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

[FarisElek]

Also, am I supposed to be getting 210+ at both Poles screws on the AC in?

 

[Purplenoise]

That's exactly what's happening to me!

Ok false alarm...stupid on my part. It should be 10+10. You got it right. I just measured my first psu and that’s how it is...no idea why I was so sure both poles measured 20 each. Sorry for the misdirection

 

[FarisElek]

What about the 210AC in? both poles?

Ryan

 

[Purplenoise]

What about the 210AC in? both poles?

Ryan

I got around 270 on yellow pole

 

[FarisElek]

Whether loaded or unloaded, I'm getting 0VAC at the second pole where the black wire goes from the  transformer to the pole.

 

[FarisElek]

It was actually super long so I shortened it a little just now and resettled it in. Nothing. I’m busy working but tonight I’m going to get the alligator clips out and see if there is any current coming out the black wire at all. I don’t think there is.

 

[Purplenoise]

Whether loaded or unloaded, I'm getting 0VAC at the second pole where the black wire goes from the  transformer to the pole.

That’s correct, mine is the same way

 

[FarisElek]

Ok here we go. I'm so close.

Changed R2 to 25ohm 5W and lifted it very high. Doesn't smell and runs cooler.  Getting good voltage and all that jazz.
But, I'm getting a constant buzz. Whether or not the mic is plugged in. The sound gets a little higher in pitch and volume sounding when it's not plugged in, When I plug the mic in and turn it on there is around 300 ohms between the mic body and chassis and it very very slowly lowers. I haven't sat around long enough to see it fall below 250. ohms.

Ryan

 

[FarisElek]

My mic sounds borderline thin. I wouldn't say thin, but it's very radio ready. The only thing that bothers me about that is that the low cut switch does nothing. Which worries me that it's stuck on or something. There is a steep cut at 100h when I monitor the EQ on a really nice deep acoustic guitar I own. Which sounds great, but seems off.


Ryan

 

[Purplenoise]

So both 67s I’ve build ( k870 capsules, moby bv12, haufe bv12) perform great and sounding extremely close to our reissue 67s. There is a slight different timbre that I guess comes from the carbon film resistors that give them a vibe closer to the vintage u67 I had here briefly ( reissue uses metal film). The reissue sounds slightly cleaner but d67 sounds a touch smoother.
There isn’t much difference between mobys and haufe bv12. If anything mobys is more extended in the highs and I had to use a 200pf filter cap to tune it to my taste. For the haufe I put the standard 100pf. Also the haufe seems a little “cleaner” but we are splitting hairs here.
Coupling caps do make a difference. Second 67 has an electrolytic cause I tried to keep it as close to the reissue. The sound seems a little faster and snappier, I actually like it. On the first one after swapping a few I ended up with a vishay 1839. Very smooth, balanced and “easy” on the ears. Not the best fidelity wise but the one that works best in the mix. As far as fidelity and smoothness the best one I tried was two wet tantalums in series but I had some noise issues so I took em out to be safe. Wish I could fit a PIO in there to try out but the ones I got were too big.

 

[poctop]

So both 67s I’ve build ( k870 capsules, moby bv12, haufe bv12) perform great and sounding extremely close to our reissue 67s. There is a slight different timbre that I guess comes from the carbon film resistors that give them a vibe closer to the vintage u67 I had here briefly ( reissue uses metal film). The reissue sounds slightly cleaner but d67 sounds a touch smoother.
There isn’t much difference between mobys and haufe bv12. If anything mobys is more extended in the highs and I had to use a 200pf filter cap to tune it to my taste. For the haufe I put the standard 100pf. Also the haufe seems a little “cleaner” but we are splitting hairs here.
Coupling caps do make a difference. Second 67 has an electrolytic cause I tried to keep it as close to the reissue. The sound seems a little faster and snappier, I actually like it. On the first one after swapping a few I ended up with a vishay 1839. Very smooth, balanced and “easy” on the ears. Not the best fidelity wise but the one that works best in the mix. As far as fidelity and smoothness the best one I tried was two wet tantalums in series but I had some noise issues so I took em out to be safe. Wish I could fit a PIO in there to try out but the ones I got were too big.

8) 8) 8)

 

[Delta Sigma]

So both 67s I’ve build ( k870 capsules, moby bv12, haufe bv12) perform great and sounding extremely close to our reissue 67s. There is a slight different timbre that I guess comes from the carbon film resistors that give them a vibe closer to the vintage u67 I had here briefly ( reissue uses metal film). The reissue sounds slightly cleaner but d67 sounds a touch smoother.
There isn’t much difference between mobys and haufe bv12. If anything mobys is more extended in the highs and I had to use a 200pf filter cap to tune it to my taste. For the haufe I put the standard 100pf. Also the haufe seems a little “cleaner” but we are splitting hairs here.
Coupling caps do make a difference. Second 67 has an electrolytic cause I tried to keep it as close to the reissue. The sound seems a little faster and snappier, I actually like it. On the first one after swapping a few I ended up with a vishay 1839. Very smooth, balanced and “easy” on the ears. Not the best fidelity wise but the one that works best in the mix. As far as fidelity and smoothness the best one I tried was two wet tantalums in series but I had some noise issues so I took em out to be safe. Wish I could fit a PIO in there to try out but the ones I got were too big.

This is great info! These things are so subjective that it's hard to describe results after component changes. Generally, I try to record changes I make so I can refer to the recordings later and make sure my ears weren't lying to me. I like that you enoyed the elctrolytic. I preferred metalized paper in mine but I always go for character (distortion) over clean. Probably shouldn't though!

 

[Purplenoise]

This is great info! These things are so subjective that it's hard to describe results after component changes. Generally, I try to record changes I make so I can refer to the recordings later and make sure my ears weren't lying to me. I like that you enoyed the elctrolytic. I preferred metalized paper in mine but I always go for character (distortion) over clean. Probably shouldn't though!

Very true..highly subjective. I like the electrolytic just because...I wanted to make it as close to the reissue haha. I opened up our reissue and sourced the same parts more or less...very common parts by the way, 1839 caps etc. The differences are not vast but enough to keep you second guessing yourself haha. By the way, for those that are thinking about using the Beesneez k67 go for it. It actually sounds like a nice “aged” Neumann k67. Really smooth with all the Neumann character. I would have absolutely no problem substituting a BeesNeez for the Neumann

 

[FarisElek]

Ben drew this out for me. Can anyone explain to me which of the pins on the left go to what on the pcb?



Update: I figured it out. I figured out what the primary, secondary, and tertiary of the the T67 was and based on Ben's drawing figured out where what should go.
I'm done. Everything works and there is low noise. It's amazing. I'm ecstatic.

My build was Beesneez k67, Beesneez BV12., and a NOS EF86. It sounds really good. My city just shut down due to the virus so I have plenty of time to make sound samples if anyone is interested.

Update 2: After some testing, it's a bit lacking in the 10k area. Is this where the C17 comes in? It sounds amazing when I EQ about +3-4 decibels into the 10k range.  What do you recommend?

 

[Purplenoise]

Ben drew this out for me. Can anyone explain to me which of the pins on the left go to what on the pcb?



Update: I figured it out. I figured out what the primary, secondary, and tertiary of the the T67 was and based on Ben's drawing figured out where what should go.
I'm done. Everything works and there is low noise. It's amazing. I'm ecstatic.

My build was Beesneez k67, Beesneez BV12., and a NOS EF86. It sounds really good. My city just shut down due to the virus so I have plenty of time to make sound samples if anyone is interested.

Update 2: After some testing, it's a bit lacking in the 10k area. Is this where the C17 comes in? It sounds amazing when I EQ about +3-4 decibels into the 10k range.  What do you recommend?

I am really glad man, that’s so good to hear. C17 attenuates the highs yes. What value are you using?

 

[FarisElek]

I'm using the standard 100.  It needs about +2 decibels to sound normal, and about +3 to sound great. Should I remove the cap all together?

Also, how close do you want the mic voltage? The heater after an hour makes its eventual rest at 6.25v and the B+ at 208.5. They can easily go higher, but I wanted to be in safe zone. Does this affect sound? Is this a good voltage?
Ryan

 

[Purplenoise]

I'm using the standard 100.  It needs about +2 decibels to sound normal, and about +3 to sound great. Should I remove the cap all together?

Also, how close do you want the mic voltage? The heater after an hour makes its eventual rest at 6.25v and the B+ at 208.5. They can easily go higher, but I wanted to be in safe zone. Does this affect sound? Is this a good voltage?
Ryan

Yes voltages are perfect. I keep mine at 6.2v and 209. As far as the c17 don’t remove it. Try a styrene 50pf first and if you need more high end go to 10 or 20pf.

 

[FarisElek]

Great! I just picked up some polystyrenes in 10, 20, 33, 50, and 80. I’ll report back what works best with the BeesNeez transformer and get some sound samples with a week or two.

Kind regards,
Ryan

 

[Purplenoise]

Great! I just picked up some polystyrenes in 10, 20, 33, 50, and 80. I’ll report back what works best with the BeesNeez transformer and get some sound samples with a week or two.

Kind regards,
Ryan

Awesome, start with 50pf. You are not going to hear much difference with 80pf.

 

[poctop]

What about Start with nothing just for the sake of a baseline  .
D.