The Ultimate DIY U47 - Build Thread (And some PSU questions)

[Moby]

Agreed. The plan is to mill the screw heads slightly smaller. The brackets that the screw attach to have to be milled to clearance as well.

You can use slotted head fastener and then mill it. Maybe that looks better. Vintage German mic' used slotted ones.

 

[StormsofVogue]

You can use slotted head fastener and then mill it. Maybe that looks better. Vintage German mic' used slotted ones.

Good point. A slotted screw could be made smaller and would look nicer. I'll have to track some down.

 

[StormsofVogue]

Long overdue update. I have my PSU nearly complete. I'm doing some testing and I ran into a weird issue. With the C1 capacitor connected (highlighted in red), I get a significant voltage spike across the whole circuit. It jumps from 105v to 140v under load measuring at the output.

I'm using a choke instead of R1. Is that the reason? Should I be leaving C1 out when using a choke?

Thanks as always!

EDIT: I did some further reading. Looks like the C1/Choke/C3 section is called a Pi filter. I read some sketchy documentation that says that Pi filters have higher voltage output. Maybe this is an expected behavior? Do I just need to increase the resistance of R4 to account for this?

 

[Lampie519]

Somehow i miss the "Ultimate" here... maybe i just don't get it LOL.
It looks nicely done though.

 

[StormsofVogue]

Somehow i miss the "Ultimate" here... maybe i just don't get it LOL.
It looks nicely done though.

Maybe if I spray-painted it pink?

 

[Lampie519]

Try replacing R2 with the choke instead of R1.

 

[StormsofVogue]

Try replacing R2 with the choke instead of R1.

That'd be a last resort. I'd have to reconfigure my layout.

I haven't seen an actual build of the schematic I'm following. I think perhaps it was assumed that a resistor would be used in R1 with the printed values for R4. I've seen a number of builds with choke using Dan's PCB kit and he's using a 1k resistor for R4 + a 1k trim pot. In contrast, the schematic I'm following calls for a mere ~220ohms in R4 and a 500ohm trim pot. Dan's circuit is the same except for these values. I'm 90% sure the behavior I'm getting from the Pi filter is expected and I just need to increase the resistance in R4 and the trim pot.

Would love it if someone could confirm. I installed a 1k resistor in R4 and got the output voltage down to 115v (from 140v) with my 500ohm trim pot maxed out. I don't have a 1k pot on hand, but I think that would do the trick to get me to 105v under load.

 

[terry setter]

Try pulling C1 from where it is (the voltage will then fall noticeably. Move C1 to be parallel with R5/LED, or C5. You'll get back the filtering action of the cap and the voltage should be closer to what you are wanting.

 

[jose2hype]

Edit: Yes, it's 2023 and this build is still in progress.

Hey all! I've been working on this U47 build for a while. My initial plans were just to get a cheap U47. As I've done research it's become more of an attempt at a holy grail clone than a cheap one. I do have a couple of questions I'd love to get some input on, but first a quick summary of my build.

The Mic​

I'm sure you're all familiar with Dan's work. I purchased a mic body from him as well as some other parts. Much of my schematic information has come from him as well.

View attachment 86329

I don't think there's a more perfect U47 replica chassis in existence. Incredible work by Dan.

View attachment 86330

I was originally considering an EF-800 tube, but ended up going with the Phaedrus Audio VF-14M. The capsule is a BeesNeez K47. Transformer is a Cinemag CM-2461Nico, but I'll likely be switching it for an AMI BV8R.

The PSU​

View attachment 86331

This is where things get a little uncertain. Since my original plans involved an EF-800 tube, Dan's PSU circuit for that tube was a no-brainer. I actually kind of liked the idea of having a separate line for the heater voltage rather than the big drop-down resistor. The problem is the Phaedrus requires 35vdc and the EF-800 circuit only supplies 5v.

The Dilemma​

View attachment 86332

This is kind of what I'm aiming for at the moment. I've done rivets on G-10 board before and I love the look of it. I might even go with turrets. The trick is coming up with an appropriate circuit.

View attachment 86333
This is Dan's EF-800 PSU schematic. I half-way thought I might be able to just use 105v side of this circuit and use the drop-down resistor to get my 35v to H+. However, I've noticed that the standard 105v PSU circuits that are used along with the pull-down resistor usually feature these beefy wire-wound ceramic resistors and a choke filter. I must be missing something.

I'm also concerned about sourcing the correct pull-down resistor. I think I'll need to get pretty close to that 35v to make the Phaedrus not-really-a-tube thing happy and I'm not sure I'm going to be able to source a resistor that's able to do that. If the schematic's I've found are correct, I need a heat-sinked resistor with somewhere around 1750ohms. I did some searching on Mouser, and these don't seem particularly easy to come by.

​

My Options​

So I'm kind of stuck. Here's the basic summary of my options and concerns:

• Build standard U47 PSU
  • I kinda' don't like the giant wire-wound resistors, and I'm not sure I'm going to be able to source the correct pull-down resistor.
• Use the EF-800 105v circuit by itself along with the internal U47 pull-down resistor
  • I'm pretty sure this isn't going to work, plus it still leaves me with the issue of sourcing a pull-down resistor.
• Use the EF-800 circuit concept, but redesign the 5v side for 35v operation
  • I don't mind this option, but redesigning the 5v side is currently outside of my skillset. I may research this option further if it seems to be the most ideal.

Any advice, assistance or opinions are welcome and very much appreciated. Thanks!​

 

[jose2hype]

Hello, I've been researching the great task of building a U47 clone. First off, I am no greenhorn when it comes to building DIY projects. I have many under my belt I am however, new to the mic DIY side of things. I've seen kits on numerous websites that go from 799 on up. I've seen BOMs, capsules, mic bodies, PCBs, etc etc on different websites. Many are from 10+ years ago to more current Mic & Mod type deals. Needless to say its all very confusing. I'm convinced that I personally would like to just gather all the parts myself and just build. I wish there was just a current PDF of what exactly is needed and where to source. I just seen what you have posted and would be very interested in going this route. Any help, guidance, BOMs, Websites, contacts, etc would be greatly appreciated. As a side note, I am not an electronics engineer just a guy that loves to solder and use what I put together in my project studio.

 

[Roman Beilharz]

Hello, I've been researching the great task of building a U47 clone. First off, I am no greenhorn when it comes to building DIY projects. I have many under my belt I am however, new to the mic DIY side of things. I've seen kits on numerous websites that go from 799 on up. I've seen BOMs, capsules, mic bodies, PCBs, etc etc on different websites. Many are from 10+ years ago to more current Mic & Mod type deals. Needless to say its all very confusing. I'm convinced that I personally would like to just gather all the parts myself and just build. I wish there was just a current PDF of what exactly is needed and where to source. I just seen what you have posted and would be very interested in going this route. Any help, guidance, BOMs, Websites, contacts, etc would be greatly appreciated. As a side note, I am not an electronics engineer just a guy that loves to solder and use what I put together in my project studio.

Hey Jose,

I feel you. I know what its like, I've been there. Hence I'll give this a quick shot, knowing your question calls out for lengthy answers that can go all kinds of ways. Please allow me to categorize:

A) You want this mic badly and fast
Then you should absolutely go down the complete-kit-path and order at micparts (I think they currently just have a C12ish kit on offer, great pricing when your're in the US) or micandmod.com (the PSU is already built, you'll be done in a net mic building time of 3 hours max, everything's in the box, no surprises, the chinese and czech parts are carefully selected, the evolved EF86-based circuit is not just a copy of the Archut designs and sounds great plus their support is awesome - a business model in it's own right and not just a ripoff as many members seem to promote here). If you want an even better sounding U47ish mic, you can easily swap components later on and upgrade capsule, transformer, capacitors and/or tube.

B) You want a high-end clone for not much more, don't mind altering hardware parts and time is not an issue
Then I'd personally prefer to build this circuit (links to BOMs for mic and PSU included)
Vintagemicrophonepcbkit.com
order everything listed under "Vintage-Microphone PCB D-EF47 Project" including the relay here
Vintagemicrophonepcbkit.com

plus this body
MK47 microphone body kit (rev 2)

and search the web for
-a fitting PSU housing
-a fitting 60mm diameter shockmount
-a proper 7pin XLR mic cable (Gotham or the like)
-a couple of fitting new/NOS EF80(0/2) tubes to select your favorite/the least noisy one

Then order this classy German M7 capsule (cheaper than the D7 clone on vintagemic; it's being used in the current Telefunken U47 mic that sells for 11k)
Thiersch elektroakustik
Just email Rico Vetterlein ( info@mikrofonunion.com ) to order a STW7 red line capsule (PET) he's a great guy. The STW7 blue line PVC-version seems to sound a tad bit sweeter, but I would not want my capsule to deteriorate within years due to chemical decay.

Andreas Grosser's partner still has a couple of Haufe BV08 transformers left on stock, which he sells for just 200 Euros (which is about 60% of the original price). It's also being used in lots of expensive U47 clones like the Telefunken ones:
Haufe BV 08
Don't be fooled by the German captions saying "8:1" transformer: It isn't, the Haufe BV08 is 6.5:1 as in most of the later original Neumann U47s.

The only cons of this build are:
-this version doesn't have a multipattern switch: it's either cardioid or omni (the micandmod one and some others have 9-fold MP-switches)
-if the relay fails, you might grill your capsule due to over voltage

Good luck!

 

[jose2hype]

Thank you for your reply!!! This is a huge help. I am not in a rush for this build. I just want a good quality mic that will last. Once again, thank you and I’m sure this will help many others as well.

 

[jose2hype]

Update.........unfortunately everything under the "Vintage-Microphone PCB D-EF47 Project" is "sold out" at Vintagemicrophonepcbkit.com. Unable to order anything at all. What a bummer.

 

[Barry Hufker]

Hey Jose,

I feel you. I know what its like, I've been there. Hence I'll give this a quick shot, knowing your question calls out for lengthy answers that can go all kinds of ways. Please allow me to categorize:

A) You want this mic badly and fast
Then you should absolutely go down the complete-kit-path and order at micparts (I think they currently just have a C12ish kit on offer, great pricing when your're in the US) or micandmod.com (the PSU is already built, you'll be done in a net mic building time of 3 hours max, everything's in the box, no surprises, the chinese and czech parts are carefully selected, the evolved EF86-based circuit is not just a copy of the Archut designs and sounds great plus their support is awesome - a business model in it's own right and not just a ripoff as many members seem to promote here). If you want an even better sounding U47ish mic, you can easily swap components later on and upgrade capsule, transformer, capacitors and/or tube.

B) You want a high-end clone for not much more, don't mind altering hardware parts and time is not an issue
Then I'd personally prefer to build this circuit (links to BOMs for mic and PSU included)
Vintagemicrophonepcbkit.com
order everything listed under "Vintage-Microphone PCB D-EF47 Project" including the relay here
Vintagemicrophonepcbkit.com

plus this body
MK47 microphone body kit (rev 2)

and search the web for
-a fitting PSU housing
-a fitting 60mm diameter shockmount
-a proper 7pin XLR mic cable (Gotham or the like)
-a couple of fitting new/NOS EF80(0/2) tubes to select your favorite/the least noisy one

Then order this classy German M7 capsule (cheaper than the D7 clone on vintagemic; it's being used in the current Telefunken U47 mic that sells for 11k)
Thiersch elektroakustik
Just email Rico Vetterlein ( info@mikrofonunion.com ) to order a STW7 red line capsule (PET) he's a great guy. The STW7 blue line PVC-version seems to sound a tad bit sweeter, but I would not want my capsule to deteriorate within years due to chemical decay.

Andreas Grosser's partner still has a couple of Haufe BV08 transformers left on stock, which he sells for just 200 Euros (which is about 60% of the original price). It's also being used in lots of expensive U47 clones like the Telefunken ones:
Haufe BV 08
Don't be fooled by the German captions saying "8:1" transformer: It isn't, the Haufe BV08 is 6.5:1 as in most of the later original Neumann U47s.

The only cons of this build are:
-this version doesn't have a multipattern switch: it's either cardioid or omni (the micandmod one and some others have 9-fold MP-switches)
-if the relay fails, you might grill your capsule due to over voltage

Good luck!

This is an excellent post and the kind that means so much to builders like myself who are eager but otherwise lost in the ocean of information presented on this site. Thank you!

 

[doqmemory]

Update.........unfortunately everything under the "Vintage-Microphone PCB D-EF47 Project" is "sold out" at Vintagemicrophonepcbkit.com. Unable to order anything at all. What a bummer.

Dan said in another post that the shop was on vacation for August, or something like that

 

[Roman Beilharz]

Update.........unfortunately everything under the "Vintage-Microphone PCB D-EF47 Project" is "sold out" at Vintagemicrophonepcbkit.com. Unable to order anything at all. What a bummer.

Sheesh, I wasn't aware of that; they should add their "out of stock" earlier and not only when you try to check out items. I am sorry.

But maybe they are just on vacation, indeed (another thing that for sure feels more homemade than usual pro business, DIY is more like a family in all respects: a love and hate relationship). If you don't want to wait and see and have a budget of about 1.3k, then you could still order this kit w/o the capsule straight away (that's what I did, even including the capsule to examine the differences and the capsule is way better than I thought, but still Thiersch is the real deal):
U47 DIY Microphone Kit - Telefunken Neumann U47 Clone - Mic & Mod

Order the Thiersch M7 (STW7 red line including long neck holder, email Rico, see above). To me the M7 sounds clearly more interesting and different to most mics that I have in my locker, so I would highly recommend to go down this path rather than the RK47-one. Then see whether you like the sound of the stock Replica Microphones BV8-transformer or order one of the Haufe BV08's at Voxorama while they still have them (link see above, PM me about the wiring scheme - the colors don't match).

One comment about audio examples you can find online: The notion where they put 4-5 mics in front of the same singer/player is misleading, as the on-axis mics will sound best in most cases even if you level-match the examples. When it's similar but different takes and the mics are being swapped at the same position, you can't tell what's what as well, because, well... they are all different takes. And we are talking about sound nuances that need great speakers/room and/or the best headphones you can get hold of. Most of the downloadable audio files I found are technically fine but of such bad quality, artistically, that they are no fun to listen to.

Hence I came up with a standardized setup to evaluate my builds. You'll find more details about that and audio demos - with some well known mics as reference as well - here A poor (wo)man's microphone measurement equipment

Here's another link for parts that I found, if you would prefer to wait and gather the stuff for yourself. You could still use a blank grid PCB and wire this thing together for yourself, the circuits aren't complicated at all, given you have soldered together more complex stuff as you said.
Products | Premium Studio Microphone Parts | Audioparts

 

[Roman Beilharz]

This is an excellent post and the kind that means so much to builders like myself who are eager but otherwise lost in the ocean of information presented on this site. Thank you!

I am also pretty new to this and I am sure some of the experts here might think otherwise, but I tried to give something back to the community that has helped me a lot already. Glad you found this helpful

 

[ElSmurf]

I'd add two more options that offer great value for the money, and both of which are built by GDIY members : Moby's BV-08 transformer and Arienne Audio's Flat K47

Also, check out this thread for tubes.

And I'd definitely wait for Dany's boards to become available again.

 

[jose2hype]

Sheesh, I wasn't aware of that; they should add their "out of stock" earlier and not only when you try to check out items. I am sorry.

But maybe they are just on vacation, indeed (another thing that for sure feels more homemade than usual pro business, DIY is more like a family in all respects: a love and hate relationship). If you don't want to wait and see and have a budget of about 1.3k, then you could still order this kit w/o the capsule straight away (that's what I did, even including the capsule to examine the differences and the capsule is way better than I thought, but still Thiersch is the real deal):
U47 DIY Microphone Kit - Telefunken Neumann U47 Clone - Mic & Mod

Order the Thiersch M7 (STW7 red line including long neck holder, email Rico, see above). To me the M7 sounds clearly more interesting and different to most mics that I have in my locker, so I would highly recommend to go down this path rather than the RK47-one. Then see whether you like the sound of the stock Replica Microphones BV8-transformer or order one of the Haufe BV08's at Voxorama while they still have them (link see above, PM me about the wiring scheme - the colors don't match).

One comment about audio examples you can find online: The notion where they put 4-5 mics in front of the same singer/player is misleading, as the on-axis mics will sound best in most cases even if you level-match the examples. When it's similar but different takes and the mics are being swapped at the same position, you can't tell what's what as well, because, well... they are all different takes. And we are talking about sound nuances that need great speakers/room and/or the best headphones you can get hold of. Most of the downloadable audio files I found are technically fine but of such bad quality, artistically, that they are no fun to listen to.

Hence I came up with a standardized setup to evaluate my builds. You'll find more details about that and audio demos - with some well known mics as reference as well - here A poor (wo)man's microphone measurement equipment

Here's another link for parts that I found, if you would prefer to wait and gather the stuff for yourself. You could still use a blank grid PCB and wire this thing together for yourself, the circuits aren't complicated at all, given you have soldered together more complex stuff as you said.
Products | Premium Studio Microphone Parts | Audioparts

Great info!! I’ll wait until they return from vacation. I’m not in a rush. I know this project will take some time. I’ll start on the bom and get what I need. I’ve already reached out to Andreas for the BV08 you recommended. Thanks again!!

 

[Roman Beilharz]

Great! I am sure the Moby transformer is also a great choice, but this is a rare sale and the Haufe BV08 will keep its value or even increase it. FYI, Andreas Grosser used to be one of the best German independent microphone engineers but sadly passed away . His company is still up and running, though, lead by his partner Riza Coertlen.

Update: I just found this :-(



Sorry, mate. I would have to setup a group buy through my books and do the shipping, which as our baby will be born within the next couple of days is not really a feasible option. So Moby would indeed be your best bet now.