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Neumann U67 2018 reissue internal View Condenser Microphones
Old 1 week ago
  #931
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jjblair's Avatar
After some further exploration today, I will say that changing the tube made an enormous difference in the low end, which I heard very clearly when recording acoustic. Not subtle at all. Yuge. All I will say is that it was a vintage tube, and not a Telefunken, but it was a very high quality EF86. It really changed the whole over all EQ of the mic to something more preferable, if you ask me. Helped smooth out the pointy mids of the capsule tuning. as well. But I'm going to say that as much as the capsule tuning is a culprit in diminished low end response, the tube was an even bigger game changer.

It's too bad that the Tung Sol is the only production tube option they have.

Russian tube is the first half and vintage tube is the second half. Mic is same distance and position, and strumming was same hardness in same location. This is using the new K67 with S2 snipped.
Attached Files

nu67 tube test.wav (4.15 MB, 1676 views)

Old 1 week ago
  #932
500 series nutjob
 
pan60's Avatar
 

bigg diferance JJ even in the uppers mids.
Old 1 week ago
  #933
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I think this was the main reason (the Reissue tube), as to why trying out the "new" U67 was...

A relative disappointment for me.

I'm glad though that some GS members, bought ones they are very happy with!

I'd be curious JJ, if anyone could shoot out the U67 Reissue (with your latest tube on it) vs. the Bock 67. That'd be a most interesting comparison IMHO.
Chris
Old 1 week ago
  #934
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IkennaFuNkEn's Avatar
 

How come you left out the name of the tube?


....
Hey guys I just got a new tube for my mic. Can’t tell you the name of it, but please tell me how good I sound

Last edited by IkennaFuNkEn; 6 days ago at 06:41 PM..
Old 1 week ago
  #935
Lives for gear
Quote:
Originally Posted by jjblair View Post
After some further exploration today, I will say that changing the tube made an enormous difference in the low end, which I heard very clearly when recording acoustic. Not subtle at all. Yuge. All I will say is that it was a vintage tube, and not a Telefunken, but it was a very high quality EF86. It really changed the whole over all EQ of the mic to something more preferable, if you ask me. Helped smooth out the pointy mids of the capsule tuning. as well. But I'm going to say that as much as the capsule tuning is a culprit in diminished low end response, the tube was an even bigger game changer.

It's too bad that the Tung Sol is the only production tube option they have.

Russian tube is the first half and vintage tube is the second half. Mic is same distance and position, and strumming was same hardness in same location. This is using the new K67 with S2 snipped.
Are you playing what I think you're playing?

"Dreams are for those who sleep. Life is for us to keep..."

I noticed the difference in the bottom end. The extra bottom did nothing for this track IMO. But I suppose it would be good for other things. What kind of guitar is this? That extra sheen on top seemed to help though.

I guess it's true that those Russian tubes do interfere with your electrons.
Old 1 week ago
  #936
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jjblair's Avatar
Quote:
Originally Posted by u87allen View Post
Are you playing what I think you're playing?

"Dreams are for those who sleep. Life is for us to keep..."

I noticed the difference in the bottom end. The extra bottom did nothing for this track IMO. But I suppose it would be good for other things. What kind of guitar is this? That extra sheen on top seemed to help though.

I guess it's true that those Russian tubes do interfere with your electrons.
Yes. Bread.

I was not going for a good acoustic guitar sound. I was going for the one that would have the most bass, so that I could see how the bass changed. Pointing straight at the hole, 4 inches away. An ugly sound, but it will certainly tell you what’s going on the low-end of the mic.

Generally, I would not use a 67 on acoustic anyway. Not the sound I tend to like. Requires too much EQ.
Old 1 week ago
  #937
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jjblair's Avatar
Quote:
Originally Posted by IkennaFuNkEn View Post
How come you left out the name of the tube?
His name is Robert Paulson.
Old 1 week ago
  #938
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Quote:
Originally Posted by jjblair View Post
His name is Robert Paulson.
Old 1 week ago
  #939
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IkennaFuNkEn's Avatar
 

Quote:
Originally Posted by jjblair View Post
His name is Robert Paulson.
weird flex, but okay. glad it worked out for you i guess lol
Old 1 week ago
  #940
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Quote:
Originally Posted by jjblair View Post
Yes. Bread.

I was not going for a good acoustic guitar sound. I was going for the one that would have the most bass, so that I could see how the bass changed. Pointing straight at the hole, 4 inches away. An ugly sound, but it will certainly tell you what’s going on the low-end of the mic.

Generally, I would not use a 67 on acoustic anyway. Not the sound I tend to like. Requires too much EQ.
Gotcha. Kind of striking how much a tube swap changes things. This probably means the sound will shift as the tube ages, right?
Old 1 week ago
  #941
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Klaus's Avatar
 

Quote:
Originally Posted by u87allen View Post
This probably means the sound will shift as the tube ages, right?
You bring up an interesting point. While I have found it certainly to be true that preamp tubes, including EF86, tasked with amplification (guitar amp) DO wear out and eventually start sounding smeary, distorted and saggy in their dynamics, the same type of tube used strictly as impedance converter in a mic, i.e. working close to zero gain, does not age that way, but eventually becomes noisy, without much if any tonal character changes.

Back to the Russian 'Tung-Sol' installed in the U67 Reissue. As I wrote about the influence of its sound on the overall tonality of the mic:

"If someone insisted on how much I thought each component was responsible for the Reissue’s compromised sound, I’d assign 70% to the capsule*, 20% to the tube** and 5% each to cable and power supply. That means, replacing capsule and tube will go very far towards a sensually satisfying U67 Reissue."

* where applicable
** always applicable
Old 1 week ago
  #942
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roger's Avatar
 

Quote:
Originally Posted by Klaus View Post
You bring up an interesting point. While I have found it certainly to be true that preamp tubes, including EF86, tasked with amplification (guitar amp) DO wear out and eventually start sounding smeary, distorted and saggy in their dynamics, the same type of tube used strictly as impedance converter in a mic, i.e. working close to zero gain, does not age that way, but eventually becomes noisy, without much if any tonal character changes.

Back to the Russian 'Tung-Sol' installed in the U67 Reissue. As I wrote about the influence of its sound on the overall tonality of the mic:

"If someone insisted on how much I thought each component was responsible for the Reissue’s compromised sound, I’d assign 70% to the capsule*, 20% to the tube** and 5% each to cable and power supply. That means, replacing capsule and tube will go very far towards a sensually satisfying U67 Reissue."

* where applicable
** always applicable
....that leaves no room for the transformer, Klaus?

Last edited by roger; 1 week ago at 04:28 PM..
Old 1 week ago
  #943
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Klaus's Avatar
 

Please read the portion of my review where I concluded, by means of parts substitutions between vintage and reissue models, that the transformer, and the amplifier as a whole, is a component of the U67 Reissue that Neumann really reproduced well:
Neumann U67 Reissue: Complete Tear Down and Analysis

Last edited by Klaus; 1 week ago at 01:35 AM..
Old 1 week ago
  #944
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Klaus IRRC you now have a newly designed, capsule retentioning device. Does that help make this a worthwhile service option, for you to offer?
Thanks, Chris
Old 1 week ago
  #945
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Klaus's Avatar
 

Yes, I've now figured out how to reliably reduce diaphragm tension on those K67/87 that were over-tentioned at the factory, and do so within fairly tight tolerances.

To keep proper separation between advice and business, please contact me privately for more info.
Old 1 week ago
  #946
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Thanks Klaus for your response.
Chris
Old 1 week ago
  #947
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Quote:
Originally Posted by Klaus View Post
You bring up an interesting point. While I have found it certainly to be true that preamp tubes, including EF86, tasked with amplification (guitar amp) DO wear out and eventually start sounding smeary, distorted and saggy in their dynamics, the same type of tube used strictly as impedance converter in a mic, i.e. working close to zero gain, does not age that way, but eventually becomes noisy, without much if any tonal character changes.

Back to the Russian 'Tung-Sol' installed in the U67 Reissue. As I wrote about the influence of its sound on the overall tonality of the mic:

"If someone insisted on how much I thought each component was responsible for the Reissue’s compromised sound, I’d assign 70% to the capsule*, 20% to the tube** and 5% each to cable and power supply. That means, replacing capsule and tube will go very far towards a sensually satisfying U67 Reissue."

* where applicable
** always applicable
I'm a bit confused Mr. Klaus. I'm looking at some schematics(for a U47 and a U67) and it looks like the tube is in common cathode configuration, with much more impedance on the plate than there is on the cathode. This should produce gain, right? Am I missing something? Perhaps a feedback path that takes the gain close to 1?
Old 1 week ago
  #948
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Klaus's Avatar
 

Here is a Neumann spec sheet tabulating gain of their tube mics, including the U67:
Gain of Neumann microphones

Gain hovers around ±0 on most, with the U67 at -5dB. (U47 does not have negative feedback, M49 a very mild global FB, with single digit pF cap between grid and plate, while U67 has a convoluted feed-forward and feedback circuit, via output transformer, hence the -5dB overall gain of that model. Both use penthodes.)
Old 1 week ago
  #949
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Quote:
Originally Posted by Klaus View Post
Here is a Neumann spec sheet tabulating gain of their tube mics, including the U67:
Gain of Neumann microphones

Gain hovers around ±0 on most, with the U67 at -5dB. (U47 does not have negative feedback, M49 a very mild global FB, with single digit pF cap between grid and plate, while U67 has a convoluted feed-forward and feedback circuit, via output transformer, hence the -5dB overall gain of that model. Both use penthodes.)
Ah yes, I’m thinking about this wrong. A tube is a transcoductance device. gm x grid_voltage x Zl. And then reduced by the turns ratio. And then gm may be quite low. The transformer is probably the dominant plate load.

My mind is stuck in BJT mode.

Thanks.
Old 1 week ago
  #950
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Piedpiper's Avatar
Quote:
Originally Posted by Klaus View Post
Back to the Russian 'Tung-Sol' installed in the U67 Reissue. As I wrote about the influence of its sound on the overall tonality of the mic:

"If someone insisted on how much I thought each component was responsible for the Reissue’s compromised sound, I’d assign 70% to the capsule*, 20% to the tube** and 5% each to cable and power supply. That means, replacing capsule and tube will go very far towards a sensually satisfying U67 Reissue."

* where applicable
** always applicable
I'm curious if you listened to JJ's comparison recording. If capsule variation could be responsible, at times, for over three times as much difference as that tube made, that is scary.

Not challenging your assessment, BTW. Maybe JJ's tube is a very unusual one that leans way in the other direction from most. I guess I'm looking for confirmation from you that, in your experience, the capsule can make over three times the difference exhibited on that recording. And I'm aware of your opinion of on line recorded comparisons. And of course, ascribing numbers to these things is a bit dicey at best, so not to nit pic.
Old 1 week ago
  #951
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Klaus's Avatar
 

I cannot comment on J.J.'s experience with his client's U67 Reissue, beyond him contacting me how to open S2, (which he thought was helping the low end) and sharing with me that he thought my recommendation to switch to a NOS EF86 improved the sound of that mic quite a bit.

I personally have found that switching out the tube would improve the low end, but not dramatically. But I found using a NOS tube adds quite a bit in overall resolution, clarity and de-congestion of the mids in that mic.

Over-tensioned K67/K870 diaphragms are still the no.1 bottleneck for a balanced, emotionally attractive response, in my opinion. As I frequently buy new U87Ai for clients, I also see this a lot in the capsules installed there: a noticeable curtailment of lows, resulting in a harsh, unmusical impression.

But I need to emphasize again: this is not a uniform phenomenon; there are capsules, where one or both sides are absolutely perfect in their frequency balance.

Last edited by Klaus; 6 days ago at 09:47 PM..
Old 6 days ago
  #952
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Piedpiper's Avatar
Thanks for your further thoughts.

In case it's not obvious, I agree with JJ and others above that the difference with the tube swap was "yuge", thus my surprise that the capsule difference could be three times "yuger".
Old 6 days ago
  #953
Gear Guru
 
RoundBadge's Avatar
Sorry traveling and busy w stuff.haven't posted much.
Klaus re-tensioned my RI 67 Capsule last month.
kudos for the impeccable work and fast turnaround.
even w S2 I lifted prior,the 100 hz area is more robust,creamier mids.
everything above 5k feels about the same.I already preferred the high end over the vintage one I use.
very pleased.
the tube thing is a work in progress although the stock has been doing fine.
JJ's tube test was pretty dramatic.much more so than my Tele grey plate and Amperex experiments.need to check that out for sure.
the mic seems to need very little eq if any in post[mix].
and like any good 67 I've used handles sibilance like a champ.
tried a nos psu but didn't feel a big difference.
my main pet peeve:cable is ok although super wimpy and kinks easily.
keep it coiled properly,dont roll flight cases over it and is will last.
maybe Neumann will address this [on a flagship 7k product] in the future.
Gotham or Sommer would be nice.
I plan on sending another as soon as funds allow.
Old 6 days ago
  #954
Gear Nut
 
rwsand's Avatar
[QUOTE=RoundBadge;
my main pet peeve:cable is ok although super wimpy and kinks easily.
keep it coiled properly,dont roll flight cases over it and is will last.
maybe Neumann will address this [on a flagship 7k product] in the future.
Gotham or Sommer would be nice.


I second the thin kinky cable issue. Also couldn't they have made a better layout for it in the case so you don't have to scrunch it up?
Old 3 days ago
  #955
Lives for gear
Quote:
Originally Posted by jjblair View Post
After some further exploration today, I will say that changing the tube made an enormous difference in the low end, which I heard very clearly when recording acoustic. Not subtle at all. Yuge. All I will say is that it was a vintage tube, and not a Telefunken, but it was a very high quality EF86. It really changed the whole over all EQ of the mic to something more preferable, if you ask me. Helped smooth out the pointy mids of the capsule tuning. as well. But I'm going to say that as much as the capsule tuning is a culprit in diminished low end response, the tube was an even bigger game changer.

It's too bad that the Tung Sol is the only production tube option they have.

Russian tube is the first half and vintage tube is the second half. Mic is same distance and position, and strumming was same hardness in same location. This is using the new K67 with S2 snipped.
Gave this track a few more listens. I'm going to correct myself and say that top end stuff I heard sounded more like extension as opposed to "sheen". If you were singing it would probably sound like "air" in my guesstimation. Which would probably be bad if I was micing a distorted guitar cabinet but good if I was doing vocals.
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