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Author Topic: About The Quality of U47 Copy Mics  (Read 12456 times)

klaus

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About The Quality of U47 Copy Mics
« on: January 10, 2015, 02:35:10 pm »

On 2015-01-10 10:28, Richard Kaufman wrote:

Hello Klaus,
I've been reading the conversations that you've been part of on ProSound Web (http://repforums.prosoundweb.com/index.php/board,27.0.html), and wanted to ask you perhaps a very basic question, that hasn't appeared on the conversations for some time... probably because it too simplistic for some of the technical stuff that's being asked.
 
Basically, I wanted to know what U47 clone comes closest to the original Neumann U47 microphone?
 
I'm a total novice in this area, so don't really understand about capsules and tubes... but am aware of the numerous possibilities of capsule/tube/transistor combinations. Some maybe you might say a Flea 47 clone with Beesneez capsule for example...
 
If you could give a recommendation, then that would be much appreciated, and also I am happy if you would like to post this query into one of the online forums.
 
Many thanks,
Richard Kaufman.

 
-----------------------

Hello Richard,

The quick and simple answer: none of the copy mics reaches even remotely the excellence of sound (let alone the resale value retention) of the original.

The reason is simple as well: none of the copy manufacturers have access to any, let alone all, of the sound-shaping core components which created the magic in the original: capsule, tube, transformer, electrical components, wiring, mechanical construction etc.

Aside of the capsule, which is still made by Neumann in very good quality, no other core component is still available today, or has been re-manufactured with the same materials or processes required to qualify as equivalent.

The current availability of the Neumann K47 capsule also serves as another good example why copy manufacturers are not succeeding with their product quality at the price point they choose to compete: expense. The price for a K47 capsule is ca. $800.- (Neumann will not sell quantities of this capsule at the wholesale level price, because they sense where these capsules would end up - as component in a competing mic). That price for just one core component is untenable for a manufacturer as a cost factor if he were to sell the mic for anything less than $10,000.-

If you now add the other shortcomings of material provision you get the idea that there is no business model that supports a hand-made super-clone of equivalent quality as the Neumann U47.
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Klaus Heyne
German Masterworks®
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J.J. Blair

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Re: About The Quality of U47 Copy Mics
« Reply #1 on: January 16, 2015, 02:46:06 am »

I concur 110%.
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klaus

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Re: About The Quality of U47 Copy Mics
« Reply #2 on: January 21, 2015, 01:15:38 pm »

I removed a post and some responses about a supposed $18k U47 copy: the poster could not provide confirming information that such mic exists. If and when that information can be obtained, the discussion about it can be resumed.
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Klaus Heyne
German Masterworks®
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kidvybes

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Re: About The Quality of U47 Copy Mics
« Reply #3 on: January 30, 2015, 07:51:49 pm »

...well then, let me re-phrase the question...do you believe it's possible to achieve a level of sonic quality comparable to that of an original, albeit slightly different, by designing a "clone" utilizing components available at this point in time?...assuming the implementation of a Neumann K47 capsule (@ $800)...


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klaus

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Re: About The Quality of U47 Copy Mics
« Reply #4 on: February 01, 2015, 03:55:25 am »

...do you believe it's possible to achieve a level of sonic quality comparable to that of an original...?

If I reflect on any of the U47 copies and supposed "clones" I have heard so far- and there are many- I would have to answer: NO.
A "level of sonic quality" to me implies that the mic must be able to draw me into the music as much as a genuine, well-working U47 could. It must be able to generate a sense of well-being, of sonic attraction, but one which does not stand in the way of an exquisite performance, but translates it with great immediacy, whereby I as the listener am not forced to switch gears and get from pure listening and feeling into my analytical head.

That, to me, is what a great microphone is able to contribute to the music it records: subjective absence of the device, not getting in the way of the music, but enhancing it ever so subtlety, gently euphemizing the sound captured- that's the winner. And none of the copy mics I have heard are capable of doing that, because of the cumulative shortcomings of the components chosen, of the way the design was implemented.

If you use the original mic's shape, capsule, transformer and tube, you can get very close with a copy mic, but no one has done that to date. Of those three things, the tube and the transformer are the hard parts to source for a new line of copy mics with an authentic U47 sound.
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Klaus Heyne
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soapfoot

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Re: About The Quality of U47 Copy Mics
« Reply #5 on: February 01, 2015, 08:52:10 am »

Oliver's transformers were pretty nice, perhaps the best available, but alas...
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kidvybes

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Re: About The Quality of U47 Copy Mics
« Reply #6 on: February 01, 2015, 10:20:55 am »

Oliver's transformers were pretty nice, perhaps the best available, but alas...

True, I have one of his AMI "Classic Series" BV.08 transformers...but from what I've read, Max Kircher's BV.08 recreation is historically-correct (full size, full stack Bv.08 transformer wound to original specs including 4 seperated chambers per bobbin)...Max has built what he considers the closest alternatives to the original transformer and the VF14 tube (a dual-pentode in parallel configuration)...
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soapfoot

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Re: About The Quality of U47 Copy Mics
« Reply #7 on: February 01, 2015, 11:42:59 am »

Have you heard one of these transformers? What do we know about the metallurgy, etc?

Klaus, didn't Oliver have access to original technical literature when creating his version of the BV-08? I believe he even had a limited amount of new old-stock lamination material, correct?
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kidvybes

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Re: About The Quality of U47 Copy Mics
« Reply #8 on: February 01, 2015, 12:02:29 pm »

Have you heard one of these transformers? What do we know about the metallurgy, etc?

Yes, it's a critical part of Max's new MK-U47 clone...I have his earlier design (MK-47), and I have auditioned the newer, upgraded version...quite impressive...as far as metallurgy, maybe I can invite Max to chime in...
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klaus

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Re: About The Quality of U47 Copy Mics
« Reply #9 on: February 01, 2015, 01:26:17 pm »

Quote
  from what I've read, Max Kircher's BV.08 recreation is historically-correct
What is the proof for it? You did not cite an authoritative, third-party reference, which makes it hearsay (and I already removed promo photos from the manufacturer you posted earlier- there's no free advertising here). It would be helpful if you would provide information that is NOT from the manufacturer to prove the point that this transformer copy comes close or is equal to the historic Neumann BV8 in sound and performance.

Quote
Oliver's transformers were pretty nice, perhaps the best available
I assume that reflects your personal experience? (if not it, too, would be hearsay and does not help the discussion). If you have personal experience with Oliver's BV8 copy, have you compared it to the original Neumann transformer? And how do they compare?
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

klaus

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Re: About The Quality of U47 Copy Mics
« Reply #10 on: February 01, 2015, 01:30:11 pm »

Klaus, didn't Oliver have access to original technical literature when creating his version of the BV-08? I believe he even had a limited amount of new old-stock lamination material, correct?

Both are correct, but in our conversations, Oliver made it clear that, apart from a few prototypes which featured historic, now obsolete, core alloy he found in Germany (one of which I tested, and which was indistinguishable to my ears from an original BV8) he never went into production with it.
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Klaus Heyne
German Masterworks®
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soapfoot

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Re: About The Quality of U47 Copy Mics
« Reply #11 on: February 01, 2015, 01:36:59 pm »

I do have first-hand experience with both, Klaus.

I built a microphone with Oliver's BV8-R, which was not his flagship BV8-N (the one listed on his site as having the NOS lamination material) but was nevertheless, in my experience, an excellent-sounding transformer.

We also have an original Telefunken-badged long body U47 with a nice 1970s-era K47 capsule and the original transformer. When we got it, it had been retrofitted with the 13CW4 nuvistor. After searching for a proper VF14 for a few months, and unable to find a suitable one that came with a suitable guarantee/return policy, I spoke with Oliver, who offered to retrofit the microphone with an EF804 tube and an appropriate power supply, which is very similar to the scheme used in the Lucas CS-4.

He did, and we have been very happy with the result. This also, incidentally, makes it very close in spec to the mic I built, which I was also quite happy with sonically. I found Oliver's BV8-R transformer to be excellent, perhaps even in the same weight class as the original (though my experiments were not controlled enough, nor my sample size large enough, to make that claim, so I will stop short of it).

The most discerning ears may feel that our Telefunken is missing "something" from not having the VF-14, and they may be correct; however it is a very nice sounding microphone. Much nicer sounding than a colleague's U47 which has the original VF-14 and power supply, but a replacement Thiersch capsule.
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klaus

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Re: About The Quality of U47 Copy Mics
« Reply #12 on: February 01, 2015, 02:03:31 pm »

Here is the problem I have with your comparison: too many variables are introduced, even for a subjective listening test. You are obviously satisfied that the mic has a "nice sound" . But its sound has little chance to be comparable to an original U47, given that it is derived from an aftermarket transformer AND a tube with different construction, dimensions, gain and supply voltages.
You also did not have a VF14 in there, as starting point for a comparison.

Here is what a credible comparison would look like:

* original Neumann U47 with VF14,
* original Neumann capsule (M7 or K47),
* original BV8 transformer (or predecessor, if the mic was made before 1955)

NOW you change BUT ONE component in that mic: the transformer. Then you listen.
I do not mean to be pedantic, but I have found again and again that introducing more than one variable at a time makes it theoretically and practically impossible to discern which component is responsible for which aspect of a change in sound one hears.

Using the exact test protocol above, I have not found an aftermarket transformer (aside of Oliver's prototype- see earlier post) which, when installed in an otherwise all-original mic, sounded or performed identical to the historic BV8.

One of the impenetrable secrets: winding method. This alone can be a can of worms.
Oliver once had a conversation with an old hand who worked in the transformer company Neumann used in the 1950s. That person (now dead) told of the intricacies of the chamber winding method that was used on most Neumann tube mic BVs.
Not only were there several chambers, but supposedly different winding tensions and patterns were used from chamber to chamber.

I am not aware that Oliver left any detailed written notes about his experiments, experiences or conversations with experts which would help in reviving some of what he had learned. This is one of the reasons why even a relatively simple custom design as I use for my U87 modification was a lengthy exercise in reverse-engineering after he died, despite the fact that the same person was still winding on the same machine as before. But the data needed to be reassembled from sample transformers I resubmitted and bits and pieces of information stored on the winding machine or laying around.

P.S.: I am always ready and eager to try out copies of BV x transformers if there is even a remote chance that enough care went into the design and manufacture that would give it a chance to sound authentic.


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Klaus Heyne
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soapfoot

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Re: About The Quality of U47 Copy Mics
« Reply #13 on: February 01, 2015, 02:35:02 pm »

I have zero disagreement with any of the above, Klaus; I wasn't attempting to claim a scientific test, nor a valid comparison, even. Only that I did have experience with both, and that I did find Oliver's transformer to sound quite nice.

That, coupled with my opinion of Oliver and his knowledge (from many conversations and a pretty extensive acquaintance with the man himself, as well as much reading of things he wrote) leads me to believe that it's unlikely any other modern winder of transformers could even come as close as he did to creating something as nice as the original BV-08.

I only bring him up to voice the opinion that the bar for modern BV-08 inspired transformers has been set quite high already; for me to take a newcomer to the field seriously, I'd want to know more about their credentials, philosophies, and approaches. Oliver's background enabled him to study original technical documents and, as you stated, consult with some of the original minds that worked on the genuine article. That represents, to me, a pretty good-faith effort to "get it right" and sets the bar for subsequent attempts quite high (though not higher than the genuine article itself).

In light of that, it would be very interesting if the winder of the above-mentioned transformer could be convinced to chime in here with details on his research, strategies, priorities, etc.
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