Neumann M49 Clone : Build Thread Puck Style (TLM49 Conversion To M49 b-c)

[poctop]

Thanks Dan.

Haven't finished yet.

Of the two I posted, which version would you try first?

Thanks man,

Mike

nope it can be star grounded to psu ,  and still be efficient ,
Best,
Dan,


the version with no shield attached to ground ,
Dan,

Thanks Dan.  Neither Version 1 nor Version 2 here have the shield attached to the ground.

Of these two, I was thinking Version 1 is better. It looks like that's what you used. Am I right?

But that also means that the shield wire in the cable is left floating. Is that OK?

Thanks,

Mike

 

[Phrazemaster]

Thanks Dany. I decided to leave the #3 shield wire connected to the mic chassis/housing, and didn't connect the shield to the PCB at all. So the shield is tied to the mic housing. Basically Version 2 from my previous drawings. I accidentally didn't switch 7 and 3, as per instructions, but since they are both connected on the PCB on the ground plane, and I wasn't connecting both 7 and 3 to the cable, I don't think it matters (no noise noted).

But the big new is...

It works!

Got an original AC701K in there...sounds amazing! Thought I had fried it...all kinna weird things going on the with the last build; could never figure it out, and I'm always really meticulous on my builds too. Dany told me I had Gremlins. lol! Sigh,

I had to totally redo the mic - and Dany helped me immensely with pointers, and I started over with a new board. This time I put all premium parts - ALL styroflex caps (big mo-fos!), and Ohmcraft, Shinkoh, Vishay Bulk foil resistors...

The rebuild sounds even more open, clear, and natural than the first. And, it seems to be stable! I used the mods of removing R3, and a cap (C6?) too, to eliminate bass and high frequency rolloff. Mic sounds very full and "present." Note this is the "b" version.

This has been a huge, huge, HUGE labor of love, spanning over a year at least, with many months of grinding on it. I used to tell my friend I was "going to the rock pile" when working on this mic because I had added to the original PSU design and it was horrifically complicated, including adding a built-in voltmeter and dual voltage for England, where I want to move. The metal work,  the drilling, the aluminum dust...I used a FleA housing, so I had to totally innovate to attach Dan's PCB which involved making a custom bracket (nightmare...WEEKS!!!!)...

So I will try to post some pix soon, but a big shout out to Dany and everyone else who helped out!

Here's a pic of the last build, and a partial of the new one. New one has the huge styroflexers. )Old one is dirty because I didn't clean it after taking it out.)

Best,

Mike

 

[Phrazemaster]

Stinkin' metal work! Arg! Bracket...

 

[Phrazemaster]

FleA body...dark drama shot.

 

[Phrazemaster]

PSU shot...

 

[Phrazemaster]

Say, is there anyone in the Orange County/LA area who built one of these with a binder at the PSU who might want to help me troubleshoot some hum?

Mic sounds amazing, but my fancy PSU I think may be introducing some hum. If I could just try it with someone else's PSU it would clear up a lot...

Let me know, and thanks.

Mike

 

[Winetree]

I have 2- M49 power supplies with binder connectors with cables.
I haven't finished the mics just but I've tested the supplies.
I'm in Irvine on the weekends. Where are you?

 

[Phrazemaster]

Awesome Winetree; PM sent!

 

[Winetree]

Quote " I suggest then you install a load resistor between pin 4 and ground to rule out the psu ,
somthing like 47 ohm 1 W , you can stick it between pin 4 and gnd right in the xlr connector on the psu ,
this will load it at about 150ma for 6.3V , then you will be able to rule out the mic or psu , "

Best,
Dan,


Dan,
I'm using your P.S. board with a real Neumann AC701 M49. I need need to set the voltage to 4.0 volts.
Should I use the same dummy load 47 ohm between pin 4 and Ground to pre test the voltage?
Will your boards go down to 4 volts or will I have have to change some parts?

 

[Phrazemaster]

Hi Winetree,

That's cool but I'm not ready to desolder/muck about with/ stuff just yet...hopefully we can still test this on Saturday?

Thanks man.

Mike

 

[poctop]

Quote " I suggest then you install a load resistor between pin 4 and ground to rule out the psu ,
somthing like 47 ohm 1 W , you can stick it between pin 4 and gnd right in the xlr connector on the psu ,
this will load it at about 150ma for 6.3V , then you will be able to rule out the mic or psu , "

Best,
Dan,


Dan,
I'm using your P.S. board with a real Neumann AC701 M49. I need need to set the voltage to 4.0 volts.
Should I use the same dummy load 47 ohm between pin 4 and Ground to pre test the voltage?
Will your boards go down to 4 volts or will I have have to change some parts?

if you have used a 250ohm trimmer pot as suggested a while ago you will be fine ,
then use ohms law to calculate the dummy load and then the power ,
it should give 40 ohm (so 47 ohm should be near by) ohm at 100ma  , and about  between 0.5 to1 W will suffice,
Best,
Dan,

 

[poctop]

Added Picture for connection of Capsule and clarification o Floating connection Scheme both version and also the Cardiod only Switch ,

See page 1 and also Check Andriejus thread For upcoming Microphone Body
http://groupdiy.com/index.php?topic=60108.msg762707#new
Best
Dan,

 

[Bowie]

Hi!  Could someone advise as to the tonal influence that the composition of the C1 capacitor has in the mic (1nf which sits between front and rear diaphragms in the circuit).  I ask because I used a silver mica in my mock-up/test mic but have some very healthy Sprague Vitamin Q PIOs which I usually prefer the sound of.  I've read that C2 and C3 are influential but found no mention of C1 making a difference.  Thanks!

 

[Banzai]

It's a key part: Polystyrene caps are the period accurate choice, but because they suffer from microphonics, some – strongly – argue to use an NP0/CG0 ceramic cap instead...

If it was my mic, I'd replace the mica, and try out both Polystyrene and your Sprague PIO to hear the differences. Sound being sound, if you like what the PIO does, then there is no right and wrong: use that instead . If you want it to be period accurate, stick to Polystyrene. Just make sure to keep the leads short and the cap body glued to the board to help with the microphonics.

Hi!  Could someone advise as to the tonal influence that the composition of the C1 capacitor has in the mic (1nf which sits between front and rear diaphragms in the circuit).  I ask because I used a silver mica in my mock-up/test mic but have some very healthy Sprague Vitamin Q PIOs which I usually prefer the sound of.  I've read that C2 and C3 are influential but found no mention of C1 making a difference.  Thanks!

 

[Bowie]

It's a key part: Polystyrene caps are the period accurate choice, but because they suffer from microphonics, some – strongly – argue to use an NP0/CG0 ceramic cap instead...

If it was my mic, I'd replace the mica, and try out both Polystyrene and your Sprague PIO to hear the differences. Sound being sound, if you like what the PIO does, then there is no right and wrong: use that instead . If you want it to be period accurate, stick to Polystyrene. Just make sure to keep the leads short and the cap body glued to the board to help with the microphonics.

Hi!  Could someone advise as to the tonal influence that the composition of the C1 capacitor has in the mic (1nf which sits between front and rear diaphragms in the circuit).  I ask because I used a silver mica in my mock-up/test mic but have some very healthy Sprague Vitamin Q PIOs which I usually prefer the sound of.  I've read that C2 and C3 are influential but found no mention of C1 making a difference.  Thanks!

Thanks Banzai!  That's going in my collection of M49 notes.  Without access to an original capsule or transformer I'm not hung-up on it being period-correct.  I haven't been wild about ceramic caps in the past but I have some Polystyrenes I can compare with the VitQ.  Just wanted to make sure it was a position in the circuit that has a noticeable impact.  Thx again. 

 

[Banzai]

Let us know what you hear as difference! I'm as guilty as the next to just sticking with what's 'correct' instead of experimenting, so genuinely curious.

Thanks Banzai!  That's going in my collection of M49 notes.  Without access to an original capsule or transformer I'm not hung-up on it being period-correct.  I haven't been wild about ceramic caps in the past but I have some Polystyrenes I can compare with the VitQ.  Just wanted to make sure it was a position in the circuit that has a noticeable impact.  Thx again. 

 

[pzjones]

Well I have decided to bite the bullet and start a M49 build. We recently used a 49c to record a really talented singer from New York who specifically asked for one for the sessions. The sessions were in the UK and we managed to hire one from Tad Barker who still has some ex Tickle Hire stock. Anyway to cut a long story short I loved the sound of the mic and decided to try to build my own which would be a bit of a challenge and let me get to learn a bit about the way the mic was made. I have bought the  round PCB,s from Dany....many thanks for your swift delivery and excellent boards and have just finished the PSU which is working and after putting a dummy load on it is providing the correct voltages. Planning on a 49B using a BV11 with a 5840 and a Neumann capsule although like all best laid plans this might change. Body from Andrew I think and making up a cable using Gotham Cable and Binder connectors. Thanks for all the help I have gleaned from the threads already, I am sure there is a lot more reading to come. I have attached a quick pic of the PSU.

 

[poctop]

Hi All,  I tought I would share this with everyone , this is a Raw Picture content pictorial of the Prototype I have built for Andriejus.
While Andriejus is Polishing the Last details ,

Tip #1 always keep the lead of the HZ bridging component so you can use them to make the bridging so no need of fancy jumper and so much easier , this is build needs to be built from the top and down , except for the headbasket and capsule mount, well this is how I do it 

I am hoping you will appreciate it , this also applies to the General Build of this one ,

So here it is
https://cdn.groupbuilder.com/groupdiy/u/39511/58d02819947c9.zip?dl=0

Best,
Dan,

 

[duantro]

Hi, I purchased an AMI m49 body and it appears that your pcbs are slightly smaller than their body mounting holes. I think I may just go with the AMI plexi boards and do a point to point build, unless I can think of any other options. Does anyone have any experience or opinions on the choice between a max bv11 or an AMI bv11a (classic)? I'm using a telefunken ac701k tube also.

 

[achase4u]

Looking for a replacement for the Vishay that is no longer available at Mouser...

http://www.mouser.com/ProductDetail/Vishay/V-730P105X9250/?qs=%2fha2pyFadug6OqOJv9KYiLUiFihsz700ppmOrT0UPKP6afZ0mrDRZg%3d%3d


This is a good replacement, yes? http://www.mouser.com/ProductDetail/Vishay-Roederstein/MKT1813510255/?qs=sGAEpiMZZMv1cc3ydrPrF9YnoK4MhZ%252buq9jXZORPslk%3d

or does it need to be polypropylene like this one http://www.mouser.com/ProductDetail/Vishay-Roederstein/MKP1839510254/?qs=sGAEpiMZZMv1cc3ydrPrF%252b30hQTSgFppYCIOtfhoJws%3d