MK47 PCB tube mic kit - build thread

[ioaudio]

great - and thanks for the kind words 

 

[JW]

Still trying to figure out if the Edcor transformers for the MK7 will work for Max's MK47 supply.
Is it just a matter of adjusting resistors following the secondary to get the voltage in enough of a ballpark that the pot can adjust to 105V?

This schematic calls for 200V 100mA on the AC secondary, while the Edcor is 160V 10mA. Seems like the biggest issue would potentially be the current rating.

 

[luis]

I noticed that there is some discussions about the different PSU combinations. Is there any PSU PCB available?

Thanks,
Luis

 

[Kingston]

This schematic calls for 200V 100mA on the AC secondary, while the Edcor is 160V 10mA. Seems like the biggest issue would potentially be the current rating.

That edcor will burn to ashes if you try to power your MK47 with it.

See ioaudio White Market thread for information on suitable transformers.

 

[nashkato]

posted this transformer link before in the white market iirc.
http://www.tube-town.net/ttstore/product_info.php/info/p2192_Ringkern-Netztrafo-30VA-Preamp.html
for 230V countries only , though.
reasonable price , works perfectly in my PS .
additionally you may even experiment with tube rectifiers.( like EZ81 ?? )

 

[gary o]

Made my power supply while waiting for kit used maxes nice schematic used a transformer I had laying around 240VAC output 250Ma bit wasteful really but needs must, I added some resistance to the Max PSU doubles as a studio heater.....I have 104.1 VDC hope 
that is ok?.......
mic is living in temporary accommodation at the moment a chocolate wafer tin & has temporary capsule too a Violet Vin 67 lollipop head (its supposed to sound like a U67 when used with a flat mic amp)?......F**ck this thing has bottom end!! up until now I have agreed with mic gurus here who say mic electronics has less effect on sound than capsule I found this too with my own experiments.......but boy does this circuit have bottom end like none I have DIYed.......

I do have plenty of white noisy mush at the moment......need to look into that maybe something I have done wrong, maybe dirty high impedance section or something.......

just wondering which is best capsule to buy now..........I hear beezneez good but slightly worried about the companies own discription of their own capsules.....they say their k47 is their best capsule yet.......so does that mean their K47C isnt all that ?

Anyway just wanna say thanks to Max for this kit its brilliant....

 

[living sounds]

Can I use the transformer that came with the T-Bone SCT-700 type mics PSU? There are no ratings on it, it's 5 * 5 * 4 cms in size.

 

[Kingston]

Can I use the transformer that came with the T-Bone SCT-700 type mics PSU? There are no ratings on it, it's 5 * 5 * 4 cms in size.

No way! It'll burn to ashes. That physical size (usually directly proportional to the power output) is something like 3-10VA, while this project needs something like 30VA to be on the safe side. Again, See ioaudio White Market thread for information on suitable transformers.

People, look at the schematic for once, and not just the static voltage spec of 200VAC needed for B+.

Where does the tube heater get it's current? Where is heater PSU? Then compare to your average G7 based tube mic, or MK7...

 

[living sounds]

No way! It'll burn to ashes. That physical size (usually directly proportional to the power output) is something like 3-10VA, while this project needs something like 30VA to be on the safe side. Again, See ioaudio White Market thread for information on suitable transformers.

Thanks! I had been wondering about the heater. Still am, actually. Anyway, time to order a transformer...

 

[Andy Meyer]

I have built the MK47 head amp and now need to mount it into my Tab-Funkenwerk U47 style body.  Has anyone done this?  I am looking for any ideas to do this cleanly.

 

[idylldon]

So what are the options available for bodies and grilles/head baskets?  Here are the ones I know about:

1.)  The EQU47 group buy, which are VERY well done and affordable, but I missed out on that.  Not sure I want to wait months for the next order.

2.)  Flea products, which are great but pricey.

3.)  Tab/Funkenwerk, which are also nice but pricey.

4.)  BeesNeez, which seem to be a bit less than the above but still quite a bit of $.

5.)  Some of the Chinese mic bodies like the ones in the T-Bone line.

Any others I've missed?  While I would love to have one of the more expensive bodies, I'm not sure it will fit in the budget right now so I was wondering about other alternatives the people have used.

Cheers,
--
Don

 

[Jonkan]

You could always go hardcore and diy the complete body. Brass or copper pipe+dremel for cutouts+metal mesh for grille +a bit of solder. A bit of creativity+ an endstop which you could either lathe yourself or maybe (as i did) get a friend to help you with. Some sort of internal mounting system and you are good to go. And it will look if not stunning, atleast personal, and if youre carful with details, sound absolutely stunning.

Or....just pay up  ;D

 

[JW]

Hey guys,
What should the AC fuse be?

 

[JW]

Okay, I built the power supply up. It's easily adjusted to 105V with the pot, after adding a bit more resistance due to my AC power transformer.

My question is, how much fluctuation is acceptable?

I'm getting a fairly quick fluctuation of about .3VDC.

 

[Le Roux]

When choosing a transformer, is it wise to get one rated larger than required?

For this project, the schematics call for 200V 100mA for the PSU.
It was recommended in this thread to get a transformer 30VA, "to be on the safe side".

But would 20VA suffice?

 

[mrcase]

Sourcing parts for my MK47 PSu since I´ve nearly got all my pieces together.
But there are some things I don´t understand or am unsure off...
- unsure how the polar pattern switch works, what are you guys using, normal SPDT?
- I´m thinking of use the mogami 3172 - 6 pol should be enough (since there is no heater) or should I buy a 7pol cable? (I gonna use Skylars body)
- where to connect a jewel light?
- the triad choke substitutes the 1K 5w resistor, no?

I´m sure there´ll be more questions coming up, but thats all for now!

thank you all!

 

[mrcase]

and here we go ;-)
one more:

is it ok to use wirewound resistors in the psu like the ones from banzai?
http://www.banzaimusic.com/100-Ohm-18k-c-339/
any experience with those?

 

[Jim50hertz]

Sourcing parts for my MK47 PSu since I´ve nearly got all my pieces together.
But there are some things I don´t understand or am unsure off...
- unsure how the polar pattern switch works, what are you guys using, normal SPDT?
I'm using a Lorlin.

- I´m thinking of use the mogami 3172 - 6 pol should be enough (since there is no heater) or should I buy a 7pol cable? (I gonna use Skylars body)
That'll be fine.  I've seen starquad used without a problem (5 conductor)

- where to connect a jewel light?
If you use the Tube Town trafo there's a 6.3v tap

- the triad choke substitutes the 1K 5w resistor, no?
Yes

one more:

is it ok to use wirewound resistors in the psu like the ones from banzai?
http://www.banzaimusic.com/100-Ohm-18k-c-339/
any experience with those?

I'm using the exact same ones, haven't arrived yet but I don't see a problem, unless they're too large

 

[Le Roux]

- unsure how the polar pattern switch works, what are you guys using, normal SPDT?
I'm using a Lorlin.

Must you use a switch?
Or can you wire direct?

 

[mrcase]

Sourcing parts for my MK47 PSu since I´ve nearly got all my pieces together.
But there are some things I don´t understand or am unsure off...
- unsure how the polar pattern switch works, what are you guys using, normal SPDT?
I'm using a Lorlin.

- I´m thinking of use the mogami 3172 - 6 pol should be enough (since there is no heater) or should I buy a 7pol cable? (I gonna use Skylars body)
That'll be fine.  I've seen starquad used without a problem (5 conductor)

- where to connect a jewel light?
If you use the Tube Town trafo there's a 6.3v tap


Thank you!

- the triad choke substitutes the 1K 5w resistor, no?
Yes

one more:

is it ok to use wirewound resistors in the psu like the ones from banzai?
http://www.banzaimusic.com/100-Ohm-18k-c-339/
any experience with those?

I'm using the exact same ones, haven't arrived yet but I don't see a problem, unless they're too large

THANK YOU!! that cleared things up for me!