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

[Joekkel]

What capsule do you have in your D-U67?

My build has a K67 from Maiku in it.

Can you measure the frequency response of the mic with Moby's transformer? To me, it sounds like it has MUCH more high end. I know you "want" more high end, but the question is if it's an apple-to-apples test between the transformers.  If they have the same windings and are correctly hooked up, they should have the exact same frequency response.  I'm not saying they will be perceived to have the same amount of high end, but they will both measure that way.

I neither have the opportunity to measure the fr of the circuit. but comparing the microphone as it is now with a u87, both have around the same amount of perceived high end. before the transformer swap it was darker (by a lot), than any of my other condenser microphones. and i wouldnt describe the u87 as a particularly bright microphone.

 

[dgoszillai]

Hi all,

If anyone wants to help.. my d67 is dead :
https://groupdiy.com/index.php?topic=73908.0

thx

 

[deveng]

Does anyone know if either of the Peluso hard mount mic stand adapters fit the SYT-5  threads?

Regards,
Jeff

 

[deveng]

I dug up some info buried here. The current production SYT-5 base is an M 24 thread.  I can’t confirm since I don’t an SYT-5 yet.  Now I’d like to know what the P-67 or LDC hard mount thread size is.  I’ve contacted Peluso and will post when I get the info

Update:  there appears to be two M24 versions.  2 or 3 mm per thread .
I would need that info as well!

Jeff

 

[Studio Mollan]

I second this.
I haven't been reading this thread for a couple of years but after reading these posts about the Max BV12 i got interested again. Max Kirschers transformers are just not properly manufactured. They have always sounded extremely dark to me and i found that i got -10dB @15k with the feedback cap removed. Just like you wrote here. I have been in direct contact with him and he has always stated that his transformers are 100% original in design and sound. This is just not true. He claimed his prototype build sounded exactly like an original U67. Maybe he has cloned a faulty transformer? =)
I built one pair with Max BV12 transformers and one pair of the AMI T67 transformer. Both pairs always sounded exactly the same so this is not a build fault. I got similar results as you described when comparing your new transformer to Max's BV12. The AMI actually needed a larger cap to have the proper -10dB@15kHz, it was way to bright sounding,  and as stated above the Max BV12 measured sort of spot on with the feedback cap removed. 

This issue needs to be properly outed as i imagine Max sold A LOT of transformers and a lot of builders are using a way to dark microphone. Or more likely, are not using their microphone at all as it is too dark sounding. The microphone is sounding good now but as it has no feedback cap it is not a proper U67 clone anymore. For someone anticipating a 1:1 clone this transformer won't do it, but can still sound good with some modifications. Actually a wonderfully colored, saturated sound that i would not want to be without.
To be fair Max is not the only transformer supplier to get things wrong. AMI has made their fair share of mistakes over the years.
Poctop  has made a great DIY microphone  available here that i imagine would have been a lot easier without his transformer suppliers constantly messing it up.

/
Emil

Unfortunately, I don't have any way to so sweeps.

I also used a Beesneez K6. As far as I can tell, it sound great! It sounded good with Max's transformer and the feedback killed. It sounds better with Moby's transformer and the feedback active. The only time I wasn't happy with the sound was with Max's transformer and the feedback active. Still had its uses but it was my least favourite mic.

 

[Bonnie1]

"To be fair Max is not the only transformer supplier to get things wrong. AMI has made their fair share of mistakes over the years."

Can you be a bit more precise and give an example of this?  Hoping to understand where your experience that AMI "got things wrong" comes from and hopefully clarify any misunderstandings.

-dmax

 

[Studio Mollan]

Wrong color coding on leads? This was a returning issue a few years ago.
I had my transformers reversed in my u87 clones. Not easy for an amateur builder to realize that.

"To be fair Max is not the only transformer supplier to get things wrong. AMI has made their fair share of mistakes over the years."

Can you be a bit more precise and give an example of this?  Hoping to understand where your experience that AMI "got things wrong" comes from and hopefully clarify any misunderstandings.

-dmax

 

[rockinrob86]

I built mine with a T67 and a Neumann k67, 100pf in c17 and I feel like it is a little bright.  Compared with my D87 with a cinemag transformer and a maiku k87, it is a lot brighter.

Now I’m unsure if the T67 is the issue, c17 should be larger, or my D87 has a problem and is too dark! Or maybe everything is good in all mics?  The D67 has a very good sound, just seems a little brighter/grainier than expected.  I built the mic originally with a Chinese capsule and the overall timbre was similar, but it now sounds way more alive/3D/impressive.  The D87 is kind of mellow and flat.  Good but not great, takes eq and always works, just isn’t exciting sounding and is dark. 
For comparison, my D47 has a much thicker sound that an all of these, with a subtle but present high end.  It is velvety sounding, but not as exciting as the D67.  The D67 vocals have more energy and kick to them, if that makes sense

 

[Vac11]

Try Maiku K87 with much lower value of C6 (or omit C6). Its eye opening experience.

 

[rockinrob86]

Try Maiku K87 with much lower value of C6 (or omit C6). Its eye opening experience.

Thanks, I’ll check that out.  The D87 sounds good and is my go to “general” mic, guitars, piano, room, even background vocals when I don’t want to heat up a tune mic.  It has similar qualities but a different timbre to my c414eb p48.  But now this d67 has me confused!

 

[Bonnie1]

Wrong color coding on leads? This was a returning issue a few years ago.
I had my transformers reversed in my u87 clones. Not easy for an amateur builder to realize that.

Yes that's correct, In 2012 data sheets on 4 transformers were uploaded onto the website that had errors and/or caused confusion. T13, T8, T47 &T49 were affected.  We have updated the data sheets and have been diligent in correcting the confusion this caused.

Btw, The BV12 is the only proper transformer for a historically correct U67 circuit.  Oliver designed the T67 as a economical alternative for folks buying inexpensive microphones and modifying them.  Sensible people generally don't buy a $300 transformer to install in a sub $500 microphone.
The T47 & T49 were also designed as economical alternatives for BVO8, BV11.

T67,49,47 are used by numerous individuals/ companies some have modified the circuits accordingly. 

 

[rockinrob86]

Has anyone used beesneez’s bv12? 

I have a t67 in mine and I’m thinking I just want to go for the full on thing.  Trying to decide between max’s, BeesNeez or paying $350 for Neumann...

 

[Delta Sigma]

Has anyone used beesneez’s bv12? 

I have a t67 in mine and I’m thinking I just want to go for the full on thing.  Trying to decide between max’s, BeesNeez or paying $350 for Neumann...

I don't believe you'll get anything more out of the Sennheiser BV.12 than you would from Moby or AMI's BV.12. Personally, I would trust AMI and Moby more than Sennheiser. Yes, they still prduce fantastic capsules but I'm not sure there's any reason to think that they're heavy hitters in transformer manufacturing. I think you'd be paying for the name.

If you want a high end transformer to match your genuine K67, I think you should go with Moby or AMI. Moby's BV.12 has been used to replace Max's BV.12 by two of us and I think we both felt it was a significant upgrade. AMI is obviously well respected and you'd certainly be ahppy with their BV.12.

A subjective note on AMI vs Moby:

I had an AMI BV.11r in my M49. The BV.11r is meant for the 5840. I swapped my 5840 for a 6S6B and wanted to try a regular BV.11. The goal of the BV.11r is to provide more of the low-mids that the 5840 is lacking. When I installed Moby's BV.11, I heard less low-mids as expected but I also could hear more colour and I prefer that sound. This may be due to the fact that the BV.11r is a different design or it could be that Moby's transformers have more colour.

When I replaced Max's BV.12 with Moby's, I found that there was more colour, as well as the high end Max's was lacking.

This is the furthest possible thing from a scientific conclusion but I'm left wondering if Moby's BV.12 would have more colour than AMI's. The reality is; though, the only way you can find the transformer you like the most is to buy multiple and compare.

I really think that you'd be happy with the AMI's real deal BV.12 or Moby's BV.12. Just pick one and go for it.

 

[Delta Sigma]

I got to spend more time with my Moby BV.12 equipped DIY 67 and found a harshness to the high end I didn't like on the recording I was doing. To be honest, the harshness was probably there and undesirable from the moment I put Moby's BV.12 in. I was probably a little too excited about getting the high end that was missing and only heard what I wanted to hear.

The mic otherwise was perfect for the recording so I was a little disappointed.

I rememberd that I played with C17 when I had Max's xfmr in there. I cracked the mic and found C17 was 100pF. The Neumann schematic shows C17 is selected from 80-160pF. I seached my ceramic stock for 160 but unfortunately didn't have one. I found a 220pF C0G and threw it in and the mic sounded great. More high end than with Max's transformer and C17=100pF but the harshness was tamed.

Next mouser order I'll get a selection of C0G ceramics between the 100 & 220pF caps that I have and see if there's anything that works better than the 220pF.

 

[Studio Mollan]

The proper cap to use here is polystyrene. They are available at mouser too o believe. I haven’t done any comparisons between them and ceramics but the general consensus is to use polystyrene in filtering applications where applicable. Why, I don’t know, but makes sense to keep true to the original design when possible. If you can’t find the correct value you can always put two in parallel/series to get right.

I got to spend more time with my Moby BV.12 equipped DIY 67 and found a harshness to the high end I didn't like on the recording I was doing. To be honest, the harshness was probably there and undesirable from the moment I put Moby's BV.12 in. I was probably a little too excited about getting the high end that was missing and only heard what I wanted to hear.

The mic otherwise was perfect for the recording so I was a little disappointed.

I rememberd that I played with C17 when I had Max's xfmr in there. I cracked the mic and found C17 was 100pF. The Neumann schematic shows C17 is selected from 80-160pF. I seached my ceramic stock for 160 but unfortunately didn't have one. I found a 220pF C0G and threw it in and the mic sounded great. More high end than with Max's transformer and C17=100pF but the harshness was tamed.

Next mouser order I'll get a selection of C0G ceramics between the 100 & 220pF caps that I have and see if there's anything that works better than the 220pF.

 

[Studio Mollan]

C17 is supposed to be selected with respect to the microphone calibration. Select a value that gives you -15db @15kHz compared to 1kHz. The procedure is in the manual on the first page. i really don’t think removing the capsule is necessary, as long as you can read the peak value from the tone generator over the noise from the room. I think I needed over 300pF to get my ami t67 to specs. Definitely a place to experiment though. A ceramic cap might sound great!

I got to spend more time with my Moby BV.12 equipped DIY 67 and found a harshness to the high end I didn't like on the recording I was doing. To be honest, the harshness was probably there and undesirable from the moment I put Moby's BV.12 in. I was probably a little too excited about getting the high end that was missing and only heard what I wanted to hear.

The mic otherwise was perfect for the recording so I was a little disappointed.

I rememberd that I played with C17 when I had Max's xfmr in there. I cracked the mic and found C17 was 100pF. The Neumann schematic shows C17 is selected from 80-160pF. I seached my ceramic stock for 160 but unfortunately didn't have one. I found a 220pF C0G and threw it in and the mic sounded great. More high end than with Max's transformer and C17=100pF but the harshness was tamed.

Next mouser order I'll get a selection of C0G ceramics between the 100 & 220pF caps that I have and see if there's anything that works better than the 220pF.

 

[Purplenoise]

I got to spend more time with my Moby BV.12 equipped DIY 67 and found a harshness to the high end I didn't like on the recording I was doing. To be honest, the harshness was probably there and undesirable from the moment I put Moby's BV.12 in. I was probably a little too excited about getting the high end that was missing and only heard what I wanted to hear.

The mic otherwise was perfect for the recording so I was a little disappointed.

I rememberd that I played with C17 when I had Max's xfmr in there. I cracked the mic and found C17 was 100pF. The Neumann schematic shows C17 is selected from 80-160pF. I seached my ceramic stock for 160 but unfortunately didn't have one. I found a 220pF C0G and threw it in and the mic sounded great. More high end than with Max's transformer and C17=100pF but the harshness was tamed.

Next mouser order I'll get a selection of C0G ceramics between the 100 & 220pF caps that I have and see if there's anything that works better than the 220pF.

Hi, I am about to start building a d67 with a Moby bv12. I am new at this and I could use some help wiring the transformer to the pcb. Could you please share this info with me? What color goes to which pin on pcb? It would be greatly appreciated, thanks.

 

[TillM]

Look at the original schematic.
Moby always use the original color codes.

 

[Moby]

Look at the original schematic.
Moby always use the original color codes.

I did detailed wiring guide for the D-U67 with my transformer but I would be happy if someone can double check it before Dan publish it. Someone who already connected my Bv.12 with D-U67?  Someone?

 

[Purplenoise]

Look at the original schematic.
Moby always use the original color codes.

Hi, thanks. My schematic reading skills are far from good. I am already in contact with Moby ( great help, amazing  dude) but I thought of asking somebody that has already installed in this kit. If it’s not too much trouble of course. Thanks again.