Neumann U67 - help please!

[Angus Kerr]

Calling for help again

Thought I'd fire up the U67. It's been in the cupboard for some years.

No output. On further investigation, by removing the grille, I see the diaphragm is sucked into the capsule body, I guess it's unable to vibrate like it should and it's shorted out.

Power supply seems OK, 230V on the plate and heater at -7. I don't have a scope, so I'm not able to see the ripple.

Any idea where I can go to from here?

Thanks

Angus
Durban, South Africa.

[geoff]

Needs re-tensioning. Or if damaged, repair/replacement. There are a few
people (as well as Neumann) who offer this service.

Gunter Wagner (ex-Neumann) did my U87 with great uccess.

http://www.wagner-microphones.com/

geoff

[Scott Dorsey]

Angus Kerr <an...@tropical.za.net> wrote:
>Calling for help again
>
>Thought I'd fire up the U67. It's been in the cupboard for some years.
>
>No output. On further investigation, by removing the grille, I see the diaphragm is sucked into the capsule body, I guess it's unable to vibrate like it should and it's shorted out.

The PVC diaphragms do that. I'd call Oliver Archut or Klaus Heyne, who can
reskin those capsules with modern mylar. Getting the tension correct on
those capsules is difficult and more art than science unfortunately.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Phil Allison]

Angus Kerr wrote:

> Calling for help again
>
> Thought I'd fire up the U67.
> It's been in the cupboard for some years.
>
> No output. On further investigation, by removing the grille,
> I see the diaphragm is sucked into the capsule body, I guess
> it's unable to vibrate like it should and it's shorted out.
>
> Power supply seems OK, 230V on the plate and heater at -7.

** The EF86 plate voltage should be +75V, the DC supply +210.

http://recordinghacks.com/images/mic_extras/neumann/U67-schematic.jpg

> Any idea where I can go to from here?

** So the diaphragm now looks like the surface of a golf ball - right ?

Gently warming the capsule usually makes a stuck diaphragm pop off the back plate - so try placing the mic a warm place, like the inside of a window facing the sun for a hour or so.

If that does not do the trick, try playing *warm* air on the diaphragm. A hair dryer set to "lo" and held away by about 0.5 metre is about right.



.... Phil

[Mike Rivers]

On 9/25/2015 9:38 AM, Scott Dorsey wrote:
> The PVC diaphragms do that. I'd call Oliver Archut or Klaus Heyne, who can

> re-skin those capsules with modern mylar. Getting the tension correct on

> those capsules is difficult and more art than science unfortunately.

Sadly, Oliver left us last year, though Klaus is still around and
working. There are many people who do this sort of work and everyone has
his favorite.


--
For a good time, visit http://mikeriversaudio.wordpress.com

[Scott Dorsey]

In article <mu3ne8$rh9$1...@dont-email.me>, Mike Rivers <mm1...@yahoo.com> wrote:
>On 9/25/2015 9:38 AM, Scott Dorsey wrote:
>> The PVC diaphragms do that. I'd call Oliver Archut or Klaus Heyne, who can
>> re-skin those capsules with modern mylar. Getting the tension correct on
>> those capsules is difficult and more art than science unfortunately.
>
>Sadly, Oliver left us last year, though Klaus is still around and
>working. There are many people who do this sort of work and everyone has
>his favorite.

Jesus, I didn't hear about Oliver. What happened? He wasn't that old.

[Angus Kerr]

Pity, because it is an original capsule.

But it's unusable at this stage. Pops and squeaks, she eventually came up.

Out of the question for vocals.

But I'm not hearing the quality Neumann sound.

I guess, no user serviceable parts inside....

[Angus Kerr]

-snip-

> ** The EF86 plate voltage should be +75V, the DC supply +210.
>
> http://recordinghacks.com/images/mic_extras/neumann/U67-schematic.jpg
>

You're right, supply is 230 (there is no option for 230 - 240V AC, only 220) - running a little high. Didn't check the plate voltage

>
> > Any idea where I can go to from here?
>
>
> ** So the diaphragm now looks like the surface of a golf ball - right ?

Ironically, the back capsule looks like a golf ball when I select Omni or Figure 8, even though I get no sound from the back capsule.

The front diaphragm looks like there is dust and debris UNDER the surface, between the body and the diaphragm. As soon as the diaphragm is sucked on all these pockmarks appear, so not golf ball shaped divots to match the matrix holes, but random sharp bumps, that disappear if I breathe gently on it which seems to short out the capsule.

The back diaphragm looks like it's got a tiny crescent shaped tear or divot in it, maybe the result of a ham handed cleaning attempt?

>
> Gently warming the capsule usually makes a stuck diaphragm pop off the back plate - so try placing the mic a warm place, like the inside of a window facing the sun for a hour or so.

After fiddling on the bench measuring voltages and stuff, I put the headphones on, and there was output. Something, but not Rolls Royce Neumann sound. More like Land Rover Defender sound.

>
> If that does not do the trick, try playing *warm* air on the diaphragm. A hair dryer set to "lo" and held away by about 0.5 metre is about right.
>
>
>
> .... Phil

I guess the capsule is well and truly ****ed. Given the amount of work I am likely to do, I must just be inclined to auction it off on ebay as is. What do you think? Vintage mics are fine and all, but I suppose they're like vintage cars. Need loving and caring owners, they're not the daily driver. I'm looking for the daily driver.

Suggestions?

[Rick Ruskin]

Send it to me and I'll get it fixed. You can have supervised
visitation.


Rick Ruskin
Lion Dog Music- Seattle WA
http://liondogmusic.com

[Angus Kerr]

-snip-

> >Suggestions?
>
>
> Send it to me and I'll get it fixed. You can have supervised
> visitation.

Hah! You really got a belly laugh out of me there....


Sounds like a bargain......

-A.

[Phil Allison]

Angus Kerr wrote:

>
>
> Ironically, the back capsule looks like a golf ball when I
> select Omni or Figure 8, even though I get no sound from the
> back capsule.

** Must have almost no tension in the diaphragm at all.

> The front diaphragm looks like there is dust and debris UNDER
> the surface, between the body and the diaphragm. As soon as the
> diaphragm is sucked on all these pockmarks appear, so not golf
> ball shaped divots to match the matrix holes, but random sharp
> bumps, that disappear if I breathe gently on it which seems to
> short out the capsule.

** For dust to get inside, there has to be a hole in one of the diaphragms. Plus having 60VDC on the perforated plate attracts dust particles, big time.

Once the diaphragm is badly contaminated, the surface becomes conductive soon as you breathe on it. The stored charge leaks away and output stops.

Mics made like this need to be very well looked after, covered when not in use, always kept in a warm, dry place and never subjected to human breath. A pop screen is essential. Neumann point this out in their user manuals but folk still ignore it.

It is possible to clean contaminated diaphragms using a warm water and detergent solution applied from an eye dropper, rinsing with clean water and then drying with warm air. Patience and *great delicacy* is required, but the end result is a mirror clean surface and a working mic.


FYI: Some condenser capsules ( particularly omnis) avoid the problem by having the diaphragm grounded and taking the output signal from the back plate.


... Phil

[Angus Kerr]

On Saturday, September 26, 2015 at 8:11:00 AM UTC+2, Phil Allison wrote:
> Angus Kerr wrote:
>
> >
> >
> > Ironically, the back capsule looks like a golf ball when I
> > select Omni or Figure 8, even though I get no sound from the
> > back capsule.
>
> ** Must have almost no tension in the diaphragm at all.

Could it have been wired incorrectly?

>
>
> > The front diaphragm looks like there is dust and debris UNDER
> > the surface, between the body and the diaphragm. As soon as the
> > diaphragm is sucked on all these pockmarks appear, so not golf
> > ball shaped divots to match the matrix holes, but random sharp
> > bumps, that disappear if I breathe gently on it which seems to
> > short out the capsule.
>
>
> ** For dust to get inside, there has to be a hole in one of the diaphragms. Plus having 60VDC on the perforated plate attracts dust particles, big time.

The little crescent shaped divot could be a culprit, although it doesn't look like a tear. And also, you never know with an old mic like this, who has been fiddling around in the 35 years of use before you purchased it.

>
> Once the diaphragm is badly contaminated, the surface becomes conductive soon as you breathe on it. The stored charge leaks away and output stops.

This I was aware of.. Seems to be a problem with Neumanns? My Oktava MK219 does not do this. It's probably about 17 years old at least (guy gave me a pair to pay for studio time). Pity the 219 does not have the silky tops of the U67 or U87. It's not bad, but....

>
> Mics made like this need to be very well looked after, covered when not in use, always kept in a warm, dry place and never subjected to human breath. A pop screen is essential. Neumann point this out in their user manuals but folk still ignore it.

Partially what happened is it appears there was foam in the box, put by a well meaning soul, which totally disintegrated between when I last used the mic. The foam embedded itself in the paintwork as well, just for good measure. I should have packed it in a plastic bag and secure with a rubberband, so I'll do this in future...

>
> It is possible to clean contaminated diaphragms using a warm water and detergent solution applied from an eye dropper, rinsing with clean water and then drying with warm air. Patience and *great delicacy* is required, but the end result is a mirror clean surface and a working mic.
>

What kind of detergent? I'll have a go at the capsule- I don't really have anything to lose, the mic probably needs a reskin anyway.

>
> FYI: Some condenser capsules ( particularly omnis) avoid the problem by having the diaphragm grounded and taking the output signal from the back plate.
>
>
> ... Phil

Thanks,
-A.

[Scott Dorsey]

Phil Allison <palli...@gmail.com> wrote:
>** So the diaphragm now looks like the surface of a golf ball - right ?
>
>Gently warming the capsule usually makes a stuck diaphragm pop off the back plate - so try placing the mic a warm place, like the inside of a window facing the sun for a hour or so.
>
>If that does not do the trick, try playing *warm* air on the diaphragm. A hair dryer set to "lo" and held away by about 0.5 metre is about right.

I've never thought of doing that with a PVC diaphragm... the problem with
them is that the plasticizer outgasses and they become brittle and fail,
kind of like old car seats.

But, it can't hurt to try it. Worst that could happen is that you have to
replace the diaphragm, which you'd otherwise have to do anyway.

The problem with these mikes is that the top end gets very peaky when the
diaphragm hardens, and some people like that and have associated that with
the "Neumann sound" in their heads. Put a modern diaphragm on and tune them
to factory specifications and they don't sound like that.

[Angus Kerr]

On Saturday, September 26, 2015 at 2:00:16 PM UTC+2, Scott Dorsey wrote:
> Phil Allison <palli...@gmail.com> wrote:
> >** So the diaphragm now looks like the surface of a golf ball - right ?
> >
> >Gently warming the capsule usually makes a stuck diaphragm pop off the back plate - so try placing the mic a warm place, like the inside of a window facing the sun for a hour or so.
> >
> >If that does not do the trick, try playing *warm* air on the diaphragm. A hair dryer set to "lo" and held away by about 0.5 metre is about right.
>
> I've never thought of doing that with a PVC diaphragm... the problem with
> them is that the plasticizer outgasses and they become brittle and fail,
> kind of like old car seats.
>
> But, it can't hurt to try it. Worst that could happen is that you have to
> replace the diaphragm, which you'd otherwise have to do anyway.

I emailed Klaus, and of course he suggests that I send it to him. He is thinking that the bumps I am seeing is actually moisture that has found its way into the capsule behind the diaphragm. He does not think the diaphragm is collapsed. He suggests a capsule replacement, and he is probably right. Meantime, is there anything I can do to get the moisture out the capsule? Put it in an oven at about 40 deg C (104 F)? Reminds me of a watch where for some reason water got inside it and you could never get it out.

I really am loathe to replace the capsule, because it's original, Serial number 773. I was also told horror stories by the late Stephen Paul about how the tolerances of the capsule body were sacrified for automated CNC mass production.

It was actually working, of a fashion, today and I was actually able to sing into it. But the sound is not to spec. It's very smooth and unhyped on the top end, I don't know if its supposed to have a presence peak, because I can't hear one. Unfortunately it doesn't have much bottom end (I presume because the diaphragm is not free to move), and a nasally peak at around 1kHz which does not agree with my voice.

I've A/Bed against the U87 and the Oktava MK219, and I'm pretty sure it that capsule was healthy it would sound fantastic.

For now it's between the 219 and 87. The 219 seems to have a presence peak that gets a little sibilant, and the 87 is much more unhyped and smooth on top, but still with a little bump around 900 - 1.2kHz. Tops are there if I want them, but I'm kind of liking the natural character it gives a vocal.

> The problem with these mikes is that the top end gets very peaky when the
> diaphragm hardens, and some people like that and have associated that with
> the "Neumann sound" in their heads. Put a modern diaphragm on and tune them
> to factory specifications and they don't sound like that.
> --scott

To my ears, the Neumann sound is the detail of top end that gives the lower mids character. They seem to be directly coupled - I've never heard that directness with any other microphone. It's been said they excellent transient response. Amazing that you can put two mics together that have identical frequency response plots and you can clearly hear differences.

-Angus

[Phil Allison]

Angus Kerr wrote:
>
>
> Unfortunately it doesn't have much bottom end (I presume
> because the diaphragm is not free to move), and a nasally
> peak at around 1kHz which does not agree with my voice.

** FYI, the diaphragm of a condenser mic barely moves in normal operation - unlike dynamic or ribbon types that move quite a bit at low frequencies.

The reason is that the output signal depends purely on the displacement of the diaphragm rather than how fast it is moving. IOW for a given sound pressure, the amount of movement is much the same at low, mid and high frequencies.

Also being non rigid, it is possible to pin the diaphragm stationary in the middle without changing it's operation too much - as you can see with your Neumanns.


... Phil

[Scott Dorsey]

Angus Kerr <angus...@gmail.com> wrote:
>
>I emailed Klaus, and of course he suggests that I send it to him. He is thi=
>nking that the bumps I am seeing is actually moisture that has found its wa=
>y into the capsule behind the diaphragm. He does not think the diaphragm is=
> collapsed. He suggests a capsule replacement, and he is probably right. Me=
>antime, is there anything I can do to get the moisture out the capsule? Put=
> it in an oven at about 40 deg C (104 F)? Reminds me of a watch where for s=
>ome reason water got inside it and you could never get it out.=20

Baking it in a box with a light bulb will work for a lot of capsules, but
if you have one of the original PVC capsules that might not be advisable
either. The problem, though, is that if you have enough condensation,
you will have contamination that came in along with it, and that means
taking the capsule apart to clean.

>I really am loathe to replace the capsule, because it's original, Serial nu=
>mber 773. I was also told horror stories by the late Stephen Paul about how=
> the tolerances of the capsule body were sacrified for automated CNC mass p=
>roduction.=20

Klaus should be able to repair the capsules but it might be more expensive
than replacing it with a new one from Gefell.

The tolerances of those original capsules actually weren't all that good,
mostly because it's very difficult to tension the diaphragm precisely and
the method Neumann used in the fifties is pretty crude. The modern capsules
have very different designs, in part so that the diaphragm can be tensioned
by machine and dropped into place and this actually results in much better
consistency.

Other issues include getting the backplate perfectly flat and perfectly
parallel to the diaphragm, both of which can be done better by machine
these days than they could be done by hand in the fifties. The key to
this is that we now have easy go/no go tests for flatness using laser
interferometers, rather than a guy on the production line putting an
optical flat on the backplate and shining a bright light and looking for
Newton's rings, so the production engineers have a better grip on what
is actually being shipped.

Gefell, though, is pretty much making the capsules the same way Neumann was
making them seventy years ago. I'm not sure if that's a good thing or a
bad thing.

>It was actually working, of a fashion, today and I was actually able to sin=
>g into it. But the sound is not to spec. It's very smooth and unhyped on th=
>e top end, I don't know if its supposed to have a presence peak, because I =
>can't hear one. Unfortunately it doesn't have much bottom end (I presume be=
>cause the diaphragm is not free to move), and a nasally peak at around 1kHz=

> which does not agree with my voice.

These are the signs of a PVC diaphragm going bad. The capsule can be
reskinned, or it can be replaced.

>I've A/Bed against the U87 and the Oktava MK219, and I'm pretty sure it tha=

>t capsule was healthy it would sound fantastic.

I don't know, I never really liked the U47 or U67. The top end just does
not sound at all realistic to me. I always liked the U47 fet more than
the nuvistor one, and the nuvistor one more than the original. Go figure.

>For now it's between the 219 and 87. The 219 seems to have a presence peak =
>that gets a little sibilant, and the 87 is much more unhyped and smooth on =
>top, but still with a little bump around 900 - 1.2kHz. Tops are there if I =
>want them, but I'm kind of liking the natural character it gives a vocal.=

Take the 219 apart, glop bathtub caulking around the inside of the case so
that it doesn't ring. Cut out the vertical bars on the diecast case that
block the grille. Remove one of the layers of the grille. (You will probably
want to repaint the case after removing the bars). You'll find all of the
things you didn't like about the 219 go away when you do this. It's all
mechanical stuff.

>> The problem with these mikes is that the top end gets very peaky when the

>> diaphragm hardens, and some people like that and have associated that wit=
>h
>> the "Neumann sound" in their heads. Put a modern diaphragm on and tune t=

>hem
>> to factory specifications and they don't sound like that.
>

>To my ears, the Neumann sound is the detail of top end that gives the lower=
> mids character. They seem to be directly coupled - I've never heard that d=
>irectness with any other microphone. It's been said they excellent transien=
>t response. Amazing that you can put two mics together that have identical =

>frequency response plots and you can clearly hear differences.

And that goes to show you first of all that the frequency response on-axis
tells you very little...

[Angus Kerr]

-snip-

>
> Baking it in a box with a light bulb will work for a lot of capsules, but
> if you have one of the original PVC capsules that might not be advisable
> either. The problem, though, is that if you have enough condensation,
> you will have contamination that came in along with it, and that means
> taking the capsule apart to clean.

Can this be done? can the diaphragm be removed from the body without slacking the tension? And then there's the thought of tackling the screw in the centre post, slipping of and gouging the diaphragm - I could have nightmares about that. Special slip proof screwdriver required?

> Klaus should be able to repair the capsules but it might be more expensive
> than replacing it with a new one from Gefell.
>

> The tolerances of those original capsules actually weren't all that good,
> mostly because it's very difficult to tension the diaphragm precisely and
> the method Neumann used in the fifties is pretty crude.

-snip-

I was thinking of a clone like this http://www.ebay.com/itm/RK-87-Microphone-Capsule-Neumann-K67-K87-clone-34mm-True-Condenser-/201323393173?hash=item2edfcf3095 for a cheap fix.

>
> Gefell, though, is pretty much making the capsules the same way Neumann was
> making them seventy years ago. I'm not sure if that's a good thing or a
> bad thing.
>

-snip-

>
> These are the signs of a PVC diaphragm going bad. The capsule can be
> reskinned, or it can be replaced.
>
> >I've A/Bed against the U87 and the Oktava MK219, and I'm pretty sure it tha=
> >t capsule was healthy it would sound fantastic.
>
> I don't know, I never really liked the U47 or U67. The top end just does
> not sound at all realistic to me. I always liked the U47 fet more than
> the nuvistor one, and the nuvistor one more than the original. Go figure.
>

I've probably never heard a healthy U67 anyway.

-snip-

>
> Take the 219 apart, glop bathtub caulking around the inside of the case so
> that it doesn't ring. Cut out the vertical bars on the diecast case that
> block the grille. Remove one of the layers of the grille. (You will probably
> want to repaint the case after removing the bars). You'll find all of the
> things you didn't like about the 219 go away when you do this. It's all
> mechanical stuff.
>

I've seen your excellent mods in Recording magazine, which apart from making the mic sound a lot better, also make it look a lot better too.

I have a fondness for my 219's, I love the utilitarian austere Russian coffin box styling. And they don't sound half bad either. I might even go the whole hog and pimp them to the max, Dorsey style! Electronics and all! MK219SD ftw!

Even unmodded, they look a lot better than the ridiculous lipstick green C12VR.

> >> The problem with these mikes is that the top end gets very peaky when the
> >> diaphragm hardens, and some people like that and have associated that wit=
> >h
> >> the "Neumann sound" in their heads. Put a modern diaphragm on and tune t=
> >hem
> >> to factory specifications and they don't sound like that.
> >

The only thing that does concern me about the Neumann sound, is it just might not work for my voice -I am no Pavarotti. But we'll find out.

> And that goes to show you first of all that the frequency response on-axis
> tells you very little...

Maybe our ears are better than we think.

-A.

[Scott Dorsey]

Angus Kerr <angus...@gmail.com> wrote:
>-snip-

>>=20

>> Baking it in a box with a light bulb will work for a lot of capsules, but
>> if you have one of the original PVC capsules that might not be advisable

>> either. The problem, though, is that if you have enough condensation,=20

>> you will have contamination that came in along with it, and that means
>> taking the capsule apart to clean.
>

>Can this be done? can the diaphragm be removed from the body without slacki=
>ng the tension? And then there's the thought of tackling the screw in the c=
>entre post, slipping of and gouging the diaphragm - I could have nightmares=

> about that. Special slip proof screwdriver required?

The diaphragm is garbage. You remove it and throw it away, then you put
a modern mylar diaphragm on the capsule in place of the original unstable
PVC. Getting the tension correct on the new diaphragm is nontrivial and
very much a fine art, but Klaus can do it. Not many other people can.

>I was thinking of a clone like this http://www.ebay.com/itm/RK-87-Microphon=
>e-Capsule-Neumann-K67-K87-clone-34mm-True-Condenser-/201323393173?hash=3Dit=
>em2edfcf3095 for a cheap fix.=20

Who knows who made those?

Tensioning the diaphragm on these older capsules is very much a fine art
and there aren't a lot of people who can do it. Certainly the people in
the Chinese factories have not figured out any consistent way of doing it.

My inclination would be to avoid the clone capsules. Get your original one
repaired, or get a new original one from Gefell.


>I have a fondness for my 219's, I love the utilitarian austere Russian coff=
>in box styling. And they don't sound half bad either. I might even go the w=
>hole hog and pimp them to the max, Dorsey style! Electronics and all! MK219=
>SD ftw!

The electronics mods on the 219 make a little difference, but the body
modifications make a much greater difference in the sound. The Oktava
capsule and electronics designs are actually very good... all the problems
with the 219 and 319 have to do with the case (and the fact that they could
not consistently get good components in the Soviet and immediate post-Soviet
era).

>The only thing that does concern me about the Neumann sound, is it just mig=

>ht not work for my voice -I am no Pavarotti. But we'll find out.

Then use it on someone else's voice. Or sell it and buy something else;
you can get a whole box of RE-20s for the price of a U67 and nobody ever
sounded bad on an RE-20.

[Angus Kerr]

On Monday, September 28, 2015 at 4:36:16 PM UTC+2, Scott Dorsey wrote:
-snip-

> The diaphragm is garbage. You remove it and throw it away, then you put
> a modern mylar diaphragm on the capsule in place of the original unstable
> PVC. Getting the tension correct on the new diaphragm is nontrivial and
> very much a fine art, but Klaus can do it. Not many other people can.

-snip-

> My inclination would be to avoid the clone capsules. Get your original one
> repaired, or get a new original one from Gefell.
>

If it's affordable. Our currency has plunged against the dollar. Imported goods are now 40% more expensive..., and they were expensive to begin with...

> The electronics mods on the 219 make a little difference, but the body
> modifications make a much greater difference in the sound. The Oktava
> capsule and electronics designs are actually very good... all the problems
> with the 219 and 319 have to do with the case (and the fact that they could
> not consistently get good components in the Soviet and immediate post-Soviet
> era).

Well I've just done the body for 219 #1. Not too difficult. Now to wait for that awful Silicone to cure...You never considered acrylic sealant instead? Water soluble when uncured, much easier to work with.

Just also saw how the switches worked, with little magnetic reed switches. One would have thought the action of those switches would be silky smooth, but not in Russia.

@Scott: I wanted to ask you what you recommend. I see there are two grilles, inner and outer. Should I put both back, or is it better with just one? I see the Michael Joly mod uses single grille. What's your take?

>
> >The only thing that does concern me about the Neumann sound, is it just mig=
> >ht not work for my voice -I am no Pavarotti. But we'll find out.
>
> Then use it on someone else's voice. Or sell it and buy something else;
> you can get a whole box of RE-20s for the price of a U67 and nobody ever
> sounded bad on an RE-20.

And I would love an RE20 - never seen or heard one in the flesh, but I've probably heard it plenty on radio broadcasts.

Just went over my tracks comparing the 219 vs the U87 vs the sick U67 on vocals. The U87 is a clear winner. The U67 is sick, so it doesn't count, and the 219 is as sibilant as hell.

@Scott - I'm hoping the mods take some of that away. I'm also hearing over-hyped top end. Hard to believe from what I'm hearing that the U87 have a presence peak and the 219 does not. It sounds the other way round to me. Will taking the baffles out smooth it out? It's a lot more aggressive in the top end than the U87, which brings out none of that sibilance.

-Angus.

[Angus Kerr]

On Monday, September 28, 2015 at 9:38:59 PM UTC+2, Angus Kerr wrote:
-snip-

>
> Well I've just done the body for 219 #1. Not too difficult. Now to wait for that awful Silicone to cure...You never considered acrylic sealant instead? Water soluble when uncured, much easier to work with.
>

I'm going to leave the second one stock, and then compare them. I'm looking forward to hearing the difference. Unfortunately, I didn't make a recording with the first one before I plunged in with the hacksaw and sidecutters....

-A.

[Scott Dorsey]

Angus Kerr <angus...@gmail.com> wrote:
>
>@Scott: I wanted to ask you what you recommend. I see there are two grilles=
>, inner and outer. Should I put both back, or is it better with just one? I=

> see the Michael Joly mod uses single grille. What's your take?

I tend to leave both in because it's more rugged. It might sound better
with one, but it won't take a drumstick.

>@Scott - I'm hoping the mods take some of that away. I'm also hearing over-=
>hyped top end. Hard to believe from what I'm hearing that the U87 have a pr=
>esence peak and the 219 does not. It sounds the other way round to me. Will=
> taking the baffles out smooth it out? It's a lot more aggressive in the to=
>p end than the U87, which brings out none of that sibilance.=20

Both the U87 and the 219 have exaggerated top end, but they are different
kinds of exaggerated top ends.

[Angus Kerr]

On Monday, September 28, 2015 at 10:08:52 PM UTC+2, Scott Dorsey wrote:
-snip-
>

> I tend to leave both in because it's more rugged. It might sound better
> with one, but it won't take a drumstick.

Thanks, I think I'll put one on for now and keep the second if required.

-snip-

> Both the U87 and the 219 have exaggerated top end, but they are different
> kinds of exaggerated top ends.

Taking off the baffle will do ....? Or should I just take one off and take a listen...

Awesome mod, btw. I can just see that they are going to sound better - it's hard to imagine anything got through those old grilles - There's more metal than space! Ok, it's 50% metal.

-A.

[Peter Larsen]

As I recall this from some mic-modder site the 219 has a hf resonator in
front of the membrane that causes its peak. Remove it and - still from
memory - it will roll off from 10 kHz instead with a much more benign
and easili compensated response. My recollection may be incomplete, do
not read as a how2 manual, but as a search4.

> --scott

Kind regards

Peter Larsen

[Scott Dorsey]

Angus Kerr <angus...@gmail.com> wrote:
>> Both the U87 and the 219 have exaggerated top end, but they are different
>> kinds of exaggerated top ends.
>
>Taking off the baffle will do ....? Or should I just take one off and take a listen...

Do you mean the resonator in front of the capsule? Don't remove that, it
does add a high frequency pole but that's not a bad thing.

[Angus Kerr]

On Sunday, September 27, 2015 at 5:22:10 PM UTC+2, Scott Dorsey wrote:

-snip-

> Klaus should be able to repair the capsules but it might be more expensive
> than replacing it with a new one from Gefell.
>

Update: emailed Klaus with pictures - he has comfirmed the capsule is original, and undertaken to fully restore it for $500.

$500 will hurt me, but it's probably worth it, as a fully working U67 is going to sound good, and be worth more than $500 over a non working one..

> The tolerances of those original capsules actually weren't all that good,
> mostly because it's very difficult to tension the diaphragm precisely and
> the method Neumann used in the fifties is pretty crude. The modern capsules
> have very different designs, in part so that the diaphragm can be tensioned
> by machine and dropped into place and this actually results in much better
> consistency.
>
> Other issues include getting the backplate perfectly flat and perfectly
> parallel to the diaphragm, both of which can be done better by machine
> these days than they could be done by hand in the fifties. The key to
> this is that we now have easy go/no go tests for flatness using laser
> interferometers, rather than a guy on the production line putting an
> optical flat on the backplate and shining a bright light and looking for
> Newton's rings, so the production engineers have a better grip on what
> is actually being shipped.
>
> Gefell, though, is pretty much making the capsules the same way Neumann was
> making them seventy years ago. I'm not sure if that's a good thing or a
> bad thing.

To me, it's all about originality. The vintage-ness of these things is in the original components, good or bad.

Similar to classic cars. People will go to extreme lengths to get original parts, even though newer ones might be better.

-Angus.

[Frank Stearns]

Angus Kerr <angus...@gmail.com> writes:

snips

>To me, it's all about originality. The vintage-ness of these things is in the
>original components, good or bad.

>Similar to classic cars. People will go to extreme lengths to get original parts,
>even though newer ones might be better.

I understand the sentiment, but perhaps it's a difficult comparison to make. Would
you, for example, use your classic car to go to work or to the grocery store?

Probably not; it'd be something more of a show piece brought out once or twice a
year for people to look at while parked (and not running) at an auto show -- rather
than as a utilitarian piece of your everyday kit.

To me while doing recording tasks, I'd want to make frequent use of that piece of
legend that I owned -- as after a few minutes the nostolgia of simply looking at it
would wear off.

While certainly a consideration, I would not be so concerned about a non-original
part that still got me close to the original spec or sound. And while I might
ultimately say "no", I'd entertain the idea of using parts that got me /better/
performance.

One of my frustrations came on a project a few years back where I had several
"classic" mics at my disposal -- 250s, KM88s. I might be off on the model number,
but the 250s -- a U67 better at rejecting RF, or something like that -- simply
didn't sound all that great, even though Klaus had gone through it. The KM88s were
quite nice, but on cardioide had weird HF lobes which made for isolation pains at a
location where choir and orchestra were being recorded.

During overdubs, the 250/U67 was again available. It fell rather short
side-by-side on the same voice compared to a Shure KSM44 -- painfully so when you
consider the 10x and in some markets 20x price differential.

A quick look with a spectrum analyzer revealed much of the issue. The 250/U67 had
steep roller-coaster response from 1K to 13K (+/- 10 dB every third octave or so),
and then about an 18 dB/octave roll-off starting at 13K. And as I said, Klause, had
gone though this microphone.

If I'd owned that microphone, I would have been tempted to "cash it in" for its
fleeting market value and gotten another KSM44 and perhaps another 2-3 Gefell
M930s.

I try to let the magic come from the performers, and not let balky kit (regardless
of reputation) get in the way as that magic is captured.

But that's just me; YMMV. (The owner of those microphones finally threw up his hands
at trying to get tubes that lasted -- and sold off the entire collection a few
years later.)

Frank
Mobile Audio

--
.

[Angus Kerr]

On Wednesday, September 30, 2015 at 1:59:33 PM UTC+2, Frank Stearns wrote:

> Angus Kerr writes:
>
> snips
>
> >To me, it's all about originality. The vintage-ness of these things is in the
> >original components, good or bad.
>
> >Similar to classic cars. People will go to extreme lengths to get original parts,
> >even though newer ones might be better.
>
> I understand the sentiment, but perhaps it's a difficult comparison to make. Would
> you, for example, use your classic car to go to work or to the grocery store?
>
> Probably not; it'd be something more of a show piece brought out once or twice a
> year for people to look at while parked (and not running) at an auto show -- rather
> than as a utilitarian piece of your everyday kit.
>

You're absolutely right. I am however, looking at this from a semi-perspective of retaining the value of the mic rather than having it as an everyday workhorse.

Although this mic sounded gorgeous when I bought it, the reality was that when I wanted to use it, it had all sorts of issues. I managed to do vocals for one album with it. I often think, that some of us probably use our hearts rather than our ears when we decide to record with the 'vintage tube mic'. To the general listener, unless the differences are obvious, they'd be hard pressed to tell the difference between a C12, C414, C3000, RE20, U67, U87, or even an Oktava MK319 or Shure SM7 or SM57.

I mean, my Oktava MK219's, as mentioned in a previous post, just work flawlessly every time I pull them out. No pops, squeaks or ear splitting crackle. Just clean audio. Not the best, but there's a lot to be said for reliability.

So yes, if I don't have the resources to care (and use) a U67, o Toyota microphone might work very well.

-snip-

> While certainly a consideration, I would not be so concerned about a non-original
> part that still got me close to the original spec or sound. And while I might
> ultimately say "no", I'd entertain the idea of using parts that got me /better/
> performance.

I'd agree if I wanted to keep the mic.
-snip-

> During overdubs, the 250/U67 was again available. It fell rather short
> side-by-side on the same voice compared to a Shure KSM44 -- painfully so when you
> consider the 10x and in some markets 20x price differential.
>
> A quick look with a spectrum analyzer revealed much of the issue. The 250/U67 had
> steep roller-coaster response from 1K to 13K (+/- 10 dB every third octave or so),
> and then about an 18 dB/octave roll-off starting at 13K. And as I said, Klause, had
> gone though this microphone.
>

-snip-

> I try to let the magic come from the performers, and not let balky kit (regardless
> of reputation) get in the way as that magic is captured.
>

There's nothing worse than making performers wait while you try to coax faulty gear to co-operate.

But that's just me; YMMV. (The owner of those microphones finally threw up his hands
> at trying to get tubes that lasted -- and sold off the entire collection a few
> years later.)

It seems to me that one pays a lot for the 'snob' value of the tier 1 microphones.

To me, while I love the idea of owning an M149 tube, mics are colours that you use to paint a sonic picture. Sometimes the cheaper mic is just perfect.

I just last night listened to a shootout of the usual large diaphragm condenser suspects: U87, C414, C3000, MK319, SM58(!) on a female vocal. Solo'ed, the C3000 was by far the least best sounding, although the distance from the mic was inconsistent. In the track, (very pop / synth) the C3000 to my ears was perfect. It just sat in the track, sounded processed, but completely right. The others, the warmth just didn't fit with synth pop stuff. Almost none of the commenters agreed with me though.

-Angus.

[PStamler]

On Sunday, September 27, 2015 at 10:22:10 AM UTC-5, Scott Dorsey wrote:

> These are the signs of a PVC diaphragm going bad. The capsule can be
> reskinned, or it can be replaced.

According to Neumann's cumulative mic data sheet, the U 67, unlike the U 47, never had a PVC diaphragm. According to that, it was "PE", for polyethylene, or Mylar.

Peace,
Paul

[Phil Allison]

PStamler wrote:

>
>
> > These are the signs of a PVC diaphragm going bad. The capsule can be
> > reskinned, or it can be replaced.
>
>
> According to Neumann's cumulative mic data sheet,
> the U 67, unlike the U 47, never had a PVC diaphragm.
> According to that, it was "PE", for polyethylene, or Mylar.
>

** The trade name "Mylar" refers to treated polyester or PETP film.

It is also know as "BoPET" as explained by Wiki.

https://en.wikipedia.org/wiki/BoPET

First available in the 1950s, it was quickly adopted for the di-electric in general purpose capacitors, diaphragms for dynamic and condenser mics plus dome tweeters, electrostatic speakers and as the backing for most recording tape.

It is also used as wrap insulation for machine wound, toroidal power transformers.



.... Phil

[Scott Dorsey]

Hmm... if that's the case, the chances of getting the thing to work
without tearing it down are much greater.

[gray_wolf]

Somewhere about that time they changed some of the better film stock from the
old brittle acetate to mylar