Neumann Vintage U87 Clone : Build Thread.

[kante1603]

Hi,

there´s no change between legs 1 and 3 (the outer legs),they show the overall resistance of the pot (or better the max.).
Leg 2 is the wiper (the leg in the middle of the pot).So either you measure 1 or 3 to the wiper(2) the resistance should change when turning the pot screw.If it doesn´t maybe the pot seems to be broken.

Udo.

 

[yankimusic]

Large a thank you with you two.
I succeeded. In fact, I reversed the potentiometer, and I realized that the catch where my oscilloscope was connected, didn't have grounded.
All is ok now.
The mic is amazing ! Very good job Dan !
Now, I've a problem with my mic body (Behringer B2 Pro).
The PCB Taper is too large.
Can I drill other holes on the PCB and put it over the top?
There will be no problem of ground? Because I see the screws that hold the PCB are connected to the circuit ...

 

[kante1603]

Good to hear,

now go to page 12 and see my reply #221 (attached PDF!) for pcb mounting and to my reply #225 for doing a ground connection,it's all there,all refering to B2 Pro builds.

Have fun,

Udo.

 

[yankimusic]

Thanks a lot Udo !
You're a genius !

 

[kante1603]

Not a genius,just a diy-guy looking for solutions....and sometimes find them ;D

Good night,

Udo.

 

[JessJackson]

Hi Guys,

Does anyone have mouser part numbers for the three switches for the switch board please.?

I broke my switches trying to remove them from the original board

 

[poctop]

Hi Guys,

Does anyone have mouser part numbers for the three switches for the switch board please.?

I broke my switches trying to remove them from the original board

Check on Reply #1522
Dan,

 

[Volume11]

So, I verified that my capsule sides aren't isolated. I am thinking of using it in a u67 build instead but, I don't know the differences between the 87 and 67 capsule other than the sides being isolated. Are they tuned the same? Is this a bad idea? If so, I'll just use the mic in cardiod only.

 

[poctop]

So, I verified that my capsule sides aren't isolated. I am thinking of using it in a u67 build instead but, I don't know the differences between the 87 and 67 capsule other than the sides being isolated. Are they tuned the same? Is this a bad idea? If so, I'll just use the mic in cardiod only.

The only difference is indeed that the 2 backplate are isolated in the K87 not in the K67 , except for this it is the same capsule,

fun fact is that the K87 can be easily converted into a K67 by shorting the 2 backplate but the reverse cannot be done.

Best,

Dan,

 

[Volume11]

That was quick! Thanks once again Dan! Now its time to order a new capsule 

 

[poctop]

If so, I'll just use the mic in cardiod only.

you can do that in the meantime for sure,
Best,
D

 

[TheGuitarist]

Update on my figure 8 problem, comparing it to my working mic, both are absolutely identical... aside from one just having a very quiet output JUST in figure 8 mode... which i find quite odd... i'm trying to work out why it would work in omni but not figure 8...

 

[poctop]

is that only one side of the fig 8 that is low output ? that is a strange problem.

sometime it can be confused as when you hear the 2 different side they are out of phase an you have to reverse the polarity in your pre to properly listen to the same thing trough you headphone or similar depending on your setup. if you sing on the side of the mic in figure 8  a good capsule will null out the 2 phase and you should hear close to nothing . I would verify the wiring trough the pattern switching if the omni works fine then the figure 8 must be really near of working too    just verify continuty trough your switch between the 2 pin on the jumper,


Best,
DAn,

 

[TheGuitarist]

Checked all the continuity, it seems fine onto pin 2...

Basically the level is very low in level, one side of the capsule seemingly doesn't work, and the rear side is very low level...

haha you see why i'm quite confused... my understanding was that different polar patterns were achieved by applying different voltages across different places... but just trying to work out what could be wrong for figure 8 if the others are working perfectly...

on the PCB at least... the voltages seem to be the same on both mics... getting very confused...

 

[poctop]

what capsule are you using how is it connected ? ,  take a moment to see what happens with the schematic when you flip the switch and you will find out,

are you using a switch for the patter or the jumper ,  if so , remove your wiring and install the jumper instead and see what happens , 

the jumper techmique never fails unless something is not wired properly,  Make sure the proper backplate are isolated and also are connected in the right spot

if you inverted them as front and back you will have those sort of issue,

Dan,

 

[TheGuitarist]

Found it!!! it was a small short with one of the capsule connectors touching the other backplate!!

Thanks heaps for all your help!

 

[kante1603]

Found it!!! it was a small short with one of the capsule connectors touching the other backplate!!

Thanks heaps for all your help!

Cool!

Now have fun recording,

Udo

 

[3nity]

Just want to clarify some observations when i used the D-U87 with my 1272.
It actually performs better than what i thought.

The low gain was due to some experimenting i was doing but when the 1272 is stock it sounds amazing!
I actually consider to be a good match of mic/pre.

Sorry for the confusion!

 

[ramshackles]

I have a pair of these now and they are wonderful. CM2480's and RK-87 (the 'cheap' options )

Has anyone ever tried water-transfer printer paper to label their mics?

Also, seeing the above, what (DIY) pre's do people use/think go well with this mic?

 

[Pip]

OK I give. I've made huge mistakes before but......

I chose to use the Behringer B-2 "PRO" as my donor. Because it had all the switches! WRONG!!!!

But as always I only have myself to blame. In an effort to save others the grief. These are the reasons why:

- Too small.

- Mounting points for PCBs do not line-up with the mounting holes of build PCBs (I do have the tapered PCB's in case you were wondering). This goes for up and down or width ways. You can make one side but this leaves no room for transformer height ways. Also I noticed that this is also an integral part of the grounding scheme.

- Switches?! Don't get me started on switches. I reverse engineered the PCB that has the stock switches mounted on it and made it work after pulling off the components that were there for the stock circuit and cutting a trace. Also the pattern switch has the labels on the cover in the wrong places for this build.

- Need to take apart capsule mount and cobble together from new and old mount depending on capsule, this because of the way the stock post mounts on the top plate. I used the microphone-parts RK-87. That is a nice capsule.

- I also made the mistake of keeping the the capsule assembly pin connection system as I thought it would help facilitate the biasing process. Wrong again the connections are shoddy and the plastic melts very easily you have to work very fast or you melt it to pieces. Doing this also meant I had to drill through holes to get the pad, filter and pattern wire looms to the switches.

OK thanks I feel better! The good news is the build powered up and made noise even though it was low output. I can't blame anything for this yet until I get rid of the pin connections and hardwire everything to the PCB's.

So in closing this cathartic though I hope helpful rant. What does the forum recommend as the optimum donor body for this build? I will review the thread for answers but I always appreciate guidance. I wish I had bought a couple of the microphone-parts donor bodies when they were available. I hope they're listening.

Now Relaxedly yours

Pip