Neumann U67 Clone : D-U67 Tube Microphone Build Thread.

[micaddict]

I hear you. 

And I'll repeat that I personally don't consider the U67 a dark microphone.

 

[ruairioflaherty]

Because of the semantic nature of many of these recent response/posts, I'll say I too have used a few U67s.
They have a defined and articulated high end.
I used the word airy because in direct comparison to the two immaculate original U67s -
the IO audio D67 sounded dark and the U67s sounded like there was a distinct high end extension and articulation not present in the IO audio fitted D67, confirmed by two other engineers beside myself.
I called it 'airy'. Guess that word stuck in some jowls... :-X (see tag)

As I say I don't have a opinion on the transformer issue, it seems people are losing hi end somewhere.  If you are saying that the 67s you heard were airy next to non functioning mics then I guess that makes sense but in the wider mic world a 67 is not airy. 

It's not a big deal at all but I'm thinking about builders out there who won't have access to originals, if they are expecting a very open top end they might think they have an issue when they don't.

In very broad terms -
Dark - AEA R84, Beyer
Neutral/balanced - U67/U47
Bright/Airy - Manley Reference, C12/24, C251

 

[stitch-o]

I think you meant the ELAM251. I've used those, and original C12's, and RCAs and everything you have mentioned.
Again, the D67 with the IO transformer is NOT non-functioning. It function's fine.
Again, in comparison of orig....eh, whatever  :-X

 

[ruairioflaherty]

Yes Elam!  Sorry, no green tea yet.

I'll stay out of the transformer conversation, I haven't read enough to even know what's going on.

I spent some time really looking inside my 67 yesterday, perhaps one day I'll build it a brother.

 

[mickdundee63]

On a (sorta) related point – I have the AMI board and have stuffed it ready to go but ended up getting the AMI BV12 classic which I understand is a drop in replacement for the original tranny and so wound the same way. Is there going to be a workaround with the AMI tranny board or if the IOaudio tranny is also a drop in replacement should I just re-order the ioaudio board, dremel off the transformer portion and re-wire the severed traces?

 

[poctop]

On a (sorta) related point – I have the AMI board and have stuffed it ready to go but ended up getting the AMI BV12 classic which I understand is a drop in replacement for the original tranny and so wound the same way. Is there going to be a workaround with the AMI tranny board or if the IOaudio tranny is also a drop in replacement should I just re-order the ioaudio board, dremel off the transformer portion and re-wire the severed traces?

If you have Have Stuff the AMI board this one is made to have room for an external transformer just install the transformer in the cavity wihout the AMI adaptor board and wire it to the main mic pad as per the corrrected wiring note and you should be able to go ,
Best,
Dan,

 

[kaguenpituak]

I have placed with a switchboard the possibility of putting in parallel with the transformer of exit a small condenser. This way I make  less brilliant u67 (Ami) if I wish it

 

[kaguenpituak]

I had ground connected across the plug to electrical net and across the xlr (3pin). Due to it the electromagnetic interference was appearing

 

[mickdundee63]

This is AMIs BV12C transformer. I have requested a data sheet but haven't heard anything back - has anyone installed one before? As you can see in the picture the wires are arranged

white ------------ blue
        ------------black
yellow------------red

grey  ------------white
        ------------black
green------------orange

I'm operating on assumptions: the left hand side is the primary so yellow and grey should be linked and green and white used - polarity i'm not sure but have to hope that the physical orientation has been setup to match the schematic. The blacks are to be grounded, blue and white are audio same as in the original schematic and therefore red and orange are the feedback windings.

Anyone able to offer any guidance?

 

[poctop]

This is AMIs BV12C transformer. I have requested a data sheet but haven't heard anything back - has anyone installed one before? As you can see in the picture the wires are arranged

white ------------ blue
        ------------black
yellow------------red

grey  ------------white
        ------------black
green------------orange

I'm operating on assumptions: the left hand side is the primary so yellow and grey should be linked and green and white used - polarity i'm not sure but have to hope that the physical orientation has been setup to match the schematic. The blacks are to be grounded, blue and white are audio same as in the original schematic and therefore red and orange are the feedback windings.

Anyone able to offer any guidance?

you need to ask Oliver a complete and exhaustive datasheet on this one ,
as i understand this is the wired version of the T67 but I have never used it before ,
you could take a DMM and start measuring DCR to know more but you also need to know the polarity on this one as it is important for final wiring ,
Please when you have it please post it here as well,
Best,
dAN,

 

[poctop]

This is AMIs BV12C transformer. I have requested a data sheet but haven't heard anything back - has anyone installed one before? As you can see in the picture the wires are arranged

white ------------ blue
        ------------black
yellow------------red

grey  ------------white
        ------------black
green------------orange

I'm operating on assumptions: the left hand side is the primary so yellow and grey should be linked and green and white used - polarity i'm not sure but have to hope that the physical orientation has been setup to match the schematic. The blacks are to be grounded, blue and white are audio same as in the original schematic and therefore red and orange are the feedback windings.

Anyone able to offer any guidance?

you need to ask Oliver a complete and exhaustive datasheet on this one ,
as i understand this is the wired version of the T67 but I have never used it before ,
you could take a DMM and start measuring DCR to know more but you also need to know the polarity on this one as it is important for final wiring ,
Please when you have it please post it here as well,
Best,
dAN,

here is the documentation you requested,

https://cdn.groupbuilder.com/groupdiy/u/39511/58d028199420e.pdf

Best,
dan,

 

[JessJackson]

I built a u67 inside a u87ai last month using that bv12, the mic sounds COMPLETELY different to the du67 with t67 in a GREAT way. i don't know why but ill make a separate post v soon! at the moment i'm loving this mic.

 

[micaddict]

I built a u67 inside a u87ai last month

Interesting.

Did you use Dany's PCB, and if so, how did you make it fit?

Also, did you use the U87ai's capsule?

Henk

 

[JessJackson]

I built a u67 inside a u87ai last month

Interesting.

Did you use Dany's PCB, and if so, how did you make it fit?

Also, did you use the U87ai's capsule?

Henk

Hi henk,

I built it all point to point on perfboard from scratch as a almost identicle to original u67.

I measured all internals of original using digital calipers. Used danys psu though. I used the original hwadbasket and capsule. Just changed the low cut cap value as per u67 but added ground pin hookup to pass through to headbasket like u87ai

Best

J

 

[micaddict]

Cool, Jess!

Be prepared, though.
Once the word spreads, your inbox a.o.t. might overload quickly.



Henk

 

[poctop]

I built a u67 inside a u87ai last month using that bv12, the mic sounds COMPLETELY different to the du67 with t67 in a GREAT way. i don't know why but ill make a separate post v soon! at the moment i'm loving this mic.

Do you mean you have built it with this new Classic Series BV12 From Oliver ?

LEt me know ,
Best,
DAn,

 

[MetalD]

I built it all point to point on perfboard from scratch as a almost identicle to original u67.

I measured all internals of original using digital calipers. Used danys psu though. I used the original hwadbasket and capsule. Just changed the low cut cap value as per u67 but added ground pin hookup to pass through to headbasket like u87ai

Best

J

I think we're going to need to see some pictures because that sounds awesome and I want to see

 

[mickdundee63]

This is AMIs BV12C transformer. I have requested a data sheet but haven't heard anything back - has anyone installed one before? As you can see in the picture the wires are arranged

white ------------ blue
        ------------black
yellow------------red

grey  ------------white
        ------------black
green------------orange

I'm operating on assumptions: the left hand side is the primary so yellow and grey should be linked and green and white used - polarity i'm not sure but have to hope that the physical orientation has been setup to match the schematic. The blacks are to be grounded, blue and white are audio same as in the original schematic and therefore red and orange are the feedback windings.

Anyone able to offer any guidance?

you need to ask Oliver a complete and exhaustive datasheet on this one ,
as i understand this is the wired version of the T67 but I have never used it before ,
you could take a DMM and start measuring DCR to know more but you also need to know the polarity on this one as it is important for final wiring ,
Please when you have it please post it here as well,
Best,
dAN,

here is the documentation you requested,

https://dl.dropboxusercontent.com/u/43869772/U67/BV12.pdf

Best,
dan,

Perfect. Thankyou Dan. I am installing this very soon in a DU-67 then just have to sort a tube. I am V jealous of Jess Jackson's p2p model. I instead have smashed a KK87 capsule and head basket on an sty-5 body. Oh boy will it be ugly . I am also building a second with standard sty-5 body/head grill and t67 transformer so will be interesting to hear the difference.

 

[poctop]

This is AMIs BV12C transformer. I have requested a data sheet but haven't heard anything back - has anyone installed one before? As you can see in the picture the wires are arranged

white ------------ blue
        ------------black
yellow------------red

grey  ------------white
        ------------black
green------------orange

I'm operating on assumptions: the left hand side is the primary so yellow and grey should be linked and green and white used - polarity i'm not sure but have to hope that the physical orientation has been setup to match the schematic. The blacks are to be grounded, blue and white are audio same as in the original schematic and therefore red and orange are the feedback windings.

Anyone able to offer any guidance?

you need to ask Oliver a complete and exhaustive datasheet on this one ,
as i understand this is the wired version of the T67 but I have never used it before ,
you could take a DMM and start measuring DCR to know more but you also need to know the polarity on this one as it is important for final wiring ,
Please when you have it please post it here as well,
Best,
dAN,

here is the documentation you requested,

https://cdn.groupbuilder.com/groupdiy/u/39511/58d0281994237.pdf

Best,
dan,

Perfect. Thankyou Dan. I am installing this very soon in a DU-67 then just have to sort a tube. I am V jealous of Jess Jackson's p2p model. I instead have smashed a KK87 capsule and head basket on an sty-5 body. Oh boy will it be ugly . I am also building a second with standard sty-5 body/head grill and t67 transformer so will be interesting to hear the difference.

Not Sure if understand the Smashed KK87 capsule or the syt-5 mic ,  did you dropped it if so i am sorry for you ,
if you do have a KK87 make sure you have the backplate shorted togheter to render it in a K67 style capsule ,

you will also need a schematic complement of the AMI pcb pad connection to make sure you wire te new BV12 transfo correcty , i will post it later tonight for you ,
as per the T67 please consult the first page for proper corrected wiring for the feedback loop to work correclty.

Best,
dan,

 

[mickdundee63]

No that is just my colourful language the kk87 isn't broken i just mean it looks a bit awkward with the two put together as they are a bit of a mismatch. I do know to short the backplates together and thanks very much for posting the AMI pcb pad document later.