Re: Neumann U87 Vintage Circuit Build Thread
« Reply #580 on: May 08, 2012, 11:39:32 PM »
How does the pattern selection work on the PCB.  If I short pins 1 and 2 I get what? 2 and 3?  then is it 1 and 3?  I will just have to open the mic and do it by hand with the shuter/jumper clip thingy.

-Scott


Re: Neumann U87 Vintage Circuit Build Thread
« Reply #581 on: May 09, 2012, 12:18:24 AM »
How does the pattern selection work on the PCB.  If I short pins 1 and 2 I get what? 2 and 3?  then is it 1 and 3?  I will just have to open the mic and do it by hand with the shuter/jumper clip thingy.

-Scott

Indeed,
No Jumper = Cardiod
Jumper (pin1-pin-2) = figure 8
Jumper (pin 2- pin-3)  = Omni,

Cheers,
Dan,

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #582 on: May 09, 2012, 12:56:27 AM »

Mine looks just like the pic on the website.

Same here.

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #583 on: May 09, 2012, 03:05:46 AM »

Mine looks just like the pic on the website.
Don't know..... :'(

sr1200

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #584 on: May 09, 2012, 11:14:52 AM »
Has anyone used a OSP body for this mic? 
OSP stm-1300C
Its a pretty low price point, and has all 3 switches.  Only downfall is that the existing circuit board has the transformer MOUNTED to the board, so theres no cool little "cap" to cover the replacement trafo.  (the board thats in that mic is WEIRD lookin too...)

I should be getting my transformer any day now, but still waiting on that one cap that ONLY newark seems to stock.  The switches on that OSP are all mounted on a separate little board.  Ill post a pic tonight when i get to the shop.  just wondering what the wiring is going to be like for this thing...
MEI Studio - Long Island, NY: http://www.meirecords.com

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #585 on: May 09, 2012, 12:02:59 PM »
Has anyone used a OSP body for this mic? 
OSP stm-1300C
Its a pretty low price point, and has all 3 switches.  Only downfall is that the existing circuit board has the transformer MOUNTED to the board, so theres no cool little "cap" to cover the replacement trafo.  (the board thats in that mic is WEIRD lookin too...)

I should be getting my transformer any day now, but still waiting on that one cap that ONLY newark seems to stock.  The switches on that OSP are all mounted on a separate little board.  Ill post a pic tonight when i get to the shop.  just wondering what the wiring is going to be like for this thing...

Check this thread they talk about that for that generic mic body wihout the cap there discussion about lenght and other dimension , i never had a body like this in my hand but from reading this thread  it seems it will work ,

http://www.groupdiy.com/index.php?topic=48552.0 and Here : http://www.groupdiy.com/index.php?topic=48061.0

Cheers,
Dan,


sr1200

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #586 on: May 09, 2012, 12:40:15 PM »
After trolling the hardware store, i found a plumbing cap that will fit perfectly for about $2. :) :)
MEI Studio - Long Island, NY: http://www.meirecords.com

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #587 on: May 09, 2012, 02:32:01 PM »
After trolling the hardware store, i found a plumbing cap that will fit perfectly for about $2. :) :)

Oh nice! I need one of those covers too. Which hardware store did you find it at? Or is it a pretty generic product that I could find at most hardware stores? Might you post a picture?

Thanks,

-DUDE GUY
If it sounds good, it is good.

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #588 on: May 09, 2012, 02:40:24 PM »
To those waiting on a T13:

I received my T13, but it doesn't look like the pic in the spec sheet. I emailed AMI to see if my transformer is actually a T13. It turns out it is a normal T13 (not a prototype). AMI said that one of their new employees tested and sent out some T13's before wrapping them with the yellow wrap that says, "T13 AMI Made in USA." So if you get one that doesn't look like the pic in the spec sheet, do not fear, you still have a T13.

-DUDE GUY
If it sounds good, it is good.

sr1200

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #589 on: May 09, 2012, 03:04:01 PM »
Home depot in the plubming aisle lol, its a copper cap.  they are in little baggies where the connectors would be.
MEI Studio - Long Island, NY: http://www.meirecords.com


Re: Neumann U87 Vintage Circuit Build Thread
« Reply #590 on: May 09, 2012, 08:37:39 PM »
Hello all,

HELP!!!

Having issues with my T13. I installed it and then all my voltages changed drastically and I couldn't even see the 1k with my scope. I checked and double checked the wiring and I think it's good. I removed the T13 and voltages went back to normal.

Wiring (oriented the same as T13 spec sheet pic):

Yellow Left: 1 (RT)
Black Left: 4 (WS)
Yellow Right: 2 (SW)
Black Right: 3 (BL)

Should I see continuity between the two yellow leads of the T13? When I installed the T13, both of the yellow leads showed a continuity to ground. Then when I uninstalled the T13, my dmm showed continuity between the two yellow leads. Is this normal or do I have a bad T13?

Thanks,

- DUDE GUY

EDIT: After thinking more about it, continuity between both pairs of wires would make sense-yellow leads=primary, black leads=secondary. Anyone?
« Last Edit: May 10, 2012, 03:09:55 AM by DUDE GUY »
If it sounds good, it is good.

wave

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #591 on: May 09, 2012, 09:27:44 PM »
Dudeguy,
Your wiring looks like it was correct. I don't know about the continuity issue as mine is soldered in and I put shrink tube over the pins.

Dave

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #592 on: May 10, 2012, 06:01:28 AM »
More T13 trouble.

With the T13 installed, I get 1.5V at L1 and L2, .15V at FET drain, and .8V across the Zener...

I'm guessing I have a bad T13?

Voltages measured normal without the transformer.

Thoughts?

-DUDE GUY
If it sounds good, it is good.

MagnetoSound

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #593 on: May 10, 2012, 06:47:21 AM »
More T13 trouble.

With the T13 installed, I get 1.5V at L1 and L2, .15V at FET drain, and .8V across the Zener...

I'm guessing I have a bad T13?

Voltages measured normal without the transformer.

Thoughts?

Did you forget the coupling cap?

Dan

I don't think people realize what an embarrassment of riches this place is   -  Paul Gold

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #594 on: May 10, 2012, 01:36:21 PM »
More T13 trouble.

With the T13 installed, I get 1.5V at L1 and L2, .15V at FET drain, and .8V across the Zener...

I'm guessing I have a bad T13?

Voltages measured normal without the transformer.

Thoughts?

Did you forget the coupling cap?

I don't think so...I populated the entire board with BOM. Which cap is the coupling cap? Am I missing something? Thanks.
If it sounds good, it is good.

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #595 on: May 10, 2012, 02:07:37 PM »
More T13 trouble.

With the T13 installed, I get 1.5V at L1 and L2, .15V at FET drain, and .8V across the Zener...

I'm guessing I have a bad T13?

Voltages measured normal without the transformer.



Thoughts?

Did you forget the coupling cap?

I don't think so...I populated the entire board with BOM. Which cap is the coupling cap? Am I missing something? Thanks.

Could you remove the traffo and retake the Volatge reading again might somthing happen to the zener diode , this is very fragile component as you can have all the roght voltage dont not put the T13 yet,  before we are straight the traffo,
Dan,

MagnetoSound

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #596 on: May 10, 2012, 02:11:24 PM »
Which cap is the coupling cap? Am I missing something? Thanks.

The 1u cap between the drain and the primary winding.

This cap blocks the DC from the drain circuit from reaching the transformer, if you connect the primary winding directly to the drain it will load down the drain voltage.

As long as the coupling cap is in place it should not affect the drain voltage when you connect the transformer.

You should try connecting the primary wires first and see what happens - the cap could be leaky - if the voltages stay OK, connect the secondary wires and observe the difference.

You may also just have made a solder bridge somewhere that is causing a short. Sharp eyes needed.  ;)

Dan

I don't think people realize what an embarrassment of riches this place is   -  Paul Gold

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #597 on: May 10, 2012, 04:32:46 PM »

You should try connecting the primary wires first and see what happens - the cap could be leaky - if the voltages stay OK, connect the secondary wires and observe the difference.

I disconnected the secondary leads and my voltages went back to normal. Then I reconnected the secondary and my voltages went bad. What does this mean? Thanks.

-DUDE GUY
If it sounds good, it is good.

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #598 on: May 10, 2012, 05:52:44 PM »
Can you verify that you xlr pin out is good ,
number 1 on pcb=  is hot  pin 2 xlr
number 2 on pcb= is cold pin 3 xlr
number 3 on pcb = gnd

verify on the silk screen if this is correct, it is labeled there ,

Dany,





 

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