D-87M Build By Andrew Schaapdsa

 

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As a musician and recording enthusiast, I have sought to achieve better recording results by using several different microphones. Until the recent surge of the DIY movement, many of the most highly sought after microphones were out of reach for a typical consumer. The recent DIY explosion has made owning one of these incredible microphones a reality. This is a step-by-step approach to making a clone of a vintage Neumann u87 microphone. More information on the microphone can be found here:

http://recordinghacks.com/microphones/Neumann/U-87

Ok, lets get started. First, we source our parts. Keep in mind there are several different places to get microphone bodies and parts but these are some of the current favorites. The PCB:

http://www.vintagemicrophonepcbkit.com/DU87.html

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The pcb version I chose is the D-87M. This is the latest version of the PCB at the time of this writing and fits the SYT5 body. There is a bill of materials (BOM) listed at the top of this site that should be current as well. Click on the order menu on the top of the site and make your selections under the Vintage Microphone PCB D-U87 Project. Select the following:

1. D-U87M (Blue) (Switch PCB Not Included)

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2. Switch PCB (Blue) For D-U87M

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I also opted for the StyroFlex Capacitor Kit for U87 Buid (ALL)

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The microphone body:

http://store.studio939.com/product/syt-5-microphone-body-kit

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On the drop down box on the order page for the SYT5, select body kit 3 pin.

This will include the 3-pin XLR insert for the microphone.

I used the Cinemag transformer for my build.

http://store.studio939.com/product/ami-microphone-transformers

From the dropdown box select: Cinemag CM 13113.

 

When I ordered there was a shockmount option available from Studio939s store as well. At the time of this writing, only the U47 mount was available.

 

For the capsule I ordered from Eric Heiserman. Eric can be contacted over at groupdiy.com. His handle is tskguy. Just ask him for pricing and time table. Capsules are also readily available from Peluso. P-K87i capsule 

 

The hardest part is waiting for the parts to arrive. Before we begin populating the PCBs, a few words of advice. Make sure to use a good soldering iron. I picked up a temperature-regulated iron from Radio Shack. Its not cheap but it performs a lot better than some of the cheap irons Ive tried in the past.

 

https://www.radioshack.com/radioshack-digital-soldering-station/6400053.html#start=2&q=soldering%2Biron&sz=12&srule=price-high-low

Also, invest in a good n0-clean solder. It will make your life a lot better.

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Next, R18 and R19 need to be matched to within 4% of each other. My multimeter doesnt have this sensitivity so I followed a method I learned about from Chungers build thread called a wheatstone bridge.

http://www.head-fi.org/t/295983/tutorial-how-to-match-resistors-up-to-0-01-using-a-cheap-dvm

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The black and red leads are extensions from my multimeter while the yellow goes to the 9v battery negative lead and the green goes to the positive side. I had to swap about 8-10 resistors out before I found a match which ended up being 2.188k.

Now Im ready to start populating the PCB. I start with the resistors and diodes and work my way up to the capacitors and larger components.

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The yellow tantalum and blue electrolytic capacitors have polarity so make sure the + and - go in the right holes on the pcb.

The isolating pin on the main board gets pressed into GG on the pcb. Also notice that the middle leg of the black JFET gets attached to the isolating pin and not the through hole on the PCB.

 

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The smaller board gets populated next. Note that only one leg of R7 gets placed in the through hole of the PCB. The other end gets attached to the isolating pin that goes in the hole labeled g. Also notice that the cap next to the isolating pin has a leg attached to the isolating pin as well and not the through hole.

I wait to place R4 and R5 on the PCB until last. These are sensitive to fingerprints and getting bodily oils can change their value. I use gloves from this point on.

Next its time to connect the two pcbs to each other. They are connected with 4 wires. I use 26 gauge silver teflon wire. This wire is readily available in a variety of colors from eBay. The thin gauge keeps micro-phonics to a minimum.

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The boards are connected as follows:

a aa

b bb

c cc

isolation pin isolation pin

I solder the wires from the back of each pcb to keep things looking clean. Be sure to keep some slack in the wire if you need to take the boards apart in the future for trouble-shooting.

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And the connected wires to connect the switch pcb. I connected the wire to the isolation pins at the base and cut off the excess pin length.

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Next I populate the switch pcb with the switches. Two of the switches are two- position while the third is three-position for the polar patterns. Make sure this goes in the PAT slot. I solder the middle pin on each switch first so I can make any final alignment adjustments to the switches before soldering the rest of the pins.

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Wire up the switch PCB next. Again, leave a little extra length in the wires to allow for possible troubleshooting in the future.

OMN PAT 1

CRD PAT 2

8 PAT 3

PAD PAD holes 1 & 2

LC LC holes 3 & 2

Next I wire up the transformer. I have the Cinemag CM 13113:

red p+

brown p-

yellow s+

orange s-

I feed the yellow and orange wires through the opening in the pcb before working the transformer into place. Its a snug fit. The red and brown wires I feed through the hole next to the solder points for the transformer so I can solder them all from the back side.

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Then I take zip ties and secure the transformer to the pcb so it doesnt fall out when that cheap microphone stand you havent bothered to upgrade collapses and your u87 clone falls to the floor.

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Now its time to connect the switch pcb to the frame. Take the washers and spacers and fasten them.

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Next I wire up the 3-pin xlr insert.

1 1

2 2

3 3

I use a little heat shrink on the connections as well to tidy things up.

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Alright! Its time to pump a little 48v phantom power into this baby to see what we have cookin! Connect your mic preamp of choice, preferably one that works, and turn on the phantom power. Were going to calibrate the drain on the microphone to 11.5 volts. Take your multimeter and put the red probe on r6. This is right next to the FET. Take your black probe and put it on the ground hole. Take a small flat-head screw driver and tweak the pot until you measure 11.5 volts.

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Now for the capsule installation. Hang in there, were getting close.

The spacing isnt quite right for the capsule on this mount so I also had to drill some extra holes.

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In my effort to extend one of the holes because it wasnt quite where it needed to be, I exerted a little to much power and the drill slipped out the side.

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The screw still held well so it wasnt too bad of a mistake.

My capsule is tskguys capsule. The wiring to the capsule is as follows:

RBK Rear Backplate

RD Rear Diaphragm

FBK Front Backplate

FD Front Diaphragm

There is no front to the capsule as both sides are identical, so just choose the side thats the most beautiful. The capsule comes with (2) wires and screws. Use the screws to fasten the wires to the backplate.

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Next Im ready to fasten the PCBs to the frame of the microphone body. For whatever reason I didnt have screws that came with the body. I found these at Home Depot and they worked well. Youll need (8) total screws.

 

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Oh, did I mention I built two? Gotta have a pair of these babies.

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If I had to do it again Id probably make the switch wiring a bit shorter. I probably made them a bit longer than necessary but I doubt if these will effect the sound of the mic. The capsule wires are probably more critical here and they arent too long.

They both worked from the start so I figure with my level of expertise I may have gotten lucky. The sound? Well, they sound un-hyped. The are very smooth on the top end with a nice, well balanced low end. Im very happy with them. Best microphones I own without a doubt.