Hello everyone,

long time since my last post, I had and still have a LOT of work on my job so it took me a long time to diy something on the side but finally here it is.
I made something from the bottom of my heart, a microphone which is modular, it is a tube mic and at almost the same time solid state mic in a custom oak case with the most interesting PSU case.

Here it is...

The tube circuit is based around a EF806 pentode wired as a triode, the rest of the circuit is like the um57, like my older design. The transducer is the M7.
The yellow switch is used to add feedback to minimize the tube distortion and hope to leave only the transformer distortion and the transducer distortion of course.

Here is the side where the modules are connected. The hole in the PCB through which you can see the tube was made cause there was not enough space for the tube to fit in.

And the modules are basically different transformers to change the flavor of the tube sound and a solid state module based around AD's op467 quad opamp wired as an instrumentation amplifier with a differential output with a simple first order butterworth LP filter. The gain of the SS module is 1, and the sensitivity of the transducer is around 17.5mV/[email protected] so the output level is pretty high!
On the following pics the transformers are Lundahl LL1538 and Cinemag CM-2461NiCo, I just MUST get one of the Sowters to add to this group.

Here is a pic with one of the modules in its place.

Next up is the PSU.
It is made out of PCB material, more precisely FR4 2.4mm thick.
It is soldered together and than lacquered at a car shop. It is very light and extremely strong and very very cheap. Fantastic for diy!!!
The front and back panels are also made of PCB material! In other words the whole PSU case is made at the same PCB manufacturing service provider.
I made this case after I ordered 5 aluminium cases which I planned to sand than anodize but it was just too much trouble compared with this.

The PSU has high voltage regulation for the 160V rail made of two LM317's (one for pre-regulation). And +6.3V and -6.3V rails for the opamp also with pre-regulation each. AN OVERKILL!
The PSU transformer is custom wound 30VA - 230V : 135V + 13V +13V

Some pics together with the mic.

And now the Case!
It is hand made out of Oak by my friend than colored brown-red to give it a Rosewood kinda look, after that it was lacquered with one of the best polyurethane lacquers (used in yacht interiors) in three layers for the deep shine.

The handle was CNC cut than hand rounded.

Front look.

Than I "killed my self" while I finally found a moisture repelling, no-particle-disposing sponge for the inside. It cost me an arm and a leg.

While designing the case I was thinking where to put the cables, should they be beside the mount? If so, the case would have to be bigger more heavier and more expensive.
Than I thought if I make the mic carrying board removable I could place the cable underneath the PSU.

And some final pics for the end...

All together it took me a little less than two years to complete this, lots and lots of failed tries.
At the moment I hired a pro photographer to take some pics, I am also making a web site, where I'll post some sound clips and comparisons with other mics.

Best regards to all, Renx.
« Last Edit: April 30, 2011, 04:35:16 PM by renx »


 that's f**king nuts!

 looks awesome!



Would fit well in Hans Zimmer's work place...
« Last Edit: April 30, 2011, 11:46:24 AM by Sredna »
Hmm... in which direction do the electrons actually go?


WOW  !!!   :o :o :o

  Incredible work !!   Looks Fantastic !!  How does it sound with the three different flavors ? 
" Music washes away from the soul, the dust of everyday life "   ... in loving memory of my Father.


man... you got talent.
VERY nice work!
"we'll fix it in the shrinkwrap" fz


Xlnt work!  Congrats!



Wow, nice work.




I love it!

Do tell us more about the different modules and how they sound!

Ribbon microphone services
Microphone blog



Truly ARE...

Mister Incredible!!!

stunning work!
"A waist is a terrible thing to mind"
Quote from: PRR
Ah, but that was 1999; we don't party like that any more.





wow   very nice work
čovječe savršeno



Sused svaka čast!


wow :o :o :o 8) 8) 8)

but somebody have to say it, there is one error >:(
change the mic connector on the PSU to female, it contains high voltage ...


Wow, that's a lot of work, very nice Congrats
Would fit well in Hans Zimmer's work place...



Zoinks! You made a case out of FR4. That is insane; I love it.


Holy sh*t! Incredible work! The case is absolutely gorgeous, and the mic is stunning. I would also love to hear some comparisons of the different modules.

You sir, are a maniac!


looks great! Can't wait for sound samples. At first I wasn't sure about the fr4 case, but it's growing on me. Was the benefit for using that material only that you could have the pieces easily manufactured? I'd be constantly worried about it getting kicked by a rowdy rock singer.

but somebody have to say it, there is one error >:(
change the mic connector on the PSU to female, it contains high voltage ...

I would agree, if it were a commercial product. I'm pretty sure he's not going to let this mic out of his sight, and I would hope he's smarter than to stick his finger in there...
- Rodney

" better call Kenny Loggins, 'cause you're in the danger zone."


Thank you all for your replies.

So far I tested it in two studios after working hours, when the kind folks that own these studios gave me a chance to do so for free.
It was only tested on my voice, just speaking, because I didn't want to kill anyone or anything with my excellent singing abilities.
Now comes the part which I hate the most - explaining how something sounds.

The tube-cinemag version has a stronger lower-end and maybe more saturation than tube-lundahl which is more silkier and has more middles present.
The solid-state is something totally different, I wouldn't say more neutral character but less ... I don't know how to put this.  ???
When the feedback is turned on in any of the two tube combinations, it makes no difference to my ears. But the guys at the mixing desk say there is.
I would like for you all to wait for a week or two, until I make a couple of recordings with a pro singer. Then, hopefully I'll have comparisons with other mics as well, in parallel with each combination of my mic, but bare in mind that it is capable of 5+ sound flavors, which will take a bit of time to record:

1. tube-cinemag without feedback switched
2. tube-cinemag with feedback switched
3. tube-lundahl without feedback switched
4. tube-lundahl with feedback switched
5. solid state

and two additional which I will incorporate with an external box by adding each transformer (one at a time) to the output of the solid state mode.
This means that you would have an external box which you would connect in series with the mic output on the PSU when in ss mode, which would contain either lundahl or cinemag as the output transformer, adding additional two flavours:

6. solid state + cinemag
7. solid state + lundahl

Silent Arts:

you are right! Although I did put a sign on the back saying "Danger, high voltage" to remind me.  :D


At the beginning I was thinking the same thing, but I must say that for me, the FR4 case is really amazing. When you take thicker slates it is hard, it is elastic and you can "glue" it together with solder very very hard and then "un-glue" it and then "re-glue" it, and you can do it very precisely very easy. And since it is cheap it can be replaced cheaply as apposed to metal cases which are expensive in small quantities.
It is also fantastic because you can truly make almost any type of custom case you need in very high precision since it is all CNCed, just draw it in your favorite PCB software (mine is Alt*um).
Take ventilation holes on the side for example, you can get them made in any kind of way you can think of (text, logo plain holes like mine ...) if you wanted to do this in metal, the cost for CNC cutting would be too great, also the mounting parts, the screws, the holes for the countersunk screws and so on.
Another thing which is very useful is that you can solder brass nuts or screws to the case which gives you even more possibilities. The best thing for me is that all this is accessible in quantities of one! Where ever I asked for any type of custom aluminium case it was to expensive if you made only one piece, not to mention that almost no one even wanted to make just one.
And the last thing - IT IS CHEAP!!! That's because there is less film making, no etching, no lacquering just cutting and text pressing -> less time to produce -> cheaper!
And did I say that it looks great!

The next thing I will have made out of FR4 will be a 1RU front panel, 4mm thick, just to test it out.

Stay tuned for sound samples!

Regards, Renx.


Good points about no etching/silkscreen etc. Would you mind me asking how much it cost to have it cut alone?
- Rodney

" better call Kenny Loggins, 'cause you're in the danger zone."


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