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

[Studio Mollan]

Everything seems to be working super with my mic. Sounds unbelievable!
My final question is about the 40Hz filter. Is that on with or without the jumper?
/
Emil

 

[poctop]

Everything seems to be working super with my mic. Sounds unbelievable!
My final question is about the 40Hz filter. Is that on with or without the jumper?
/
Emil

With the Jumper on S2 internal is default if you want to have a bit more Proxy and Move the lc further remove the Jumper on S2.

I am very Glad that you like it ,  it is one of those mics..   Wich Trio do you have Tube, cap and Tran

Thanks for your post ,. appreciate it .
Best,

edit : 
<dAn

 

[Studio Mollan]

Everything seems to be working super with my mic. Sounds unbelievable!
My final question is about the 40Hz filter. Is that on with or without the jumper?
/
Emil

With the Jumper on S2 internal is default if you want to have a bit more Proxy and Move the lc further remove the Jumper on S2.

I am very Glad that you like it ,  it is one of those mics..   Wich Trio do you have Tube, cap and Tran

Thanks for your post ,. appreciate it .
Best,

edit : 
<dAn

Thanks!
I'm using beesneez capsule, vintage telefunken ef86 and ioaudio transformer. I'm building a pair of these and then a second pair with the same specs but ami transformer.

 

[JessJackson]

whats everyone building these inside now… since the sty-5 is not available?

 

[Phrazemaster]

Hi gang, just got my chunger body back from the machinist...I wanted to install an Amphenol connector instead of the 7-pin XLR. I don't have tools for boring the base myself, or I'd DIY it.  Came out great! Here's some photos prior to me installing the wiring. Excited!

Mike

 

[JessJackson]

whats everyone building these inside now… since the sty-5 is not available?

anyone?

 

[Phrazemaster]

She's breathing! Just plugged in my completed D67...a pulse! She passes audio! Wow! First try!!

A little concerned about voltages...H- is -6.29 at the lowest possible setting - can only turn pot up from there, and B+ only goes as high as +201 (measured inside the mic of course!). Unloaded at the psu I get 245v and -16v. I also noted that testing ground from the mic frame to the psu (through the cable) yielded about 12.1R, which kind of surprised me. Can anyone else test their ground resistance through the mic to the psu and report back? I had a sneaking suspicion I should have used that black wire along with the blue one for the ground but...I didn't...

Oh if anyone thinks it matters I used 22awg in the mic for both H- and B+...the thicker cable was a huge hassle and I ended up just using my teflon stuff...I know it's a little smaller guage but it's only a 2 inch run so I figured that shouldn't matter.

Anyone have any thoughts? Tube has not burned in at all - just plugged in and waited a couple minutes, maiden voyage so to speak...making that cable took a lot out of me lol!

Tried posting an mp3 but I see we cannot...dang would have loved to have shared how good it sounds but I'm not up for figuring out external storage right now.

What I can't get over is just how GOOD the thing sounds! I mean, WOW! It just oozes quality. Very, very clean, high-end, pro sounding and very complimentary to the voice! And it didn't cost me a house!

And by the way this is with a Max (ioaudio) BV12, a Phillips Mullard tube, Shinkoh resistors, stock capacitors from build,  and a super cheap Chinese capsule; I have a beeskneez coming....it will only get better from here!

Thanks to Dan and everyone else on this forum for making it so incredibly fun and, well, worthwhile!!

Thanks all!!

Mike

 

[Phrazemaster]

I just want to go on the record and say, those gearsnobs who spout things like "there's NOTHING like an original xyz" have never had the thrill of creating something so incredible, and so good sounding! I could give a rat's --- if this mic isn't a "real U67" by golly it's an amazing mic! And my singers in my studio will agree what an incredible tool this is going to be...all hand made in the US of A!

Poctop, Dan, we all owe you big for your generosity of spirit in helping everyone, your genius in coming up with these DIY-able designs, your great support, and awesome attitude!

Not to mention, you've cloned every great mic in existence by now haven't you? Wow!!!!

This one's for you Dan!  ;D 8)

Mike

 

[poctop]

I just want to go on the record and say, those gearsnobs who spout things like "there's NOTHING like an original xyz" have never had the thrill of creating something so incredible, and so good sounding! I could give a rat's --- if this mic isn't a "real U67" by golly it's an amazing mic! And my singers in my studio will agree what an incredible tool this is going to be...all hand made in the US of A!

Poctop, Dan, we all owe you big for your generosity of spirit in helping everyone, your genius in coming up with these DIY-able designs, your great support, and awesome attitude!

Not to mention, you've cloned every great mic in existence by now haven't you? Wow!!!!

This one's for you Dan!  ;D 8)

Mike

Thanks For the kind word it is appreciated, 

H- is -6.29 at the lowest possible setting - can only turn pot up from there, and B+ only goes as high as +201 (measured inside the mic of course!). Unloaded at the psu I get 245v and -16v. I also noted that testing ground from the mic frame to the psu (through the cable) yielded about 12.1R, which kind of surprised me. Can anyone else test their ground resistance through the mic to the psu and report back? I had a sneaking suspicion I should have used that black wire along with the blue one for the ground but...I didn't...

sometimes different tubes will put up slighlty different plate and heater current ,  to bring back the 210VDC loaded you will need to adjust the external resistor on the B+ Pot you should have currently 56K over there as this is what works for me , in your case you should go ahead and replace the 56K resistor with a lower value like 33K 1/4 watt is ok and you will get the upper range back ,  -6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm ,

as per the continuity make sure you mic pcb ground and mic chassis is zero ohm, make sure you installed the jumper in the psu SHLF as this is a sheild lift for pin 3 to bring back star ground on the psu,  keep me posted,  unpower everyting and check your ground scheme and ground continuity untill you find the culprit,

you may have taken the filament resistance pad to check your continuity as this might have gven you a reading of approx 12 ohm depending on the tube ,

hope this helps,
Dan,

 

[Phrazemaster]

Thanks For the kind word it is appreciated, 

Deserved!!

sometimes different tubes will put up slighlty different plate and heater current ,  to bring back the 210VDC loaded you will need to adjust the external resistor on the B+ Pot you should have currently 56K over there as this is what works for me , in your case you should go ahead and replace the 56K resistor with a lower value like 33K 1/4 watt is ok and you will get the upper range back

Understood...I just hated having to desolder in the PSU just to match a tube, so maybe I'll try my second tube. Sounds gorgeous by the way, even at just 200v...! I mean full and silky and warm even with the Chinese capsule!

-6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm

Didn't know if I should try to underheat the tube...I could leave this as-is; any recommendations? Will the tube last longer if I put it at -5.8v, or will this cause buildup of unwanted chemicals in the tube over time if underheated? What are people doing, just using spec'ed -6.3v? Thx.

as per the continuity make sure you mic pcb ground and mic chassis is zero ohm, make sure you installed the jumper in the psu SHLF as this is a sheild lift for pin 3 to bring back star ground on the psu,  keep me posted,  unpower everyting and check your ground scheme and ground continuity untill you find the culprit,

Yes I do have the jumper installed in the PSU. Within the PSU internally, and within the mic internally, grounding is .2R or .1R; my Fluke always has a tiny little bit of resistance showing maybe the probe leads. But it's when I check through the mic cable that I get the 12R. I'm wondering if the mic cable needs redoing; it was a bugger getting it soldered up right. I'll look into it more carefully tonight...I was just so jazzed it worked at all (not that I doubted you Dan...just something about making something yourself and breathing life into it....Frankenstein lol!).

you may have taken the filament resistance pad to check your continuity as this might have gven you a reading of approx 12 ohm depending on the tube

Actually I used the mic rails for the mic ground point and the PSU case for the PSU ground point...Are there different points I should use for ground resistance check? Would what I used account for the 12R? Bothered me since I was so careful with this build!

hope this helps,
Dan,

Yes it's all helpful Dan; you're awesome! Thank-you!

 

[poctop]

Thanks For the kind word it is appreciated, 

Deserved!!

sometimes different tubes will put up slighlty different plate and heater current ,  to bring back the 210VDC loaded you will need to adjust the external resistor on the B+ Pot you should have currently 56K over there as this is what works for me , in your case you should go ahead and replace the 56K resistor with a lower value like 33K 1/4 watt is ok and you will get the upper range back

Understood...I just hated having to desolder in the PSU just to match a tube, so maybe I'll try my second tube. Sounds gorgeous by the way, even at just 200v...! I mean full and silky and warm even with the Chinese capsule!

-6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm

Didn't know if I should try to underheat the tube...I could leave this as-is; any recommendations? Will the tube last longer if I put it at -5.8v, or will this cause buildup of unwanted chemicals in the tube over time if underheated? What are people doing, just using spec'ed -6.3v? Thx.

as per the continuity make sure you mic pcb ground and mic chassis is zero ohm, make sure you installed the jumper in the psu SHLF as this is a sheild lift for pin 3 to bring back star ground on the psu,  keep me posted,  unpower everyting and check your ground scheme and ground continuity untill you find the culprit,

Within the mic internally, and within the PSU internally, grounding is .2R or .1R; my Fluke always has a tiny little bit of resistance showing maybe the probe leads. But it's when I check through the mic cable. I'm wondering if the mic cable needs redoing; it was a bugger getting it soldered up right.

you may have taken the filament resistance pad to check your continuity as this might have gven you a reading of approx 12 ohm depending on the tube

Actually I used the mic rails for the mic ground point and the PSU case for the PSU ground point...Are there different points I should use for ground resistance check? Would what I used account for the 12R? Bothered me since I was so careful with this build!

hope this helps,
Dan,

Yes it's all helpful Dan; you're awesome! Thank-you!

Thanks ,

Understood...I just hated having to desolder in the PSU just to match a tube, so maybe I'll try my second tube. Sounds gorgeous by the way, even at just 200v...! I mean full and silky and warm even with the Chinese capsule!

you dont have to desolder anything on the pcb since you will change or add an external resistance to the external Pot in the psu
For sure you could install a 200ohm pot 5W for the heater if you wish it will cover all need sometimes it is quicker just to add a resistor on the leg of the pot and choose your own range 

I havent notice any major difference in underheating a tube well not yet ,  but you should not underheat under 10% IIRC,


Might the cable has a cold solder or an issue but it should read 0 ohm or ver very close from the mic rail to the psu
you could take a wire from the psu pin 3 and pinch it on the mic rail and you will have your answer about the cable , remember the SHLF jumper must be installed.

Best,
Dan,.

 

[Phrazemaster]

Thanks Dan for the encouragement and awesome support!

I disconnected power and systematically checked 1-7 connections. Here's what I got:

Pin R
1 0.9
2 0.9
3 0
4 0.2
5 0.9
6 0.9
7 0.1

interesting the thinner 22awg cables all got .9R and the fatter heater and ground (3,7) were at .1 and .2R. The gigantic cable shield pin 3 was dead 0R. I'm using a Fluke 87 and compensated for the meter probe resistance. My last mic cable I wired up was also Gotham GAC-7 and as I recall I was getting about 1R for the thinner wires and .4R for the thicker ones, so this is in the ballpark. I think that says the cable must be OK, right?

Also measuring from the mic rail to ground on the PSU, or from mic rail to the chassis on PSU, I got 0.1R, which is inline with what you said Dan.

When I was doing the measuring last night I did have the unit on and powered; I turned it on just now and tried just measuring the PSU chassis to the mic rail and again got a high reading - 16.5R - but that's with the unit ON. Off, the resistance is what I shared above. Why would that be? Just curious; I think the cable/grounding is fine but to me it's odd I would get resistance when the unit is powered vs when it is unplugged from the wall.

What value resistor would you recommend adding to the H- to bring the pot more into useable range? I will try another tube and find out if it needs different voltages.

Thank-you Dan and everyone for everything; great forum!

Mike

 

[Phrazemaster]

Just swapped the tube out; now I get a tiny bit more range in the H-, still gets to -6.3v, and B+ goes to 209 at the top end. I think I will change out the resistor in the B+ to get a little more range.

Thanks all,

Mike

 

[Phrazemaster]

Quick question about the B- resistor Dan,

You had said earlier:

"-6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm , "

I'm not the genius you are please bear with me...

Currently the B- pot range with tube installed is 6v ~ 9v. So roughly a 3v span.

If I wanted the range to drop to say, 4v ~7v, a 2v drop in overall range, and we know the B- eats about roughly.2A per schematic, wouldn't a good value be calculated:

v=ir
2v=.2A x r
r = 10 Ohms

Or is the current different or am I not understanding something?

Thanks a million man.

Mike

 

[JessJackson]

Heres a Question,

Do you think this could be built inside a u87ai body?

Reason I ask is that I'm building mine with neumann capsule which is roughly $800, u87ai's can be gotten for 1,500 or less which wouldn't be much for a great body, grill and capsule.

J

 

[poctop]

Quick question about the B- resistor Dan,

You had said earlier:

"-6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm , "

I'm not the genius you are please bear with me...

Currently the B- pot range with tube installed is 6v ~ 9v. So roughly a 3v span.

If I wanted the range to drop to say, 4v ~7v, a 2v drop in overall range, and we know the B- eats about roughly.2A per schematic, wouldn't a good value be calculated:

v=ir
2v=.2A x r
r = 10 Ohms

Or is the current different or am I not understanding something?

Thanks a million man.


that is correct,  now you have to calculate the dissipated power as per P=VI
so P = 2V*0.2A  = 0.4W or P= R*I(square that you will give the same results)
Best,
DAn,

Mike

 

[poctop]

Heres a Question,

Do you think this could be built inside a u87ai body?

Reason I ask is that I'm building mine with neumann capsule which is roughly $800, u87ai's can be gotten for 1,500 or less which wouldn't be much for a great body, grill and capsule.

J

I could not tell you because i never been able to attempt it, but someone here on the forum is atempting to build the 269c inside a U87 body he will  let us know if it can be done look at the white Thread for more info or the 269c thread , but in the meantime i have a feeling that Chunger SyT-5 mic body should be returning pretty soon,

Best,
dAn,

 

[Phrazemaster]

Quick question about the B- resistor Dan,

You had said earlier:

"-6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm , "

I'm not the genius you are please bear with me...

Currently the B- pot range with tube installed is 6v ~ 9v. So roughly a 3v span.

If I wanted the range to drop to say, 4v ~7v, a 2v drop in overall range, and we know the B- eats about roughly.2A per schematic, wouldn't a good value be calculated:

v=ir
2v=.2A x r
r = 10 Ohms

Or is the current different or am I not understanding something?

Thanks a million man.


that is correct,  now you have to calculate the dissipated power as per P=VI
so P = 2V*0.2A  = 0.4W or P= R*I(square that you will give the same results)
Best,
DAn,

Mike

Thanks Dan. Good to know my brain is still functioning. Thx for the advice on the wattage; makes sense. Again, how do you have time to not only produce all these amazing pcb's and designs, but help all the newbies through their growing pains??? Amazing! Thank-you!!!!

 

[poctop]

Quick question about the B- resistor Dan,

You had said earlier:

"-6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm , "

I'm not the genius you are please bear with me...

Currently the B- pot range with tube installed is 6v ~ 9v. So roughly a 3v span.

If I wanted the range to drop to say, 4v ~7v, a 2v drop in overall range, and we know the B- eats about roughly.2A per schematic, wouldn't a good value be calculated:

v=ir
2v=.2A x r
r = 10 Ohms

Or is the current different or am I not understanding something?

Thanks a million man.


that is correct,  now you have to calculate the dissipated power as per P=VI
so P = 2V*0.2A  = 0.4W or P= R*I(square that you will give the same results)
Best,
DAn,

Mike

Thanks Dan. Good to know my brain is still functioning. Thx for the advice on the wattage; makes sense. Again, how do you have time to not only produce all these amazing pcb's and designs, but help all the newbies through their growing pains??? Amazing! Thank-you!!!!

I am really trying to do my best , thanks for the nice words,
Best,
dAn,

 

[JessJackson]

Question on the P.S

I wanted to bypass the PCB for modulation.

Is this correct to link all together:

[[ XLR pin 3 > Chassis > Pin 7 > Pin 3 > PCB Gnd ]]

Reason I ask is because of switch on pin 3 to pin 7, default on schematic shows open position yet still goes to chassis regardless.

Cheers