I'm writing my degree on the U47 and need your help

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@CoolCat I called them but they wouldn't let me know the passkey 🙄 The first of the tube mics worked first try today, so really happy with that. Managed to snag a Fet47 Body from ebay (been looking for weeks!) and will start assembling later.

On another note, a kind gentleman agreed to meet up to measure his vintage U47 (K47) next week, so maybe I can persuade him to let me record with it too. Would be awesome to have the sonic comparison between a vintage unit with M7 capsule and a vintage K47 capsule. At minimum we'll have some data on polar patter and frequency response 🙂
 
My better half's father is a well-known international singer/recording artist. He was a vintage U47 in his studio, about ten minutes from our house. I don't have a U47, but I do have a U87ai, and despite what I read online, I prefer the newer 87 on my gf's vocals. OTOH, she sold a lot of her records singing into that U47, so who knows?

I do think his 47 sounds great on the outside kick, and sometimes I'll borrow it for that purpose. Usually, I use a Mojave 201 FET, which works nicely and costs much less.

I have an API The Box with a 3124+, and he has a well-maintained Trident Series 80. I've done good recordings in both spaces.
 
I spoke to a friend of mine who is expressed some doubts over the suitability of this as a degree subject due to the probably impossibility of conducting enough research. She wondered about the problem of collecting enough of them to show the primary evidence on performance is sound. If you only have one mic, how do you know it is typical, or what its aging process has been. If you elect for a historical approach, the manufactures data will be in German, and the factory would need a visit because historic documentation will not have been digitised, so it will cost a fortune to go to Germany. In terms of internet info there is quite a bit but most subjective so how will qualitative and quantitive requirements be validated. She thought study of a single mic interesting but crazily difficult to do. Even if you visited studios with them in use, how could you compare them? You might get ten pages of opinion and secondary evidence but for the focus of a degree thesis you will struggle. A hundred pages or more is going to be very difficult. The history and evolution of the brand might be doable but a single rare mic less so!
 
noah330 said:
My better half's father is a well-known international singer/recording artist. He was a vintage U47 in his studio, about ten minutes from our house. I don't have a U47, but I do have a U87ai, and despite what I read online, I prefer the newer 87 on my gf's vocals. OTOH, she sold a lot of her records singing into that U47, so who knows?

I do think his 47 sounds great on the outside kick, and sometimes I'll borrow it for that purpose. Usually, I use a Mojave 201 FET, which works nicely and costs much less.

I have an API The Box with a 3124+, and he has a well-maintained Trident Series 80. I've done good recordings in both spaces.
Click to expand...
It boggles my mind someone using a U47 on a kick drum or anything that could blow it out and damage it.
Is it the U47 FET or U47 tube?
I was just reading about U47 FET being an attempt that didn't make the cut really in replacing the U47 tube, and did go to the kick drum fame position not vocal.

The U87 however seemed to be accepted in the family tree for vocals from the U47 tube, U67 tube to the U87.....and then the more sensitive better noise spec U87ai.

I'd be afraid to use a U47 tube...lol its too expensive and a museum piece in my mind, the cable , power supply...age alone. What was it only 3000 or so made, how many are left in working condition?
 
md431 said:
@CoolCat I called them but they wouldn't let me know the passkey 🙄 The first of the tube mics worked first try today, so really happy with that. Managed to snag a Fet47 Body from ebay (been looking for weeks!) and will start assembling later.

On another note, a kind gentleman agreed to meet up to measure his vintage U47 (K47) next week, so maybe I can persuade him to let me record with it too. Would be awesome to have the sonic comparison between a vintage unit with M7 capsule and a vintage K47 capsule. At minimum we'll have some data on polar patter and frequency response 🙂
Click to expand...
comparison of capsules, your getting deep into the other side, where few travel....lol...sounds fun.
 
CoolCat said:
I'd be afraid to use a U47 tube...lol its too expensive and a museum piece in my mind, the cable , power supply...age alone. What was it only 3000 or so made, how many are left in working condition?
Click to expand...
Neumann made ~6000 U-47s and 800 U-48s. The U47 is a bit like the '59 Les Paul. The joke is that of the 643 made and shipped, only 1,426 are still in existence. The biggest issue is the availability of the VF14M tubes. The original VF14 was only spec'd for about 20 years of high performance usage. That was 75 years ago! That means that ZERO of the available tubes can be expected to meet spec. Here's bit of history on the tube for those who don't understand the issue:

History of the VF14 tube and the Phaedrus Audio equivalent VF14M

VF14M VF14 Telefunken VF14M Neumann selection difference between VF14 and VF14M U47 microphone rare tubes
phaedrus-audio.com

I was just reading where someone was doing comparisons and it was one of those "can this $600 mic equal a $40,000 mic?" things. What really irks me is about these click bait comparisons is that the U-47 wasn't a $40,000 mic, any more than a '59 Les Paul was a $450,000 guitar. In 1959, a Les Paul was $420. In 1954, the U-47 was $390. Using the infamous inflation calculator it would be around $4500 today, which isn't really that out of line with higher end Neumann mics today. A U-67 is $7500, the U-87 is $3750. Where does the extra $35,000 come from?

The inflated pricing is because someone either has convinced themselves they must have it and money is no object, or it's what someone is asking. If I paid someone $50,000 for the AT2020 that Billie Eilish used, does that mean suddenly all AT2020s become $50k mics, even though there are thousands of them available for $80 to $100? We really need to understand that someone's inflated price on things in limited supply doesn't correspond to the actual value of an item from a working aspect.
 
interesting.
like the Banana with tape auctioned, someone paid $6mill for it recently as a Art ...or joke....Sotheby's must live in that head game world.

here's an auction!

auction-team.de

Neumann U47 Condenser Microphone - Auction-Team Breker

Bruno RĂĽckert Musikwerke, Leipzig, coin-activated disc musical box for 16 1/4 in. discs, 82 teeth in three combs (1 tooth broken), elegant walnut case with reverse-painted glass (renewed), overall size 23 3/5 x 15 Âľ x 75 in., including 14 discs.
auction-team.de auction-team.de
 
this ones worth more thanks to Zappa!
 

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rob aylestone said:
I spoke to a friend of mine who is expressed some doubts over the suitability of this as a degree subject due to the probably impossibility of conducting enough research. She wondered about the problem of collecting enough of them to show the primary evidence on performance is sound. If you only have one mic, how do you know it is typical, or what its aging process has been. If you elect for a historical approach, the manufactures data will be in German, and the factory would need a visit because historic documentation will not have been digitised, so it will cost a fortune to go to Germany. In terms of internet info there is quite a bit but most subjective so how will qualitative and quantitive requirements be validated. She thought study of a single mic interesting but crazily difficult to do. Even if you visited studios with them in use, how could you compare them? You might get ten pages of opinion and secondary evidence but for the focus of a degree thesis you will struggle. A hundred pages or more is going to be very difficult. The history and evolution of the brand might be doable but a single rare mic less so!
Click to expand...
Hi Rob, thanks for the input. I very much agree with you, though I might have to make some clarifications: I used the term degree meaning a bachelors degree, which is the lowest tier (bachelor - master - doctorate), so there is a certain limit on what I can do in the timeframe given (3 months). More so, I've got very limited financial resources (which we usually don't have at all). Nevertheless you're quite correct that ideally I would have a larger sample source all recorded in the same location on the same take to make any solid and refined objective observations.

In my case I can only compare one vintage example against a few replicas. As many variations there are in the original ones are in the available copies. And maybe that's also kind of the point: you expect a certain sound and get something that you hope will get you close. It could be original No.46 or original No.371, FLEA clone or BeezNeez Clone and all will sound slightly different - so maybe there is this sort of arbitrariness that justifies looking at an exemplary smaller sample group. I'm measuring at least two vintage U47s in the anechoic chamber, hopefully I'm allowed to record with the second one too - that would at least give you a better ideas of the sonic range one could expect from vintage units.

Regarding the trip to Germany, fortunately I live here - I've tried being in contact with Neumann but haven't got through yet. I'll keep trying though, maybe the'll let me have a peek in their archives. Original Frequency and Polar Pattern measurements would be gold, as I'm certain that the U47s that survived sounded different when they were new.
 
TalismanRich said:
Neumann made ~6000 U-47s and 800 U-48s. The U47 is a bit like the '59 Les Paul. The joke is that of the 643 made and shipped, only 1,426 are still in existence. The biggest issue is the availability of the VF14M tubes. The original VF14 was only spec'd for about 20 years of high performance usage. That was 75 years ago! That means that ZERO of the available tubes can be expected to meet spec. Here's bit of history on the tube for those who don't understand the issue:

History of the VF14 tube and the Phaedrus Audio equivalent VF14M

VF14M VF14 Telefunken VF14M Neumann selection difference between VF14 and VF14M U47 microphone rare tubes
phaedrus-audio.com

I was just reading where someone was doing comparisons and it was one of those "can this $600 mic equal a $40,000 mic?" things. What really irks me is about these click bait comparisons is that the U-47 wasn't a $40,000 mic, any more than a '59 Les Paul was a $450,000 guitar. In 1959, a Les Paul was $420. In 1954, the U-47 was $390. Using the infamous inflation calculator it would be around $4500 today, which isn't really that out of line with higher end Neumann mics today. A U-67 is $7500, the U-87 is $3750. Where does the extra $35,000 come from?

The inflated pricing is because someone either has convinced themselves they must have it and money is no object, or it's what someone is asking. If I paid someone $50,000 for the AT2020 that Billie Eilish used, does that mean suddenly all AT2020s become $50k mics, even though there are thousands of them available for $80 to $100? We really need to understand that someone's inflated price on things in limited supply doesn't correspond to the actual value of an item from a working aspect.
Click to expand...
Hey, again thanks for the VF14 link - very interesting 🙂 Also, the absolut madness that these vintage musical market prices have become in certain aspects...it certainly is one of the reasons I got drawn to this topic in the first place. And in the end: what does a 20.000€ mic do good, when the music that's recorded is boring?
 
CoolCat said:
interesting.
like the Banana with tape auctioned, someone paid $6mill for it recently as a Art ...or joke....Sotheby's must live in that head game world.

here's an auction!

auction-team.de

Neumann U47 Condenser Microphone - Auction-Team Breker

Bruno RĂĽckert Musikwerke, Leipzig, coin-activated disc musical box for 16 1/4 in. discs, 82 teeth in three combs (1 tooth broken), elegant walnut case with reverse-painted glass (renewed), overall size 23 3/5 x 15 Âľ x 75 in., including 14 discs.
auction-team.de auction-team.de
Click to expand...
Exactly! I can buy bananas for 65 cents/lb and a roll of duct tape for about $5. Investment cost of $6. Sell it for $6 million? Total BS. That's what I often call "stupid money" If you want to support an artist, hand him a check for $6 million. Don't put up the farce that a banana and a ft of tape is worth $6 million.

The hero worship of things built in the past would lead you to believe that the human race forgot how to make a microphone in 1965 after the U-47, how to make a guitar after the 59 Les Paul, how to build a car after 1963 (Ferrari 250GTO), etc.

I'm sure that U-47 in the auction will perform exactly as it did when made 75 yrs ago. The capsule is obviously dirty, the VF14's damping is completely destroyed and the tube is 50 years past it's expected lifetime. Who knows what conditions it's been subjected to in it's lifetime. Yet someone will spend a bunch of money and think this is the absolute pinnacle of sound reproduction.

Call me a skeptic!
 
CoolCat said:
interesting.
like the Banana with tape auctioned, someone paid $6mill for it recently as a Art ...or joke....Sotheby's must live in that head game world.

here's an auction!

auction-team.de

Neumann U47 Condenser Microphone - Auction-Team Breker

Bruno RĂĽckert Musikwerke, Leipzig, coin-activated disc musical box for 16 1/4 in. discs, 82 teeth in three combs (1 tooth broken), elegant walnut case with reverse-painted glass (renewed), overall size 23 3/5 x 15 Âľ x 75 in., including 14 discs.
auction-team.de auction-team.de
Click to expand...
Apparently the guy ate the banana.
 
Good luck. You don't say what course this paper is for. What school? Major?
Without that information stated here, results you get will get here is likely be skewed. I know you mentioned that, but that is an impossible date set to quantify.
I could say I love them. Have I ever used one? No. Have I ever seen one? No. So my opinion is worthless.
 
Hey @Old Music Guy, it's for a Bachelor degree in Sound, Music & Production at University of Applied Sciences in Darmstadt, Germany. Actually for my thesis your opinion is as valuable as others, even though you might have never used an original or clone! This is because I partly seek out what usability and sonic conceptions people have regarding this type of mic (and how that overlaps with the results from the blind test in a few weeks). Very few will have been lucky enough to handle an original yet there is a substantial market for replicas. So there must be some kind of preconception to U47 mics and I'd love to find out what that is. If you have 5 minutes, I'd really love to hear your thoughts.
 
Can you be more specific as to what "control" mix your using? There are a variety of U47s (FET pre, Tube Pre),
I will gladly take part in your poll. but a little more info would be helpful.
Full disclosure: I have been in electronics for over 40 years, and to me, these things matter.
 
@Old Music Guy thanks for having a look! The first poll is only regarding the expectations, the second poll will be with the audio blindtest. I'll be doing the recordings next tuesday, so hopefully I'll have it ready soon.

The reference will be a Schoeps MK4 small diaphragm condenser, not a mix per se. Tested will be
  1. vintage U47 with M7 capsule and original VF14M tube
  2. vintage U47 with K47 capsule and original VF14M tube (just confirmed today, so hooray for that!)
  3. micparts V47 DIY kit with M7 capsule and 12AY7 tube
  4. micparts V47 DIY kit with K47 capsule and 12AY7 tube
  5. DIY Fet47 with K47 capsule matched to 4) and very similar head basket.
  6. Townsend Sphere L22 modelling microphone with U47 emulation
Heres the link to the first poll: https://forms.gle/j7s5sinCDNKUBcjRA
 
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As a more general update: I finished building the FET47 yesterday and besides accidentaly wiring it as a omni first try, all three mics work great (see pictures attached). Met up with a lovely chap today and measured the first vintage U47 in the anechoic chamber today. Unfortunately I was so in the zone that I completely forgot to take pictures. It was his grandfathers who worked for the local broadcast, just like he did. He'd actually studied at my university and had used the chamber for his own builds 40 years ago, so we got on well and I'm thankfully allowed to lend it for the upcpming recording session.


IMG_6729.webp
IMG_6728.webp
 
OK. Here's my contribution. Expressions in dB are based on the perceptional change in volume in human hearing is 3dB (debatable).

Having never used one, my expectations are based on research and anecdotes.
Expectations are that it would be the only microphone I would ever need for any application. That expectation is (likely) wholly unrealistic.
It has, from research, a frequency response that is flat within +/- 3dB with a gradual slope of 2-3dB @ from 2kH to 5kHz. Small enough to be noticeable but not enough to EQ out. This obviously makes this ideal for vocals. The highest pitch for Frank Sinatra (~400Hz) and Barbra Streisand (~800Hz) fall within +/- 1dB of flat in that range, yet the subtle increase beginning at ~200Hz will add a slight mid-range warmth.

Based on specs, IMHO there is no better mic for piano than the U47. The roll off at 100Hz and the gradient +3dB rise beginning at 200Hz and subsequent roll off at 5kHz is ideal. Given the U47 dynamic range of >120dB dynamic range, and the mics roll off characteristics, the U47 almost acts as perfect natural compressor without flattening the piano's dynamics.

@md431 Let me know what YOU think of this reply so far. I'm not done yet if you approve.
 
You have one big advantage over the majority of DIY mic folks today. I always read the comments about how great it sounds. Its so smooth, it's warm, the sound blooms, etc. However, very few people have done a single measurement to know if it's even close to having decent specs. What's the frequency response? How loud will it go before you get horrible distortion. Whats the S/N ratio? It takes a good test chamber to do that right.

Instead you get the flowery language descriptions.

Its like the reviews in the high end audio press, it's always the removal of "veils" in the sound. Eventually you remove so many veils that the emperor has no clothes!
 
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