e.oelberg

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #180 on: May 25, 2017, 04:43:46 PM »
My arm is getting tired holding the M49 all the time...  :P
Any suggestions for a shockmount or swivel?

I really like the m600 from enhanced audio


kosi

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #181 on: August 06, 2017, 09:51:45 AM »
does anybody have an idea, how one could mount the poctop pcb in Banzais bodykit ?
I attach a pic, where you can see, that the pcb is a bit too small.
I thought about buying an acrylic glass with diameter of 66mm, drill the necessary holes and use this as an adapter-plate.
But maybe the whole construction get's too high ?
Never did this before.

Every idea is welcome !

http://www.ebay.de/itm/Acrylglas-Rund-3mm-10-100mm-Scheibe-Kreis-Zuschnitt-Plexiglas-/201705737623?var=&hash=item2ef6994d97:m:mfhDfz79y7XzEfgAqnSTbVw

stelin

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #182 on: August 06, 2017, 08:44:35 PM »
I could be wrong, but I think Neumann used an adapter made of rubber.
That way, the "guts" of the mic will have no  metal to metal contact with the body.
That will hopefully reduce vibrations from the floor and the mic stand a bit, especially when you use a swirvel mount.
If you use an adaptor made from rubber, I think you also need to put some sort of soft rubber ring around one of the upper PCBs, to keep the PCBs away from the body tube. 

kosi

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #183 on: August 07, 2017, 04:11:28 AM »
thanks for the suggestion.
useme2305 gave me the idea to order a 67mm/3mm plexiglas disc, which is very cheap (1€) and I'll see, where this is going.
Rubber is very interesting, but I can imagine, that it's not easy to work with.
Another idea would be a 3d printed part.

I also shot a mail to Andriejus, wether he sells his whole mounting construct alone.

Avgatzeblouz

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #184 on: August 07, 2017, 09:22:04 AM »
You should contact OPR, he seems to make very nice plexis designed for this exact body.

kosi

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #185 on: August 12, 2017, 01:28:32 PM »
I finished the first one and I'm deeply impressed by the quality of this mic.
I used the K47 from Banzai, poctops M49c pcb and ioaidio's BV11 transformer in combination with 6S6B tube.
This mic is so smooth and : very quiet !!!
I love it.

It was a bit tricky to install the pcb into the body, but in the end, I got everything in.
Next steps now: different TX, Cinemag CM6511.

useme2305

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #186 on: August 12, 2017, 01:41:27 PM »
congrats! pics?

kosi

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #187 on: August 13, 2017, 09:51:27 AM »
some pasted pics. You can see on the lower left picture, that poctops transformer pcb sits on a 3mm plexiglass disc, which itself is screwed to the body. Next time, I will leave out the transformer pcb and raise the plexiglass disc about 15mm higher.
I also had to modify the diameter of the uppermost capsule-holder pcb, took away about 1mm, that it fits into the mic basket.
« Last Edit: August 13, 2017, 09:55:46 AM by kosi »

e.oelberg

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #188 on: August 16, 2017, 09:36:24 AM »
Hi Kosi !

how did you bias the 6s6b ? what values ?


kosi

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #189 on: August 16, 2017, 09:43:42 AM »
Funny that you ask, I was just about posting this question on poctops thread.
I took the 1,6V cathode voltage from the orig M49c schematic as reference. To reach this, I have about 47V on the plate.
I don't know, wether this is he proper way to do this, but the Mic sounds fantastic. And the noise is very low, which is important to me. I ordered 5 6s6b and took the first without testing it.


Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #190 on: August 16, 2017, 01:27:00 PM »
Funny that you ask, I was just about posting this question on poctops thread.
I took the 1,6V cathode voltage from the orig M49c schematic as reference. To reach this, I have about 47V on the plate.
I don't know, wether this is he proper way to do this, but the Mic sounds fantastic. And the noise is very low, which is important to me. I ordered 5 6s6b and took the first without testing it.

If your B+ is set to 120V, then you have the perfect recommended 0.73mA plate current:

120V B+
47V plate voltage
100K plate resistor
I = V/R

(120 - 47) = 73 / 100 = 0.73mA

With 116V B+, you'll want around 43V plate voltage:
(116 - 43) = 73 / 100 = 0.73mA

The recommended I and V values are marked on the M49C schematic, right above the plate.

kosi

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #191 on: August 16, 2017, 03:05:21 PM »
thank you very much for the explanation !
I have 120 V B+ btw.

Murdock

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #192 on: August 16, 2017, 03:27:22 PM »
Funny that you ask, I was just about posting this question on poctops thread.
I took the 1,6V cathode voltage from the orig M49c schematic as reference. To reach this, I have about 47V on the plate.
I don't know, wether this is he proper way to do this, but the Mic sounds fantastic. And the noise is very low, which is important to me. I ordered 5 6s6b and took the first without testing it.


You didn't change anything else in the circuit? So the 6S6B is really a "drop in" replacement except for the heater voltage?

kosi

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #193 on: August 16, 2017, 04:14:50 PM »
You didn't change anything else in the circuit? So the 6S6B is really a "drop in" replacement except for the heater voltage?

correct. I didn't change anything.
I will build a second one over the next weeks, where I will use an  AC701, which I luckily still own. I also have access to some real M49, so I plan to do a nice comparison .

Murdock

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #194 on: August 16, 2017, 04:32:40 PM »
correct. I didn't change anything.
I will build a second one over the next weeks, where I will use an  AC701, which I luckily still own. I also have access to some real M49, so I plan to do a nice comparison .


Yes, please do! That sounds promising!

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #195 on: August 16, 2017, 06:09:56 PM »
thank you very much for the explanation !
I have 120 V B+ btw.

And just in case, I simplified the calculation from:

73 (plate resistor voltage drop) / 100'000 (plate resistor value) = 0.00073A = 0.73mA

kosi

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #196 on: August 27, 2017, 05:26:55 AM »
Tight, but works.
But I wouldn't recommend it, cause the mic is too heavy, and the clamping mechanism from Rycote is, ahm, not so good....

kosi

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #197 on: August 27, 2017, 05:38:51 AM »
I finished both my kits, one with BV11 and one with the Cinemag.
I have the feeling, that the Cinemag has more air. This is a first impression, I only have one mic holder, so on my tests, both were laying side by side on my couch...
But the sound is fantastic. I compared it with a TLM49, a Chunger C12 with Haun capsule/ CInemag tx and a Schoeps CMC5 w cardiod capsule for reference, I know it very well.
TLM sounds very clean and boring, but has the lowest noisefloor of them all, the C12 is a bit strange, sound seems to be processed somehow... Schoeps sounds like Schoeps, business as usual.
Both M49 have really incredible nice midrange, I love it !

micaddict

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #198 on: August 27, 2017, 07:27:13 AM »
Quote
I finished both my kits, one with BV11 and one with the Cinemag.
I have the feeling, that the Cinemag has more air.
But it's also 6S6B versus AC701, right?

Re: Neumann M49 DIY Bodykits – CLOSED
« Reply #199 on: August 27, 2017, 09:46:59 AM »
Tight, but works.
But I wouldn't recommend it, cause the mic is too heavy, and the clamping mechanism from Rycote is, ahm, not so good....

Hey Kosi,

Did you sign up for shockmounts from the new batch?

They'll be here in a few weeks  ;)