Neumann Vintage U87 Clone : Build Thread.

[marshman]

Thanks Dan and Udo!

Udo, I built a test rig almost identical to what you have. Worked great. I tested both ways (resistor/voltage drop and current) just for the experience and got pretty much identical numbers.

The two lowest I had were 10.20, so I am using those.

Thanks!

mm

 

[kante1603]

Thanks Dan and Udo!

Udo, I built a test rig almost identical to what you have. Worked great. I tested both ways (resistor/voltage drop and current) just for the experience and got pretty much identical numbers.

The two lowest I had were 10.20, so I am using those.

Thanks!

mm

Hi marshman,

Yep,that's nearly the middle of 2 and 20 mAs,you're ready to go!

Udo.

 

[poctop]

Hi All,  Matt from Microphone Parts is looking for 1-2  Beta tester excluding myself  ;D,  to have a try to the capsule rK87  the only thing is that the capsule will be sent to the person who's having the whole mic built and ready to go ,wihout capsule, because he'd like to have feedback as quickly as possible question of planning for the future ,

http://microphone-parts.com/rk87-microphone-capsule/

those Beta Tester who are interested please PM as soon as you can there is only 2 opening,   

Dan, 

 

[poctop]

and a link to a thread I made just for the gearslutz, with a few more explicit pictures 

http://www.gearslutz.com/board/so-much-gear-so-little-time/724466-check-out-pair-u87s-i-built.html

I really would like to see the Kissing picture here out too, Love it or Love em  :-*
congrats
Dan,

 

[rmaier]

Congratulations on your builds, Adept - very nice, the finish looks great. Judging by the photos, it seems safe to assume you're happy with the twins!

 

[kante1603]

Yes,congrats from germany too,well done!

Have fun fecording,

Udo.

 

[HellfireStudios]

I ordered a Peluso BV11P just before I found out about the T13. So I was wondering about a few things. Will the BV11P work with the U-87i circuit? (I've heard that the ratio is 5:1) Also, can someone confirm that this is the correct ratio for the BV11P? I know more output would result, but would biasing become problematic? Thanks.

-James

 

[adeptusmajor]

Thanks for the comments everyone.

Dan - to answer some of your questions from your PM - I used the Peluso capsules from the group buy and the AMI transformers, polystyrene and tantalum caps, and the mica. I had the mics working perfectly with the trimmers in there, didn't really get to put them through their paces because I didn't have a shockmount that I trusted enough at the time, but they were sounding great on the few tests I did. I replaced the trimmers with resistors after finding the bias value, and after about 80-100 resistors I guess I still didn't get a pair that were close enough to the trimmer values. I now have some hissing and distortion in both mics, so I am putting the lower profile side adjust trimmers in both mics and calling it a day. I just wasn't comfortable with the amount of stress that the mic body was putting on the original trimmers, they had to come out. Anyway, I PM'ed you regarding my interest in Matt's beta test, I would be glad to help if you'd like me to.

 

[adeptusmajor]

and a link to a thread I made just for the gearslutz, with a few more explicit pictures 

http://www.gearslutz.com/board/so-much-gear-so-little-time/724466-check-out-pair-u87s-i-built.html

I really would like to see the Kissing picture here out too, Love it or Love em  :-*
congrats
Dan,

Well, I try to keep the "low brow" trolling efforts over at gearslutz, seems the only thing that place is good for anyway, but since you asked nicely:

 

[poctop]

Thanks for the comments everyone.

Dan - to answer some of your questions from your PM - I used the Peluso capsules from the group buy and the AMI transformers, polystyrene and tantalum caps, and the mica. I had the mics working perfectly with the trimmers in there, didn't really get to put them through their paces because I didn't have a shockmount that I trusted enough at the time, but they were sounding great on the few tests I did. I replaced the trimmers with resistors after finding the bias value, and after about 80-100 resistors I guess I still didn't get a pair that were close enough to the trimmer values. I now have some hissing and distortion in both mics, so I am putting the lower profile side adjust trimmers in both mics and calling it a day. I just wasn't comfortable with the amount of stress that the mic body was putting on the original trimmers, they had to come out. Anyway, I PM'ed you regarding my interest in Matt's beta test, I would be glad to help if you'd like me to.

Do you mean the mic was not hissing or distorting before  you replaced R11? we have some upper little margin there, better put it a bit higher so you go past the point where the FET opens and surely not be arround this point just digging into spl a bit , have you scope biased .  ?

 

[poctop]

I ordered a Peluso BV11P just before I found out about the T13. So I was wondering about a few things. Will the BV11P work with the U-87i circuit? (I've heard that the ratio is 5:1) Also, can someone confirm that this is the correct ratio for the BV11P? I know more output would result, but would biasing become problematic? Thanks.

-James

I must have misheard from John the BV11 is 5:1  it will not belong here then , i will try confirming that with him as the impedance ratio as well, if it is not the Case then i will remove that erroneous information , my appologies.

 

[adeptusmajor]

Do you mean the mic was not hissing or distorting before  you replaced R11? we have some upper little margin there, better put it a bit higher so you go past the point where the FET opens and surely not be arround this point just digging into spl a bit , have you scope biased .  ?

I returned your pm regarding this. I did bias with a scope, and the hissing was after I put a fixed resistor in. What you are saying makes sense because the values of the resistors were slightly low. I don't think I had but a few from the batch I got that were higher values, or nearly as close to what I needed. I will look again. If not I will probably put the old trimmers back in place while I wait for a lower profile ones. I was able to get the old ones to fit in the body, it was just tighter than I would like it to be, especially if I am removing the body every time I want to change the pattern.

I know somebody had a picture on here with a shorter side adjust trimmer, anyone have the mouser part number? Searching anyway...

 

[poctop]

Here is a new pot that i added in the Bom,

it is 3mm lower than the original and only 4mm wide so it should be fitting even better in any body, it is 12 turns.http://www.mouser.com/ProductDetail/Murata/PV37X253C01B00/?qs=sGAEpiMZZMukHu%252bjC5l7YWQ4frFPcQ6jyZnR59GhPbA%3D

 

[HellfireStudios]

I must have misheard from John the BV11 is 5:1  it will not belong here then , i will try confirming that with him as the impedance ratio as well, if it is not the Case then i will remove that erroneous information , my appologies.

If the BV11P is supposed to be similar to the BV11, the ratio should be around 10:1 based on the AMI info on their BV11 replacement. Others have stated the BV11P as 11.5:1. I'm still without a definitive answer, and Mr. Peluso hasn't answered my email yet. Is there any way to test the transformer before sticking it in the mic?

 

[poctop]

I must have misheard from John the BV11 is 5:1  it will not belong here then , i will try confirming that with him as the impedance ratio as well, if it is not the Case then i will remove that erroneous information , my appologies.

If the BV11P is supposed to be similar to the BV11, the ratio should be around 10:1 based on the AMI info on their BV11 replacement. Others have stated the BV11P as 11.5:1. I'm still without a definitive answer, and Mr. Peluso hasn't answered my email yet. Is there any way to test the transformer before sticking it in the mic?

If you do find out let me know as i can correct the infomation in the thread  ,
Dan,

 

[wave]

Don't you hate when a better part for the job is discovered after you've already ordered all the parts for your build?
I sure do (sigh). It's a good thing I'm working on like 4 different projects right now and I'm sure another Mouser order is right around the corner.

So I've got this idea for some mic body finishing (if using the standard brass Aurycle body) totally in the spirit of DIY including a custom mic badge that hopefully will be easy to form to the radius of the mic body. I've got some sample aluminum stock on the way. If everything works out, I will post a guide on doing everything.
Stay tuned...

Dave

 

[poctop]

Don't you hate when a better part for the job is discovered after you've already ordered all the parts for your build?
I sure do (sigh). It's a good thing I'm working on like 4 different projects right now and I'm sure another Mouser order is right around the corner.

Using the Aurycle body wich is pretty tight ,all i had to do is to file a bit the edge corner of the pot and it slides right in, Maybe the other pot will make it even easier no filing at all,  i prefer it out (solder with wire) to bias and forget about the pot.
Dan, 

 

[kante1603]

So I've got this idea for some mic body finishing (if using the standard brass Aurycle body) totally in the spirit of DIY including a custom mic badge that hopefully will be easy to form to the radius of the mic body. I've got some sample aluminum stock on the way. If everything works out, I will post a guide on doing everything.
Stay tuned...

Dave

Hi Dave,

funny I did the same yesterday.Took the cover of an old hard disc drive and put a transparent inkjet foil on it.Looks very nice.
I experimented with a lot of kitchen tools to get them bent.There are some nice working solutions.
Have put clear laquer on it,it´s drying at the moment.
Will report back when I´m done,

cheers,

Udo.

 

[kante1603]

I know somebody had a picture on here with a shorter side adjust trimmer, anyone have the mouser part number? Searching anyway...

Hi,

that was me.Bad news is I don´t have mouser parts numbers since I´ve sourced it here in germany,sorry :-\
See my replies #299 and #305.

Cheers,

Udo.

 

[wave]

Udo,
That is a great idea. God knows I have enough old hard drives around here. Time to re-purpose them!

Dave