MK47 PCB tube mic kit - build thread

[poctop]

No ones has any information on this CCCP bypass cap,  was this cap in the original circuit or just the one that fitted there the most ?
any substition experiment out there ?
DAn,

[SKJGProject]

anybody knows a source for the little bastards in germany??? i can't find them and don't want to spend 20€ shipping just for 2 20cent pieces...

These little guys are your friends:
     
Mouser PN: 534-621

I used 2 of them on one of my MK7s along with short 4-40 flat undercut brass screws.
          
On this build, all the wiring is solid-core silver teflon, and it's STIFF, which really helps keep the board in place. In fact, I can remove the brackets, and the PCB is still held in place solidly under the support of only the wiring.


Now, mounting the G7 takes a little more imagineering.
Using parts that I had lying around...
     
This one is fun. Looks a little steam-punk, but we like that kind of thing around here, right?
There are plenty of ways this could be done better, but this improvised approach works in a pinch and provides some adjust-ability.
[You will notice that the side rails are all bent outta shape. That's the result of my testing procedures...of course, they still work fine. A trip to the vise will straighten them back up again.]   

[grantlack]

anybody knows a source for the little bastards in germany??? i can't find them and don't want to spend 20€ shipping just for 2 20cent pieces...

i'm placing a mouser order soon, i can send some your way if you want to drop me a line by pm.

[kante1603]

anybody knows a source for the little bastards in germany??? i can't find them and don't want to spend 20€ shipping just for 2 20cent pieces...

Hi,

in germany this could work,mounting stuff for D-Subs like this:

http://www.reichelt.de/Befestigungssaetze/SV-WMG/index.html?;ACTION=3;LA=444;GROUP=C125;GROUPID=3212;ARTICLE=19873;START=0;SORT=artnr;OFFSET=500;SID=11Ts03q38AAAIAAD4EOiM488d01c62fad0a865a65237798186f50

or at Bürklin (if you have an account),they have nearly all sizes as well as massive small cubes ("Gewindewürfel"):

https://www.buerklin.com/default.asp?event=ShowPHNode(SE,vt,6007)&l=d&jump=PHNode_SE_vt_6007&ajaxLoadPHNodeTagId=PHNode_SE_vt_6007&ajaxLoad=true

If you want real diy then go to "OBI" and get yourself an L-bracket (aluminium) in 1 or 2m pieces and cut/drill them to the size you need (available starting from 10mm sides) .

Best regards from germany,

Udo.

[bezen4uk]

No ones has any information on this CCCP bypass cap,  was this cap in the original circuit or just the one that fitted there the most ?
any substition experiment out there ?
DAn,

Hi Dan,
These are russian "MBGO" paper-in-oil capacitors. Not original, just same type.  I'd use modern Wima FKP4 or MKP4 or vintage Siemens PIO caps.

[poctop]

No ones has any information on this CCCP bypass cap,  was this cap in the original circuit or just the one that fitted there the most ?
any substition experiment out there ?
DAn,

Hi Dan,
These are russian "MBGO" paper-in-oil capacitors. Not original, just same type.  I'd use modern Wima FKP4 or MKP4 or vintage Siemens PIO caps.

Thanks bezen4uk this is exactely the information i needed ,
Super,  will probably try a orange drop sometime in there , just to see,

[Ishi]

Please give me advice about the PSU transformer of MK47.

The wall socket of my country is 100v.　Can I just get the transformer which can convert 100v into 200v?　The following transformer seems to increase 115v to 230v.　Although it seems that this transformer increases 100v to 200v, isn't there any mistake in my thought?　Can this transformer work MK47 in the country of 100v?

http://us.mouser.com/Search/ProductDetail.aspx?R=VPT230-220virtualkey55310000virtualkey553-VPT230-220

[poctop]

This is the transformer i used so it is ok wire it in parralle for 120V contry and replace the 680 330 pair with a 1.5 K with the 1K pot 5 W and youl be fine ,

Dany,

[dandeurloo]

I built my kit up during my daughter nap today!  Nice kit.  I can't wait to figure out what capsule I'm gonna try and get the PSU going.

Thanks Ioaudio.  Good work.

[electrisizer]

hi,

my build is complete (first batch + beezneez capsule + t.bone housing), but mik dosent work the right way...


i have lot of "windy" noise and the output is very very low... on the other hand the mik is very sensitive in case of touching or moving. perhaps a grounding problem?

the cable is the original t.bone and seems not to be in best condition, but  measuring doesnt advertise any problem.

does anyone have an idea?

[drgrateful]

For those who might be interested, 1K5 10W aluminium housed, chassis-mount resistors similar to that used by JamesW can be found in Europe from RS-Online. The RS Stock No. is 252-2530 or 720-4827. Tolerance is 5%, but it should suffice.

[nashkato]

 

  Tolerance is 1%, but it should suffice.

  did you use precision components inside your mic ??

[drgrateful]

did you use precision components inside your mic ??

No, sorry, I meant 5% tolerance. I corrected my post. 

Matteo

[Volume11]

Hey guys, I am working on building the power supply and I am having trouble locating some of the parts on mousers site. Can someone please tell me what fuse type and value would be most appropriate. A mouser part number would really help me out . This is for a US model.  Also, what lamp have people used and liked so far? I have noticed a lot of Fender amp style lamps being used, which I think looks really cool.
Thanks

[wave]

Hey guys, I am working on building the power supply and I am having trouble locating some of the parts on mousers site. Can someone please tell me what fuse type and value would be most appropriate. A mouser part number would really help me out . This is for a US model.  Also, what lamp have people used and liked so far? I have noticed a lot of Fender amp style lamps being used, which I think looks really cool.
Thanks

I think these will work

http://www.mouser.com/Search/ProductDetail.aspx?R=20105000021virtualkey57610000virtualkey576-20105000021

If you use a power transformer with a 6.3 VAC tap you can use this

http://tubedepot.com/lamps.html

-Dave

[madreza]

Hi Guys
I have strange noises coming out of the mics from time to time ( it can work for hours and suddenly noise ! )
http://dl.free.fr/dIzDp5o9a
a sample in the link

in 1 of my mics, I think i have a transformer problem. how can I test that ?

Cheers

[Volume11]

Hey guys, I am working on building the power supply and I am having trouble locating some of the parts on mousers site. Can someone please tell me what fuse type and value would be most appropriate. A mouser part number would really help me out . This is for a US model.  Also, what lamp have people used and liked so far? I have noticed a lot of Fender amp style lamps being used, which I think looks really cool.
Thanks

I think these will work

http://www.mouser.com/Search/ProductDetail.aspx?R=20105000021virtualkey57610000virtualkey576-20105000021

If you use a power transformer with a 6.3 VAC tap you can use this

http://tubedepot.com/lamps.html

-Dave

Thanks!

[poctop]

Hope it can help for givig an idea where the capsule should end,
Cheers,
Dany

[wave]

This is the transformer i used so it is ok wire it in parralle for 120V contry and replace the 680 330 pair with a 1.5 K with the 1K pot 5 W and youl be fine ,

Dany,

Dany
Are you saying that if the VPT230-110 is used the 680/330 resistor pair is switched for a 1.5K and the 500 ohm 5W pot is switched for a 1K 5W pot?

Dave

[grantlack]

Are you saying that if the VPT230-110 is used the 680/330 resistor pair is switched for a 1.5K and the 500 ohm 5W pot is switched for a 1K 5W pot?

Dave

yep, i mentioned this previously but should have been more clear.  i used a 1k pot and 1k resistor this way with no problems dialing in either psu.