First Microphone Build Woot Woot! Crap now I need help :)

[Carnesd]

So I'm pretty excited my first build went together pretty darn well,  It's a D87 built from an Aurycle mic body.  I used the two switches on the body for pad and high pass and using the internal jumper for pattern switching.  So far it is sounding really good but I haven't had to time try it out much.  The one thing I notice off the bat is compared to my other condensers (c414 and modded SP B1)  It seems to have quit a bit lower output.  More like a dynamic I've got to crank the preamp a bit to get a good signal.  It sounds wonderful with no noise or anything so Just wondering if this is normal or is something amiss? 
Thanks to Dan and everyone's help on the forums so far,  looking forward to some more builds in the future. 
Here some pics just for fun.
stuffing the boards

Switches Wired up boards ready to go in.

Capsule ready to be wired up

New home,  just waiting on Bias resistor and ready to rock

 

[micaddict]

Nice job. Congrats!

The vintage U87 does have lower output than "modern" condensers, so I don't think you have a problem.

 

[Carnesd]

Awesome,  I was thinking this was the case as It sounded too good.  I already can't wait for the next project. 

 

[micaddict]

Awesome,  I was thinking this was the case as It sounded too good.

Yeah, and an added benefit of the less hot, vintage version is that it has better headroom.

I already can't wait for the next project. 

What do you have in mind?

 

[Carnesd]

What do you have in mind?

Thats the question I keep asking myself haha,  I've got too much in mind for my wallet  .  I'm either thinking of a GSSL in a 1u or starting a 500 series rack with some CAPI and SoundSkulpter pre's.  Also Chunger's write up on the C12 makes it look like an easy one for a noob like me.  I want to build it all lol. 

 

[maq3396]

Congratulations on your first build!
Technique looks very precise.
Lots of options out there for the next build....and the one after that....and....

 

[dchang0]

If you think the U87i gain is too low, avoid the U47fet.

Also, Chunger sells Matador's PCB that can be used to convert the U87i to nearly U87Ai specs (higher gain, lower self-noise, lower headroom). I am considering going this route for my two D-87/U87i builds

 

[Carnesd]

Thanks for the comments guys,  there are a couple things I wish I did a little better but overall I think it turned out pretty good.  As far as the mic gain,  as long as its normal its not much of a problem,  It just gives me more incentive to build some good Preamps

 

[Carnesd]

So I been playing around with the mic a little bit and realize that this thing really needs alot of gain to have a good signal level,  Its about even with my ribbon mic so I went decided to look into it a bit more. 
And I realize I may have skipped/misunderstood a couple steps in the Optimization process  :

Apparently I needed to bias the FET with the transformer leads disconnected?  I have 11v at the fet drain with the transformer and capsule connected.  When I first did it without the capsule connected I had settled at 11.3v

And I also did not check the IDSS of the FET,  (kinda wondered why the bom included three :-\)  Is it worth it to order 15 more and get one that is low IDSS?

And last but not least I only matched R18 and R19  to 4% from the build thread I was reading and now realize it should be .4%,  I went through all 10 and picked the closest match,  How much of a difference would this make?

Thanks for all your help.
Dustin C.

 

[Carnesd]

So I went ahead and used Matador's method to checking IDSS on the other two Jfets I have from the BOM.  Well the two I have are at 8.3ma and 8.1 ma.  Then I pulled the Jfet originally installed and tested it and got 7.6ma.  Does the lower IDSS give you more or less output?

So I downloaded the Scope program and decided to give it a try,  I disconnected the capsule from the board and injected a 1khz tone into R6,  After fiddling around a bit with the view I got a good sine wave in the scope.  I slowly raised the gain on the sign wave until I got some clipping,  whats weird is it looks as if both sides are clipping at the same time or close to it. 
HOW DOES THIS LOOK?

Here are some pictures of me raising the gain on the tone-

I also decided to do something about the dull brass Aurycle body so shined it up a bit.

 

[poctop]

whats weird is it looks as if both sides are clipping at the same time or close to it.

That is excately the idea.

Like it has been said many times before yes the U87i has 10db less output than a modern high shooter mic. 
and that is also the idea.
Well one thing comes to mind, the D87 Gain has never been an issue in my studio ,  but well for sure a Golden age 73 will not cut it 
Best,
Dan,

 

[Matador]

Everything you've done looks spot on.

Yes, lower IDSS will give slightly higher gain, but it's so little it may not even be audible.

How does it sound?

 

[Carnesd]

That is excately the idea.

Like it has been said many times before yes the U87i has 10db less output than a modern high shooter mic. 
and that is also the idea.
Well one thing comes to mind, the D87 Gain has never been an issue in my studio ,  but well for sure a Golden age 73 will not cut it 
Best,
Dan,

Haha  you caught that picture I see.  I've already got a 500 series rack on order I'm not too terribly concerned with the gain but I realized I had not optimized the circuit like I should have so I just wanted it to be as correctly done as possible.  This was also the first time I've tried using an oscilloscope and wanted to make sure I was looking at it correctly.    Overall this has been an awesome learning experience and I'm thinking my next microphone will be your D-251,  It looks pretty fun with the point to point section.  Thanks again.
Dustin C.

 

[Carnesd]

Everything you've done looks spot on.

Yes, lower IDSS will give slightly higher gain, but it's so little it may not even be audible.

How does it sound?

Ok,  thanks I was just wondering if there would be mch difference.  I will stick the original Jfet back in.  It sounds great so far with the minimal amount I've messed with it.  Hopefully this week i can get some recording time in and put it through some real tests.  Thanks Again,
Dustin C.

 

[poctop]

Everything you've done looks spot on.

Yes Matador is right , you have done a great job , clean , precise and well placed , if this is your first project then you will have great sucess in your future project , those are the skill required to be efficient and proactive in the DIY World,

Overall this has been an awesome learning experience

yes indeed if you didnt learn anything all this work would worth absolutely nothing

Keep up the good work ,
Best,
Dan,