ECM8000 Mods

Thank you guys.

Now, how to make a ground connection...
First, take a braided solder remover and remove solder (this one sounds great, isn't it? :) ) from the contacts on the capsule. You will see a tiny hole and a FET's leg, bent over to the top side. The picture will tell you the rest. Don't forget in the end to seal the hole with silicon, otherwise you'll get LF loss.
 

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Thanks Marik, excellent idea!!!

Thanks also for the info on external voltage. 100V is quite a lot. I guess it wouldn't make sense to try external polarization, even if one used a DC-DC converter. How much voltage do you think this thing could take?
 
This must surely be one of the best threads in here ever! But I still think my own ECM8000-mod is by far the best bang for the buck: I have shrunk black plastic on to the mic bodies, so now they look like DPAs! :D
 
Marik said:
DJL,
...as I have to pick my fianceee from the airport exactly the same time.

Oh, that's too bad. I guess we won't be seeing too much of you around here for the rest of your life.

It's never too late to say

NO!


:D:D
 
<How much voltage do you think this thing could take?>

Rossi,
Do you mean polarization voltage? I wouldn't fuss with that. Too much trouble for probably 1 or 2db of output... I'd think that it won't do much for quality of the sound either, as the tension of the diaphragm is high, and diameter of the capsule is way too small. Plus, you have to make a DC-DC converter, which means a new PCB and all that stuff. Naw, not worth it.
I had an idea to rediaphragm the capsule with higher tension, and thus to increase the HF to 40Khz. The sensitivity should drop by 6db, though. One day I might probably try it...

<...as I have to pick my fianceee from the airport exactly the same time.
--------------------------------------------------------------------------------
Oh, that's too bad. I guess we won't be seeing too much of you around here for the rest of your life.
It's never too late to say
NO!>

Hey Crazydoc,

Do you imply I had to leave her in the airport forever? Not nice! :D

No, although I have some duties like cleaning basement and my stuff in the house, she is very nice and extremely patient to all my...... hm......koo-kooos. In fact, I don't honestly know how she still stands me after five years....
 
Thanks Marik, yeah I meant polarization voltage. But speaking of voltage: the capsules are specified at 10V max operating voltage. But I suspect they could take more. The ones in my old Radio Shack PZMs can take 12V.

And hold on to that girl!
 
Marik said:
...she is very nice and extremely patient to all my...... hm......koo-kooos. In fact, I don't honestly know how she still stands me after five years....
Some don't start barking out orders until the kids arrive. Then... lookout!!! :D
 
Marik said:
In fact, I don't honestly know how she still stands me after five years....
She doesn't know how she stands you either - I mean five years? She had no idea she would have to be nice to you for so long before you'd marry her.:D

But really, the harsh realities of conjugal life, in most circumstances, require that you put your childish toys aside and concentrate on the aspects of family life that she considers important. Hell hath no fury like a woman ignored. :)
 
To return to the original topic...

Somewhere in this thread I said that from what a Chinese guy said in this forum a while back and from what I'd seen on the Tenlux website before it was closed down, I'm pretty sure the ECM8000 is made by Tenlux, Taiwan. I now found a site that substatiates this. Take a look at http://www.superlux.us and go to "test equipment" or go directly to http://www.audiotoolbox.us/ and there you'll find a measurement mic that looks exactly like the Behringer one, except that it's black.

I know there's a couple of measurement mics that look very similar, but it's clear that neither MBHO nor Audix for example would fabricate a mic at Behringer's price. So, I guess we can now be almost 100percent sure it's a Tenlux mic. I wonder if Behringer had any part in the board design, though.
 
Rossi,

Thank you. There are some things which still puzzle me, though. The first revision was transformer coupled. The picture on the box also clearly shows transformer. Why later they switched to transformerless bipolars, and why they even did not bother to change a pic on the box? Is it purely budget thing? I don't want to start any speculations, but it is no secret for anybody what kind of practice Behringer performs for its production. So, did they find anything "better"? Ausrock also informed that his one has a different layout. Is it the same schematics? Then, why would they change the whole production line for making new PCBs? It doesn't seem that they invest "too much" into development and research, esp. into THAT CHEAP mic. In this respect I am really interested in seeing Audix, Chessrock kindly offered for examination. However, first I'd like to completely finish the mods. Hey Chessrock, hope you did not change your mind.
 
Considering the quality of the Chinese transformers I've seen, they did us all a big favor by switching to the transistors for phase splitting and impedance matching.

I doubt that's why they changed, though. Transformers probably went up a couple of cents.
 
Hmm, I'm not sure how much Behringer itself is involved in the design of their mics. To me they all look pretty much like OEM off the shelf designs of the respective manufacturers (Tenlux, 797Audio, whatever). But I really don't know.

re the transformer: first of all I was surprised to see a transformer on the packaging. Considering this is a measurement microphone, I found it unusual that there should be a transformer. Whether or not you're into transformers, they do alter the sound a bit. A good transformerless design is usually more neutral sounding than a transformer coupled output. Anyways, I too think that they (Behringer or Tenlux?) dropped the transformer for monetary reasons. Remember that the ECM8000 used to be twice its price today. If you go back to Harvey's post that made them popular, you see that he became interested, because Behringer announced to cut the price for most of their products by 50% at that time. I suppose at their current price there simply is no margin for a transformer, and I'm acutally glad they switched to a transformerless design instead of going for an el ultra-cheapo transformer.

Does anybody have a transformer and a transformerless ECM8000? Would be interesting to hear comments from a user.
 
OK Gentlemen,

Time for next update.

Huh, I spent a great deal of time working on this project, trying different circuits and literally spending many hours for listening, evaluations, and comparisons. The target is--to come up with a circuit, which is as simple as it is possible. The main reason is that from my experience the simplest, but well optimized one usually has better sonics. Another reason is that more or less 'soldering iron friendly' folks could do the mod easily.

I was reading a lot of comments on this mic. The main complains seem to be 1) noise 2) SPL handling 3) hurshness. Now I am using WM61 capsule, which has a few dbs less noise. This one has higher output and with 'Linkwitz mod' (sorry, I was spelling his name wrong) I can get rid of BC118 on schematics and all parts around it, and feed the output buffer directly from the capsule. Currently it is my favorite in term of sound. I still have a few more ideas to try, so I might change my mind... Basically, the whole mod would be:
1) Cut the traces on WM61 capsule.
2) Take the mic apart.
3) Replace the stock capsule.
4) Remove most of the parts from PCB.
5) Put a couple new parts.
6) Change a couple parts with different values.
7) Put the mic back together.
8) Connect to the pre and listen if it works.



I made a Scott Dorsey's mod as well, using internal FET as a phase splitter. It works, and sounds very clean and clear, however the bass is a little bit rolled off. I could not find an explanation, so I posted the question, along with some others on TT. The problem is that the internal FET is quite an interesting in its behavior device. I could not find any data on those and think that it might be even kinda special 'in-house' part. Probably PRR can handle this question (this guy knows everything about electronics--history, theory, practic matters, tubes, mics--everything! Really!)
So stay tuned Gentlemen, I will be back.

P.S. Meanwhile, I made a holder for 7 capsules array. Idea is to use it with my ribbon mic for a HF compensation and cardioid pattern, but it might be something interesting as it is, in the end.
 
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OK, you shamed me into taking time to open up my ECM's and take a couple of pics............to my non-techie eye there are differences, but whether or not it is the same circuit as earlier pics here that has been layed out differently I won't attempt to guess.

:cool:
 

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And here's the underside of the PCB.

BTW, before anyone asks WTF it is that has RODE on it in the previous pic, it is a set of jewellers screwdrivers compliments of RODE:)
 

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Marik said:
...Probably PRR can handle this question (this guy knows everything about electronics--history, theory, practic matters, tubes, mics--everything! Really!)...
Good ol' PRR. Scary to think where we'd be without him! :eek:
 
Ausrock

That looks like a "standard" type circuit. It looks alot like the circuit in sampsoms C01s and C02s.

The single transistor should be a fet marked 105 or 305 the IC is a dual PNP pair I believe. Could you post the numbers and values of the caps I can't see. The two small ceramics "should" be marked 102 1000pf RF reduction caps. If I have time I will trace the schematic from the pics.
 
Ausrock,

It seems to be the same circuit I posted earlier. The surface mount caps changed to electrolitics, though. Thank you for taking these pics! :)
 
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