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).

 

[djivano]

as i said before, in a u47 , the headamp is 20% of the sound.

if we admit that there is a 10% variation between for example a true vf14 and another replacement, then we can make clones and record some music in peace.

As far as i'm concern, i spend most of my time to find some good capsules because it's 80% of the sound.

this is what i've found:

for u47, Neumann still produce the k49, and it's worth the price....
M7 Thiersch and K47 Flea skinned by Thiersch are not my cup of tea ...too colored in the mids for me
Nor the M7 beesneez (too dark) : K7 much better

keep in mind that quite big differences exist between identical capsules

i've tested recently a true VF14 during one week, and i can tell you that the differences are not that huge with ef14/13 and 13cw4
there are differences, YES it's true, but i keep in mind that if the singer moves of 10cm the difference is much bigger...
In a full mix it's almost undistinguishable...
that's why i'm still experimenting (for the fun) for a usable solid state replacement, but i must admit that i already have some very usable solution with EF13/14 and 13cw4
i'll post here my schematic as soon as possible...

cheers

Hi Frederic,

I would like to build me a U47 clone with a Telefunken EF13 tube, of which I have several and a Beesneez K7 capsule.
I can solder but I am a total noob in microphone building.
Do you have advice, sources from where you got your (specific) parts, schematics and further tips for me, perhaps? You can also send me a private message if more convenient.

Thanks in advance, Jeff

 

[kingkorg]

Hi Frederic,

I would like to build me a U47 clone with a Telefunken EF13 tube, of which I have several and a Beesneez K7 capsule.
I can solder but I am a total noob in microphone building.
Do you have advice, sources from where you got your (specific) parts, schematics and further tips for me, perhaps? You can also send me a private message if more convenient.

Thanks in advance, Jeff

Waking up 10yo thread asking questions about stuff available, and discussed to death on this very forum. If you use search and do some reading you might get closer to your goal.

 

[gyraf]

..ef13 is a remote-cutoff pentode, not really suitable here..?

 

[pasarski]

..ef13 is a remote-cutoff pentode, not really suitable here..?

Surprisingly it seems to be. Thanks for @Accelerator for pointing to this article yesterday. http://www.moxtone.com/mU47_U47_part3.html

 

[gyraf]

..you can see already from those curves, for the EF13 not being equi-distant, that you're asking for distortion..? Or do we rely on signal level being so low that it gets negligible?

 

[pasarski]

..you can see already from those curves, for the EF13 not being equi-distant, that you're asking for distortion..? Or do we rely on signal level being so low that it gets negligible?

Of course we want distortion, why else we would use tubes? (Sorry, couldn't help it )

 

[Accelerator]

@djivano

Do you have advice, sources from where you got your (specific) parts, schematics and further tips for me, perhaps? You can also send me a private message if more convenient.

Thanks in advance, Jeff

Hi Jeff, welcome aboard, greetings from Greece!...

For the schematic, you can take a look at the Oliver Archut U47 Alternative Tube schematic by Oliver Archut (RIP) of Tab – Funkenwerk that I attached below…

If you would like to build a U47 clone with a Telefunken EF13 tube, of which you have several (you lucky one!...) The Flea47 mechanical kit is the perfect choice for your task!...
The Beesneez K7 capsule that you have it is a nice one, although I'll prefered a Thiersch Elektroakustik M7 Blue line capsule, but as you guess it is a matter of choice about what vibe & tone you way or may not you search after...

For transformer take a look at the Moby Transformers Bv.08 (U47, U48)
For us -the Europeans- the Banzai Music GmbH is a nice choice for the Passive Components

 

[djivano]

@djivano

Hi Jeff, welcome aboard, greetings from Greece!...

For the schematic, you can take a look at the Oliver Archut U47 Alternative Tube schematic by Oliver Archut (RIP) of Tab – Funkenwerk that I attached below…

If you would like to build a U47 clone with a Telefunken EF13 tube, of which you have several (you lucky one!...) The Flea47 mechanical kit is the perfect choice for your task!...
The Beesneez K7 capsule that you have it is a nice one, although I'll prefered a Thiersch Elektroakustik M7 Blue line capsule, but as you guess it is a matter of choice about what vibe & tone you way or may not you search after...

For transformer take a look at the Moby Transformers Bv.08 (U47, U48)
For us -the Europeans- the Banzai Music GmbH is a nice choice for the Passive Components

Thank you so much, Accelerator. I will look into the info you sent me. Very enlightening.

 

[Accelerator]

@djivano

Thank you so much, Accelerator. I will look into the info you sent me. Very enlightening.

You welcome Jeff and I would like to thank you back for your very kindly words!...

I highly recommend you to read these triple series of articles by the Croatian Moxtone Lab, as these articles will helps you a lot to your task, especially the third one about the Output Characteristics of the EF13 valve:

A Journey into the Legend: The U47

A Journey into the Legend: U47 power supply

A Journey into the Legend: The Output Characteristics of the VF 14 and its Substitutes

Basil.