Neumann Vintage U87 Clone : Build Thread.

[Lowfreq]

Interesting comparison. I thought the RK-87 sounded fuller than the other capsule, but without being there to hear what the guitar sounded like in real life, it's hard to say what capsule was closer to the source.

The RK-87 could sound tubby on some things compared to the Eric capsule. They sure sound different.

 

[wave]

Interesting comparison. I thought the RK-87 sounded fuller than the other capsule, but without being there to hear what the guitar sounded like in real life, it's hard to say what capsule was closer to the source.

The RK-87 could sound tubby on some things compared to the Eric capsule. They sure sound different.

Thanks for the comment. I have added a couple scratch vocals including one done with my AKG 414 TLII.

https://www.dropbox.com/sh/04bghkvc9m22b9i/bYHNf_5RiF

EDIT: I noticed a little distortion on the word Why leading the third phrase on the Vox Eric's K-87.wav track . This was a peak on input to the recorder. Sorry guys.

Dave

 

[gevermil]

Thats a dramatic difference  ???

 

[kante1603]

Hi Dave,

Have both mics been in the same position?
How far away have they been?
What transformer did you use?
Is there a hpf set too high on eric's capsule?
From what I hear and not knowing the original sound of the guitar both capsules don't match in any case.Both are completely different microphones soundwise.

On the RK87 there is way too much bass (proximity effect?),on some low notes there are resonances (!!!) and even distortion (slightly but well noticable).This sound is faaaaaaarrrrrrrrr off from anything a Neumann does,it sounds "chinese"in a way-I definetely don't like it.
Eric's capsule is way closer to the "goal",but is lacking of sub frequencies.I like the mid/high section and definition.
Can you explain a bit more in detail how the setup was (position/transformer/micpre and hpf)?

Thanks,

Udo.

P.S.:I would never take a 87 for recording acoustic guitars,but that's a different story........

 

[kpearsall]

isn't the RK-87 a thinner material too? I would expect it to be more detailed than I'm hearing in those files.

 

[wave]

Udo,
I guess I should have said that this was as about as controlled of a recording test that I could muster.
The mic was setup about 8 inches off of the 12th fret of my guitar.

I used the same mic for each recording and swapped the capsule. It's not 2 mics.
I used the same mic pre for both recordings, an Amek 9098
The HPF is set to 60Hz.

Dave

 

[kante1603]

Udo,
I guess I should have said that this was as about as controlled of a recording test that I could muster.
The mic was setup about 8 inches off of the 12th fret of my guitar.

I used the same mic for each recording and swapped the capsule. It's not 2 mics.
I used the same mic pre for both recordings, an Amek 9098
The HPF is set to 60Hz.

Dave

Thanks Dave,

I think I got that right with swapping the capsules.
What I mean saying "...Both are completely different microphones soundwise...." is that they form completely different sounding microphones.It was some kind of an translation error,sorry for that.
Anyway,at least I know which capsule not to buy ever.....at 8 inches proximity begins maybe very slightly,but not like this-compared to the real thing of course.Where would the RK87 end up when doing close-miking....an earthquake ?
Can you tell us again which transformer it was and the caps setup (all styrenes or not) please?
Thanks for sharing,

Udo

 

[wave]

Udo,
All styrenes and T-13 trafo. I'm gonna swap the RK back in and do another test. Maybe when I was playing I moved some or got into it too much.
I just cut another track with Eric's K87 in place and made sure I played very static.
Sometimes I have a heavy pick hand too. it comes from being a rocker and banging on my Gibson on stage.
The last track I cut I was easy on the strum and I backed off the mic pre 6db to make sure there were no peaks on input

Dave

 

[kante1603]

Udo,
All styrenes and T-13 trafo. I'm gonna swap the RK back in and do another test. Maybe when I was playing I moved some or got into it too much.
I just cut another track with Eric's K87 in place and made sure I played very static.
Sometimes I have a heavy pick hand too. it comes from being a rocker and banging on my Gibson on stage.
The last track I cut I was easy on the strum and I backed off the mic pre 6db to make sure there were no peaks on input

Dave

Thanks Dave,
Moving while playing is o.k. as long it's not too much,I hope you monitor yourself during recording ;D
Setup is nearly the same as mine electronically except of the mica.As said this combination with the peluso capsule brought me pretty close to an U87Ai soundwise.
Will work on my gain issue in a couple of weeks or so when I have holiday time.The more I think of it the more I believe it's just the fet,not more.Meanwhile I have around 60 pieces here,all idss checked.
A comparison between Eric's and John's capsule would be very interesting in this cap/trafo combination.
But there is an air-line distance of 7.274,107km between us,maybe we can meet in the middle (don't forget your bathing suit,I'll bring the field recorder). ;D

Cheees,

Udo.

 

[burglar]

Good comparison,

IMO the K-87 is the winner and clearly the closest to the original.  It has the present mid range and very little sibilance.  I'm willing to bet that it would take eq better. 
Both sound good, but by & large, I tend to lean toward darker condensers for male vocals because in my experience, they are far easier to deal with come mixdown. 

Also, didn't like the transient/body ratio of the RK on acoustic guitar compared to the K-87 

 

[BarneyBrougham]

Hey Everyone.

I have finished 2 U87s now....they both work.
Im using the Peluso capsule and the CM transformer.

Just a question....when testing them next to a cheap AKG c3000b the difference in level is quite a lot.

i have the level on my API with the AKG on 0 and the level is totally enough, actually i need to use a pad if the sound source is loud.

with with both neumann clone i have to turn the API up half way....theyre both set at 10.5v.

is this normal? is this the normal character of the microphone....low gain....it also sound quite dark.

cheers,
Damian

 

[kante1603]

Hey Everyone.

I have finished 2 U87s now....they both work.
Im using the Peluso capsule and the CM transformer.

Just a question....when testing them next to a cheap AKG c3000b the difference in level is quite a lot.

i have the level on my API with the AKG on 0 and the level is totally enough, actually i need to use a pad if the sound source is loud.

with with both neumann clone i have to turn the API up half way....theyre both set at 10.5v.

is this normal? is this the normal character of the microphone....low gain....it also sound quite dark.

cheers,
Damian

Hello Damian and welcome,

The low level is absolutely normal.Look at the Neumann specs for U87 (not U87A!,this is the next generation introduced in 1986 with a way higher output level).
It is at 8mV/Pa while your C3000B is at 25mV/Pa.This difference is extremely huge!

About sound:

Yes,a U87 is darker compared to most cheap condenser mics,especially when comparing them directly to another.This way the Neumann will be too dark to your ears at the moment,but this impression is wrong.Do it the other way round (U87 first,then AKG)'then you'll feel the AKG sounding very harsh,but after some short time you'll maybe even like it.This is the same effect as when using these horrible exciters in the early days they came up,your ears will accustom to the sound pretty fast,followed by wanting even more!Definetely one of the major errors in doing a mix wrong.
Give your ears a good break!
Record say vocals and then try to place them in the mix-you'll know what I mean then.
A Neumann nearly always sits right in it while cheap mics won't,even with heaviest use of equalizers.
They secret is "burried" in their mid/high mid range which make them sound like a Neumann!
Today most of the younger people have seriously damaged their ears by using mp3 players etc. at full level.This is irreversible!!!I always tell my students not do that.Also because of this they are not used to what a good sound or well balanced mix is,and their ears are not in training.

Of course this all is a matter of taste partwise,but we can't talk about things like sound when not knowing anything about basics.So always listen,listen,listen,get experienced.Your brain is able to store millions and billions of so-called Sound or Acoustic Patterns,but you can only use them when you train your ears all the time and learn as much as you can.
Listen to all sound sources with an open mind,even to music or noise in your environment you don't like,it's the best recommendation I can give to young people.

And take care of your ears,they are the most valuabe instruments you have when you really love the wonderfull world of sound.The rest is pure experience.

Hope to have helped,

Udo

 

[tskguy]

Nicely put Udo ;D I agre with you completly, I have recorded vocals with a number of microphones but I havent ever had a vocal track sit as well as my new u87 clone. I of coarse think my capsule has something to do with that as well. 

Eric

 

[kante1603]

Nicely put Udo ;D I agre with you completly, I have recorded vocals with a number of microphones but I havent ever had a vocal track sit as well as my new u87 clone. I of coarse think my capsule has something to do with that as well. 

Eric

You can bet on it.It's the 40th anniversary of the real thing now,and it still gets awards,not bad!
So there is a reason why....
If all summed up the right capsule and transformer together with the original schematics and the"original parts" e.g. styrenes will do their job.

Cheers,

Udo.

 

[BarneyBrougham]

Hey there.

Can i hurt my U87 clones by having them in front of a loud guitar speaker cabinet?

i just finished 2....had 1 in the front of my cab all day, and today when i turned the 48v on, the mic started making a weird sound...kind of like there is wind blowing. sounds like wind through my monitors.

any ideas?

thanks

 

[wave]

Did you use styrenes in your build? Double check your capsule connections too. I had mine accidentally reversed and I had the same noises. Could be one of the caps if you used styrenes as well.

Dave

 

[HellfireStudios]

Are the styrenes from the BOM polarized? I don't see any markings that indicate polarity. The tantalums/electrolytics are, but I haven't heard of polarized styrenes. If so, wouldn't the silkscreen indicate the positive or negative side for proper installation?

 

[mukole]

This is my first post here,

I'd like to thank poctop for making this project possible, and all the others who have contributed their valuable information.
I've built 5 of these sets using styrenes/tantalums and using the t13 transformer. I'm in Australia so the best i could seem to find
for a donor body with all 3 switches locally was the isk bm600 which i managed to get at a discount locally for 5. The pcb's fit the mic body comfortably
and the pcbs including the switches are easily modified to work in this project. The bm600 doesn't include a can for the transformer however as the original circuit has the transformer mounted on the pcb, but this seems to make little difference.

I'm now just trying to decide which capsules to use, i originally intended on the rk87, but after listening to Daves sample's am inclined toward Erics k87 capsules. My first real test will be on drum overheads and as room mics so if anyone has any feedback to offer on the different capsules it would be appreciated.

One thing i wanted to share is that i had a lot of trouble biasing the fet at the start.
I followed the instructions using the scope method, but every time i connected the oscilliscope to the drain of the fet and increased the signal level the sine would lean over into a sawtooth. I tried various methods for generating the tone, a couple of different sources for phantom power, as well as pc based oscilliscope using the output of the mic into an mbox2 which just showed clipping on the positive side of the wave regardless of the bias setting.

Also I noticed that with the scope there appeared to be much more level at the gate than the drain of the fet.
So after rechecking all my voltages, checking my transformer wiring, and looking at the schematic i tried again with the primary of the t13 disconnected.

Voila!!! The biasing worked as it was intended.

I referred to the instructions several times during my attempts at biasing, and didn't notice any notes about the transformer needing to be dissconnected, but please excuse my ingorance if its already stated.
I'm not sure if this is a problem with the cinemag but it definetely made scope biasing impossible with the t13.

Apart from that, i've tried one mic in cardoid mode with the stock capsule connected and it sounds very promising.
I can't wait to hear my final build.

Are the styrenes from the BOM polarized? I don't see any markings that indicate polarity. The tantalums/electrolytics are, but I haven't heard of polarized styrenes. If so, wouldn't the silkscreen indicate the positive or negative side for proper installation?

No styrenes aren't polarised, I believe only electrolytics including tantalums are.


Cheers

Mick

 

[HellfireStudios]

Much like mukole, I've been running into problems with biasing the FET with a scope. I'm using a Carvin CM-87S with stryrenes/films/tantalums and a Peluso BV8P-S wired 11:1. Peluso capsule, as well, but that doesn't matter at this point.

The scope is Signalscope Pro for the iPad. All ins and outs are handled by an Alesis I/O Dock. When the signal is sent directly to/from the iPad, a perfectly good sine wave appears on screen. When sent through the mic (with phantom power being supplied by a standalone phantom supply), the signal resembles what was described as oscillation earlier in the thread (I believe wthrelfall was having this problem). When I get the chance, I'll try and post some screenshots of my scope.

I'm using a 2N3819 with an IDss of 3.8mA. Below are my measurements. As I can't get the scope/mic combo to respond properly, the pot (25k) is in an arbitrary position a few turns from fully counter-clockwise.

top of L1 - 47.2v
top of L2 - 47.2v
top of R18 - 47.2v
top of R19 - 46.6v
bottom of R17 - 23.4v
top of R17 - 23.4v
Zener 23.4v
FET drain pad 6.7v
FET source pad 2.8v
top of R12 6.7v
top of R13 21.3v
top of R14 20.2v
top of R8 11.5v

Some of my readings don't seem to be right. Any suggestions as to what could be causing these unsettling problems?

 

[tskguy]

I am pretty sure Wave was refering to the actual microphone capsule wires being reversed.  Not the styrene caps. You also may have a bad capsule. Does the capsule do this worse when you breath on the capsule? It could be getting sucked to the backplate. Its really hard to say without hearing the sound as well. Anyway I hope you get it figured out. And Mukole please let me know, I would love to have some of my capsules down under!!

Eric