D-EF47 Tribute To Oliver Archut U47 Build Thread.

[innercityman]

So I finally got to try the heiserman hk47. Wow…wonderful capsule. Although not an exact Neumann clone it has that neumanesque 3D image that I don’t hear in other k47 clones. A little more tamed in the mids but beautiful sounding and smooth with a very nice but not shrill presence.
i need to do further testing but I believe that the synergy of hk47 and ef800 can bring you a lot closer to the k47/vf14 combo than k47 and ef800. I have a feeling that ef800 doesn’t have the sparkle of the vf14 so the hk47 with the touch of extra air works better.

I would have been surprise that a 350$ capsule didn't give you this kind of U47 magic... Definitely not for everyone's budget

 

[Purplenoise]

I would have been surprise that a 350$ capsule didn't give you this kind of U47 magic... Definitely not for everyone's budget

For sure but…compared to the Neumanns $900 price tag I think it’s a really good price for what you get. Most quality capsules are priced similarly though ( thiersch, beesneez, Tim Campbell etc). I’d rather build a mic with $1000 in parts than buy a mic for a $1000 with $200 worth of parts. That’s how I think of it…given that I build it right of course hahaha

 

[doqmemory]

I’d rather build a mic with $1000 in parts than buy a mic for a $1000 with $200 worth of parts.

Exactly! Little tyke wants his money's worth!

 

[Purplenoise]

Exactly! Little tyke wants his money's worth!

Haha…doesn’t everyone. The truth of the matter is that the less resources you have the more ingenious and knowledgeable you become to overcome the limitations. I have seen people come up with amazing sounding stuff using very affordable parts. Unfortunately I am nowhere close to that so…better parts and proven designs help me sleep better at night haha

 

[negaikast]

So I finally got to try the heiserman hk47. Wow…wonderful capsule. Although not an exact Neumann clone it has that neumanesque 3D image that I don’t hear in other k47 clones. A little more tamed in the mids but beautiful sounding and smooth with a very nice but not shrill presence.
i need to do further testing but I believe that the synergy of hk47 and ef800 can bring you a lot closer to the k47/vf14 combo than k47 and ef800. I have a feeling that ef800 doesn’t have the sparkle of the vf14 so the hk47 with the touch of extra air works better.

Purple,

I ALMOST pulled the trigger on a 3U M7 and was reading through and listening to samples just one more time. Had HK47 also in mind but is twice the I can’t get the D7 currently.

How would you describe the differences between the D7 and the HK47?

I’m trying to replace the stock capsule on my Miktek CV4. Sounds really good but with the high shrill, just doesn’t have that “magic”.

Jake

 

[Purplenoise]

Purple,

I ALMOST pulled the trigger on a 3U M7 and was reading through and listening to samples just one more time. Had HK47 also in mind but is twice the I can’t get the D7 currently.

How would you describe the differences between the D7 and the HK47?

I’m trying to replace the stock capsule on my Miktek CV4. Sounds really good but with the high shrill, just doesn’t have that “magic”.

Jake

Hey Jake, they are different. Hk47 is more detailed with great depth and high end extension. Not an exact k47 but definitely captures the vibe and works great with ef800 tubes. Actually I like it more to a Neumann k47 when paired with an ef800.
The D7 and 3u M7 are similar. Very creamy and smoky…more vintage sounding…Really smooth capsules that also work great with the ef800. I have a feeling an M7 style will work better in cv4 if you go after a really smooth sound especially for vocals

 

[wave]

So I finally got to try the heiserman hk47. Wow…wonderful capsule. Although not an exact Neumann clone it has that neumanesque 3D image that I don’t hear in other k47 clones. A little more tamed in the mids but beautiful sounding and smooth with a very nice but not shrill presence.
i need to do further testing but I believe that the synergy of hk47 and ef800 can bring you a lot closer to the k47/vf14 combo than k47 and ef800. I have a feeling that ef800 doesn’t have the sparkle of the vf14 so the hk47 with the touch of extra air works better.

You have described/explained this exactly how I would...

 

[doqmemory]

You have described/explained this exactly how I would...

I agree with you both, too. The 3U Audio M7 (or D7, when Dan finally gets his new lab set up) will give more of a contrast to the stock K67-style capsule in the CV4. I really like the HK47/EF802 (from Bowie) combo in my U47 clone (Oliver's alternate schematic), but the M7/EF800 in a similar mic sounds nice, too. The bottom line is that you will likely love either one, but you will probably want both.

 

[Purplenoise]

I agree with you both, too. The 3U Audio M7 (or D7, when Dan finally gets his new lab set up) will give more of a contrast to the stock K67-style capsule in the CV4. I really like the HK47/EF802 (from Bowie) combo in my U47 clone (Oliver's alternate schematic), but the M7/EF800 in a similar mic sounds nice, too. The bottom line is that you will likely love either one, but you will probably want both.

I forgot it’s a 67 style capsule in cv4…unless the capsule itself is tuned do you think they have some sort of internal high end attenuation ? K47/m7 might be a touch dark in the mic then ( above 10k).
Hey did you do different biasing in Oliver’s circuit for the 802?

 

[doqmemory]

Hey did you do different biasing in Oliver’s circuit for the 802?

No, I bias the same for EF80/EF800/EF802.

 

[wrentema]

I've contributed very little to this thread. But thanks for all the info (and the great PCB Dan!). I just fired it up. It's so quiet I wasn't even sure if it was on haha. So far it sounds very promising!

R2 and the H+ pot are fairly hot.. Not comfortable to touch.. Is this normal? The wattage should be fine R2 is 3W and pot 5W. The voltages are perfect..

 

[doqmemory]

R2 and the H+ pot are fairly hot.. Not comfortable to touch.. Is this normal?

Yes, see post #73 on page 4 for Dan's reply.

 

[wrentema]

Yes, see post #73 on page 4 for Dan's reply.

Yes I saw it. I'm mostly wondering about R2. I can't really touch it. It's isn't smoking or anything.

 

[Purplenoise]

So the experiment with the more modernized 47 style worked unexpectedly well.
-Stock Dan’s circuit and bias
-Heiserman hk47
-Terrapin toroidal 7.5:1 transformer
-0.47uf output cap ( Russian k42).
Very punchy and 3D with a great sense of realism yet very flattering. This seems to work equally well with instruments, male and female vocals…more versatile than a straight up 47 clone. To my ears it’s a wonderful blend of modern and vintage. The heiserman capsule is really awesome.

 

[mihi_fuchs]

Hello,

I'm currently trying to build the microphone. I have everything running, but instead of using the PSU described herein, I used the PSU of a C12 build (Vintagemicrophonepcbkit.com). I was able to set the voltages for B+ and the Heater to the D-EF 47 values (105 B+, 5.5 Heater) and everything is working and the mic sounds great. Nevertheless the microphone is significantly more noisy than e.g. the C12 or the ElaM-251. Is that due to the different PSU or do I need to search for the mistake somewhere else?

Any hint would be highly appreciated - even if it just means the U-47 is noisier per se ...

I attached some pics below. Capsule is a Maiku K47, transformer is a GZT-47 in the metal can at the bottom of the mic.

So thanks in advance for any hints,
and thanks a lot for the great design and sharing it here!!!

Best regards,
Michael

 

[Delta Sigma]

@mihi_fuchs what kind of noise? Can you record or describe? My EF-47 is very quiet.

 

[mihi_fuchs]

@mihi_fuchs what kind of noise? Can you record or describe? My EF-47 is very quiet.

hi,

the noise is just regular background noise. similar to a cranked preamp. it is fine if recording rock music, but for acoustic or vocal solo parts it may be annoying.

i recorded it but i‘m out for the holidays - i can post it on tuesday.

thanks a lot for your help,
best regards
michael

 

[TLRT]

hi,

the noise is just regular background noise. similar to a cranked preamp. it is fine if recording rock music, but for acoustic or vocal solo parts it may be annoying.

i recorded it but i‘m out for the holidays - i can post it on tuesday.

thanks a lot for your help,
best regards
michael

The c12 psu uses lm317 for heater regulation and the DEF47 mic circuit derive the cathode voltage/current from the heater voltage, so it is more sensitive to noise. (C12 is anode follower ,the cathode is grounded and the -1v control voltage comes from b+ unregulated supply) The regulator IC's (at least the lm317)are more noisy than the classic RLC choked unregulated psu design.

 

[mihi_fuchs]

The c12 psu uses lm317 for heater regulation and the DEF47 mic circuit derive the cathode voltage/current from the heater voltage, so it is more sensitive to noise. (C12 is anode follower ,the cathode is grounded and the -1v control voltage comes from b+ unregulated supply) The regulator IC's (at least the lm317)are more noisy than the classic RLC choked unregulated psu design.

Thanks, that's exactly the answer I was looking for. Corresponds also with the fact that upon change of the tube the noise gets more or less (Telefunken vs. Siemens EF800).
That's very good news, then I'll look for alternatives to the PSU first. Is there a less noisy alternative to the lm317 or should I directly follow the unregulated PSU design provided herein?

Thanks again for your help and the great explanation. That was really good news, as I like the mic and its sound a lot (I only had to increase the coupling cap a bit by get another 1uF in parallel to get the bottom end right. with a new PSU it may turn to one of my go-to mics ...

Best regards and all the best
Michael

 

[stokesmusic]

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!