Measured VF14 characteristic

[o3misha]

Have you got any measurements of the capsules? If you rely only on the ear, can be greatly mistaken about the linearity characteristics. I also believe that in the absence of any measurements, except for the subjective assessment "by ear," we can not talk about the concept of coloring. Or need to add - in my opinion.

 

[granger.frederic]

frequency plots without an anechoic chamber and  one ultra linear source, are simply useless , and maybe with also ...

moreover, i'm always surprised how two capsules have nearly the same frequency plot and sound so different.

However, i make some "FuzzMeasure pro" of each capsule that i test, i always compare with all other parts equal, and with high end gear.

http://www.supermegaultragroovy.com/products/FuzzMeasure/    (very useful software)

But i must admit that these reviews are purely subjective and someone else could obviously have the opposite feeling.

 

[o3misha]

frequency plots without an anechoic chamber and  one ultra linear source, are simply useless , and maybe with also ...

moreover, i'm always surprised how two capsules have nearly the same frequency plot and sound so different.

However, i make some "FuzzMeasure pro" of each capsule that i test, i always compare with all other parts equal, and with high end gear.

http://www.supermegaultragroovy.com/products/FuzzMeasure/    (very useful software)

But i must admit that these reviews are purely subjective and someone else could obviously have the opposite feeling.

All I wanted to say: when you don't like or you do like the capsule , you can' t say anything about its frequency response. Its just your feelings, no more no less. Frequency response and any harmonic colorations have to be compared with absolutely leaner mic in anechoic room. This measurements can say exactly what I mean no more no less. Of course, you may be very surprised how your feelings and preferences differ from reality.,.

 

[granger.frederic]

Dear Misha,

the frequency response measure is made with a sinus sweep , and for a fixed amplitude .
the kind of source never exists in the real world.
the plot shows eventually an global character (dark or clear) but not at all how the mic sounds.
the sound of a human voice for example, and the sound of a mic , are much more complex and non measurable, thus i think that we can talk and debate about our feelings in peace...

 

[o3misha]

Dear Misha,

the frequency response measure is made with a sinus sweep , and for a fixed amplitude .
the kind of source never exists in the real world

So, why  talk about linearity or coloration of sound of capsule? Lets talk about our preferences , not real measurements , which are not the same things with our feelings.

the plot shows eventually an global character (dark or clear) but not at all how the mic sounds.

Microphone sound ?First, you talked about the capsules, and not on the amplifier. This is a very delicate moment. Because the linearity of the capsule and linearity of the full microphone - different things.

 

[granger.frederic]

Dear Misha,

please don't split hairs and read my previous posts again

i was just giving my feelings about some capsules because :

a-to repeat that it's the most important part of a LDC
b-why not ?
c-someone asked me

if it's a problem for you, or if it's too delicate for you, then feel free to read another topic !

 

[bockaudio]

I have 3 PSUs, and the original as well. My favorite - my own. With a tube rectifier (kenotron) instead of the original selenium rectifier. I hear a slight difference, believe me, between the transistor and a lamp. Another thing is that I'm not a purist. Important to me that with VF14EF I can work with loud sound sources with greater efficiency. Sound more transparent in the upper part of the spectrum. Sometimes it's better than VF14, which is more than 50 years old, it is not the best issue and quite small headroom, even when it was in his best form. There many engeneers in Europe ( two of them are my friends) who admitted that Fet design is fantastic replacement for U47. Nobody said that Fet is equal to tube. There many other  tasks that transistor replacement performs at least no worse than VF14s (which, by the way, all the sound differently, and not all good). For many engeneers, old, withered and lost elasticity PVC membrane sound better than new caps of Thiersch. So what? Whose opinion is assumed to be correct? What is the original sound if the microphones is 50 years old? I have met 10 U47s . Not one I would  want to buy. Only 11th and 12th I bought. And then, only after a serious overhaul. And again: it is almost impossible to find good VF14s today. There are many VF14s traveling between different owners. But most of them were used and are not in good condition or they are not even tested for microphone usage. And price is so big, that I don't want to use mic for every day.

Now we are getting somewhere. Having an original mic with the psu allows you to have an opinion. And then a tube rectifier! Not sure what "between the transistor and the lamp" means.
My mistake if I though you were claiming to have a fet sound like a tube in a mic.
I have never seen a case where an engineer thinks his dreid up pvc membrane sounded better than the new one. As you mentioned they loose elasticity, and consequently, bass then mids. And they become "screechy" sounding, no one likes that.
RE: many U47's don't sound great: Absolutely! When I was at Oceanway in the 1990's we had one building which had the smaller collection of U47's, and it was quite a surprise to learn (one day) that four of them didn't sound good. So it's true not every U47 sounds good as is.

 

[bockaudio]

What do YOU think prevents a solid state mike from sounding like a good tube mike?
What are the technical issues?  What are the sonic issues? Mr. Bock, how about giving us your views on why this is difficult .. as an experienced mike designer?

Might be difficult to actually discuss above the noise of this thread.
While on the surface, it would appear to be a simple feat, as the fet Z is certainly high enough to compete with a tube, fet and fet/bjt combos never seem to have the same amplification of a tube, the compression of a tube (bringing up the backround the same way), or the onset of distortion (though a simple CC'd fet mimics it).
An example of a fet/tube combo sounding more tubelike is Tim DeParavachini's mic which uses a fet as the bottom of a cascode (basically). But it had an active shunt so it's a different beast than a classic tube mic anyway. He has talked about it having a great ability to deliver current, which is coincidentally a feature of the U47.
An example of a fet replacing a tube and sounding like a fet was the U47 I heard at a trade show using such a device. No one who has heard a U47 even cursorily (like my wife) though it sounded like a U47. They all said, "what happened?".
Regarding building a thesis on "why a fet can't sound like a tube in a mic", I'm not about to enter the arena! My job is to know what sounds like what and not BS my customers about it. It could be a great project for a grad student with the time and inclination, and connections to non-BSers (to keep his or her moral sonic compass true). And really, if I knew ALL the reasons they don't sound the same, I could probably circumvent them, and have the no maintenance fet versions of the tube mics we all want already.

 

[ricardo]

.. fet/bjt combos never seem to have the same amplification of a tube, the compression of a tube (bringing up the backround the same way), or the onset of distortion (though a simple CC'd fet mimics it).
An example of a fet/tube combo sounding more tubelike is Tim DeParavachini's mic which uses a fet as the bottom of a cascode (basically). But it had an active shunt so it's a different beast than a classic tube mic anyway. He has talked about it having a great ability to deliver current, which is coincidentally a feature of the U47.

Thanks for this David.  I need to ruminate on this I think 

Anyone have a link or copy of Tim de Paravicini's mike circuit?  I seem to remember a patent on a Schoeps variant with Cascode input.

 

[o3misha]

Now we are getting somewhere. Having an original mic with the psu allows you to have an opinion. And then a tube rectifier! Not sure what "between the transistor and the lamp" means.
My mistake if I though you were claiming to have a fet sound like a tube in a mic.
I have never seen a case where an engineer thinks his dreid up pvc membrane sounded better than the new one. As you mentioned they loose elasticity, and consequently, bass then mids. And they become "screechy" sounding, no one likes that.
RE: many U47's don't sound great: Absolutely! When I was at Oceanway in the 1990's we had one building which had the smaller collection of U47's, and it was quite a surprise to learn (one day) that four of them didn't sound good. So it's true not every U47 sounds good as is.

1.I mean: I can hear a small difference ( not very dramatic as you are sure) between Tube (VF14) and Fet replacement inside mic . And would prefer Fet replacement than 9 from 10 VF14 tubes, because good sounding VF14 is rarest tube. It is almost impossible to get "legendary sound" with most of VF14s today.
2. About M7: aging the PVC leads to both things, loosing not only low end but also high end. Thats why old capsules may sound softly and compactly (for many people). 
3. I told about 3 different PSUs to express that I prefer my own PSU ( also  not stabilized like NG, but with kenotron).