Matador

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #980 on: July 23, 2012, 01:54:26 PM »
I meant which capsules and transformers you will use,pardon my bad english,still learning.... :)

Oops, my fault you asked very clearly. ;)

I'm using two K67 type capsules matched by Dave Thomas at AAMicrophones.  They are essentially the same as those sold by Microphone Parts, but they are re-skinned with 6 micron Mylar.  They should have slightly less high frequency lift in the 7-9kHz range as a typical K67 type capsule.  Since I already have two "dark" versions using K47 type capsules, I'm hoping this pair has slightly more "air".

More sonic crayons to add to the box!


kante1603

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #981 on: July 23, 2012, 02:05:09 PM »
Cool,thanks!

Udo :)


sr1200

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #983 on: July 24, 2012, 04:53:04 PM »
I know this is almost blasphemy, but I used mine in front of a kick drum (with the pad on about a foot infront of the front skin) HOLY HUGE KICK DRUM SOUND!!!!
MEI Studio - Long Island, NY: http://www.meirecords.com

kante1603

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #984 on: July 24, 2012, 05:03:15 PM »
I know this is almost blasphemy, but I used mine in front of a kick drum........
Yes.

HellfireStudios

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #985 on: July 24, 2012, 06:15:13 PM »
I know this is almost blasphemy, but I used mine in front of a kick drum........
Yes.

Not when used with a pop filter in front of it...
"Tommorrow is just yesterday in reverse. Just like friends are enemies in reverse." -Gary Busey

kante1603

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #986 on: July 25, 2012, 01:50:29 AM »
Not when used with a pop filter in front of it...
Right,and one can use a U47 as a salt shaker and a CMV3 as a rolling pin......

HellfireStudios

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #987 on: July 25, 2012, 03:20:53 AM »
Not when used with a pop filter in front of it...
Right,and one can use a U47 as a salt shaker and a CMV3 as a rolling pin......

Even a ribbon, which is known for its fragility, can be used in front of a kick, if the air blast is properly dissipated/absorbed, and can take the SPL. A pop filter does the former very well. Notice how I didn't say INSIDE a kick drum? The pressures all around the capsule would be ridiculous for a condenser mic, and no pop filter is going to be sufficient for the job.

-James-

P.S.- The badge on a CMV-3 would make it difficult to use it as a rolling pin, and the U-47 would require a total redesign to implement a salt shaker-style operation. :)
"Tommorrow is just yesterday in reverse. Just like friends are enemies in reverse." -Gary Busey

kante1603

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #988 on: July 25, 2012, 03:51:55 AM »
Even a ribbon, which is known for its fragility, can be used in front of a kick, if the air blast is properly dissipated/absorbed, and can take the SPL. A pop filter does the former very well. Notice how I didn't say INSIDE a kick drum? The pressures all around the capsule would be ridiculous for a condenser mic, and no pop filter is going to be sufficient for the job.
I know how to choose and use microphones....
P.S.- The badge on a CMV-3 would make it difficult to use it as a rolling pin,
...but makes pasta dough quite unique....
and the U-47 would require a total redesign to implement a salt shaker-style operation. :)
...leave out the innards,especially the mounting plate for the capsule,fill in the salt before assembly,done....

Completely OT again.....

HellfireStudios

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #989 on: July 25, 2012, 04:07:07 AM »
Wouldn't salt leak from the side grills, as well? :)

Let's move on to more relevant topics. Like the thread at hand.

-James-
"Tommorrow is just yesterday in reverse. Just like friends are enemies in reverse." -Gary Busey


kante1603

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #990 on: July 25, 2012, 04:57:57 AM »
Wouldn't salt leak from the side grills, as well? :)

Let's move on to more relevant topics. Like the thread at hand.

-James-
Yes. ;D

Hank Dussen

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #991 on: July 26, 2012, 07:46:10 AM »
I think I managed to bias the FET. But since the IDss of all (5) my FET's are rather high (around 12) the voltage at the drain is rather low.
Maybe it would be better to to have some FET's with a lower IDss.
Instead of having to buy another 50 or so is anyone willing to sell me 2 of their leftover but 'within specs' FET's?

Pieter

kante1603

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #992 on: July 26, 2012, 09:24:18 AM »
I think I managed to bias the FET. But since the IDss of all (5) my FET's are rather high (around 12) the voltage at the drain is rather low.
Maybe it would be better to to have some FET's with a lower IDss.
Instead of having to buy another 50 or so is anyone willing to sell me 2 of their leftover but 'within specs' FET's?

Pieter
PM sent!

Udo ;)

geekmacdaddy

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #993 on: July 26, 2012, 07:30:41 PM »
Got the mic together sans capsule (I'll do that last, as I don't want to keep it exposed any longer than needed), here's some photos;














Having a problem biasing. I have one audio track in logic with a tone recorded to it. This is being outputted via out 1, which has a mono 1/4 in plug going into 2 wires w/alligator clips. Those are connected to; a) rail of the mic chassis, b) R6 directly. The mic is routed to track 2's input. I have pulled up a software oscilloscope in track 2. Problem? No signal in to track 2. Just a bit of low level hum. I'm doing something stupid, I'm sure...(Yes, track 2 is in record) Thoughts?

Thanks in advance
Geek

tskguy

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #994 on: July 26, 2012, 07:37:14 PM »
Geek,

Have you set the voltage at the drain? I would start with around 11.5v or so. Its a good place to start. It will also verify that the circuit is working.

Eric

HellfireStudios

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #995 on: July 26, 2012, 09:19:56 PM »
Geek,
You are not supposed to use the mic's XLR output for biasing. Make another gator clip cable, and attach the positive side of the cable to the drain of the FET. The negative to the mic's ground. That should help. This info alluded me too.

-James-
"Tommorrow is just yesterday in reverse. Just like friends are enemies in reverse." -Gary Busey

geekmacdaddy

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #996 on: July 27, 2012, 06:48:32 AM »
Thank you James and Eric. Back to the "real" world for another couple of days, then I will have at it again. Eric, I may collect on that phone call sometime soon... ;)

tskguy

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #997 on: July 27, 2012, 08:03:23 AM »
Anytime,
I will be around all weekend! ;D

HellfireStudios

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #998 on: July 30, 2012, 09:32:17 AM »
None of the good deals on evibay for oscilliscopes include probes (I will be lucky, if I get a power cable), and the probe selection on evilbay is somewhat slim at the moment. Which probe (10x or 100x) do I need to bias this mic? Does the MHz rating on the probe need to match the scope (150MHz)? If I get a Tektronix scope, do I need Tektronix probes? If there are "universal" probes, where do I find them as cheaply as possible (my budget is strained at the moment)? Thanks.

-James-
« Last Edit: July 30, 2012, 02:19:48 PM by HellfireStudios »
"Tommorrow is just yesterday in reverse. Just like friends are enemies in reverse." -Gary Busey

Beeswax

Re: Neumann U87 Vintage Circuit Build Thread.
« Reply #999 on: July 30, 2012, 01:54:50 PM »
Would the Mxl V6 body accommodate the build? 
Dear Noah,
We could have sworn you said the ark was leaving at 5pm.

Sincerely,
The Unicorns


 

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