BV 08 Transformer Laminations Alloy

[Moby]

I asked. And I believe it sounds cool

 

[BraFra]

Ni 72-80% some parts of Mo, Mn, Si and Cr and Fe to balance

I'm talking about this. That's not a recipe , thats overall info and it's believe or not used as start point for BV8's lam's chem. Original is custom made and my measuring shows that. Again, it's possible to replace original alloy with modern mixtures and tweak it to same permeability with proper final treatment but it will be still just similar. I have no problem with that, but if we are talking about exact alloy used in original BV8 then we are wrong. So what' the point of this thread? To make something or just to  feed users curiosity. If it's curiosity , than yes, you are right. that's it
edit: Yes , Neumann used 2 different alloys (maybe more but I found 2) One is variation of VAC's from 1957 and second is from Krupp but we don't have Krupp's document from 1950's . Just modern one (and mixture inside is partial)

I've made this thread to know more about the subject, and for doing this I'm sharing all the documents that I've found about, in the other way you are saying that all these document are incomplete and that you have measuring to prove this, but you are not sharing them, so the point of the topic is to make something, but for making something we all have to be together, finding and sharing with the others

Bra and other users in this topic, why you hide your mail and PM? I have a feeling like talking with ghosts

About my mail it's hided only because I just receive a lot of spam and I don't want more, but my PM isn't hided so if you want you can contact me by PM, I will be glad to answer you or if you want my email, just ask me and I'll send you a PM with my address...I'm not a ghost

 

[Moby]

Cool, I missed the open PM . I wanted to contact you, but now you made this topic and everything is OK.  About sharing my measuring results... I have the access to serious lab ,but they have the rights for numbers. I can use it for possible production but I have no rights to share. Papers you share here are free to share so there is no problem. Btw i have VAC's 1957 document for a long time and unfortunately it doesn't tell enough .  Also,  I don't criticize any of your efforts, just comparing and commenting. Please try to understand that. Personally I don't think that making this obsolete alloy again is possible by few U47 lovers. Try to read production process at VAC's site for example. Vacuum smelting, (few tons) , hot rolling, cold rolling, heat treatment, forming and again heat treatment in gas protected environment. Because of that I was shocked when "know it all" guy wrote that he produced his laminates "in house" . It's the job for big industries not for DIY , so if we want something original we have to be prepared for serious quantity and serious money

 

[BraFra]

I'm not of the same advice, I've seen a lot of "group buy production" that started here, some of them were made in china and with relatively low costs for the users. We just need to find the right company that is involved in this kind of business

 

[Dr_J]

Hi Moby,

i read a long... and a lot of points you pointed out seemed to be ok.
But, if you spend so much time and efforts at university on research work, why isn't there just one scientific paper of the results? As a "real" scientist you have to publicized your cases in some notable journals.

It's just the scientist in me writing... but in the end it's just the sound that counts...  ;D

ROCK-ON!

 

[Moby]

Hi Moby,

i read a long... and a lot of points you pointed out seemed to be ok.
But, if you spend so much time and efforts at university on research work, why isn't there just one scientific paper of the results? As a "real" scientist you have to publicized your cases in some notable journals.

It's just the scientist in me writing... but in the end it's just the sound that counts...  ;D

ROCK-ON!

Good one Give me some time it will be published, but not on the paper.  I prefer NiFe materials  8)

 

[marcus4audio]

Any news? It will be great to have some lams  8)

 

[Dobrilo]

I'm not of the same advice, I've seen a lot of "group buy production" that started here, some of them were made in china and with relatively low costs for the users. We just need to find the right company that is involved in this kind of business

let me know if someone happens with that idea...im in for that

 

[o3misha]

Interesting fact. Quite popular today BV8 AMI transformer was very far from the original sound that matches it in design. Haufe BV8 appeared much closer to original. Able to measure the inductance. In 211 H it was Haufe,  and Amy-150 H. The difference is small, but Haufe gives almost the same sound as the original with very similar saturation, and AMI produces much lighter sound. It is a pity that you can not buy Haufe commercially available. I was very disappointed AMI. Lamp in the test was the standard VF14 M, by the way, coupling cap was 1uF PIO.

 

[Moby]

Interesting fact. Quite popular today BV8 AMI transformer was very far from the original sound that matches it in design. Haufe BV8 appeared much closer to original. Able to measure the inductance. In 211 H it was Haufe,  and Amy-150 H. The difference is small, but Haufe gives almost the same sound as the original with very similar saturation, and AMI produces much lighter sound. It is a pity that you can not buy Haufe commercially available. I was very disappointed AMI. Lamp in the test was the standard VF14 M, by the way, coupling cap was 1uF PIO.

Hi Misha. Yes, true. Haufe used the original soft magnetics material produced by VAC Germany. Small inductance change was because slight different final heat treatment, but besides few Hz lower -3db point there is no difference from original Neumann BV.-08 Übertrager.
Also, "lighter sound" must be because of different distortion coefficients in soft magnetic materials. Did I mentioned before that I'm working on new prototypes of all UI30/25 Neumann transformers for one German repair company?
BTW, when you measured the "victims" did you used Ls or Lp circuit? Also, which measuring frequency you used in measuring 150H & 211H? I ask because I have slightly different numbers.

 

[o3misha]

I tested transformers at Andreas Grosser's lab  in Berlin.  As far as I remember 200Hz and 1kHz. Anyway, the inductance is not the main thing. Very important are:  interturn capacity, the magnetic permeability of the core, harmonic ratio, and ,of course,- impedance Z. When I tried to talk about the  AMI bv08 and learn the reasons why the transformers do not sound right, on forum Lefora I was immediately banned. Strange people, these Americans.  Any opinion that is different from their own beliefs, often erroneous - offends them. The truth can not be offended, - it's my belief. They think differently - well, it is their right. Oliver Archut generally carried some nonsense about Haufe bv08 . He said that HaufeBV08 closer to U47 Fet nransformer than to original bv08. Then I realized that Oliver is extremely biased and all his interest lies in the field of commerce. He think that he knows everything, but I never get honest  professional answer on my question. The only answer I could get from David Bock: AMI BV08s are good enough for their microphones. No fact, no understanding of the problems I saw. I, to my regret, I have no deep knowledge of the transformers and their structure. But I am a musician, and my ears are not fooled. I have no aspirations to blacken someone just wants to get for $ 450 (this was the price of the  Oliver's BV08 NOS lamination transformer) a better result than just "good enough". Agree that this is so crazy money for remote copy. BTW, Peluso's bv08 transformer is closer to original than AMI bv08 and it is less expensive. I have only persuade Flea give me their  transformer for test. Unfortunately, they did not want to sell it. Maybe they would not refuse to Andreas? In any case, I'll let you know.

 

[Melodeath00]

The Peluso is closer than AMI in sound?

 

[o3misha]

The Peluso is closer than AMI in sound?

Yes, Peluso's BV8 copy is better and a bit closer to original, although it is still  far from the original. If I need the good copy of BV08 x-former,- I'd choose Peluso (Haufe is not sold on the open market). Fortunately, I have two U47 (original)  at my studio, and I have something to compare.

 

[Melodeath00]

Can you describe the sound difference? What does "lighter" mean exactly? And are you putting the different transformers into the same exact mics?

 

[o3misha]

No, I used third mic with all the same components (capacitors type and value, resistors type and value). I used one tube, and one head with capsule. And one PSU, of course. I replaced only transformers in third mic. The difference was in all spectrum. Original trasformer has different coloration on loud sources. It has softer oily sound, less high frequency, different harmonics. Feeling a little more convex low middle, although this is due to a possibly more with a set of harmonics than the actual frequency response. In one word I would describe the sound of  AMI bv08 - lighter or, maybe, sterile , although someone might call it more clean.
I can not say that AMI is bad. But it is definitely different.

 

[Moby]

I never touched the Peluso tx so i can't comment, but I believe you Misha. Again, I 'm not suprised with your tests, sounds resonable from scientific view. So, you were banned from the forum because you asked too much?
Regarding original sound there is few variations too. At least when we talk about BV.-08. And diferences are not subtile because  I analyzed and tested 5 diferent materials used under the same design. But they shared similar sonic charachter. It's very hard to measure those details and define them in numbers, but for example, early bv.-08's made from low Ni% material (not mumetall) sounds really diferent from later Hi Ni% Bv's. But they share same "mid clarity". Also, the inductance of the primary is huge so it's really hard to compare them in the same microphone. Can you picture your original Bv? Maybe i can figure out the material from that. Also, can you remember circuit used for measuring your tx's. Ls or Lp can give huge diference in measuring. Same as frequency :/

 

[o3misha]

Thank you for help, but I would not want to disassemble and disconnect transformers in my microphones, I can only say that this is the standard horizontally mounted transformers. I think we 're talking about different degrees of differences. My two U47s really are a little different in color (in proper test with the same tube and capsule), but the difference in the sound of transformers is almost invisible , as compared with AMI . I would say more , I came across different U47 , they all sounded differently , but none of them was like the AMI's equipped. I think that Oliver uses a similar nickel content material . He is a great expert in these matters. However, there are other factors that may not have been reflected in production. This he does not want to think , as most fans are happy with AMI transformers.  As a method for measuring inductance , then Andreas uses a very expensive instrument that measures inductance. I will try to learn from him the name of the company , but I assure you , this is a serious test equipment . Do not forget that the measurement of AMI bv08  inductance  coincided with the statement on the Tab Funkenwerk website. Andreas told me, that impedance Z is more important factor than inductance.
As far as I understand you sure that the material of the core is only the key to get real BV8? Dont you think that there are other important factors?
Thanx

 

[Moby]

No problem, no need to disasemble your mic. I was just curious about your version of the tx. But it doesn't matter, you are right, all of them share the same charachter. Also, I have no doubts about Andreas equipment, just wonder which circuit you used to measure inductance. From your numbers I would say Lp at 400hz but who cares Also, Ni content is just the start to define lamination alloy. There is few (or more) elements what makes that harmonic charachter. Modern (mostly Chineese) alloys use the same NI content as Vac's but they miss the rest of composition. Also, I found a ton of myths about original Bv lams on the net and they are mostly from nowdays manufacturers. For example that "special color of the lamination is because of hydrogen atmosphere used in final heat process".  LOL! I know that some people here don't understand the relationship between core alloy and sound but I'm sure that most of them can hear the difference. Only problem is that just a few of them have a chance to compare the real thing to copy. In that situation they read and believe commercial bulshit. In that manner we are talking about the same degrees of diference I would be happy to have a time to make a compare test side by side of all the copies but unfortunately "me no time" I will spent that spare time for evaluating the new version of UI30/25 tx's , of course with the original material inside.

 

[o3misha]

Known is also a factor of degradation of the core material, i.e. the changes of its magnetic properties. This process is much more fleeting than it seems at first glance. Therefore, today's materials can never repeat aged transformer .
P.S I see what you already know about the materials and the intricacies of the production of cores more than many experts. I would be glad if ever your research will lead to the desired result: obtaining copies of modern BV8 not inferior to the original.
Thanks to these enthusiasts like you, someday it could. It is a pity that nothing can be done with VF14.

 

[Moby]

Well, Vf 14 is the another story... I spoke few years ago with some experts (Ei Nis) and they told me that is possible to make it but they asked some garanties about sales. I'm not a salesmann so, I stopped that research
To be honnest, I don't know what other experts know about producing right lamination for Neumann tx's but all I know is from good relationship with few ex and nowdays VAC employers. Also from my personal experience in the past few years on this subject. One more thing... I never met the 4 hole type transformer in the original U47. At least in the approx 25 victims I opened Only one I know is Haufe version, (and modern replicas) but that's not the original, just good enaugh replacemnet part. Does somebody knows something about it?