo,
Thanks for the recommendations.  As far as doing DBLTs on $129 mics purchased just for their cheap price rather than buying a 3 switch mic body from a body seller at $170, or buying two copies of the same cheap a$$ $129 Chinese mic for that purpose, I'd sooner spend $30k blueprinting a 1972 aluminum head Volkswagen engine to put into a rusted out beetle body.  If your book only defines "kicks it's ***" as sounds better then your book needs a few more definitions added under that phrase and is the cliff notes version of the Webster's unabridged microphone analysis dictionary.  Also, sounds better is subjective.  Value for price paid is what I was talking about.

Your DBLT comments don't belong in this thread as they have no application to the topic or process of which we speak.  But if you don't want to admit that, apologize for giving me a worthless out of place sermon, or become a real contributor to this thread, and instead you would rather puff out your chest and still keep pushing your extended pinky elitist tripe about blueprinting VW engines for go carts, then I say to you ....whatever rocks your boat.... too and I've heard all I need to hear from you on this topic.  Also I'm afraid I'm prone to discount any thing you post in the future because it is apparent your ego drives your posts rather than a sincere desire to teach.  You designed the best mic of the 20th century?  Really?  No Sh*t?  From 1900 until 1999 there was nothing better?  Wow!!!!!!!!  No wonder when folks search on Google or Bing "Best microphone of the 20th century"  The Calrec Heritage pops up 20 pages of links.

You know what, I suggest that you find a thread where changing a single coupling capacitor from polypropylene to paper in oil on a $20k vintage microphone is being discussed and sing your little song there.

 

[ricardo]

If your book only defines "kicks it's ***" as sounds better then your book needs a few more definitions added under that phrase and is the cliff notes version of the Webster's unabridged microphone analysis dictionary.

I'm soo.oo sorry.  I though 'sounds better was one of the aims of this exercise. 

I see I'm totally mistaken.  Have fun with your donors. 

 

[Gus]

FWIW  I bought 4 microphones for under $100 US for the bodies.  As always I opened them up and traced them before testing them.  I was surprised how good they sounded.  Not sure of the capsule source but not a bad sounding 6 micron 67 like.  So instead of using them for the bodies I am thinking about small changes to the circuit
A version of the JFET to PNP circuit that has good operating points and looks like has selected bias resistors for the JFET and even the PNP was biased OK with not my favourite one resistor B to C biasing.
They use Al electrolytics however they have proper uF to not sound bad and have lower distortion

So it looks to me like someone has designed a nice N JFET to PNP to about 2:1 transformer microphone for under $100 US on sale even has a stainless steel grill and nice body

Look close at the Circuit EQ curve in the link I posted before in this thread.  In that link were small changes more for operating point and EQ keeping most of the stock parts and adding one resistor

Search this forum for the Brauner phantom C thread look close at the circuit

Your microphone looks like it has a nice circuit check the transistor voltages Drain, Gate and Source, Collector, Base and Emitter and power supply nodes
K30? or K170? JFET I like the K30 better in this type circuit
EDIT I see K30 in the picture

 

[bnwitt]

Well I tested this recording tools MC 700 this morning and right out of the box the figure 8 pattern doesn't even work .  So, it is the donor body I expected it to be.  You get what you pay for and I got what I expected when I paid a mere $129 for this Chinese piece of junk.  Off to the surgery room for either repair or gutting.

Gus,
Thanks for the information.  I'll check out the links you referenced.  This mic goes silent for up to 20 seconds when switching between it's three patterns.  Omni works, Cardioid works but figure 8 has no sensitivity on the rear diaphragm.  Any ideas on what might display these symptoms?

Ricardo,
You sir are suffering from delusions of grandeur.  Please don't waste any more of my time posting in my threads.  The only thing you've said that is correct is "I see I'm totally mistaken." and that goes for everything you've said in this thread from the assertion that I should buy two of these mics, to I need to do DBLT before I gut this mic and the real laugher that you probably designed the best mic of the 20th century.  I've seen nothing from your participation in this thread but elitist tripe and insults.  Please go away.  I'm sure there is a reason why you "....used to design mics for a living"  I would imagine your loss of the job had something to do with the excessive lab hours it took you to get a product out the door.  It is clear by your statements and attitude that you are a legend in your own mind.

 

[tubestation]

Bnwitt, calmdown, please.
Ricardo is a really respecected  and very helpfull Person here in this Place. He doesn t  have it nessesary that you comment his work.!!If you like personal Attacs and Dissing, this may be absolutly the wrong Place here!!!!!
You were asking about a 200 Buck 47 and Ricardo gave you some Answers and usefull Links. Bthw your Donor Mic isn t that great for the Money, the 179 Bucks mic Body from Chunger is much more practical and you get  a good Capsule with it. Please stay friendly here, and say something positiv and post some technical Stuff instead of lalala.
Lothar

 

[bnwitt]

Tubestation,
I am perfectly calm.  So if one is respected here he/she is allowed to insult others right?  He or she is allowed to accuse others of chasing virgin built junk and being too dumb to understand microphones on any level  Maybe you should read his posts in this thread more carefully before you throw a bunch of exclamation marks at just me.  Obviously you don't respect me at all or you wouldn't just be chastising me for my half of this thread and saying nothing to Ricardo.  And thank you for making my point about the mic I have being junk only suitable for modding.  That's what I said from the beginning.  You know this is my first thread in this forum and if this is the norm (having some elitist insult me and than having a friend of his chastise me) then it will probably be my last.

 

[Gus]

I wound not call it junk yet. It looks to have good potential to my eye. Dual bobbin transformer K30 etc.  It looks like someone(s) put some work into the circuit and PCB
The back board looks like a +- DC to DC converter.
Cardiod and Omni would use one voltage and the other would be switched in for the rear membrane

So flip the capsule to see if the problem follows the capsule
If it is the electronics check the DC to DC voltages
Then check the switches
Look for solder issues or a wire in the wrong place

The n channel k30 into a PNP can sound very good set up correctly that microphone looks interesting because of the higher capsule voltage you can get from a DC to DC converter.

IIRC the phantom C uses a j201 to a n channel jfet instead of a PNP (I like BJTs better as followers) and no DC to DC  in the pictures that were posted at this forum in the past around 2004.

The time delay can be adjusted by changing the RC filtering

Post the voltages if you take the measurements use the mxl 2001 v67 etc schematics you can find for tracing the gain stage without the EQ

If you get it running try a M7, K47, C12 type capsule before putting a tube in it

FWIW I am finding tube microphones less interesting from a design standpoint and have been working on more solid state phantom and external powered designs

I even thought of buying one to trace and adjust if needed.