kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #480 on: May 02, 2012, 01:28:22 PM »
Udo,
That is a great idea. God knows I have enough old hard drives around here. Time to re-purpose them!

Dave
Yes Dave,

this is true diy!
Here´s a little "proof" of my prototyped badges,I was just fooling around with colours and materials-because I´m still bored of waiting....
This is the "How To Create Badges" from hard discs,should we open a thread for it ;D
(BTW:I still don´t know how to bias a cheesecake).
Will do more experiments,I might have a sheet of chromium metall somewhere,who knows.....

Have fun!

Udo ;)


wave

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #481 on: May 02, 2012, 02:26:18 PM »
I dig it! I actually ordered an aluminum sample pack from an online metal place.
It's 6 - 4"x4" sheetes in various thicknesses (pretty thin tho) Should be easy to bend. I've been talking to Chae at Prodigy engraving about laser engraving them as he did a great job with my first batch



These are 2mm anodized aluminum and were pretty hard to bend. I ended up using a ratchet strap with the badge on a piece of steel pipe first. A little hammering also helped  :)

Dave

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #482 on: May 02, 2012, 02:36:18 PM »
Wow!Looking great!

Udo.

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #483 on: May 02, 2012, 02:41:49 PM »
This is amazing stuff hooray for recycling and having fun doing it , you guys are impressive,

Can't wait to see those working mic under those badges  ;)

Dan,

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #484 on: May 02, 2012, 03:17:13 PM »
Yes,that's a lot of fun!
The more I'm waiting for my trafos the more ideas come to my mind.
Next step is modelling a mic body from potato salad with a head basket from crocheted parsley ;D

Udo.

HellfireStudios

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #485 on: May 02, 2012, 04:11:11 PM »
Just some info I was able to obtain about the BV11P transformer.
I tested the step-down voltage of the BV11P against the CM-2480. The 2480 takes 10.6VAC to about 1VAC off the secondary. This indicates the 10:1 ratio is accurate. The BV11P takes the same voltage down to only 2.2VAC. I can only assume this means it is in fact a 5:1. Please tell me I am wrong.

The 2480 I have is for a Royer mod I'm in the middle of. I'd hate to stall that project while waiting to afford the 4-5 Cinemags I'm going to need next.
I should find out if the BV11P would work in that circuit... I just hope I didn't waste my time/money.
"Tommorrow is just yesterday in reverse. Just like friends are enemies in reverse." -Gary Busey

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #486 on: May 02, 2012, 06:26:41 PM »
Just some info I was able to obtain about the BV11P transformer.
I tested the step-down voltage of the BV11P against the CM-2480. The 2480 takes 10.6VAC to about 1VAC off the secondary. This indicates the 10:1 ratio is accurate. The BV11P takes the same voltage down to only 2.2VAC. I can only assume this means it is in fact a 5:1. Please tell me I am wrong.

The 2480 I have is for a Royer mod I'm in the middle of. I'd hate to stall that project while waiting to afford the 4-5 Cinemags I'm going to need next.
I should find out if the BV11P would work in that circuit... I just hope I didn't waste my time/money.

i am sorry to hear this and i will take all the blaim for it , i was totally induced in error from my conversation with John, so i removed all reference to this transfomer since it is 5:1 ratio like as you determined ,  that does not mean that the traffo will not work tough you will proably end up with more gain and a slighty different impedance ratio but i think it would still worth a try you could be surprise by the result in a good manner i hope. 
Sincerly
Dan,

wave

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #487 on: May 02, 2012, 07:16:16 PM »
Hey Udo,
I forgot to ask, what did you end up cutting your aluminum with? I'm diggin the way you're doing it – super DIY!

Dave

Blue Jinn

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #488 on: May 02, 2012, 07:36:35 PM »
Quote
Just some info I was able to obtain about the BV11P transformer.
I tested the step-down voltage of the BV11P against the CM-2480. The 2480 takes 10.6VAC to about 1VAC off the secondary. This indicates the 10:1 ratio is accurate. The BV11P takes the same voltage down to only 2.2VAC. I can only assume this means it is in fact a 5:1. Please tell me I am wrong.

FWIW/FYI, I'm getting a pair of "BV11" transformers from AAMicrophones for the HST-11a mod. His specs are 5:1 also.
not my thing. I am here just to unbalance the equation --pucho812

 http://www.bluejinn.org

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #489 on: May 03, 2012, 01:33:34 AM »
Hey Udo,
I forgot to ask, what did you end up cutting your aluminum with? I'm diggin the way you're doing it – super DIY!

Dave
Hi Dave,

In german it is called "Blechschere",I guess it's "metal shear",a small one.

Udo.


HellfireStudios

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #490 on: May 03, 2012, 09:39:01 AM »

FWIW/FYI, I'm getting a pair of "BV11" transformers from AAMicrophones for the HST-11a mod. His specs are 5:1 also.

That's what I was afraid of...
"Tommorrow is just yesterday in reverse. Just like friends are enemies in reverse." -Gary Busey

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #491 on: May 03, 2012, 09:56:24 AM »
what size wire is used on the transformers.  I am looking for heat shrink tubing for that size wire and some for 1/4w resistors and components.  What size tubing should i get?

HellfireStudios

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #492 on: May 03, 2012, 10:44:27 AM »
what size wire is used on the transformers.  I am looking for heat shrink tubing for that size wire and some for 1/4w resistors and components.  What size tubing should i get?

If left in the original transformer casing, electrical tape would be a fine alternative to heat shrink tubing (no one would see the ugliness that accompanies electrical tape either). If not, the smallest size at Radioshack (usually in multi-size packs) will work. The transformer wires tend to pretty thin.
"Tommorrow is just yesterday in reverse. Just like friends are enemies in reverse." -Gary Busey

Matador

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #493 on: May 03, 2012, 12:21:06 PM »

FWIW/FYI, I'm getting a pair of "BV11" transformers from AAMicrophones for the HST-11a mod. His specs are 5:1 also.

That's what I was afraid of...

All may not be lost....what will you be plugging this mike in to?  What kind of preamp?

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #494 on: May 03, 2012, 03:29:50 PM »
 :o :o I tought i was driving nuts but i finally decided to call John Peluso myself and asked him again about the BV11P and said that the BV11P is really 10:1   ;D ;D  i said his first batch long time ago had a tap for 5:1 and 10:1 operation and this is the source of the confusion,

I am really pleased to annonce that your BV11P will be just fine afterall,  Sometime information maybe misleading but the Conversation on the phone with the creator is for sure the right thing, Enjoy!

Cheers,

Dan, 

Blue Jinn

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #495 on: May 03, 2012, 04:25:18 PM »
I'm still confused (although that isn't hard to do)

Dave Thomas's BV11's are published at  5:1 (I don't have one yet)

This thread says the orig BV11 was 5:1: http://www.groupdiy.com/index.php?topic=34417.0 and hellfirestudios voltage test for the BV11P vs the C-2480 were different. (see post from 2 May)

However, AMI says their T49 is the same as the BV11 and states a 10:1 ratio....

not my thing. I am here just to unbalance the equation --pucho812

 http://www.bluejinn.org

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #496 on: May 03, 2012, 05:18:06 PM »
I'm still confused (although that isn't hard to do)

Dave Thomas's BV11's are published at  5:1 (I don't have one yet)

This thread says the orig BV11 was 5:1: http://www.groupdiy.com/index.php?topic=34417.0 and hellfirestudios voltage test for the BV11P vs the C-2480 were different. (see post from 2 May)

However, AMI says their T49 is the same as the BV11 and states a 10:1 ratio....

I did mentionn those data to John and he did not seems to worried about that he said that the actuall ratio of the cinemag maybe just be higher than it spec,  the only thing i can confirm for sure is that if you ask John personnally yourself he will tell you that it is a 10:1  wich is why i did originally included the BV11P as potential traffo , i did removed it tough since this confusion, and intersting thing i mentionned also was that his c12 style t14 are actually 14:1
Hope this helps.
Dan,

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #497 on: May 03, 2012, 10:15:41 PM »
Hey Guys,
Ok I was doing a little testing and fooling around with the microphone and recording and this is a new first or i never really noticed it before.  As I was recording and listening to dead air I heard some little popping in the mic.  Its not the preamp or anything else except for that little ground hum I need to fix.  I crank the gain up on my 1073 clone.  I hook up my akg c414 and did not hear any little pops.  But once I plug the 87 back in I can hear them.  Now granite they are very low and you probably wound not hear them in a mix but I gotta figure out what is causing the little pops.

here is an mp3 to listen to, hope fully you can hear them i did juice the mic up for it.

http://www.ehornstudios.com/media/little%20pops.mp3

-Scott

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #498 on: May 03, 2012, 11:50:26 PM »
Hey Guys,
Ok I was doing a little testing and fooling around with the microphone and recording and this is a new first or i never really noticed it before.  As I was recording and listening to dead air I heard some little popping in the mic.  Its not the preamp or anything else except for that little ground hum I need to fix.  I crank the gain up on my 1073 clone.  I hook up my akg c414 and did not hear any little pops.  But once I plug the 87 back in I can hear them.  Now granite they are very low and you probably wound not hear them in a mix but I gotta figure out what is causing the little pops.

here is an mp3 to listen to, hope fully you can hear them i did juice the mic up for it.

http://www.ehornstudios.com/media/little%20pops.mp3

-Scott
Well, for sure i will not hear this with my laptop speaker  ;D
You do have abnormal crackle artefact at -60 db you should consider checking for [RC] [FC] section and also the [G] Pad for flux contamination or grease, clean with alcool  or fluxsolv between the pads, That should take care of the problem.
hope that helped.
Dan,

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #499 on: May 04, 2012, 06:53:15 AM »
Thanks Dan,
I did clean the area in between the pads of Fc and Rc.  I scraped these areas with a tool I have and I also used isopropyl alcohol to clean it.  Its still there but it might be a tad softer, hard to tell though.

can I remove the capsule wires to see if its there without the wire connected?

The only thing I did was bias with a scope on the rt and sw section.  I have a little solder left on those rings from when  I soldered a wire on to each area.  Could this be causing it.

Could a component be bad, maybe a cap or resistor?

What is the best way to put new ends on the capsule wires,  they are very thin.  Too thin for strippers.

Thanks
-Scott




 

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