Neumann Vintage U87 Clone : Build Thread.

[solarplexus]

Hi, I am wondering which one of the capsules are best for this project?  The Peluso or the Microphone Parts?  Quite a bit difference in price... is there quite a bit difference in quality?

 

[tskguy]

Solarplexus,

There is anther option as well, here is a shameless plug for my capsule. It's made by me nothing imported. Here is slink to my white market thread. There are some sound clips for you to check out.
The peluso as well as the microphone parts are both Chinese imports although peluso claims on re skinning them here in the states.
http://www.groupdiy.com/index.php?topic=49859.0

Please send me a pm if your interested.

 

[lolo-m]

Hello,

I'm trying to source the pattern and pad/filter switches for poctop or chunger's switch pcbs and I found these switches on mouser. Can anyone tell me:

Will this work as the pattern switch?

http://www.mouser.com/ProductDetail/CK-Components/ET03SD1ABE/?qs=sGAEpiMZZMtn8lxF5bBjIQWcN3oQfoXv

Will this work as the pad/filter switch?

http://www.mouser.com/ProductDetail/CK-Components/ET01MD1ABE/?qs=sGAEpiMZZMuIC3ROaEqRYe45DaHRdpBu

Thanks,

-Kevin

First of all Chunger is selling his donnor bodys with switches. The only thing you can regret is the length of the actuator part. The switches are too long IMO and even if they are a lot more easy to activate I don't like very much the aesthetic of those actuators getting to much out of the body.

As I am going to make an order to Mouser I will try those ones that should fit perfectly and I will tell you if they does or not :
patern : http://fr.mouser.com/ProductDetail/CK-Components/ET03MD1ABE/?qs=sGAEpiMZZMvudeGI7i40XCtw4Fd8ZUmCnC%252blw%2fFanIU%3d
pad / filter: http://fr.mouser.com/ProductDetail/CK-Components/ET01MD1AGE/?qs=sGAEpiMZZMvudeGI7i40XCtw4Fd8ZUmCSL%252bogZhXbYQ%3d

They are meant to work under 20v but we don't have any power there so I think they should be OK. If someone doesn't agree feel free to post about this. Thanks !

I received the switches today. I will test them in a few hours to know if there's nothing wrong with audio but size is a lot better IMO

 

[lolo-m]

First of all Chunger is selling his donnor bodys with switches.

The only thing you can regret is the length of the actuator part. The switches are too long IMO and even if they are a lot more easy to activate I don't like very much the aesthetic of those actuators getting to much out of the body.

Mouser sell those switches that only get out of the body of 2mm (vs 4 with Chunger's) :
PATTERN switch (x1) : http://fr.mouser.com/ProductDetail/CK-Components/ET03MD1ABE/?qs=sGAEpiMZZMvudeGI7i40XCtw4Fd8ZUmCnC%252blw%2fFanIU%3d
PAD / FILTER switch (x2): http://fr.mouser.com/ProductDetail/CK-Components/ET01MD1AGE/?qs=sGAEpiMZZMvudeGI7i40XCtw4Fd8ZUmCSL%252bogZhXbYQ%3d

They are meant to work under 20v but we don't have any power there so I think they should be OK.
I tested them and they work. I don't think they'll break but I can't be really affirmative, even if I doubt the few µA going into them are able to destroy them but who knows ??? I will use them and keep Chunger's switches for something else or as spares !

 

[wave]

Hi, I am wondering which one of the capsules are best for this project?  The Peluso or the Microphone Parts?  Quite a bit difference in price... is there quite a bit difference in quality?

Dude,
Get one of Eric's (tskguy) capsules. You won't regret it.

 

[neonwitch]

Hello,

I am working on version 1.2 of this PCB.  I noted that there are 3 solder pads for R11.  Does leg 3 still need to be clipped off and leg 2 bent to fit into solder pad 3?  There does not appear to be a trace going to solder pad 3.

I am biasing using my DAW oscilloscope.  Changing the value of R11 does not appear to have any effect on the sine wave or the sound of the tone.  The potentiometer at r11 is functioning normally according to my DMM.  The sine wave is distorted and of low amplitude when the probe grounds are attached to the mic ground rails, and normal when the probe grounds are lifted.

When I was trying to determine JFET IDss, I shorted the wrong two legs together when hooking them up to a 9v battery.  Would this have fried the FET by biasing it in the wrong direction?  Also, when I was soldering a component, I accidentley let the soldering iron rest on the transistor for approx. 3 seconds.  It seems that the first place I need to look for a fault is the FET.  Based on this information, would you agree? 

Any help would be greatly appreciated.
Thanks,
Greg.

 

[poctop]

Hello,

I am working on version 1.2 of this PCB.  I noted that there are 3 solder pads for R11.  Does leg 3 still need to be clipped off and leg 2 bent to fit into solder pad 3?  There does not appear to be a trace going to solder pad 3.

I am biasing using my DAW oscilloscope.  Changing the value of R11 does not appear to have any effect on the sine wave or the sound of the tone.  The potentiometer at r11 is functioning normally according to my DMM.  The sine wave is distorted and of low amplitude when the probe grounds are attached to the mic ground rails, and normal when the probe grounds are lifted.

When I was trying to determine JFET IDss, I shorted the wrong two legs together when hooking them up to a 9v battery.  Would this have fried the FET by biasing it in the wrong direction?  Also, when I was soldering a component, I accidentley let the soldering iron rest on the transistor for approx. 3 seconds.  It seems that the first place I need to look for a fault is the FET.  Based on this information, would you agree? 

Any help would be greatly appreciated.
Thanks,
Greg.

could you post a picture of your boards  in question ,  trying another FET after this process might be a good idea,
Dan,

 

[neonwitch]

here is the board, as requested

 

[neonwitch]

and the backside...

 

[poctop]

you pot should be install with the 3 legs in the 3 small hole you actually have it right there,  only need 2 leg for the pot both it does not matter if you have them all soldred ,  the active legs have traces from the boards,

the thing with biasing is that you have to have your mic output wired in order to supply the mic ciurcuit with the phantom power ( 48V) if not then the circuit is not powered on    Let me know if this helps,
Dan,

 

[wave]

the thing with biasing is that you have to have your mic output wired in order to supply the mic ciurcuit with the phantom power ( 48V) if not then the circuit is not powered on    Let me know if this helps,
Dan,

There's your problem! Haha! I'm totally kidding as I almost forgot this same thing on the last mic I built before I went to test it!

Dave

 

[kjdemarest123]

How do I wire the patterns on my PCB if my mic only has two options, an omni and hypercard (no figure 8)?

Also, my capsule only has three wires: FC, BC, and a body wire. Which label should I solder the body wire to?

 

[poctop]

How do I wire the patterns on my PCB if my mic only has two options, an omni and hypercard (no figure 8)?

Also, my capsule only has three wires: FC, BC, and a body wire. Which label should I solder the body wire to?

What capsule do you have ?
Dan,

 

[kjdemarest123]

For now I'm using the capsule that came with the donor mic I purchased (Stageworks LD3). I do not know the capsule specs. I was planning on purchasing one of the capsules you have listed on the first page of the thread, but wanted to hear what the original capsule sounded like before making this purchase.

 

[poctop]

How do I wire the patterns on my PCB if my mic only has two options, an omni and hypercard (no figure 8)?

Also, my capsule only has three wires: FC, BC, and a body wire. Which label should I solder the body wire to?

Then,  there a jumper of 3 pin for the pattern labeled PT or P depending on your version  ,    if you short the pin 2-3 = omni , if you short pin 1-2 = figure 8 , when there is no short or basically the 3 pin are isolated from each other it is cardiod

now you have a capsule that will make cardiod only so dont bother wiring the switch for now  the mic will be in cardiod with nothing wired.

connect the capsule in the FC section =  and then connect front diaphragme to  FD pad and the backplate "body" to FBK pad  and leave the back diaphragme unconnected and put some Shrink tube at the end .

Hope this helps,
DAn,

 

[kjdemarest123]

Great! Very helpful. Thank you!

 

[ramshackles]

Hi,
I've finished my u87 and it seems to work well except that I get loud pops when I flick the switches.
I'm guessing I have some kind of grounding problem, or perhaps a general wiring problem?

I just used bits of bread board to attach the switches to the body..perhaps that isn't the way to go (Chunger seemed to have a nice switch PCB on his build thread...that available anywhere?)

Here is how I wired the pattern select switch, looking at it from the bottom:

Here are some shots of the switches:

 

[poctop]

Hi,
I've finished my u87 and it seems to work well except that I get loud pops when I flick the switches.
I'm guessing I have some kind of grounding problem, or perhaps a general wiring problem?

I just used bits of bread board to attach the switches to the body..perhaps that isn't the way to go (Chunger seemed to have a nice switch PCB on his build thread...that available anywhere?)

Here is how I wired the pattern select switch, looking at it from the bottom:

Here are some shots of the switches:

When you flip the switches and the pattern are responding appropriately , they you are fine ,  the loud pop is absolutely normal and the original does that also
it is because the capsule sees a sudden change in polarisation voltage and it is absolutely normal in this circuit ,

the Switch PCB are available trough Chunger White thread or you can have some from me if you desire , 
here http://www.groupdiy.com/index.php?topic=50015.0
well congrats for the DIY switching thing , 
Best,
dan,

 

[neonwitch]

Hello,

I biased the FET using the listening method and was able to find the sweet spot fairly easily.  I measured 11.5v at the FET drain after I had found this spot.  The mic does pass signal, but is very noisy with random popping.  Turning on the pad or high pass has no effect on the pops. If I tweak R11 past the sweet spot so that I measure >26v at the drain, the pops disappear.  The noise floor is still very high though.  Also, when the drain voltage is set to 11.5v, I only have 11v at the zener.  When R11 is set too high, the zener voltage is correct.  I have cleaned both sides of the board with isopropyl alcohol and toothbrush.  I did not use styrene caps for this build.  Is the transistor shot, or is there a problem with one of the components?

thanks,
greg

 

[poctop]

Hello,

I biased the FET using the listening method and was able to find the sweet spot fairly easily.  I measured 11.5v at the FET drain after I had found this spot.  The mic does pass signal, but is very noisy with random popping.  Turning on the pad or high pass has no effect on the pops. If I tweak R11 past the sweet spot so that I measure >26v at the drain, the pops disappear.  The noise floor is still very high though.  Also, when the drain voltage is set to 11.5v, I only have 11v at the zener.  When R11 is set too high, the zener voltage is correct.  I have cleaned both sides of the board with isopropyl alcohol and toothbrush.  I did not use styrene caps for this build.  Is the transistor shot, or is there a problem with one of the components?

thanks,
greg

hard to say quick but , i would suggest you measure all the reference voltage according to the schematic the important point ,

The zener Voltage  should be 24V ish no matter what the drain value is or bias . set R11 reach ,  i might looks like somthing is loading down all the voltage from the Zener or the Zener is shot (this component is very sensitive  been there done that that is why there is 3 in the BOM in case of accident ) and at this point there is just no regulation or a super current drain ,  , checking the voltage reference and trying to make a logic out of it before starting replacing component is always best,  i really would suspect the Zener integrity here.

Keep us posted,

I will be out for next week in vacation  , I will check on you when i return.
Best,
Dan,