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Author Topic: T-USA U47M (Modified by J.J. Blair)  (Read 15447 times)

Barry Hufker

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T-USA U47M (Modified by J.J. Blair)
« on: September 06, 2008, 06:29:14 pm »

The Telefunken USA U47M I purchased new was ordered with a Neumann K47 capsule and a low-noise VF14 tube.  The folks at T-USA were very easy to work with and quite concerned with customer satisfaction.  I have purchased from them before, buying a vintage pair of AKG C12A microphones and a new pair of their excellent RM-5C ribbon microphones (made by Silvia Classics).  In all cases the purchases have been great.

The microphone arrived in excellent condition, in a beautiful case, resembling a vintage suitcase, with power supply, power cord, microphone cable (with tuchel connectors) and a nice shock mount.

The sound was good.  I was initially quite pleased with what I heard but over time I came to realize it was worth the time and trouble to make a decent microphone excellent.

That's when I contacted J.J. Blair.  As J.J. is a moderator of this forum he may be embarrassed that I bring all this to public attention but tough!

J.J. was kind enough to accept the challenge and I couldn't have been luckier.  He had long and frequent conversations/emails with several microphone experts, while performing extensive searches online.  My description here can't do justice to the time, effort, insight, persistence, experimentation, craftsmanship, devotion and love he put into this microphone.

J.J.'s goal was simple - the best sounding U47 that could be created.  Toward that end he replaced part after part, listening carefully to each change.  He tracked down any and every lead someone gave him.  He analyzed his U47s in-depth making a huge effort to instill in the T-USA 47 the best qualities he found in others.  He also rebuilt important sections of the power supply.

He also kept me up to date with great emails about his latest thoughts and developments.  This way I could not only follow along but learned something with each new communication.  His effort to make me a part of the process is very much appreciated.  I felt as tho' I was standing next to him as he thought this through.

The end result? An incredible U47.  One which is as authentic inside as it could possibly be.  The sound?  WOW!  A beautiful, full bottom, a smooth midrange (and smooth is *the* word for the mic in general) and a lovely, silky top end.  It is a gorgeous sound.  It is classic in character and seductive.  This is the U47 I had hoped to own.  I would put this mic up against anyone else's 47.

I have an AKG C24 with a very sexy sound and tho' they are very different, J.J.'s 47 is easily as sexy.  Other fine mics I own have great qualities - and I am blessed to own them, but these two mics are THE TWO.  What is cool about that is to know what J.J. had to start with and what he was able to make it.  

Thanks J.J.!!

Special thanks goes to Klaus Heyne for his tremendous generosity and willingness to share his knowledge and experience.  Many thanks Klaus!

The signal path: It varies, but most recently an SSL Duality to Sound Devices 722 (line input with its built-in A/D).


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J.J. Blair

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #1 on: September 06, 2008, 06:42:45 pm »

Thanks, Barry.  I'm glad you like it.  

A huge nod also to Larry Janus, David Bock and Oliver Archut for sharing their experience.  Larry, particularly, gets huge props for his patience and terrific explanations about things electrical.
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They say the heart of Rock & Roll is still beating, which is amazing if you consider all the blow it's done over the years.

"The Internet enables pompous blowhards to interact with other pompous blowhards in a big circle jerk of pomposity." - Bill Maher

"The negative aspects of this business, not only will continue to prevail, but will continue to accelerate in madness. Conditions aren't going to get better, because the economics of rock and roll are getting closer and closer to the economics of Big Business America." - Bill Graham

JGauthier

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #2 on: September 06, 2008, 06:53:25 pm »

What percentage of the electronics would you say were replaced from the original unit? Any one part that just made a night and day difference- or was it the result of everything together?

Klaus put one of Oliver's transformers in a U87 he modded and I love it! Great to see so many R/E/P posters/mods are also the go to for real expertise!



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J.J. Blair

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #3 on: September 07, 2008, 02:16:39 am »

The only thing I left in the mic was the transformer, the VF14 tube and the K47 capsule, which I actually reversed, preferring the backside.  Everything else, I literally gutted and replaced.  Every single capacitor and resistor was changed, and I even modified the PSU, as it was supplying too much voltage to the mic.  

My biggest problems, which are well documented in Klaus' forum and somewhere on GS, is that the drop resistor T-USA used was overheating the inside of the mic to unacceptable levels.  It is my understanding that as a result of my posts on the matter, they will be fixing this in future revisions.  I could be wrong though.  I wound up using two Caddock film resistors, heatsinked to the body, to rectify that problem.

I found the capacitor selections really poor as well, in terms of material and value choices, and I feel that changing those went a long way to improving the sound of the mic.  There was a standing wave in the midrange which I suspected was a result of the BMI electrolytic coupling cap they use in both their 47 and 251 mics.  A really horrible sounding cap, that has no business in that position, IMO.

If I learned anything from Klaus, it's that some components definitely sound better than others.  Read my interview with him, and that's a point he makes over and over.  

I replaced all the metal film resistors with carbon comps, which seem to have a more classic sonic signature, and I replaced the Ohmite Flatso resistors in the capsule bias and grid shunt position with old school spiral carbon, like the originals Neumann used.    The metal film might measure quieter than the carbon comps, but I was trying to get more of a vintage sound out of this mic.  It surely seemed less strident with the carbon comps.  

Oh, and one final thing: I flattened that ridiculous looking dome shape on the basket that the T-USA, Wunder and Wagner mics have.  That just looks horrible, and inauthentic.  It was driving me nuts.
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studio info

They say the heart of Rock & Roll is still beating, which is amazing if you consider all the blow it's done over the years.

"The Internet enables pompous blowhards to interact with other pompous blowhards in a big circle jerk of pomposity." - Bill Maher

"The negative aspects of this business, not only will continue to prevail, but will continue to accelerate in madness. Conditions aren't going to get better, because the economics of rock and roll are getting closer and closer to the economics of Big Business America." - Bill Graham

Barry Hufker

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #4 on: September 07, 2008, 11:00:08 am »

I may be wrong in my recollection but I think flattening the dome was one of the first things you did.  That act seemed to symbolize the entire project - I'm going to make this right and here's proof!

Normally, I would advocate replacing carbon resistors with metal film, but your decision to do the reverse couldn't have been a better one.

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J.J. Blair

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #5 on: September 07, 2008, 11:44:29 am »

Barry, a lot of thought went into that decision.  I discussed with with four guys who have all designed some very highly respected pieces of gear, and they all agreed that carbon comp had a sound more in line with what we were looking for.  The consensus was that metal film had a definite sound, and it was not great.
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studio info

They say the heart of Rock & Roll is still beating, which is amazing if you consider all the blow it's done over the years.

"The Internet enables pompous blowhards to interact with other pompous blowhards in a big circle jerk of pomposity." - Bill Maher

"The negative aspects of this business, not only will continue to prevail, but will continue to accelerate in madness. Conditions aren't going to get better, because the economics of rock and roll are getting closer and closer to the economics of Big Business America." - Bill Graham

wwittman

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #6 on: September 07, 2008, 06:35:41 pm »

out of curiosity,

between the original Telefunken US mic and its upgrades, plus the costs of the mods JJ did... what's the TOTAL cost of the mic?


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William Wittman
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Extreme Mixing

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #7 on: September 07, 2008, 09:05:55 pm »

JJ,

When are you going to start doing Mods on C12VR's?

Enquiring minds want to know.

Steve

J.J. Blair

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #8 on: September 07, 2008, 11:18:57 pm »

C12VR is well beyond my area of not-so expertise.  The U47 and 251 are easy.  Inside, they are the mic equivalent of a '57 Chevy.  All I did was follow the original schematics, something the manufacturer didn't do, and use better components, and miraculously, the mic sounded better.  It wasn't reinventing anything, just following directions.  Taking a mic that is one thing and turning it into something else is out of my realm.  
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studio info

They say the heart of Rock & Roll is still beating, which is amazing if you consider all the blow it's done over the years.

"The Internet enables pompous blowhards to interact with other pompous blowhards in a big circle jerk of pomposity." - Bill Maher

"The negative aspects of this business, not only will continue to prevail, but will continue to accelerate in madness. Conditions aren't going to get better, because the economics of rock and roll are getting closer and closer to the economics of Big Business America." - Bill Graham

ioaudio

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #9 on: September 08, 2008, 01:29:22 pm »

Extreme Mixing wrote on Sun, 07 September 2008 20:05



When are you going to start doing Mods on C12VR's?

Enquiring minds want to know.



hi,

i´m currently working on it. original biasing, which also means updated psu etc. if its ok i´ll post the work.
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JGauthier

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #10 on: September 08, 2008, 05:11:52 pm »

J.J. Blair wrote on Sun, 07 September 2008 20:18

All I did was follow the original schematics, something the manufacturer didn't do, and use better components, and miraculously, the mic sounded better.  It wasn't reinventing anything, just following directions.  


That made me LOL! Is it somehow infringement, potential lawsuit, if they do? Sounds so simple...

I was also surprised to hear you left the transformer as often thats a piece everyone wants to change out! Too bad the OP doesn't have an unmodded on hand to give us some audio of the two! I bet its quite a difference!
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J.J. Blair

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #11 on: September 08, 2008, 06:16:20 pm »

Joe, they are using the AMI/TAB transformer, which is probably the best made BV8 around, and certainly the only one with the original lamination material, if I understand correctly.

And just to clarify, the follow the schematic in terms of the circuit.  It's incorrect values that were a problem.  
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They say the heart of Rock & Roll is still beating, which is amazing if you consider all the blow it's done over the years.

"The Internet enables pompous blowhards to interact with other pompous blowhards in a big circle jerk of pomposity." - Bill Maher

"The negative aspects of this business, not only will continue to prevail, but will continue to accelerate in madness. Conditions aren't going to get better, because the economics of rock and roll are getting closer and closer to the economics of Big Business America." - Bill Graham

JGauthier

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #12 on: September 08, 2008, 06:47:43 pm »

J.J. Blair wrote on Mon, 08 September 2008 15:16

Joe, they are using the AMI/TAB transformer, which is probably the best made BV8 around, and certainly the only one with the original lamination material, if I understand correctly.

And just to clarify, the follow the schematic in terms of the circuit.  It's incorrect values that were a problem.  


Gotcha! I wasn't familiar with the specific transformer in that mic or most mics actually! So its more an issue of component inconsistency.

I find this topic interesting because of the difference I noticed with my modded u87- it was leaps and bounds better! But I don't have the technical expertise to specifically explain any of it!
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Jørn Bonne

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #13 on: September 09, 2008, 06:19:17 am »

J.J. Blair wrote on Sun, 07 September 2008 20:18

Too bad the OP doesn't have an unmodded on hand to give us some audio of the two! I bet its quite a difference!



Yes. Would also be interesting to hear samples of Barry's modded Telefunken copy up against an all original in top working order.

And even, if possible, to hear these two up against the Telefunken U47AE and Wunder Audio's latest incarnation of the CM7.

Could give us an idea of how close the copy-cats are getting to the sound of the real deal, and what can be done by finetuning componentry in the copies.

JB


BTW: I'm looking for a stock U47 in top working order, if anyone has a lead on one. I'll let one of my vintage Stratocasters go if I find what I'm looking for.
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Tricatel

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Re: T-USA U47M (Modified by J.J. Blair)
« Reply #14 on: September 09, 2008, 09:12:43 am »

Hello J.J.,

I am happy to hear that you seem to get the wanabe Telefunken U47 to original specifications, my tech
tried but the cost would have been higher than buying a real one.
About two years back I bought one of their so called recreations and aside that it did not sound like a U47 at all, the parts they used were just a joke.

When it first showed up here, there were loose parts inside, the PSU was a pretty poorly retrofitted N12 (the housing that AKG used)and over all the first impression was just sloppy workmanship.

My service tech, a 30 year Neumann veteran in Berlin took a look at it and after his examination I decided to send it back.

Even the Tele guys promised that the mic is up to snuff with any vintage 47, it was more or less a joke.

The capsule they use was suppose to be a genuine Neumann, with a super low noise VF14.
But after my Tech examination I found out that the capsule was NOT a NEUMANN or even Gefell, but it came from a guy in London that sells them on e-bay. The skinning was done by an ex Gefell tech.
The VF14 was noisy and foremost microphonic, the wiring was iffy and the "Made to a Standard Mic" was just made with a microphone kit that sells here in Germany for around $1200 (depending on the exchange rate).
And last but not least, those bunch of f*#$^&g idiots have nothing to do the the original Telefunken AG.

At least they gave me my money back!

Jack.
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