D-EF47 Tribute To Oliver Archut U47 Build Thread.

[Zjcc56]

Hello all,

So I recently built this mic with a blueline m7 and a ami transformer and it is truely glorious, and also very sensitive and quite louder than my other mics

Anyways,  there has always be this buzz in it when it's in card mode, not a problem with loud sources like drums it's quite low but when recently doing a voice over project I had a quiet talker and when I put about 30db of gain on it the buzz makes it unusable. I've tried different cables pres and the ever dangerous ground lift to alleviate it but with no success. When I switch it to Omni it pretty much goes away it's still there but only if I max my gain out and at that point the noise floor hiss and anything happening within a mile is picked up (not really but you get the point?)

So I did basic trouble shooting
1. Change cables pres etc.
2. Checked grounds with a beeper, all seems well
3. Quick visual check, noting the to see here
4. Lifted xlr ground on the 3 pin and 7 pin
5. Removed shelf jumper

None of these things worked

However when I disconnected the relay (pattern) in the psu the noise went away.
So it's usable in card only which is what I use it in most of the time but I do like the pattern switching....

Any thoughts?

Edit: spelling and poor grammar

 

[hugo]

Did you ordered from micandmod? If yes, you all have an issue with cardioid mode. But solution is on previous posts

 

[Zjcc56]

No I did not, i ordered the from vintigemicpcb. I have read that post though.
Am I supposed to get 0v when it's in card mode? When I measured the relay connection (the terminal block)  with the mic connected at the power supply I got around 18v in card and around 50v in Omni.

 

[hugo]

No I did not, i ordered the from vintigemicpcb. I have read that post though.
Am I supposed to get 0v when it's in card mode? When I measured the relay connection (he terminal block)  with the mic connected at the power supply I got around 18v in card and around 50v in Omni.

sorry, it was on an other post : http://groupdiy.com/index.php?topic=63415.0

 

[Zjcc56]

So after re reading that thread and this one and a lot of pondering at work i have found my error,
the switch wiring was very close to my lamp so when i switched to card mode it would just pick up all the crap coming  off of it.
The solution in the thread hugo pointed me to would work OR i could just reroute the wires so when the relay line is floating its noise free.

if i was really anal about it i could get another rotary switch with more poles to simultaneously switch the pattern to 0V and the relay load thing in.

Thanks to Hugo and all those who posted in this thread before me for the information!

 

[poctop]

i am not sure i totally get this but IIRC to relay return coil should always be connected to 0V  ?
i wish i had the time to check this mic and mod confusing tutorial in any case you should not use this mic and mod tutorial 
.#$%43&^%*&^*&^

Edit : Yes sometime we have to make choice when routing  wire in PSU been there done that , 


Best,
Dan,

 

[Colorblind]

Where can I find screws small enough to mount the AMI BV08 Classic to the PCB?  I've got it secured with a zip tie for now, but it's not ideal.  I think I need M2 screws, but can't find any that are long enough.

Thanks,

C

 

[Colorblind]

After a few bumps in the road and some advice from a couple of members here, we are up and running!  Time to burn in the tube.

Thanks all!

C

 

[Murdock]

Looks great!
Mind telling me, what type of PSU case you used?

 

[poctop]

After a few bumps in the road and some advice from a couple of members here, we are up and running!  Time to burn in the tube.

Thanks all!

C

Congratulation for your Build ,
the capsule you have looks awesome  i bet it will sound terrfific 
Best,
Dan,

 

[Colorblind]

Looks great!
Mind telling me, what type of PSU case you used?

It's a Hammond 1453B.  I was going to go with one of Dan's, but I wanted to give myself lots of space so I went with something bigger.

Thanks Poctop!  I bet the capsule will sound great.  A fellow Canuck builds them 

 

[wilberweb]

Awesome colorblind. That mic and psu look great!!
Good job 

-Larry

 

[Phrazemaster]

After a few bumps in the road and some advice from a couple of members here, we are up and running!  Time to burn in the tube.

Thanks all!

C

Looks absolutely smashing!!! Great job man!!!

Wishing you many happy hours of recording!!!  :-*

 

[TLRT]

Where can I find screws small enough to mount the AMI BV08 Classic to the PCB?  I've got it secured with a zip tie for now, but it's not ideal.  I think I need M2 screws, but can't find any that are long enough.

Thanks,

C

You can use M3's, just retap the mouser L holders.

 

[Colorblind]

You can use M3's, just retap the mouser L holders.

I'm referring to mounting the transformer itself, not the PCB to the mic rails.  The holes in the laminations are really small, but I think I found some screws on eBay that will work. 

 

[Bonnie1]

Hi Colorblind,
M2 x 18mm or 2/56 x 3/4" will get your transformer mounted properly.

 

[Colorblind]

Hi Colorblind,
M2 x 18mm or 2/56 x 3/4" will get your transformer mounted properly.

Great, thank you!  Do I need to be worried about spacing the transformer far enough off of the PCB so that it doesn't make contact with the screws that fasten the PCB to the mic rails?

 

[poctop]

Great, thank you!  Do I need to be worried about spacing the transformer far enough off of the PCB so that it doesn't make contact with the screws that fasten the PCB to the mic rails?

I put a telfon spacer in betwee lam and screws and yes it is important
Best,
DAn,

 

[Colorblind]

Thanks Dan, I've got some on the way. 

 

[snork7]

Hi All
Just completed my Oliver Archut U47 and have a question.  It seems to be working, but it needs like 50-60 dB gain to get it in to a
semi reasonable signal.  Of course that increases the noise as well.  It's my first tube mic, so don't have a benchmark to compare.
The question is if that is normal.  It does not make any loud cracking or popping or anything like that, but compared to poctop/chunger's U87 I built which needs about 30-40 dB gain, it's downright dead.  It also sounds a bit dull compared to the 87.  I'm using the AMI BV08R transformer and tskguy's capsule in an Aputis body.  The tubes are NOS from NATO.  I have six of them and am burning them for 12-15 hours.  Is that the way it is supposed to sound or am I missing something?  Of course, I suspect the tube, but just wondering.
Thanks for an awesome build and Happy Holidays!
Charlie