Microphonics in VF14 and U47

[tomas.borgstrom]

How do you open German steel tubes so that you get them back together nicely? Are they glued or just clamped by these small notches?

When you remove the bakelite and pins it looks like this

 

[rock soderstrom]

Thanks. How do you get the rest out of there? This looks like a Dremel job.

 

[Tubetec]

Tin opener maybe
a small grinding wheel on a dremel , along the inside edge of the metal rim .

 

[soapfoot]

I remember Oliver stating that one barrier to new VF14 steel tube production was a certain bit of tooling—a long compound German word I don’t remember that translates roughly to “circular welding machine”

The tooling to make a proper VF14 would be very expensive… I think I remember him saying that Neumann was quoted over half a million for one machine alone when they explored the topic a decade or two ago

 

[MicMaven]

ender Strat, I remember taking off the plastic plate that covered the tremolo bar springs because I preferred the sound that way.

Yep ... a lot of guys remove that plastic plate covering the springs on the back side of the instrument. As a kid, we did that because we thought it would make the guitar more "resonant" (the word we used at the time) and also because it made it somewhat easier to change strings. AND, maybe the main reason, is, as you mention, a lot of famous guys did it first ! James / K8JHR

 

[gyraf]

..there are a range of different mechanical versions of the steel tube, not just one type..

 

[rock soderstrom]

..there are a range of different mechanical versions of the steel tube, not just one type..

That's right, the construction varies.

 

[ZHOUJUN]

Tried different tube and transformer, including EF12, 13 cw4, EF14, UF14, EF86, 407 a, 408 a, EF80, double tube 408 a similar to VF14 timbre, AMI BV8 is great, there is a call MICMOD BV8 transformer is also very good, sound with AMI is very close.

 

[maarvold]

A few thoughts. First, as a 30+ year subscriber to the also!ute sound magazine and 20 years subscriber to Stereophile (I stopped around 15 years ago because I couldn't find time to read them), over and over, I see a trend for people to incorrectly generalize about audiophile stuff. In addition, I see outright disdain/disrespectfulness among many in the pro audio community for audiophiles and audiophilia. (I know this is DIY, but there are some pros here). Highly respected mastering engineer, the late Doug Sax, once said that one of the most difficult things in the world is to play a vinyl record correctly; one of the easiest is to play a cd correctly. When I gave away my extensive vinyl collection roughly 20 years ago, I was still very aware of turntable technology. My turntable was an all air-bearing design (delrin(?)-clad 20 lb lead platter floated on a cushion of air) with a linear tracking arm (also air bearing) and the arm had a viscous-damped oil trough with a 'paddle' attached to the cartridge mount; as the arm travelled toward the center of the record, the paddle 'wicked' vibrations away from the head shell and they were absorbed by the damping oil. FWIW, this improves a characteristic brilliant recording engineer Keith O. Johnson refers to as "settling time": the time an object takes to return to that state it was in before a physical process 'excited' it. The delrin coating on the platter was used because it had a similar mechanical impedance to vinyl and, again, the vibrations from the stylus-to-vinyl interface were 'wicked' away from the contact point and into the lead platter. It also had a subchassis made from layered wood and lead. It was super-cool and a monstrosity all at the same time. But it revealed A LOT of information. Oh yeah, there was also a clamp that kept the record pressed down onto the platter.

A lot of this audiophile knowledge I have let go of, but one thing that was a hotly discussed topic in the early days of digital and cds was the fact that vinyl had quite a bit more information potentially available than cds, due to the 'minimum unit size', which I believe was the long dimension of the stylus footprint in relation to the length of the vinyl groove that passes the stylus in a given time period. Of course, resolution shrinks as the stylus moves closer to the center of the record because less material is passing the stylus (the groove circumference is smaller).

I was the technical setup person at several direct to disk/DSD recording sessions at Bernie Grundman's mastering facility (EMM Labs convertors on the first one... don't remember on the second one). On a blown take, Bernie played the lacquer right off the lathe it was being cut on and we compared it to the DSD. Bernie preferred the lacquer (the first step in the vinyl process). I thought the DSD was truer to the 2 bus: the vinyl had just a little extra, and pleasant, 'zing' to it that was not in the DSD... you might say it was more 'fun'.

My point of view is that, if current measurement methods, manufacturing techniques, materials and technologies, etc., were available at the dawn of microphone design, the ever-progressing history of recorded music would sound VERY different than the way it currently does. I believe the initial design goal of the very first mic would have been to create something totally linear and true to the source; of course, it is human nature to want to 'play in the sandbox' and who knows where designs might have gone after the original design goal was close to being achieved. BUT, with the current knowledge base at the time many of these things happened, this was simply not possible, so, imo, the goal became to make something that sounds "pleasing" or "musical" or "powerful" (the Hitler mic) or just plain "good-sounding" and this became the selling point of a particular design.

Many times over the years (I am 68), when people experience a new (at that time) technology, they are quoted as saying "It sounded like the instrument(s)/singer was right there in the room with me". When I hear that statement, I shake my head and wonder what galaxy those listeners beamed down from. When I was at my very most rabidly-obsessed with the quality of my audiophile playback source material and playback system (with EXTENSIVE room treatment: an absolute requirement for quality reproduction in most circumstances), at the very best I could be fooled for a second or 2 that some aspect of an extremely well-recorded source was actually a believable representation of a live event... or some aspect of it.

Lastly: this is a GREAT topic with a seemingly very well-executed methodology. Thank you Tomas: for the hard work in service of improved understanding of microphones and their design.

 

[kingkorg]

A few thoughts. First, as a 30+ year subscriber to the also!ute sound magazine and 20 years subscriber to Stereophile (I stopped around 15 years ago because I couldn't find time to read them), over and over, I see a trend for people to incorrectly generalize about audiophile stuff. In addition, I see outright disdain/disrespectfulness among many in the pro audio community for audiophiles and audiophilia. (I know this is DIY, but there are some pros here). Highly respected mastering engineer, the late Doug Sax, once said that one of the most difficult things in the world is to play a vinyl record correctly; one of the easiest is to play a cd correctly. When I gave away my extensive vinyl collection roughly 20 years ago, I was still very aware of turntable technology. My turntable was an all air-bearing design (delrin(?)-clad 20 lb lead platter floated on a cushion of air) with a linear tracking arm (also air bearing) and the arm had a viscous-damped oil trough with a 'paddle' attached to the cartridge mount; as the arm travelled toward the center of the record, the paddle 'wicked' vibrations away from the head shell and they were absorbed by the damping oil. FWIW, this improves a characteristic brilliant recording engineer Keith O. Johnson refers to as "settling time": the time an object takes to return to that state it was in before a physical process 'excited' it. The delrin coating on the platter was used because it had a similar mechanical impedance to vinyl and, again, the vibrations from the stylus-to-vinyl interface were 'wicked' away from the contact point and into the lead platter. It also had a subchassis made from layered wood and lead. It was super-cool and a monstrosity all at the same time. But it revealed A LOT of information. Oh yeah, there was also a clamp that kept the record pressed down onto the platter.

A lot of this audiophile knowledge I have let go of, but one thing that was a hotly discussed topic in the early days of digital and cds was the fact that vinyl had quite a bit more information potentially available than cds, due to the 'minimum unit size', which I believe was the long dimension of the stylus footprint in relation to the length of the vinyl groove that passes the stylus in a given time period. Of course, resolution shrinks as the stylus moves closer to the center of the record because less material is passing the stylus (the groove circumference is smaller).

I was the technical setup person at several direct to disk/DSD recording sessions at Bernie Grundman's mastering facility (EMM Labs convertors on the first one... don't remember on the second one). On a blown take, Bernie played the lacquer right off the lathe it was being cut on and we compared it to the DSD. Bernie preferred the lacquer (the first step in the vinyl process). I thought the DSD was truer to the 2 bus: the vinyl had just a little extra, and pleasant, 'zing' to it that was not in the DSD... you might say it was more 'fun'.

My point of view is that, if current measurement methods, manufacturing techniques, materials and technologies, etc., were available at the dawn of microphone design, the ever-progressing history of recorded music would sound VERY different than the way it currently does. I believe the initial design goal would have been to start with something totally linear and true to the source; of course, human nature is to 'play in the sandbox' and who knows where it might have gone after the original design goal was close to being achieved. BUT, with the current knowledge base at the time many of these things happened, this was simply not possible, so, imo, the goal became to make something that sounds "pleasing" or "musical" or "powerful" (the Hitler mic) or just plain "good-sounding" and this became the selling point of a particular design. Many times over the years (I am 68), when people experience a new (at that time) technology, they are quoted as saying "It sounded like the instrument(s)/singer was right there in the room with me". When I hear that statement, I shake my head and wonder what galaxy those listeners beamed down from. When I was at my very most rabidly-obsessed with the quality of my audiophile playback source material and playback system (with EXTENSIVE room treatment: an absolute requirement for quality reproduction in most circumstances), at the very best I could be fooled for a second or 2 that some aspect of an extremely well-recorded source was actually a believable representation of a live event... or some aspect of it.

My kids grew up on diverse compressed formats of audio available at Spotify, YT... Not sure if they ever listened to vynil or even cd. Nothing i could do about it, the availability and convinience times trends. They are not into music much beyond consuming and enjoying. Mostly through pods. I got them coolest looking, best possible sounding headphones only for them to scrap them and replace by "Beats". They are 19 and 23.

I performed a listening test on them. In every shootout they preferred heavily compressed formats at lower bitrates to the original hi resolution files and FLACSs. They explained the artifacts in the high end as soothing, smooth, soft, cool. All they could hear on vynil was scratches and pops, and described them as distracting, and tiring.

I grew up listening mostly to tape. And now we are witnesses of many plug-ins emulating heavy artefacts of it being present on most if not all 80's inspired hit singles. Thanks to Stranger Things, Weeknd, and such, the overstated tape sound is getting deep into kid's psychology. And charts seem to confirm this.

 

[soliloqueen]

It's almost as if it's all about fun and little else!

 

[Whoops]

Some recent story on the VF14:

2 weeks ago I recorded in a studio, the same studio I worked before as an in house Engineer for many years, this time I was there as a freelance hired by the artist.

The studio has a vintage U47, when I worked there it had a Nuvistor tube, the Mic had been modified long long time ago for the Nuvistor and that tube was installed.
It sounded absolutely great, and thousands of records were recorded in the last 40 years using it.

A new electronics tech started working in the studio, I’m talking about a top notch guy that is a specialist in vintage microphones.
He found a VF14M in the box in the studio's tech department, it seems they changed for the Nuvistor at some point because they were afraid the VF14 to die at some point with no replacement possible.
He sent the tube to Germany so it could tested by a guru (well known guy), the VF14M tested great, perfect in all the known parameters.

He then proceeded to install the original VF14 in the U47, making the circuit back to stock.

So it should sound much better than before now, right?

Well I know very well how the mic sounded with the Nuvistor, and even recorded 2 records in the past with this same singer using that Mic in the whole recording.
And now after the change for the VF14M it sounds much worse than before, actually it sounds crap compared to what it was with the Nuvistor.

Lesson learned, don’t trust everything you read on the internet, don’t trust internet hypes, don’t think something sounds better because it’s old or rare or doesn’t exist any-longer.
Most people that write on the internet (I’m not saying in this thread) never even ever tried a VF14M or a Nuvistor or any of the other alternatives in a U47.
There's no miracles and no magic tube, there’s sounds that you like or don’t like an you have to make that decision by yourself trying it.

I have no doubts now that the VF14 is completely overrated and no one should cry for it, just move on and use any of the available alternatives, maybe you like it even better like myself.

Now the U47 with the VF14M is unusable for this singer (and for my personal taste unusable for any singer really), so I used the U67 which sounded much better.

My 2 cents, it’s a real story

 

[Electrobumps]

 

[gyraf]

..and you changed everything back, including the power supply?

https://medias.audiofanzine.com/files/remplacer-vf14-par-nuvistor-477711.pdf
/Jakob E.

 

[maarvold]

Some recent story on the VF14:

2 weeks ago I recorded in a studio, the same studio I worked before as an in house Engineer for many years, this time I was there as a freelance hired by the artist.

The studio has a vintage U47, when I worked there it had a Nuvistor tube, the Mic had been modified long long time ago for the Nuvistor and that tube was installed.
It sounded absolutely great, and thousands of records were recorded in the last 40 years using it...

One of the best-sounding vocal recordings I ever did was with was a female vocal (Siedah Garrett) that was recorded with a short body U47 at George Massenburg's old studio, The Complex, and it seems pretty clear that it had a Nuvistor. Also, an extremely experienced engineer (and friend) bought, 2-3 years ago, a Nuvistor U47 because he LOVED the way the mic sounded. In my experience, the Nuvistor version does not have that 'barrel-chested'/big baritone sound that the VF14 versions (in good working condition) have.

 

[Electrobumps]

What makes a good sounding U47, Capsule and valve?

In my assisting days the studio had two U47's one sounded better. No one really looked into why the other one didn't sound bad. I know the mics were serviced on occasions, but never in house.

 

[kingkorg]

What makes a good sounding U47, Capsule and valve?

In my assisting days the studio had two U47's one sounded better. No one really looked into why the other one didn't sound bad. I know the mics were serviced on occasions, but never in house.

Capsule, headgrille and body. Presuming tube and rest of the electronics are in good shape they should just forward the signal captured by the capsule. Circuit should be flat up to 40K iirc. At higher spl tube might introduce some harmonics but at usual vocal levels i would argue that is inaudible. Based on this thread one might conclude microphonics which were earlier thought to be non-existent, can play a role. But as the experiment shows this is highly varying between tubes. On vocals shouldn't play a big role again due to lower SPL.

IMHO at higher spl with any tube mic all bets are off as several components could step into non linear region.

There are many theories that include mojo, phase shifts, psychoacoustic effects, educated guesses. Since they are difficult or impossible to quantify, probably even non-existent, chasing these is a fool's errand. In that case you just need to find a mic that checks all the boxes. I'd rather use that time for some creative work.

 

[terry setter]

Is that a switch mounted on the BV-08 (last photo of transformers and VF-14s (from Zhoujun, above)?

 

[granger.frederic]

Lesson learned, don’t trust everything you read on the internet, don’t trust internet hypes, don’t think something sounds better because it’s old or rare or doesn’t exist any-longer.
Most people that write on the internet (I’m not saying in this thread) never even ever tried a VF14M or a Nuvistor or any of the other alternatives in a U47.
There's no miracles and no magic tube, there’s sounds that you like or don’t like an you have to make that decision by yourself trying it.

I have no doubts now that the VF14 is completely overrated and no one should cry for it, just move on and use any of the available alternatives, maybe you like it even better like myself.

Dear Woops, 100% agree with you.
Too much noise with fancy tubes, capacitors, silver and gold cables which sounds WAY better...
I just serviced/repaired last week 2 U47 (one in very bad shape) with VF14s/reskinned M7s, and rejuvenated a third VF14.
I've compared once again with my mic which, at this time, hasn't a VF14.
Guess what: i prefer my mic not because of the tube, but because of the capsule... it has a genuine non reskinned (good one) Neumann capsule, not a average reskinned M7, and i preferred mine..
To me, the VF14 influence is overrated in the U47 sound...
Any well chosen tube (medium or high mu triode or pentode in triode mode, with the right output impedance, fairly high inter-electrodes insulation), with a good operation point, will do the job.
Feel free to claim the opposite...

 

[terry setter]

Is that a switch mounted on the BV-08 (last photo of transformers and VF-14s (from Zhoujun, above)?

Oh wait, that's just a long screw with a nut on it for mounting the transformer. Duh.