Re: Neumann U87 Vintage Circuit Build Thread
« Reply #300 on: April 13, 2012, 07:31:01 PM »
This is Great Stuff Udo, just wandering if it would be even better to install it the other way arround , if you want to ultimately Bias with the pot in situ and leave the pot there you would have more room and angle to stick the screw driver in,  i have question myself if i could also do the same with the original pot but i had enough room to do it this way so i kept going in this direction,  the original pot is  a tight fit but if you use a pair of small snipper to cut the edge gently or file a bit, it will slide in no problem as in this picture here,  in my case the height was not the problem more like the contigueous width,  it is just barely too wide on the edge to fit perfectly without a bit of snipping, this is an example on the Mxl body wich is the same as the aurycle.



i am not sure if the B2 Pro body is even smaller in diameter for the pot to go in ,  also i use to indent the pot from underneath to make some room for the Leg to go underneath so it does not require as much filing adjustment,

i wish i could have a mouser PN for your pot so i could add it in in case people prefer it.

thanks Again Udo for your ressourcefullness on this matter this is great contribution to this project and very appreciated,
cheers,
Dan,






kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #301 on: April 13, 2012, 08:04:48 PM »
Thanks for the nice words Dan,

In my case the height was more problematic than the width.I filed the edge and it went in the tube way better,but not good enough I thought,still too close the tubes inside.Since I had to order some stuff anyways I gave it a chance.I'm sorry I don't have parts numbers for you american guys,maybe one can try to get closer infos from the pdf on the site?
About the screw position:I will leave it this way.It comes closer to the front of the pcb,and if I remove the metall mounting plate which holds the capsules saddle it will be easy enough to reach I think.
The plate can be removed easily on a B2,it is held by 4 screws.
Will try this out over the weekend.

Best,

Udo.

Hank Dussen

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #302 on: April 13, 2012, 08:28:20 PM »
Looking at my B2 switches under a magnifying glas I can't see the brand,only that they are specified at 1,5A.
Doing a search for (sub-)miniature toggle switches it seems to be Salecom types.
Remember the pattern switch is a 3 position SPDT with center off,the others are normal SPDT.
Found this one here:

http://www.banzaimusic.com/Salecom-SKS08LP-Subminiature.html

There are some more to look at on their site.Since you are from belgium that could be a way to go,but I bet these are standard toggles.

Hope to have helped,

Udo.

Thanks a lot!


kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #304 on: April 14, 2012, 09:30:10 AM »

Seems to be the same dimentions as this one: http://eu.mouser.com/ProductDetail/Mountain-Switch/108-2MS3T2B2M6QE-EVX/?qs=r%2frvCFLFL6efW6qOhf4KRUsJkF9R1dXjZkNH%252bHqY6Vk%3d
Hi Hank,

Yes,seems to be the same,only the brand is different,cool.

Cheers,

Udo.

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #305 on: April 14, 2012, 08:10:53 PM »
This is Great Stuff Udo, just wandering if it would be even better to install it the other way arround , if you want to ultimately Bias with the pot in situ and leave the pot there you would have more room and angle to stick the screw driver in,.............
Hi Dan,

you´re right with reversing the pot!Way easier to dial in,I must have been too tired yesterday to get it right-pardon me.
Made an addendum on my post #299,thanks for the hint Dan!
I modded my pcb,and it fits the B2 housing like a glove now-nothing touches the tube´s inside.Here´s the result:





I also made a swap at the 2,2k resistors to o,1% precision types since they´re not really expensive (19 Euro cents).This way I must not spend hours on matching them.
Readings on top of zener are 23,96 vdc now,front backplate is 41,83vdc-even better than before.
Then I biased again,this time I made pics for those who are interested in my little scope setup.
The upper dmm reads the drain voltage,the middle unit is a simple signal follower I built the drawing-by-numbers way ages ago.
I only used the generator part being a "Wien bridge" oscillator as it´s level is adjustable.Very easy to dial in!
The scope is a Hameg for arround 100 Euros from evil bay.Look:

Sinewave before clipping:



Symmetric clipping after biasing:



Best,

Udo.

« Last Edit: April 14, 2012, 08:21:04 PM by kante1603 »

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #306 on: April 15, 2012, 10:42:56 AM »
Hey Udo,  i guess nobody can tell you that you are not ready to receive your capsule and transfo,  if i could throw 1 to you on the other side of the ocean i would  :D,  i cant wait for your comment of your future mic,  great picture also ,



Best,

Dan,

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #307 on: April 15, 2012, 11:09:09 AM »
Hey Udo,  i guess nobody can tell you that you are not ready to receive your capsule and transfo,  if i could throw 1 to you on the other side of the ocean i would  :D,  i cant wait for your comment of your future mic,  great picture also ,



Best,

Dan,
Then throw them,Im standing at the window with my hands open ;D
I'm close to dying of jealousy-have fun you T13 and PK87 owners (must calm down now.....).

Best,

Udo ;)

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #308 on: April 15, 2012, 02:30:44 PM »

I'm close to dying of jealousy-have fun you T13 and PK87 owners (must calm down now.....).

Best,

Udo ;)


Oh, I am... ;D

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #309 on: April 15, 2012, 05:44:05 PM »
For those who don´t have a scope but an iPad:
I tried this one in an Alesis io dock.Supersimple,2 channels,easy setup.Costs 11,99-Euros.
This will not replace a real oscilloscope,but could work in this case.
A nice toy to fool arround with,it has signal generators on-board,and if hooked up to an iPad compatible audio device (e.g. via USB)
you will have a signal source,line ins and outs,maybe mic in with phantom,a 2 channel scope, a way to monitor what happens via phones etc.I connected an external signal generator-worked from start,the auto button sets the trigger mode and levels for you to fit the displayed window.Calibration is super easy too.
If interested do a search for "Onyx" or "oscilloscope" in the app store.
Look at the attached pic.

Cheers,

Udo.


geekmacdaddy

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #310 on: April 16, 2012, 07:50:22 AM »
Mac users; Will this scope do the trick for biasing? Thanks  :)

http://duncan.rutgers.edu/physicsfreewares.htm

geekmacdaddy

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #311 on: April 16, 2012, 08:40:37 AM »
at the very least, it's a nice signal generator for this, which accepts external sound sources as well

http://download.cnet.com/WaveWindow/3000-2170_4-10532772.html

(shareware, 12.00 US)

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #312 on: April 16, 2012, 12:17:38 PM »
Mac users; Will this scope do the trick for biasing? Thanks  :)

http://duncan.rutgers.edu/physicsfreewares.htm
Doesn´t install on none of my macs (incl.ppc and intels),what OS will this run on?

Cheers,

Udo.

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #313 on: April 16, 2012, 12:39:33 PM »
at the very least, it's a nice signal generator for this, which accepts external sound sources as well

http://download.cnet.com/WaveWindow/3000-2170_4-10532772.html

(shareware, 12.00 US)
Hi,

sorry,but this is not really earth-shattering.Just 1 channel,not enough info,not really much to set in the preferences.
Was synching bad at low frequencies.No calibration possible.
My trial setup was rme fireface 800 as audio unit and Wandel & Goltermann as signal generator.
I believe there are better tools out there,so let´s do some further research.
At 1kHz it may work somehow,but I wouldn´t trust it.

Cheers,

Udo.
« Last Edit: April 16, 2012, 12:44:27 PM by kante1603 »

geekmacdaddy

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #314 on: April 16, 2012, 12:55:46 PM »
10.7.2 Udo.

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #315 on: April 16, 2012, 01:06:25 PM »
10.7.2 Udo.
O.K.,mine at home just go to 10.6.x,will give it a try at work.

Thanks for the info!

Udo.

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #316 on: April 16, 2012, 02:10:06 PM »
Cuty pie?

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #317 on: April 16, 2012, 03:23:24 PM »
so could i use my iphone as a scope and my daw which is an older mac to generate test tone is this all i would need?

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #318 on: April 16, 2012, 03:31:25 PM »
so could i use my iphone as a scope and my daw which is an older mac to generate test tone is this all i would need?
Hi,

What are you refering to,the iphone in general or the onyx software?

Udo.

Edit :The pic above shows not a cell phone but a real scope!

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #319 on: April 16, 2012, 06:09:39 PM »
Never tought one day i could bias The FET with my phone  8)

This is great stuff,  i am in,

Dan,


 

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