geekmacdaddy

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #240 on: April 11, 2012, 09:37:22 AM »
Greetings All! So excited to have ordered the boards, and to start the project, using the a460 just like Dany did. BTW Thank you for all the work you put in, Dany, and rest of the community. Aside from the biasing mysteries that lie ahead, I too was wondering if there was a pattern switch I could leave internally? If not, I have a busload of 47pf ceramic disc caps from pedal building in a drawer. Would that suffice for 51pf? Ultimately, I'll be using this as a vocal mic, so cardioid really is fine, I just want to explore the options.

Thanks!
Geek


Re: Neumann U87 Vintage Circuit Build Thread
« Reply #241 on: April 11, 2012, 12:09:12 PM »

Cool!Did you monitor/measure with the transformer installed?I wonder if I should do the biasing with my scope connected to the trafo primary pins on the pcb.Will check over the weekend and report back.

I did the bias procedure with no capsule or transformer installed. I followed Matador's instructions - xlr connected with 48V from preamp, test tone from DAW into C4, scope probe connected to fet drain, grounds connected to body. And the T13's unexpectedly showed up at my door just minutes after I finished biasing. ;D


Quote
Concerning the U89:I used them a lot in the late 80s to the early 90s,especially for classic recordings.Awesome microphones,but really completely different in sound.More direct sounding,more highs,absolutely different from an U87.It has a smaller capsule and different filtering as well as 5 polar patterns and 2 step hpf from what I remember so far.

I used to use them a lot, picked them over the U87s much of the time for instrument duties. But it's been over ten years since I've had my hands on one so I don't remember much of the details. Just looking at the model numbers and mic bodies suggest that a U87 and U89 would be similar beasts, but I guess it would be a different project altogether. Maybe one day.

Greetings All! So excited to have ordered the boards, and to start the project, using the a460 just like Dany did. BTW Thank you for all the work you put in, Dany, and rest of the community. Aside from the biasing mysteries that lie ahead, I too was wondering if there was a pattern switch I could leave internally?

FWIW, I find it easy enough to use the jumpers included in the mouser cart to switch patterns if you are leaving the switching internal. Seems like trying to find and fit a switch on the board would be more hassle than it's worth. Just keep the bag of jumpers in the case with the mic and you're good to go.

And to reiterate a point somebody else made- if you are using the Aurycle body with the Peluso capsule you will have to drill out the holes on the capsule mount to get it to fit. Be careful.

0dbfs

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #242 on: April 11, 2012, 01:04:51 PM »
I wonder if there is a suitable DIP style switch that may fit on the PCB. I don't mind keeping my greasy-grubby-paws off the PCB and using some needle-nose to place the jumpers but when it's out of my hands anything is possible, probably, and even likely.

Cheers,
jb
Music is everything!
Audio is everything else!

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #243 on: April 11, 2012, 01:32:58 PM »
just got my set of boards in! they look fantastic dan!
Adam
only got here by owning a soldering iron and bad life decisions.

xqtion

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #244 on: April 11, 2012, 02:10:37 PM »
Could anyone let me know how to wire the capsule for just cardiod pattern ? My capsule is a k67 type with just 3 wires (front, back, ground).

Thanks!!
John 3:16

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #245 on: April 11, 2012, 02:47:22 PM »
Could anyone let me know how to wire the capsule for just cardiod pattern ? My capsule is a k67 type with just 3 wires (front, back, ground).

Thanks!!

in the FC section solder the front diaphragme to (cap) pad and the backplate to (bdy) pad, you can try both side if you want and take the one that sounds best to your ear  ;D just leave the extrawire unsoldered with a mini shrink wrap
Dan, 



 

xqtion

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #246 on: April 11, 2012, 03:10:49 PM »
Ok understood~ thanks!! 
John 3:16

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #247 on: April 11, 2012, 04:52:27 PM »
Quote from: adeptusmajor link=topic=48030.msg609849#msg609849 date

I did the bias procedure with no capsule or transformer installed. I followed Matador's instructions - xlr connected with 48V from preamp, test tone from DAW into C4, scope probe connected to fet drain, grounds connected to body. And the T13's unexpectedly showed up at my door just minutes after I finished biasing. ;
Great!Does that mean that if I start biasing immediately the T13s will show up tomorrow? ;D

Cheers,

Udo.

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #248 on: April 11, 2012, 05:02:33 PM »
I wonder if there is a suitable DIP style switch that may fit on the PCB. I don't mind keeping my greasy-grubby-paws off the PCB and using some needle-nose to place the jumpers but when it's out of my hands anything is possible, probably, and even likely.

Cheers,
jb
Hi jb,

Hmmmmm....dip switches normally have either on or off position,they do not toggle.Also you want a center off position.I think if using a jumper with a small grip(?) on top of it could do the job:
It can be left in "park" position meaning just plugged to the middle pin for cardioid mode.This way it will not fall off the pin I bet.

Hope to have helped,

Udo.

Edit:I mean a jumper like this one:
http://www.reichelt.de/Stiftleisten/JUMPER-2-54GL-RT/index.html?;ACTION=3;LA=444;GROUP=C141;GROUPID=3220;ARTICLE=9018;START=0;SORT=user;OFFSET=16;SID=10T4NaaX8AAAIAAFA2Vmc8ea8dd0489375da635914b98337cee02
« Last Edit: April 11, 2012, 05:06:23 PM by kante1603 »

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #249 on: April 11, 2012, 05:37:25 PM »
Quote from: adeptusmajor link=topic=48030.msg609849#msg609849 date

I did the bias procedure with no capsule or transformer installed. I followed Matador's instructions - xlr connected with 48V from preamp, test tone from DAW into C4, scope probe connected to fet drain, grounds connected to body. And the T13's unexpectedly showed up at my door just minutes after I finished biasing. ;
Great!Does that mean that if I start biasing immediately the T13s will show up tomorrow? ;D

Cheers,

Udo.


YES!!!


kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #250 on: April 11, 2012, 05:49:12 PM »
Quote
YES!!!
COOL!!! ;D ;D ;D

xqtion

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #251 on: April 12, 2012, 02:53:10 AM »
Hi, now that I'm a lost done with the build, I'm going to do the FET biasing.
I have no scope so I'll just be doing the drain measure method to get it to about 10.5V or so.
So where exactly on the mic is the drain that everyone is talking about ? Do I measure it using my DMM ?

I went thru the whole thread but couldn't find this info.

Thanks!!
John 3:16

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #252 on: April 12, 2012, 03:36:25 AM »
Hi, now that I'm a lost done with the build, I'm going to do the FET biasing.
I have no scope so I'll just be doing the drain measure method to get it to about 10.5V or so.
So where exactly on the mic is the drain that everyone is talking about ? Do I measure it using my DMM ?

I went thru the whole thread but couldn't find this info.

Thanks!!

xqtion

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #253 on: April 12, 2012, 03:41:30 AM »
Thank you!!

Bare with me, so when I measure with my DMM, do I put both red and black test pins on pin 1 of the transistor ?
John 3:16

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #254 on: April 12, 2012, 03:48:08 AM »
Thank you!!

Bare with me, so when I measure with my DMM, do I put both red and black test pins on pin 1 of the transistor ?
Please get familiar with some basics and look how to measure with your dmm.I bet it is all written in the manual.
For now do as follows:
Set your dmm to read vdc.
Connect the probes  to the corresponding jacks on your dmm.
The red probe connected to drain,the black one to 0v which is on several pcb points as well as on the mic case.

Udo.

xqtion

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #255 on: April 12, 2012, 04:32:41 AM »
Got it thanks!!  :)
John 3:16

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #256 on: April 12, 2012, 04:56:47 AM »

xqtion

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #257 on: April 12, 2012, 08:10:43 AM »
Ok another beginner question.

When biasing just using DMM, do I just connect the mic to a pre and then turn on 48V phantom power?
John 3:16

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #258 on: April 12, 2012, 08:34:20 AM »
Ok another beginner question.

When biasing just using DMM, do I just connect the mic to a pre and then turn on 48V phantom power?
Yes,you need the phantom power.

xqtion

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #259 on: April 12, 2012, 08:36:08 AM »
Ok thank you!! :)
John 3:16


 

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