Neumann Vintage U87 Clone : Build Thread.

[kante1603]

Thanks Udo,
the primary reads 1k4 and there is any connection between them.

You mean there is no(!) connection between them,right?So all seems good with it,cool.

I just didn't understand what I must do with the wiper of trim?

The pot replaces the fixed resistor,you can leave it in after biasing.
So you just need to cut off one of the outer pins of it.
Best way to start is measure between the both pins and wind the pot up to full resistance.
Then solder it in,some pin bending might be necessary.Start from here.
Don't know what boards you have,I jad the old taper ones.Mounting the pot was a bit tricky but doable when prepared well.I have a pic of how I did it on all my mics here.

Best,

Udo.

 

[Pip]

Thanks Udo,
the primary reads 1k4 and there is any connection between them.  ???
I just didn't understand what I must do with the wiper of trim? Do I need to connect it to grnd during testing?
Thanks

Looks about right.What about the primary,should read higher,some hundred ohms or so.
And is there any connection between it and the secondary?

Udo.

The only thing you should connect with the trim pot is the wiper and one of the coil tails the other should be left floating. Thats only 2 connections the otherside of the resistive element is not used. It is to get the right resistor value for your FET bias so should be variable. You can leave it in as others have suggested. I did.

                                   
                          Connect  _/\/\/\/\_  Not Connected
                                                ^
                                                |
                                              Connected

 

[poctop]

Tutorial Document Thanks to Udo  (Kante1603) on how to wire the B2 Pro switch board Here:

https://cdn.groupbuilder.com/groupdiy/u/39511/58d0281993ee2.pdf

hoping this will help some folks along the way ,

Best,
Dan ,

 

[fred]

Thanks Dan, my clone is working great.. I put the pcb in a B2 Pro. The body is a bit small but it's the body I have at the moment. I used the B2 Pro capsule (only cardio) to try out the PCB and I am waiting for a capsule from Eric.
Encore merci

 

[jandoste]

Hi Dan&Udo,

Thanks for your replies!
I really can't find any solution for the hummm  tried everything but no chance! I think it's really stupid thing that I forget but can't find the problem! I got 11.04V and everything looks right!
I uploaded some pictures maybe you can tell me what's happening with my build,
Thanks

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[poctop]

Hi Dan&Udo,

Thanks for your replies!
I really can't find any solution for the hummm  tried everything but no chance! I think it's really stupid thing that I forget but can't find the problem! I got 11.04V and everything looks right!
I uploaded some pictures maybe you can tell me what's happening with my build,
Thanks

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in wich context you mic is humming ,
did you have the mic sleeve on and the headbasket also because if not this will humm crazy picking up all the RF arround and more...

it seems that you have an old version of the board i would sugest to replace the pot with a resistor so it will fit better in the mic sleeve just remove the pot and measure resistance between the 2 pin on the pot that are soldered on the pcb and find an near equivalent resistor and try again with the headbasket and sleeve on

hope this helps,
D

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[kante1603]

Having the sleeve on is mandatory here,so check that first.
While assembling look if the pot is touching the metal tube,it shouldn't.
After full assembly check all metal parts to pin 1 on the xlr,you must have a resistance very close to zero ohms everywhere (so the bottom part,the metal tube and-very important-the headbasket).
If your dmm reads anything far off from zero then check which part doesn't connect to his neighbour part.Sometimes there is some leftover paint or so causing it.

Tell us what you get,

best,

Udo.

 

[jandoste]

Solved, Solved, Solved, Solved | Thanks Dan and Udo
Bingooooooooooo
You were right Dan! Thanks Dan & Udo!
I put a resistor(10K) and removed the pot there! now everything works! Awesome!

Thanks again Dan!

did you have the mic sleeve on and the headbasket also because if not this will humm crazy picking up all the RF arround and more...

D

 

[kante1603]

Congrats!

If you want to go back to a pot and have the fet exactly biased there are pots existing which are way more flat and have a side screw for trimming.I have them in all my builds,they fit very nice.

Have fun,

Udo

Edit:See my reply #1980 on top of this page,it's the pot I use always.Here's a pic of it in my very first build:

 

[HellfireStudios]

It has been months since I finished my DIY87, and I wanted to say that this is an amazing mic. For those interested I'm using the Peluso 87 capsule, Peluso BV8P-S transformer, and styrene/tantalum caps. I've used it on alt. rock, rap, singer/songwriter (both male and female), and R&B vocalists. It, in conjunction with my modded GAP PRE-73, has handled them all with a sound that is on par with major label releases. Thanks to all of you who helped get this project going (especially poctop). I can finally deliver the sound my clients hear in their heads .

-James-

 

[kante1603]

Great to hear James!

Best,

Udo

 

[KDE]

So im making a pair of these and i was hoping to get some feed back on which configuration sounds the best!

So im looking for peoples advice especially Poctop's.

My options

Capsules By:
Peluso K87
Beezneez K6
TSKGuy K87

Transformers:
TABFunken T13
Cinemag CM2480
Peluso T87

Which is the winning combo?

 

[melodeath]

If it were me, I would go BeesNeez K6 and Tab T13. This is not based on any clips I've heard or anything. Just based on what I plan to buy when I build this one. I have been happy with my BeesNeez K7 and Tab BV8.

 

[micaddict]

But the K6 doesn't have isolated backplates, does it?

 

[poctop]

It has been months since I finished my DIY87, and I wanted to say that this is an amazing mic. For those interested I'm using the Peluso 87 capsule, Peluso BV8P-S transformer, and styrene/tantalum caps. I've used it on alt. rock, rap, singer/songwriter (both male and female), and R&B vocalists. It, in conjunction with my modded GAP PRE-73, has handled them all with a sound that is on par with major label releases. Thanks to all of you who helped get this project going (especially poctop). I can finally deliver the sound my clients hear in their heads .

-James-

Once again a dear fellow diy members just made my day 
Just to say that can`t be happier to have some of those posts.
Best,
Dan, 

 

[0dbfs]

But the K6 doesn't have isolated backplates, does it?

He'll make/configure it with isolated backplates if requested. At least he has in the past.

Cheers,
jb

 

[micaddict]

Yeah, good chance Ben will do that on request.

 

[Melodeath00]

Just ask for a K8 instead of a K6.

 

[Mickey Free]

@wink0195

Hi Andrew,

Ok, I can for sure cut all the leads and solder directly to the switch pins, but which pins on the switches do I attach the 2 - 3 pin ribbon cables to so that they match up with the indicated patterns? and how do they coordinate with the pcb?

I labeled the pins "1,2, and 3" so you could easily explain via message where i should solder the ribbon leads, however, "PAD" and "LC" on the PCB aren't labled "in" and "out" either so plz just refer to them as "Pad PCB left" and "Pad PCB right" in coordination to looking at the silkscreen labels side of the pcb. do you follow me?

Also did I cut all the appropriate leads? I don't wanna short out my back plate  :'(

(Click on thumbnails to enlarge and view properly)

O.K. so far,but you must cut the trace ground to the left (pattern?) switch too.Can be done with a sharp knife,it´s easy.
One thing that is imperative here:Since I don´t know how this board is mounted inside your mic it is best to run a wire from the board ground to a good point on the pcb or the mounting rails.The switch board ground connections are connected to their metall plates surrounding the switches.These are meant as shields.If not done properly the switch knobs themselves act as an "antenna" and can pick up rf-noise.When touched you would get an ugly hum too.Quite a few guys here did this wrong from what I remember.
The big ground pad on the left (on the switch board) will serve you well.

As said I don´t know which side show upwards or downwards nor do I know how your housing s labelled.
But don´t worry,it´s an easy one!
All the what you named "pin 2" connections are used.For the HPF and the pad it doesn´t matter to which of the dual connection on the main pcb they go to.But the pin 2 of the pattern switch must go to the middle connection of the triple pad on the main pcb!

Next step is to figure out which pins (1 or 3) goes where,it´s easy again:
When looking at the labels and where the knob tips show to-it´s always the oposite outer pin that refers to it!
Think toggle switches acting like a "seesaw"(hope that is the correct english word?).
An example:The switch knob tip shows to the left means the middle pin and the outer right pin are connected (ohm that out if you want).Same on the other side,tip shows to the right means middle pin connects to the outer left pin.That´s it!
The only difference is the pattern switch that has a middle position.In this case the pin 2 simply connects to nowhere.
So for the HPF and the pad one side of the switch is unconnected,the pattern switch uses all 3 connections.
Have found a nice additional explaination on how switches work,see the second drawing:

http://www.musicfromouterspace.com/analogsynth_new/ELECTRONICS/pdf/switches_demystified_assembly.pdf

Hope it´s all clear now,you´re getting pretty close to it!

Best,

Udo

Hi Guys, this is my first post on the forum and my first DIY build. Udo, I am still a little confused as to which traces need to be cut. Are ALL of the traces on the original PCB to be cut? You said above that the ground trace to the pattern switch needs to be cut, but in the picture there are 2 traces going into the large ground plate. Are both to be cut? Thanks! I must admit, I've run into more trouble than I thought i would on this project 

 

[kante1603]

Hello,

can't remember what board you are refering to.
But it's easy,the goal is just to get the switch pins ungrounded and not connected to each other while the front pins (those connecting to the swich housings etc.) must have a good ground connection.
Ohm them out and cut traces as needed.

Best,

Udo.