Neumann Vintage U87 Clone : Build Thread.

[Paul678]

Hi everyone.

I'm still in the process of moding my MCA SP-1, and so far, the Jim Williams circuit
mods are good (I'm still not sure if I'm gonna cough up $100 for the RK-47 capsule).

But this has primed me for the Neumann clone project.  But I have to ask:  Is it really
necessary to spend $95 on a Goddamned audio transformer?  That's about 25%
of the total cost, it seems! 

I mean, I know core permeability and such will affect the frequency response, and
I know people are all trying to stay with the "original" parts and circuit, to get that
"classic" U87 sound.  But no two microphones are exactly the same anyways, and
everyone appears to be using different headbaskets, which will affect the response anyways,
so why not experiment a bit with a cheaper, off the shelf transformer?  Or even wind your own:

http://www.deerloverssite.org/TRANSFORMERS.html

There's GOT to be a cheaper transformer, that will do just as good, if not a better job than
the T13 or CM2480.

$95 is a huge part of the budget of this project.....

And secondly, many people here were recommending the 2sk170 as a replacement FET,
but in the SP-1, this is considered to be a "cloudy" sounding FET, and it replaced  by the
faster J305.  How about the J305 in the Neumann circuit?  Anyone tried it?

 

[3nity]

wrong thread buddy, this is the Neumann U87 Vintage circuit build thread.
Although i share the same point about the transformers being so expensive!
Thanks

 

[Paul678]

wrong thread buddy, this is the Neumann U87 Vintage circuit build thread.
Although i share the same point about the transformers being so expensive!
Thanks

    I know this is the Neumann U87 thread, but it is my modding on the SP1
that is inspiring me do the research to perhaps tackle a U87 clone, so
I'm on the right thread, buddy.  I'm just figuring out the cost of the project
first.

    But $95 for a goddamned audio transformer is ridiculous! 

 

[kpearsall]

I don't think it's ridiculous, there's a reason the real thing costs 3 grand! Quality costs. that's why you don't see any threads about cloning any MXL mics. In my experience, to get a really great sounding mic, the two places you do NOT want to skimp on cost is firstly the capsule, and then the transformer. If you throw the cheapest parts you can get in there, you might as well just buy a low priced commercial clone. Trust me, if the cheaper parts were capable of getting the right sound, I'd be all over that.

 

[Paul678]

I don't think it's ridiculous, there's a reason the real thing costs 3 grand! Quality costs. that's why you don't see any threads about cloning any MXL mics. In my experience, to get a really great sounding mic, the two places you do NOT want to skimp on cost is firstly the capsule, and then the transformer. If you throw the cheapest parts you can get in there, you might as well just buy a low priced commercial clone. Trust me, if the cheaper parts were capable of getting the right sound, I'd be all over that.

      Ok, fair enough, but has anyone even TRIED to use a cheaper part, or wound their own transformer
for their U87 clone?

      And my second question:

          Many people here were recommending the 2sk170 as a replacement FET for the 2N3819,
but Jim Williams considers this to be a "cloudy" sounding FET, and replaced it with the
faster J305.  How about using the J305 in the Neumann U87 circuit?  Has anyone tried this?

 

[kante1603]

Hello and welcome to the forum.

      Ok, fair enough, but has anyone even TRIED to use a cheaper part, or wound their own transformer
for their U87 clone?

The people around here did a lot of possible combinations of transformers and capsules,there are quite a few soundsamples that speak for themselves.Please read through this thread if you want,I´m sure you will find some answers that will help you decide which way to go.
Sadly I´ve never heard of people winding their own transformers for this particular project.

      And my second question:

          Many people here were recommending the 2sk170 as a replacement FET for the 2N3819,
but Jim Williams considers this to be a "cloudy" sounding FET, and replaced it with the
faster J305.  How about using the J305 in the Neumann U87 circuit?  Has anyone tried this?

No,and I think it is not too easy to do.Maybe our friend "matador" can chime in at this point?

Generally speaking this is the "Neumann U87 Vintage Circuit Build Thread" started by our good friend Dan ("poctop"),so it´s not about modifying existing microphones like the one you´re talking about.
I agree with member "3nity" here.

Maybe it´s best to start a new thread about your project?

If you are about to take your mic as a donor body then you´re right here of course.

Best regards,

Udo.

 

[Paul678]

Ok, fair enough.  It sounds like those T13 and CM2480s are the only
reasonably easy way to get close to the classic U87 sound.

You misunderstand me.  I DO want to build a U87 clone.  I just want to do
it as cheaply as possible, and if you read the other posts, other people
WERE talking about using the 2sk170 as a replacement FET.  I figured
why not the J305? 

Certainly the RK-87 capsule from microphone parts is NOT the same as the original
capsule, and with all the other alternative parts, I'm sure every mic here ends
up sounding different.  Even some engineers have commented that each of the original U-87s
all sounded different and unique.

Ok, thanks for your feedback...I'm getting closer to deciding to do this......

 

[adeptusmajor]

All things considered the price of transformers and capsules, while maybe a little more expensive than you expected, is still reasonable for what you get. Your mic will still cost way less to build than buying a real u87. My pair have the AMI transformers and Peluso caps, and they sound awesome and get used on every session now. It was around $800 US to build the pair, caps were bought on group buy. Watch the wiring on the AMI's though, I got a couple of the first ones and the leads were reversed, as Dany warned about in another thread. Not sure if this has been addressed in more recent runs. Also I would probably skip the mparts capsule, don't have any experience with them personally but judging from what I've seen others post they don't really compare to the other more expensive options out there. Bottom line is you get what you pay for.

 

[Paul678]

All things considered the price of transformers and capsules, while maybe a little more expensive than you expected, is still reasonable for what you get. Your mic will still cost way less to build than buying a real u87. My pair have the AMI transformers and Peluso caps, and they sound awesome and get used on every session now. It was around $800 US to build the pair, caps were bought on group buy. Watch the wiring on the AMI's though, I got a couple of the first ones and the leads were reversed, as Dany warned about in another thread. Not sure if this has been addressed in more recent runs. Also I would probably skip the mparts capsule, don't have any experience with them personally but judging from what I've seen others post they don't really compare to the other more expensive options out there. Bottom line is you get what you pay for.

    Yes, I've heard this project is about $400 for each unit.  You ended up using the $255
Pelusi P-K87i caspule?

    Did you use this body?:

          http://store.studio939.com/product/syt-5-microphone-body-kit

      If not, which one?  Which one would you recommend for ease of installing the
switches?

    Thanks for your time.....I really want a taste of the best, for less.....      8) 

 

[3nity]

Whats the price for a Cinemag 2480?
Thanks.

 

[ramshackles]

2480's are $43.01 from cinemag, excl postage.

It's interesting that there is a discussion about making this project even cheaper...

In my experience with DIY, many projects don't really end up that much cheaper than buying a similar thing full price (perhaps £100 cheaper or whatever). It generally seems to be the front panels and cases that shoot things up ...

But this mic works out at least 5x cheaper than buying an original vintage.
I just finished one with the Chunger mic body, cinemag trafo and RK-87 cap. It worked out probably around £400 (GBP) total including postage and import tax of various parts...

 

[kante1603]

It's interesting that there is a discussion about making this project even cheaper...

Absolutely!

In my experience with DIY, many projects don't really end up that much cheaper than buying a similar thing full price (perhaps £100 cheaper or whatever). It generally seems to be the front panels and cases that shoot things up ...

Yes,same experience here.

But this mic works out at least 5x cheaper than buying an original vintage.
I just finished one with the Chunger mic body, cinemag trafo and RK-87 cap. It worked out probably around £400 (GBP) total including postage and import tax of various parts...

Mine was a bit lower than 600 Euros including all.I have the peluso and t13 built in,body was B2Pro.
One must remember that we have to pay a serious amount of money for customs fees and taxes here,not to forget shipping costs.
As I must get the most parts from overseas I ended up at a quarter to a fifth of the normal price for an original Ai over here,not bad!
And I like my mic very much,enough to build another three!

Cheers,

Udo.

 

[Paul678]

2480's are $43.01 from cinemag, excl postage.

It's interesting that there is a discussion about making this project even cheaper...

In my experience with DIY, many projects don't really end up that much cheaper than buying a similar thing full price (perhaps £100 cheaper or whatever). It generally seems to be the front panels and cases that shoot things up ...

But this mic works out at least 5x cheaper than buying an original vintage.
I just finished one with the Chunger mic body, cinemag trafo and RK-87 cap. It worked out probably around £400 (GBP) total including postage and import tax of various parts...

    Well there you go!  $43 is better than $95! 

      Where did you see the price on their website?  I couldn't find it.  I assume you have to
call them in-person to order, right? 

      Your RK-87 is the cheaper capsule from mparts, right?  How did you like the sound of it?

 

[ramshackles]

I emailed cinemag and they quoted me $43.01

The RK-87 I got for $109 from microphone-parts. It sounds great. Of course I don't have a u87 to compare it to, but this has become my first choice mic for vocals, easily outstripping the commercial mic's I have that cost about the same to buy...

Mic body is about $150...

 

[Paul678]

I emailed cinemag and they quoted me $43.01

The RK-87 I got for $109 from microphone-parts. It sounds great. Of course I don't have a u87 to compare it to, but this has become my first choice mic for vocals, easily outstripping the commercial mic's I have that cost about the same to buy...

Mic body is about $150...

    Ok, great.  You'll have saved me about $50 on the transformer!  Thanks!

    I also don't have a real U-87 to compare to.....and since ignorance is bliss, I'll probably
go with mparts.

    What model # mic body was that one?  Where did you order it?

 

[Matador]

A J305 could probably be made to work.  It's specs (VGSOFF and IDSS) are similar to the 2N3819.

As for the 2SK170...I would have to ask...what does "a cloudy sounding FET" even mean?  The 2SK170 is nice if you suffer from low output because it's gm is much higher than the 2N3819.  If you like using a U87 some distance away and you don't have a mike pre that can be tasked with providing enough gain, the 2SK170 is a great choice.

I would recommend you talk with Dave Thomas at Advanced Audio in Canada.  He sells a U67-type capsule that is very good in the $75 range (including mount).  He doesn't source any high-ratio transformers (at least that I know of), but you can't do much better for the money than the CM-2480 for less than $50.

 

[Paul678]

A J305 could probably be made to work.  It's specs (VGSOFF and IDSS) are similar to the 2N3819.

As for the 2SK170...I would have to ask...what does "a cloudy sounding FET" even mean?  The 2SK170 is nice if you suffer from low output because it's gm is much higher than the 2N3819.  If you like using a U87 some distance away and you don't have a mike pre that can be tasked with providing enough gain, the 2SK170 is a great choice.

I would recommend you talk with Dave Thomas at Advanced Audio in Canada.  He sells a U67-type capsule that is very good in the $75 range (including mount).  He doesn't source any high-ratio transformers (at least that I know of), but you can't do much better for the money than the CM-2480 for less than $50.

      Yes, I'll go with the CM-2480 if I do this.

      "Cloudy" was how Jim Williams described the 2sk170, when it came to the SP-1 mods.

        This was replaced with the "faster" j305, which may have to do with lower junction
capacitances, and therefore faster slew rates, and therefore higher frequency response
and "detail". 

        I saw your Spice simulations....very interesting stuff.  How about not just cloning the
characteristics of the U87, but using simulations to improve the circuit topology, increase
the gain, and flatten the frequency response?    I'm sure making the U-87 circuit into
a transformerless one would change the frequency response too much......

 

[ramshackles]

You can get mic bodies from here:
http://store.studio939.com/

It is the SYT-5 body or just send a pm to 'Chunger' on this forum....

For all it is nearly $100 cheaper than some of the other capsule options, the mic-parts capsule is still top quality and much better than the stuff that comes in typicall sub-$500 mic's to my ears....

 

[wave]

Being a person that used mparts in a couple mics at the beginning of my DIY mic adventure,I can confidently say that it is a good quality capsule that does a good job reproducing source but IMO there is a pronounced bump in the response around 6K.
While the capsule is very open sounding and does deliver a great range the sibilance I experienced with it didn't agree with me.
It also got a lot worse when applying any compression to it.
Tskguy reskinned a few of my mparts capsules and going up to his very high quality 6 micron Mylar and his different spacers made a world of difference. His normal cost of reskinning and the cost of the mparts capsule together is the same as one of Eric's production capsules so it makes sense just to buy an HK-87 (I know that we're not talking about reskinning mparts I just thought I would throw my experience out there)
I know we are talking about cheaper component options so as far as that goes an RK-87 is tough to beat for $100.

Dave

 

[Matador]

Eric's capsules compete with the highest quality 67 type capsules at less than 25% of the cost.  You won't find a better deal in DIY even if you tried.

In terms of flattening the frequency response:  the high frequency negative feedback is part and parcel of the U87 sound.  2SK170 does have a very high gate-source capacitance, but all of these JFET's have many MHz of available bandwidth even in these microphone applications.