Neumann Vintage U87 Clone : Build Thread.

[Splunge]

I checked the switch and wires and everything there seems correct - no shorts or unwanted grounding. The switch works fine. I can't check the 560pf capacitor because my meter doesn't go that low - although it is not shorted. I'll just have to change it and see...

 

[poctop]

Attention : Attention  :   Since some of the builder had problem sourcing the Polystrene capacitor and some of you had issue with their fragility i decided to removed the reference to them in the Mouser BOM ,  also since the original voltage rating is somehow close to limit i decided to include a Reference to much Higher Voltage rating for those Styrene capacitor now they will be rated at 630V and the sourcing of those parts will be directed for all styrene capacitor to Just Radios Site ,  I have included a orderform Pre-Filled for the
- 10pf Styroflex/630V
- 220pf Styroflex/630V
-470pf Styroflex/630V ,

here is a pre/qty filled orderform from Just Radios ,  the Voltage rating will not affect the package on the board as they are exact in size.
http://justradios.com/
https://cdn.groupbuilder.com/groupdiy/u/39511/58d0281993853

Thanks For your cooperation.

 

[dandeurloo]

I got my pair running and sounds great.  Bias makes a huge differences!

 

[JamesW]

I have 1 mic completed and sounds good the gain is in the range of sm7 so that is no problem and no noise. But we have very loud pops on switch changes. Anyone else with this issue? If the pattern switch was make before break this would help it I think. Any thoughts.

 

[HellfireStudios]

It is standard operating procedure to turn down the gain on the mic preamp when switching patterns. It has been since the U-47. Most multi-patterned mics pop loudly.

It sounds to me like your work is done. Have fun with your new mic.

-James-

 

[JamesW]

It is standard operating procedure to turn down the gain on the mic preamp when switching patterns. It has been since the U-47. Most multi-patterned mics pop loudly.

It sounds to me like your work is done. Have fun with your new mic.

-James-

Yes we do turn down the gain this mic just seemed extreme and the m/b/b switch may help the pattern.

 

[poctop]

I have 1 mic completed and sounds good the gain is in the range of sm7 so that is no problem and no noise. But we have very loud pops on switch changes. Anyone else with this issue? If the pattern switch was make before break this would help it I think. Any thoughts.

Dont Worry James ,  as the original neumann does exalctly the same thing,  not pleasant but totally normal,

 

[atticmike]

[size=14pt]EXTREMELY HUGE NEWS!!!![/size]

I went to Guitar Center to get a shockmount for my mic. Whenever I have to buy anything from GC I buy from the GC Pro sales person at my local store as he can give me much better discounts than the regular staff.

So I called him up to see if they had a mount I could use and they did. I asked if he wanted me to bring the mic in to have a listen. He did.
I showed him the mic and I could tell, since it's still the bare brass and no logo yet, that he was a little unimpressed.
He showed it to a couple other sales people there and they decided that not only did they want to listen but they wanted to A/B my mic with a brand new Neumann U87 AI.
So we all go into the studio room where they have their computer recording gear set up and they plugged in the Neumann to a Focusrite Saffire.
We did some checks and some singing into the mic. Sounds like a U87 because it is.
Then we plugged in my mic.
Their faces showed astonishment. All 3 GC guys liked my mic way better. They commented on how warm and silky it sounded. "It sounds like a tube mic" was the phrase associated with my mic.
Now they want me to do a limited production of them and sell them in the store. I said I had to think about that.
They all want me to build them one!
I am sold on the RK-87. I think the capsule is intrinsic to the sound I'm getting. That and the combo of the styrenes and T-13 has yielded one very sweet mic and now I have the experience of putting it up side by side with a real U-87.

Great project Dany. You have given us the ability to make a great sounding unique microphone!

Also, I explained to them how I could use different components (capsule, trafo, caps..etc) to shape the sound of the mic differently and they all agreed that I should change nothing.



Dave

what auricycle body were you using for your build? Any additional stand you got for the capsule?

Well, if they prefer it over an original neumann, it must be good sign.

You know I started to cudgel my brains over the sonic injury I'd be having if I didn't use the original headbasket and so on. Now that you've told that story, which I hope is true to its core, things won't be as bad as I thought they'd be.

Looks like most of you guys were drawn to the switchless body whysoever? I guess you chose by the headbasket shape?

--

In addition to that, I've checked geekmacdaddy's samples and I gotta say that the clone completely lacks the sheen created by the U87.

--

What are your thoughts on using a U47 type of body / headbasket for the microphone? Wouldn't it grand the mic a little more hf which the U87 could use?
I don't think it'd destroy the mic's vibe since there've also been U47 in u87 type of bodies by Neumann.

 

[poctop]

Have you been able to bias the FET with a scope just to let you know that 11.5V is an average and your FET  may operate at up to 13V  ,  If not try to bump that voltage up to see what happens ,

Hope this helps,
D

 

[atticmike]

I have 1 mic completed and sounds good the gain is in the range of sm7 so that is no problem and no noise. But we have very loud pops on switch changes. Anyone else with this issue? If the pattern switch was make before break this would help it I think. Any thoughts.

Dont Worry James ,  as the original neumann does exalctly the same thing,  not pleasant but totally normal,

in the range of an  sm7 ? oO

 

[geekmacdaddy]

Hi Everyone,
I have a new clip of my '87 clone. I sent my capsule back to tskguy for a rework, and I am sooo happy now! Thank you Eric for tuning this wonderful capsule to where it is. If you were on the fence about buying from Eric, check this clip. No pop filter, so there's one pop...

https://dl.dropbox.com/u/87086401/Capsule%202%20U87%20Clone.wav

 

[wave]

Night and Day. Eric  spent a lot of time on the new version and it sounds like it's paying off. I'm getting mine re-spanked to the new style.

Dave

 

[kevinkace]

Some questions regarding the build (V1.1).
- For connecting AA->A, BB->B etc, reg mic wire will do? Do they need be twisted in certain pairing?
- What are the pads labeled GNDLINK, CGND, RT and SW to be connected to/used?
- Can the transformer iron short to the chassis?

related to iSK BM-600
- Are the components on the switch daughter board necessary for this build, or should they be scrapped, and connect directly to the switches?
- What's a good way to connect the boards to the switches/capsule? Originally it has jumpers on the PCB that insert into the switch PCB.
- A good way to hold the transformer in place? (check 5th pic)
- How do you determine how to hook up the switch (ie which pads to what part of each switch)?

I'm quite new to this, so please forgive my ignorance.

Original Boards


New Board


iSK BM-600 switch



New board in BM-600 with Cinemag transformer


Gallery
http://imgur.com/a/n9xRN

 

[geekmacdaddy]

Here's a clip of me singing the same song into a real U87a

https://dl.dropbox.com/u/87086401/U87.aif

 

[sr1200]

Kevin, I scrapped all the components except the switches and connected the switches directly to the main board.  Works great!  (just make sure to wire the leads to the right sides of the switches otherwise they will operate backwards like mine fist did  :-[

 

[Volume11]

Anyone know where I can get an alternative for this (2N3819_D74Z) part number? Mouser is out and I cant seem to find a place that has them in stock. Ebay has them but they are in Thailand, which I am skeptical about. I'll go the ebay route if its my only option. Thanks

 

[poctop]

Right Here,

http://ca.mouser.com/ProductDetail/Central-Semiconductor/2N3819/?qs=sGAEpiMZZMutXGli8Ay4kAHmCxIxFTXSHfCId7bMyjI%3d

Or : http://www.ebay.com/sch/i.html?_nkw=2N3819&_sacat=0&_odkw=@N3819&_osacat=0

I have updated all FET the BOM ,
DAn,
\

 

[Volume11]

Right Here,

http://ca.mouser.com/ProductDetail/Central-Semiconductor/2N3819/?qs=sGAEpiMZZMutXGli8Ay4kAHmCxIxFTXSHfCId7bMyjI%3d

Or : http://www.ebay.com/sch/i.html?_nkw=2N3819&_sacat=0&_odkw=@N3819&_osacat=0

I have updated all FET the BOM ,
DAn,
\

Thank You! Man, you're quick

 

[kevinkace]

...connected the switches directly to the main board.

Thanks!
I'll try to get the orientation of the switches correct, not sure how to tell though.

 

[poctop]

Some questions regarding the build (V1.1).
- For connecting AA->A, BB->B etc, reg mic wire will do? Do they need be twisted in certain pairing?
regular wire you do just fine  but you may want to use telfon insulated as it does a nicer job , if you fell you could go up to silver conductor but  more $


- What are the pads labeled GNDLINK, CGND, RT and SW to be connected to/used?
the big RT and SW is an input signal for checking the pre and other stuff check the schematic
- Can the transformer iron short to the chassis? yes ,
most of transformer have even core grounding wich is CGND pas GND link is for utility purpose if you can't find a mounting hole or want to shield something like a switch board or anything else ,
hope this helps,
D