pavthefiddler

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #220 on: April 09, 2012, 10:04:39 AM »
How much difference is there to the circuit if a 68Mohm is used in place of the 60Mohm?
Also, has anyone source the 10pf styrene from justradios? It's rated at 630V. Is it physically large? Could all the styrenes be that voltage rating (from a size perpective)?

Thanks
Dave

I ordered all the optional capacitors from justradios.com a while back, they should arrive here any day now. I'll make sure I'll post some photos.


kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #221 on: April 09, 2012, 10:24:01 AM »
1. The boards don't quite fit the B2 Pro body (using the existing mount points). Has anyone come up with a tidy way to secure them and connect the PCB ground to the mic body?
Me again,
while waiting for capsules and trafos I worked a bit on this.
I widened up the mounting holes to 3mm (drill gently!).You´ll loose the ground connection at this point,but that´s no biggie:
You have several ground points on the pcb,just solder a wire to them and connect it to the mounting rail-done.
Oh-there´s an interesting thing about the rails:If your soldering iron gets hot enough you can directly solder that ground wire to the rails (worked fine on my build,I used a Weller WTCPS at 50 watts).
Or you can take a small eyelet and screw it to the rail using one of the existing screw holes.
Mounting the pcbs is easy then:Just use 2 screws (I took M2,5/16mm) and 2 nuts and washers.If you want you can secure the pcbs with a drop of 2k glue or so,but I don´t think it is needed at all after tightening the 2 screws well.

BTW:Mine is hammerite blue,hahaha.....
 
Cheers,

Udo.

See attached file please!

pavthefiddler

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #222 on: April 09, 2012, 10:47:38 AM »
1. The boards don't quite fit the B2 Pro body (using the existing mount points). Has anyone come up with a tidy way to secure them and connect the PCB ground to the mic body?
Me again,
while waiting for capsules and trafos I worked a bit on this.
I widened up the mounting holes to 3mm (drill gently!).You´ll loose the ground connection at this point,but that´s no biggie:
You have several ground points on the pcb,just solder a wire to them and connect it to the mounting rail-done.
Oh-there´s an interesting thing about the rails:If your soldering iron gets hot enough you can directly solder that ground wire to the rails (worked fine on my build,I used a Weller WTCPS at 50 watts).
Or you can take a small eyelet and screw it to the rail using one of the existing screw holes.
Mounting the pcbs is easy then:Just use 2 screws (I took M2,5/16mm) and 2 nuts and washers.If you want you can secure the pcbs with a drop of 2k glue or so,but I don´t think it is needed at all after tightening the 2 screws well.

BTW:Mine is hammerite blue,hahaha.....
 
Cheers,

Udo.

See attached file please!

Hi Udo,

Thank you for the answer, it is the most helpful! I like how thorough you are documenting the whole project.

Your paintwork looks great. I only painted the tubular part of the body, but seeing your microphone I'm considering painting the whole thing. Especially now that I found out I have to change the polar pattern description anyway... Did you write it with marker and then sprayed with transparent lacquer coating? Also if that's not too much to ask, how did you make the badge?

Regards,

Pav

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #223 on: April 09, 2012, 11:04:03 AM »
Hi Pav,

Hahaha...that was a fun thing I did since UT are my initials ;D
I tried to use water decal,but failed.Decided to use printable self adhesive foil then,transparent for inkjet plotters.Covered these with clear lacquer,about 3 layers or so.
The "badge":I used an old version of Appleworks (similar to MS Works I think).
Just create a square,fill it black,create a frame arround it and rotate the whole thing to 45 degrees.
Write something nice in and you are done-no joke.

Have fun,

Udo ;)

pavthefiddler

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #224 on: April 09, 2012, 11:39:57 AM »
Hi Pav,

Hahaha...that was a fun thing I did since UT are my initials ;D
I tried to use water decal,but failed.Decided to use printable self adhesive foil then,transparent for inkjet plotters.Covered these with clear lacquer,about 3 layers or so.
The "badge":I used an old version of Appleworks (similar to MS Works I think).
Just create a square,fill it black,create a frame arround it and rotate the whole thing to 45 degrees.
Write something nice in and you are done-no joke.

Have fun,

Udo ;)

Thanks Udo, this is the most helpful.

Regards,

Pav

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #225 on: April 09, 2012, 03:29:13 PM »
Last post for today,promised ;D???
Here´s a pic where you can see a possible ground connection.

Cheers,

Udo.
« Last Edit: April 09, 2012, 04:14:52 PM by kante1603 »

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #226 on: April 09, 2012, 03:53:50 PM »
Hey Kante ,  please feel Free to post as much time you want in here as your post are very ressourcefull to Everyone,  ;)
your Mic is Awsome i also like the use of jumpers to get acces to capsule removal and try out so easy,
your an Artist,   8)
Dan,


kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #227 on: April 09, 2012, 04:12:58 PM »
Hey Kante ,  please feel Free to post as much time you want in here as your post are very ressourcefull to Everyone,  ;)
your Mic is Awsome i also like the use of jumpers to get acces to capsule removal and try out so easy,
your an Artist,   8)
Dan,
Hi Dan,

thank you very much,nice that you like it.
Yes,I love these jumper pins-they keep everything nice and clean and are easy to service.Also you´ll have no trouble with solder flux
at the bottom side of the pcb (the high impedance parts).
Some minutes ago I made an initial voltage test as you recommended.I used an original Neumann phantom supply at 48,7vdc unloaded.
My readings are:

48,5 vdc at the 2,2k resistors
23,85 vdc at top of zener
41,7 at front Backplate connection
My reference 0v was taken from a mounting rail which I had soldered to a proper grounding point on the pcb before (therefore good working solution I think).

Doesn´t look too bad,does it :D

For now I can not do anything more because of the missing (usefull) parts like capsules and trafos,hahaha....

Cheers,

Udo.

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #228 on: April 09, 2012, 04:27:31 PM »
Quote
48,5 vdc at the 2,2k resistors
23,85 vdc at top of zener
41,7 at front Backplate connection
My reference 0v was taken from a mounting rail which I had soldered to a proper grounding point on the pcb before (therefore good working solution I think).


This is right on !,  i am waiting for T13 from Tab to put it in,
thanks again for the great information you put there ,
Dan,

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #229 on: April 09, 2012, 04:36:52 PM »
Thanks Dan,
I'm going the same way,T13 and Peluso.
Really looking forward to get it to our studios and do some tests!
Bedtime now I think,it is close to midnight here and I will have some work to do with my students tomorrow,

Best regards,

Udo (yes,my name is Udo,not kante ;)).



tskguy

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #231 on: April 10, 2012, 10:17:29 PM »
Hey all,
Just a little something I have been working on for my new U87 mic. Pretty much done with the machining, I still need to finish the outer rings and the center hole. Tuning is also pretty difficult from what I understand with this capsule so I still need to work that out. I have a rig to tune but I havent really tested it. I guess I will see. Enjoy...


Matador

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #232 on: April 10, 2012, 10:28:18 PM »
Now *that's* DIY!

Did you smelt the brass yourself too? ;)

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #233 on: April 10, 2012, 11:31:04 PM »
Well I just finished a pair of mics earlier this evening: Peluso capsule, T13, styrene and tantalum caps, Aurycle body (painted HAMMERED silver 8)).

I did a simple voice test, everything is working as it should and sounding great. I don't have a real U87 to compare to, but I can tell there is definitely a nice color to these guys, "smooth and sweet" I think they call it. I'll get to do some more extensive playing once my cheapo chinese shock mounts that I just ordered on fleabay show up.

Thanks Dan for the awesome project.


Re: Neumann U87 Vintage Circuit Build Thread
« Reply #234 on: April 10, 2012, 11:40:27 PM »
props tskguy!!! you are definitely a brave man than I!
Adam
only got here by owning a soldering iron and bad life decisions.

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #235 on: April 11, 2012, 01:39:24 AM »
Hey all,
Just a little something I have been working on for my new U87 mic. Pretty much done with the machining, I still need to finish the outer rings and the center hole. Tuning is also pretty difficult from what I understand with this capsule so I still need to work that out. I have a rig to tune but I havent really tested it. I guess I will see. Enjoy...
Now that is awesome-I wished I had the competence to do things like that.Congratulations!

Best,

Udo.

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #236 on: April 11, 2012, 01:57:26 AM »
Well I just finished a pair of mics earlier this evening: Peluso capsule, T13, styrene and tantalum caps, Aurycle body (painted HAMMERED silver 8)).
Congrats to your finished build.
Hammerite is cool (pics please?) :D
As I don't have the trafos yet,may I ask if the T13 has markings for primary and secondary or did you measure dc resistances,just curious.
Also I'd like to know which biasing method you prefered.
Seems that you have set up the mics exactly as I want to do mine,did you use the mica for the 10pf?

Best regards,

Udo.

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #237 on: April 11, 2012, 07:08:48 AM »

Congrats to your finished build.
Hammerite is cool (pics please?) :D
As I don't have the trafos yet,may I ask if the T13 has markings for primary and secondary or did you measure dc resistances,just curious.
Also I'd like to know which biasing method you prefered.
Seems that you have set up the mics exactly as I want to do mine,did you use the mica for the 10pf?

Best regards,

Udo.

I need to figure out a way to brand the mic body, maybe I'll post some pics after that. A friend of mine has some wet transfer label sheets, I know someone said they were unsuccessful trying to use those, so if anyone has any better ideas I'm all ears.

The T13 has yellow as primary, black as secondary, I just followed the schematic and T13 data sheet when wiring. Looking at the side with the leads coming out I did left side yellow to pin 1, left side black to pin 4, right side yellow to pin 2, right side black to pin 3.

I used an oscilloscope to bias the fet, it was super easy and accurate.

I used the mica from the BOM, all the other caps are "vintage spec". Hopefully I don't lose any cool points over the mica.

The mics definitely sound like U87's to me, but I no longer have access to a real one to compare to. I'm more interested in having some great usable tools than creating a precise replica, so I would say mission accomplished. Now I am curious about the U89 circuit, and if it could be done on Dan's pcb. I would love to have a pair of those as well, maybe time for some more research.

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #238 on: April 11, 2012, 07:42:00 AM »
Super Glad To hear a new Finished Build ;D ,  Congratulations Adeptusmajor ;D. thanks for the pointer on the T13 i am waiting for mine still  :P,




kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #239 on: April 11, 2012, 09:21:16 AM »
Thank you for the fast reply!
I need to figure out a way to brand the mic body, maybe I'll post some pics after that. A friend of mine has some wet transfer label sheets, I know someone said they were unsuccessful trying to use those, so if anyone has any better ideas I'm all ears.
As said I failed,the ink came off,maybe an issue since this is all water based,even after coating the printed sheet.....
The T13 has yellow as primary, black as secondary, I just followed the schematic and T13 data sheet when wiring. Looking at the side with the leads coming out I did left side yellow to pin 1, left side black to pin 4, right side yellow to pin 2, right side black to pin 3.
That looks right to me.I have seen the pic as well as the drawing,just wanted someone to confirm if they both match physically,thanks for that.
I used an oscilloscope to bias the fet, it was super easy and accurate.
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 used the mica from the BOM, all the other caps are "vintage spec". Hopefully I don't lose any cool points over the mica.
O.K.,that´s exactly how I´m prepared.When the capsule and transformer are here I´ll check this in our studio,I have them still in my ears from ages ago.Bad thing is that I have only the U87Ai versions here (1986,different capsule) to compare-not fair,but maybe a new preference on vocal tracking,who knows?.
The mics definitely sound like U87's to me, but I no longer have access to a real one to compare to. I'm more interested in having some great usable tools than creating a precise replica, so I would say mission accomplished. Now I am curious about the U89 circuit, and if it could be done on Dan's pcb. I would love to have a pair of those as well, maybe time for some more research.
Same here,I like to have a good working (and sounding) microphone first,not having an exact copy.
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.

Thanks again and best regards,

Udo.


 

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