My BRAUNER VM1 modification

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
The capsule mount/cradle itself has a negligible effect in this case. The Plexiglas base has most effect in the midrange.
The top end behaviour/character is to a large part determined by the capsule itself. I once A/B-ed the VM1 of a friend to a SM204 on drums and while the SM204 gave a smooth and well balanced representation of the kit the VM1 overemphasized the hihat in particular quite remarkably and generally sounded zingy on the cymbals.

The Neumann K49 doesn´t have this kind of top end zing. But before I changed the 3GOhm resistors to 90MOhm the highs still had a somewhat "cold" precision. Great resolution but not exactly flattering.
Since I like the sound better now with the low value resistors it might do the trick for you too. It´s reversible and cheap enough to just try it and judge yourself.

BTW, I´ve meanwhile done a bit of empirical testing with various resitors and values also in another mic. I found that not only the value makes a difference in sound but also the type/quality of the component. I didn´t expect the differences I experienced. There´s just no way around actual trying and listening!

Sorry for the late reply, I´m not here every day.
 
MS Vienna said:
BTW, I´ve meanwhile done a bit of empirical testing with various resitors and values also in another mic. I found that not only the value makes a difference in sound but also the type/quality of the component. I didn´t expect the differences I experienced. There´s just no way around actual trying and listening!

Try old carbon Beyschlag or Draloric on plate and cathode. You will be surprised much more ;)
 
With any mic improvement project, it is worthwhile to remember the hierarchy of audible changes, where the capsule is on top, followed in some distance by the tube, the transformer, and, way down, component materials (assuming an unchanged circuitry).

Ideally, all components should be selected for sonic synergy, how much they can contribute to a desired timbre. That synergy certainly was there with the classics- intentionally or unintentionally- it also was the foremost goal in the design of  the KHE.

KH
 
MS Vienna

Have you domed the top of the grill?

Is there a book or web site that explains how to select the elastomer for a microphone capsule mount?

 
I have arched the top mesh very slightly with the handle of a screwdriver. I´m sure there´s no effect because the arch is barely visible. The Plexiglas capsule base prevents any vertical standing waves anyway.

I haven´t come across any guide for the damping of capsule holders in microphones. What works is usually determined empirically.

The damping properties of the rubber element have to be in a good balance to the capsule´s mass. In commercial mics the rubber part is often much stiffer than ideal to keep the capsule from banging against the grille in case the mic is dropped. Special solutions such as the soft 4-point suspension in the current C414 models can be  close to perfect.

I´ve tried rubber elements from different Austrian and German dealers and the rubber type seems to be the same in all of them (not smelly!).
There´s a company in Vienna that produces such elements and can also custom-make them in all possible grades of elasticity ("Shore"-Values):
http://www.persicaner.at/

Here are some dimensions of standard 55° Shore elements that worked well for me:

Neumann K67/K87 (50grams):  10x10mm rubber element

Neumann K47 (35grams), AKG CK12 brass (25grams):  8x8mm rubber element
 
MS Vienna - did you get a chance to try old carbon Beyschlag or Draloric resistors on the plate and cathode?  I'd be very interested in hearing about your results.  I'm currently working on a mock U47 and this level of detail is turning out to be of importance.  I'll even be doing some work experimenting with ceramic caps in the high impedance areas of the circuit; something I thought I would never be doing again!
 
Not specifically on plate and cathode. I eventually replaced all resistors. Most of them are carbonfilm (generally Beyschlag), two 100MOhm are carbon comp now.
Except for those high resistances I replaced the original resistors with measured old ones of the exactly same value. I did not want the tolerance in the parts´ nominal value to interfere with the test result. 
I personally prefer the sound of the carbon resistors over the original ones so they stay in the mic.

There is a difference but I recommend to try it yourself. How clear the difference is audible in your case will depend on your signal chain, probably the mic´s circuit and of course your hearing performance. That said, what is preferable remains a matter of taste.

BTW, this modification is still in progress. It´s a very nice mic by now and I regularly use it to check out where there´s room for improvement left. Once it performs to my full satisfaction I´ll report back.
 
MS Vienna said:
Not specifically on plate and cathode. I eventually replaced all resistors. Most of them are carbonfilm (generally Beyschlag), two 100MOhm are carbon comp now.
Except for those high resistances I replaced the original resistors with measured old ones of the exactly same value. I did not want the tolerance in the parts´ nominal value to interfere with the test result. 
I personally prefer the sound of the carbon resistors over the original ones so they stay in the mic.

There is a difference but I recommend to try it yourself. How clear the difference is audible in your case will depend on your signal chain, probably the mic´s circuit and of course your hearing performance. That said, what is preferable remains a matter of taste.

BTW, this modification is still in progress. It´s a very nice mic by now and I regularly use it to check out where there´s room for improvement left. Once it performs to my full satisfaction I´ll report back.

High five :D
 
Tim thanks for the information about the newer capsules.
Have you seen one up close to see what it might be patterned after or if it is something different?
 
I just found this thread and thought I'd add the little bit about Brauner mics that I know.
I learned about Brauner mics very early on in Dirk's career and asked to demo one. I sent him money to show good faith and to cover costs. I liked the mic (serial number 100) but thought it was much too bright and that it needed to be better balanced tonally.

Dirk told me he had worked really hard to get that top end (reminiscent of the U67) and wouldn't change it, but he would investigate changing the holes drilled in the backplate to get more “bass” (my word meaning a better balance between hi and low frequencies). I sent the first mic back to him and received a second, serial number 200. I liked this mic much better and kept it.

Dirk told me he hadn't made 100 mics yet, let alone 200. He just wanted me to have a “century number,” which I thought was very kind and generous of him. I later purchased other Brauner models over the years. I have great respect for Dirk as a person and microphone manufacturer.
 
Back
Top