D-EF47 Tribute To Oliver Archut U47 Build Thread.

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Delta Sigma

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Joined
Dec 4, 2010
Messages
418
Location
Winnipeg
Hi everyone!

I've been following this for a little while, but waiting to start buying until I can make sure I can source a decent donor body. I know there have been some supply issues with the factory making the Studio 939 bodies. My plan is to eventually make two D-47s and two D-12s.

What's the best option right now? I'm willing to pay extra for a good headbasket design, the original screw-on Tuchel connectors and a mechanical switch.

Here's what I've found so far:

-MK47 - Studio939 (out of stock)
-Beezneez - DIY U47 style donor (checks the boxes, but $620 with shockmount)
-Equinox Systems, from Don Audio
-Gototoolz, super cheap, $82 or something
-FLEA of course, if you wanna spend $1500 for a mechanical kit...

Or should I just wait until @chunger has bodies back in stock?

Thanks in advance for any guidance!
Beesneez bodies are great but they're quite heavy. Dany's bodies are great:
 

innercityman

Well-known member
Joined
May 12, 2016
Messages
313
Location
France
Hi everyone!

I've been following this for a little while, but waiting to start buying until I can make sure I can source a decent donor body. I know there have been some supply issues with the factory making the Studio 939 bodies. My plan is to eventually make two D-47s and two D-12s.

What's the best option right now? I'm willing to pay extra for a good headbasket design, the original screw-on Tuchel connectors and a mechanical switch.

Here's what I've found so far:

-MK47 - Studio939 (out of stock)
-Beezneez - DIY U47 style donor (checks the boxes, but $620 with shockmount)
-Equinox Systems, from Don Audio
-Gototoolz, super cheap, $82 or something
-FLEA of course, if you wanna spend $1500 for a mechanical kit...

Or should I just wait until @chunger has bodies back in stock?

Thanks in advance for any guidance!
You can also check this thread... It seems that Chinese offers some good and cheap alternatives...

 

stokesmusic

New Member
Joined
Mar 25, 2021
Messages
11
Location
Berlin, Germany
Thanks Delta Sigma and innercityman! Following up on both:) I sent poctop a message to see if he had any bodies available. I had just assumed they were not.
 

wrentema

Member
Joined
Dec 16, 2020
Messages
20
Location
Berlin
Thanks Delta Sigma and innercityman! Following up on both:) I sent poctop a message to see if he had any bodies available. I had just assumed they were not.
I got the cheap Chinese body. It was definitely some work to make it all fit. But here you can see how I did it: New Chinese U47 Style Body

The new version of this body might be with some other brackets though. Not sure.
 

ElSmurf

Member
Joined
Dec 10, 2017
Messages
22
Location
Belgium
I've tested my D-EF47 this weekend and for some reason it sounds as if there's a hi-pass filter on the mic, somewhere around 1KHz. If anybody has any idea what could cause this, I'd appreciate the help.

The component values in the mic itself are all correct, visually. I DID drop the capsule when mounting it, but it looked like it came out of the fall unscathed.
 

Delta Sigma

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Joined
Dec 4, 2010
Messages
418
Location
Winnipeg
I've tested my D-EF47 this weekend and for some reason it sounds as if there's a hi-pass filter on the mic, somewhere around 1KHz. If anybody has any idea what could cause this, I'd appreciate the help.

The component values in the mic itself are all correct, visually. I DID drop the capsule when mounting it, but it looked like it came out of the fall unscathed.
Double check your transformer wiring. What transformer are you using?

Are you using all new components or any NOS like a Russian coupling cap?
 

Delta Sigma

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Joined
Dec 4, 2010
Messages
418
Location
Winnipeg
Will do that tomorrow. I'm using Moby's BV.8, all components are new.
Well, that's good to know. Not only does Moby's BV.08 sound unbelievable, he used the correct Neumann colour code.

It's possible you have one of the phases reversed; I think that would make it sound horrible and tinny. You could try wiring up a single transformer phase and see if that sounds better (for testing, not permanent). Red/green to primary (C2/ground) and white/white to audio.

BV08.png
 

ElSmurf

Member
Joined
Dec 10, 2017
Messages
22
Location
Belgium
Thanks for the suggestion! I didn't get it to work with just one phase/winding, weirdly enough the color codes from the original U47 schematic don't match up with those of the original BV.08. The white and blue leads seem to be reversed. Anyway, as I was trying various configurations I noticed that the bridge between A and B on the PCB (green to green) showed continuity to ground, because the washer holding the transformer in place was somehow making contact with the trace. I put a paper washer between the metal washer and the pcb and wired the transformer up as described in Moby's connection diagram. It sounds as if the mic is working on full bandwidth now. Will do some testing in the days to come but I'm sure it's working as it should now.
 

innercityman

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Joined
May 12, 2016
Messages
313
Location
France
Hi everyone,

simple question... Would 160V 1uf caps be ok ? considering the mic is getting 105V from the PSU. I found NOS PIO USSR caps on eBay but the 250V versions seem to be too big to fit the pcb and mic body... About 5cm
 

alphasnk

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Joined
Apr 10, 2019
Messages
53
Location
France
If you turn on the PSU without a mic plugged in, voltage might ramp up pretty high and blow those caps i think
I think he's talking about the transformer coupled capacitor in the microphone..

Measure what's the maximum voltage you have there when you power on the mic, and see where it rises and if you think it's safe to use a 160v instead of the 250v! :)
 

mrgrooves666

Well-known member
Joined
Feb 1, 2021
Messages
68
Hey all,

This my first tube mic build, and I can't wrap my head around the wiring from the 7-pin connector on the PSU, to the cable, to the mic.

On the PSU 7-pin connector, I've got the ground tab and pin 7 connected, and wires running from pins 1-7 to the corresponding number on the PSU PCB's 8-position terminal block connector.

On the cable connectors, I'm confused about pin 3. Do I just connect the cable shield to pin 3 at each end, or do I need to tie it in with pin 7 at each end, and/or the grounding tab on the PSU end of the cable connector? The build guide shows pin 3 on the microphone connector left disconnected, which I think is adding to my confusion.

Any help for this newbie would be great.

Thanks,

C

Completed the PSU today. Everything seems fine :) I hooked up a ~17 ohm load from H+ to GND and adjusted to 5.05V. With the switch in Cardioid I used a 150K load on B+ -> GND and adjusted to 105.5V. When set to omni I hooked up a 220 ohm resistor between PTRN and GND to simulate the reed switch. Voltage on B+ dropped to somewhere around 75V.

A question about the cable shield (Pin 3) on the mic side: Do you guys connect this to GND pad as well or tie it separately to the body? The GND pad on the mic PCB grounds the body as well.
Good day fellas. I'm finishing the mic as I type, still have PSU to build, but stumbled with the same question, what do I do with Pin 3 in the mic 7 pin XLR insert from PSU side it seems it will have XLR pin 1 from PSU connecting to the cable shield as well, but what about on the mic side?, did you guys figure it out? what did you did in the end, tied it to GND pad in pcb too? what about chassis lugs from the cable connectors and both 7 pin inserts (mic and PSU), should they be grounded somewhere? I'm a little confused, any help is appreciated, thanks in advance!
 
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Clakejr

Member
Joined
Oct 31, 2019
Messages
23
I just bought the D-EF47 pcb but it seems to be a lot of components are obsolete like the" Film Capacitors 0.47uF 250volts 10% Axial" -where are you sourcing these components or alternatives?
 

Purplenoise

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Joined
Sep 18, 2019
Messages
296
I just bought the D-EF47 pcb but it seems to be a lot of components are obsolete like the" Film Capacitors 0.47uF 250volts 10% Axial" -where are you sourcing these components or alternatives?
Any film cap at those values will do…as well as mp and pio caps ( metalized paper and paper in oil)
 

innercityman

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Joined
May 12, 2016
Messages
313
Location
France
I just bought the D-EF47 pcb but it seems to be a lot of components are obsolete like the" Film Capacitors 0.47uF 250volts 10% Axial" -where are you sourcing these components or alternatives?
Where do you stay ? If buying from mouser.com, you can easily find alternatives with same values.
 
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