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

[mohausler]

Hi Hank

here's 2 pics as requested

 

[mohausler]

and the second one

 

[Hank Dussen]

Thanks for the pics. It is indeed tight to fit in the FAB transformer and the tube.
It will be even harder to fit the big green PIO cap in there.  :-\

 

[Hank Dussen]

I noticed that the lead wires going to the center terminal on my Beesneez Capsule are a bit loose.
Is it save to carefully tighten these?

 

[emrr]

Anyone remember the price of Max's BV.12, when it was available? 

 

[Banzai]

I noticed that the lead wires going to the center terminal on my Beesneez Capsule are a bit loose.
Is it save to carefully tighten these?

Yes, you can make them snug.

The Spectrol trimmer tool is perfect if you have one.
Has a recessed screwdriver, makes it impossible to slip and damage the diaphragms.

 

[Hank Dussen]

Thank you. I will be very careful! 

 

[kmozart]

Hi Everyone!  Really need help with these:

I built two D67 following closely, and quadruple checking the direction in the pdf guide from the vintagemicrophonespcb.com

Voltages on the power supply are somewhat OK.  Problem I'm describing here is identical on both microphones, I'm using AMI T67 Transformers, and Microphone parts RK-87 capsules for testing purposes, I'll change them later after I got bodies working perfect.


- I can not lower the B= less than 222V, same on the power supply or on the mic body. H is adjustable. 
- There is no sound coming out of the capsule of the mic (both of them have identical issue)
- Even when no power is applied to the microphone, if I tap on the transformer I can hear it in my headphones, Like I'm tapping on a live microphone body (no, it is not microphonic tube sound).
- I don't see the dots on my transformers, so I have positioned them opposite in the bodies,  still the same problem on both mics.

 

[Delta Sigma]

Anyone remember the price of Max's BV.12, when it was available?

Not spot on because I bought mine in 2012 but here's what I paid then to get one to Canada:

1 Bv12 Transformer €179,00 Euro
Shipping & Handling €27,00 Euro
Paypal fees €8,24 Euro
total €214,24 Euro

 

[emrr]

Not spot on because I bought mine in 2012 but here's what I paid then to get one to Canada:

1 Bv12 Transformer €179,00 Euro
Shipping & Handling €27,00 Euro
Paypal fees €8,24 Euro
total €214,24 Euro

Thanks!

 

[kmozart]

These are the voltages I'm getting at various points in my microphone:


B+ : 221.8V
H-: -6.25V
R11 : -1.8V
R12 : 54.3
R15 :  107.7V
R16 : 15.99V
R10 ; -1.8V
C8 : 16V
S1 (top pin) 219.1
LC - a  : 219.1V
Turret front capsule: -1.00V
Turret backplate : 8.84V

Can anyone confirm I have the right voltages? 
Capsule is not giving any sound, I have RK-87 from Microphone parts.

I can hear tapping on the transformer, like the mic is live, but no sound from the capsule.

Any suggestion what to check?

Where exactly I should inject a signal to check if the amp is working?

Also, I'm using Mogami tube Mic cable. Can  anybody give me the color code for the pin number of the connectors for the cable between the mic and the power supply?  They are going one to one, female to male right?

Sorry, I want badly to make these microphones work, but I got stuck here.

 

[HeavyHand]

2 issues im having...

1. the switches hum when i touch them.
2. Im losing treble when i switch to omni and figure 8.

any thoughts would be greatly appreciated.

 

[HeavyHand]

bump...  anyone?

 

[SebC]

Hi all,

First post! I've been trying to prepare for this build by reading this thread and the PDFs on poctop's website. Still, being the newbie that I am some things still remain unclear. I'm not well versed in electronics, but I am patient, detailed and as a guitarist my hands are good enough for detailed work. I hope it's OK to ask here but let me know if it's better to srart a thread to ask questions along the way. Here are a few initial ones while all the parts keep arriving:

- Besides transformer, tube, capsule what else is needed? Especially for wiring. It seems I'll need gac7 cable? (ordered it). What other cables do I need to get for wiring? And which particular type of wire should I order?

- I ordered this 7 pin xlr cable  https://www.sweetwater.com/store/detail/NTK1017--rode-rode-7-pin-cable-for-k2-ntk?mrkgcl=28&mrkgadid=3274408733&rkg_id=0&product_id=NTK1017&campaigntype=shopping&campaign=aaShopping%20-%20Core%20-%20Accessories&adgroup=Accessories%20-%20Cables&placement=google&adpos=1o1&creative=249895767051&device=m&matchtype=&network=g&gclid=EAIaIQobChMInqrjwryN3AIVHIezCh2pfAo_EAQYASABEgJ42fD_BwE but now I'm unsure if all 7 pin cables are wired the same. And apparently the length of the cable matters in relation to the PSU!? Would anyone know if this cable will work?

- I will be using the no-clean solder that poctop recommends http://www.digikey.ca/product-detail/en/386876/82-121-ND/2498919 is there a recommended temperature for the iron so it's hot enough to be quick but not too hot to splatter whatever rosin is there which I understand is harder to clean?

- Not sure how to implement this diagram for the toroidal transformer. Do I twist grey with green and blue with violet and solder the ends of each pair together at the shown location?

That's all...for now! Things are still arriving. By the way, I'm using AMI BV12, and beesneez K6 capsule. I am sooooo excited!

 

[kmozart]

Hi All,

Where exactly do I insert 1Khz so I can test  the amp of the microphone?

I have the voltages coming up to the mic OK (225.6V - B+, - 6.2V H) But no signal at all. The  I tap the transformer I can hear it on y headphones, regardless if the power supply is on or off. Quadriple checked the wirings  inside the power supply to the connector, cable wiring and the transformer wiring (swapped 5 with 12, 7 with 10 and 1 with 4 between Transformer PCB and the mic main board. also connector is properly wired 1:1 pins with markings on the board.

Thanks,

Kosta

 

[SebC]

Hi all,

Most my questions have been answered by studying all the docs and this entire thread! And by building which has been just so much fun. Everything's been really addressed at one point or another. All I'd like to have here is reassurance (or being corrected) as to my PSU layout diagram. I ordered the Hammond 186B20 and I'm in the US. So I want to make sure I figured it out correct. Thanks to anyone who can give it a quick look!

I'll follow with some pics of my progress so far just to share

EDIT: In case someone might find it useful, this wiring was successful when using the Hammond 186B20 in the USA

 

[SebC]

Pic 1

 

[SebC]

pic 2

 

[SebC]

And pic 3

 

[SebC]

I finished the microphone and I'm happy to say it worked from the start. Wow!!! I can't get over the gift that this is thanks to brilliant and generous people, to poctop's outstanding design, and all the knowledge in here!!! It's really special to be able to have such a sweeeet sounding microphone! Here are some  pictures