MK47 PCB tube mic kit - build thread

[jandoste]

Have you checked the voltages inside the mike?

Are both tubes working?

Hey Sredna,
thanks.... Yes, I have checked the voltages and I got 102V for B+ and the tube pins have the same voltage but they are not very brilliant 
cheers

 

[David R.]

OK, build of 2 MK47 mics done, and they look beautiful.  Not crazy about the sound yet.  One sounds very nice, yet dark, and the other is completely lacking low end.  I will look at the connectors first, then grounding second.  Would the tubes be suspect?  Any tips for troubleshooting?

I used Skylar's body and capsule.  The psu board from Zayance.  Made the cables.  Swapped cables and psu's to verify it is the mic and not the supply or cable.

 

[david-p]

OK, build of 2 MK47 mics done, and they look beautiful.  Not crazy about the sound yet.  One sounds very nice, yet dark, and the other is completely lacking low end.  I will look at the connectors first, then grounding second.  Would the tubes be suspect?  Any tips for troubleshooting?

I should have thought it was very unlikely to be the tube.  I would suspect the input or output capacitor or the o/p txfr.  In the absence of serious test gear, having inspected everything for any obvious differences, the best way would be to swap components from one mike to the other.  I would begin with the tube, as that is easy to change.  Then the transformer.  Then the capsule... Identify the mics clearly and keep a written log of every change and test.  These things can take time to nail down.

David

 

[David R.]

Thank you, David P.

 

[jandoste]

Great Sound! Amazing Mic ! everything works here!
Thanks Max and Zayance for the PSU!
Cheers

Have you checked the voltages inside the mike?

Are both tubes working?

Hey Sredna,
thanks.... Yes, I have checked the voltages and I got 102V for B+ and the tube pins have the same voltage but they are not very brilliant 
cheers

 

[Myc]

Forgive me if I missed this in my scour of this thread plus some selective searching but I'm looking for informed opinion on wiring the tube town 30va toroid. Four wires for the primary, which are live and which are neutral?  Thanks for any help and for the great kit and psu pcb M and Z.

 

[nashkato]

my short (5 seconds ) search brought this up

Pri: 0 - 220 - 230 - 240 V (schwarz-gelb-lila-rot / black-yellow-purple-red)
Sec 1: 200 V @ 0,1 A (red / rot)
Sec 2: 6,3 V @ 1,5 A (green / grün)

from the tubetown website .
hope that makes it clear ?

 

[Myc]

Sorry, no it doesn't. What does that mean? I had the info before (its in the outside of my transformer) and an opinion as to what it meant but I kept it to myself to avoid misinterpretation and get an opinion from someone who'd wired one. The secondary is clear but which wires go where for the primary? Again I have an opinion but I want to hear from someone who knows.  Thanks for your attempt.

 

[nashkato]

i doesn´t really matter which is neutral and which is live.
there´s no right direction to plug the IEC into the outlet (0 degree or 180 degree and N/L are swapped)

the right colout code would be
here in Austria blue is Neutral = 0
                      brown is Live = 220-240V

the only effect if you do it reverse is the phase will be 180 degree , but additionally there´s no guarantee that the colours coming from your wall are correct. besides that try to measure the voltages in your house in the morning , midday , and evening . you´ll see they vary depending on the usage of power in your area.

if every household in an area would decide to turn on their oven and/or washing maching machine simultaneously , the fuse at the power plant would fall , cause the lines wouldn´t be able to handle the power.

 

[kante1603]

@myc:

You just pm'ed me for info on this.
Thought it might be important for others too,that's why the answer is here.
The question was about colour codes on the primary of the tubetown-transformer.

At first the translation german to english:

SW= Schwarz=Black
GE=Gelb=Yellow
VIO=Violett=Violet
RT=Rot=Red

SW is the start of winding.
The other colours are different taps off it.
So in either case you need SW plus the colour you need,I wired mine for 230vac operation meaning SW & VIO.

Isolate the leftover wires with some shrink tube or so.

Hope to have helped,

Udo.

 

[Myc]

Thank you both.  Very much appreciated, my opinion had been Black Red for uk 240v but I had a creeping doubt that it might have been incremental...  Thanks again both of you, you've helped me out more than it would seem.

 

[kante1603]

You're welcome,maybe you should put in your location in your profile.Helps a lot when it comes to questions about psu stuff.

Cheers,

Udo.

 

[Treelady]

Has anyone used "audiophile" caps in the power supply?  I've read some arguments that they make a difference.  Any opinions here?

 

[zayance]

Don't think you'll find any "Audio Grade" at that voltages, i might be wrong.
I think it's useless, get some good high temp Caps, Snap In or leaded, and you'll be good.


T.

 

[Treelady]

Just got my Power Supply boards from Zayance. 

I'm embarrassed that I was going to try turret boarding when these first-class PCBs are available.  People, these are very very nice.  I have no reservations about tell you to use them (but let me order more first)!

 

[ioaudio]

Just a quick reminder for those who have been interested in kits, only 9 left in my WM thread.

 

[chunger]

Thanks, ioaudio. . . this fantastic kit was a treat to build!

 

[EvLoutonian]

Tidy work, chunger! 
Very nice.

Timely inspiration for myself, also, as I'm just about finished building the PSU and getting set to move on to the mic circuit.

(Supply tests well with 105v on the test circuit).

Gotta wire up the panel sockets now.
How much ventilation is needed for the enclosure?
Mine only has a few unused screw holes, but nothing like the amount on the original Neumann units.
Will this be OK?

 

[EvLoutonian]

Painted up my PSU in hammertone - only way to go!

 

[ioaudio]

nice work, chunger!
EvLoutonian, your psu housing should be fine - add holes if you experience too much heat after a long session.