Studio Projects C1 upgrade

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

bezen4uk

Well-known member
Joined
Jul 27, 2009
Messages
134
Hi guys,
I've recently finished upgrading SP C1 microphone with Neumann U87 rev 16 circuit.
Can't resist to say what a great capsule this mike has!

There are samples with modded SP C1 and original U87:
http://k007.kiwi6.com/hotlink/fou5o883p2/u87.wav
http://k007.kiwi6.com/hotlink/mp6jeo6wa9/sp_c1.wav

There is actual circuit diagram of the modded mic in attach.
Since SP C1 has one-sided capsule, there are minor value changes.
 

Attachments

  • SP C1 upgrade.pdf
    46.1 KB · Views: 124
Hi Bez, I have a new model C1 that I was thinking of transforming using the pcb's from the vintage U87 build thread . I wanted to re- use the C1 capsule and the tranny if its ratio works. Is this what you did or did you just rework the original C1 pcb? Please do tell. Thanks
 
You can add one part to a stock C1 to adjust it. 
I have the first ver of the C1 and have done this.
 
Hi North,
The stock C1 is transformerless, you need to add 10:1 tranny.
I designed single-sided PCB, the stock PCB was dissected for 1G resistors.
I'll post PCB draw asap.
 
I listened to the samples and I am hard pressed to tell the difference between them through headphones. Yes would like to see what you've done, This sounds like a great project and using the stock capsule is even better.
 
Note that FET and some parts added at the back side of the PCB.
The trafo is self made from old russian lams.
 

Attachments

  • img2.jpg
    img2.jpg
    68 KB · Views: 136
Very interesting Bezen.

Where can we buy the Neumann U87 rev 16 circuit PCB boards?  That is what
you have in your pics, right?

And will pretty much any 10:1 audio transformer work in this case?

 
Hi,
Fixed error in schematics (C3 connection) and added PCB draw.
The best trafos for this mod are AMI T13 and CM2480.
 

Attachments

  • SP C1 upgrade.pdf
    45.5 KB · Views: 107
Hey nice work Bez. This doesn't look as populated as the the other U87 builds on here. Is it the same thing?
 
Hi,
The capsule in SP C1 has only front membrane connected and can be used as cardioid only.
Since it's cardioid only, some capacitors/resistors from original Neumann circuit are skipped.
That's why the circuit looks so different from original.
In fact it's close to original. So the sound is.
I think the sound differs mostly because of headbasket construction.
Look at the SP C1 body.
There is cavity under capsule. Original U87 body doesn't have.
Headbasket mesh size differs too.
 
Ahh very good point. I really only use cardioid so this is good. Have you done samples comparing between the C1 stock and modified?
 
Hi North,
I haven't made comparision of stock vs modded.
The stock mike had issues so I modded it :) .
 
I will have to try this. Ive never made a pcb from scratch before so this should be fun. Are there any special components that you were sure to use and any jumpers etc. that you have to make on the pcb?
Thanks again
 
Hi North,
There is nothing special.
Check pdf file in the first post: added some assembly notes (capacitor polarity marking, type etc).
Feel free to ask.
Vlad.
 
Has anyone succesfully mod a Studio Projects C3 to make it more sounding like a u87?

I'm aware of the Microphone-parts mod, but would rather get my own components saving quiet some money.
Has anyone done the microphone-parts?
 
i was hoping to hear the audio, but this kiwi6 site says "Download Disabled for this file"

can you repost, bezen4uk?
 

Latest posts

Back
Top