MK7 - tube mic project

[bradb]

Jonkan,
I just don't understand how that socket remains mounted?  are there tabs that the metal piece attaches to?

can you send a pic?

 

[Jonkan]

The metal mounting plate is firmly attached to the socket, so its working just fine. Theres a small area of the round micalex socket sticking out that has a slightly larger diameter. The metal mounting plate is bent around that, so that the socket cannot move. Dont have a camera available atm, but trust me, that socket aint going nowhere

/J 

 

[bradb]

Ahhh, that makes sense.

 

[Jonkan]

How critical is this max? "do not un-mount the transformer, do not tighten/loosen it´s screws/nuts."

I just accidently touched one of the plastic nuts holding the transformer in place, and it turned like 1/5 of a turn tighter (maybe even less). Im clumsy, i know....
I immediately turned it back to the original position. The movement was very minimal, and i cant see any difference at all on the transformer compared to the other ones i have.

Sorry if this is a stupid question, but seeing as it was under IMPORTANT with capital letters, id figure its better to ask than to deal with not knowing for sure.

Did i accidently disrupt the time/space continuum doing this?

/J

 

[bradb]

sweet!! i went back to our NA supplier, tube depot, and found that their link for the datasheet for the same part works now!

http://site.tubedepot.com/9pin_drawings.jpg

looks like mounting hole is 18.5 which isn't too dire.

 

[synthi]

Just confirming the banzai micalex noval socket works great! just enlarging the hole a bit and its perfect!

Synthi

 

[bradb]

nice, i just ordered the american equivalent....

now i can continue!

 

[bradb]

after a quick enlargement of the hole, these smaller sockets work great.

 

[matta]

after a quick enlargement of the hole, these smaller sockets work great.

Hey Brad,

Care to share a pic? Still a little confused about the orientation?

Thanks

Matt

 

[linguisticat]

Hello all,

Just discovered this thread. WOW!! I'm a little late to the party. Did you all settle on a capsule (Thiersch blue line?) or is it still up in the air? If you did, how did, what was the cost per capsule and is there a group buy for these? So far it seems like a full kit (PCB & Tran (~$200USD), PSU (?), Body(~$200USD), Capsule ($200+USD?)) is running about $700USD. Is that about right? I would be interested in one myself if I can get my hands on a full and complete kit (body, PCB & Tran, PSU, Capsule, electronics, &c.). Any news on when the next batch of boards will be available? Thanks for the info. I will keep my eye on this thread and the http://www.groupdiy.com/index.php?topic=30742.0 threads.

Regards,
Nathan

 

[bradb]

matta, lemme try words first, then i'll get off my rump if these words don't work.


the socket seen in the pictures is one piece.  the metal and plastic parts are joined.  The hole on the PCB is 18mm, i believe and the diameter of the socket is about 18.5mm.  I took a dremel and opened up the hole on the PCB, which took like 0.001 seconds.  You slide the socket into the larger hole from the bottom (the tube side of the pcb) and voila!  2 screws and its secure.

still need a pic?

 

[fazeka]

Hello all,

Just discovered this thread. WOW!! I'm a little late to the party. Did you all settle on a capsule (Thiersch blue line?) or is it still up in the air? If you did, how did, what was the cost per capsule and is there a group buy for these? So far it seems like a full kit (PCB & Tran (~$200USD), PSU (?), Body(~$200USD), Capsule ($200+USD?)) is running about $700USD. Is that about right? I would be interested in one myself if I can get my hands on a full and complete kit (body, PCB & Tran, PSU, Capsule, electronics, &c.). Any news on when the next batch of boards will be available? Thanks for the info. I will keep my eye on this thread and the http://www.groupdiy.com/index.php?topic=30742.0 threads.

Regards,
Nathan

Hi,

Trying to do some research, but my head is spinning. I guess what I am wondering is similar: what are everyone's plans for trannies, capsules/ mounts/adapters and what's the availability/source for these parts?

I see references to dale's M7 capsules (not sure the source?) and Thiersch's, thought I saw reference to Cinemag trannies in another thread, not sure if they'll work with the prototype Skylar's working on...

I'm such a newbie when it comes to DIYing mics. I've really only done pres and compressors in the past... but I'm a-wanting to try something different with this project.

Cheers,
Chris

 

[ioaudio]

i will offer a new batch of mk7 sets, but it will be a couple of weeks.

-max

 

[Skylar]

fazeka,

ioaudio's MK7 project includes the PCB & Transformer.

Some other options for building a U47-type mic are the Cinemag CM-2461NiCo (datasheet)
and AMI BV8/BV8R/BV308/etc.



Dale (dale116dot7) is a member here who makes capsules in his home shop!
I've not tried one of these capsules, but everyone seems impressed with them.
You'll have to watch the Black Market for his capsules.
A Dale capsule thread will pop up from time-to-time, and he usually sells out in a day.

I just ordered a red-line Thiersch + mount. The total was $430USD.
Send them an email, and they will prepare an invoice. Pay via PayPal.



There are a couple of threads in the Black Market for capsule mounts.
Peluso also sells capsule mounts on his site.
You can get a mount from Thiersch that is a repro of the U47 mount.
My mic body's capsule plate will allow you to use either a single-screw capsule mount (Thiersch & some Chinese mounts) or a double-screw capsule mount (Chinese-8mm hole spacing).




As far as mounting transformers, PCBs, other internals into my mic body design, you will have to do your own engineering.
I could have made the internal mounting such that the MK7 would bolt directly in, but that might have made it difficult to do other projects.
So, I made it generic.
There are holes in the mounting rails that will allow you create your own configuration.
The easiest thing to do would be to use brass/aluminum Angle/L-Channel/U-Channel or L-Brackets to mount anything you need (transformers, PCBs, etc).
Cut to length and drill the appropriate holes.
You can find this at SmallParts and Mcmaster-Carr

Brass 1/2"x1/2" <-this may be too big
Aluminum 3/8"x3/8"<-this should work
Aluminum U-channel<-this could work
Brass U-channel<-this could work



EDIT: fixed links

EDIT: after looking at the MK7 PCB hole centers, you'll need something larger than most of the suggestions above.
The internal rail spacing of my mic is 49mm, PCB hole centers are 38.5mm.
You'll need brass/aluminum angle that will give you 7mm+ lip.
So, 1/2" angle might be best. That'll give you a 13mm lip or thereabouts.

EDIT AGAIN: Okay I've updated the comments on the links again with what I think will work best.

 

[Skylar]

Here's an example with 3/8"x3/8" (1/16" thickness) angle:
You may need to do some additional metal-work on the brackets or add insulation to prevent shorting traces/components on the back of the PCB.

 

[fazeka]

Hi Skylar,

That's great, exactly the kind of answer I was looking for! And I hope it answers the question that someone else within the group stumbling on to this thread may have should that happen.

I am waiting with bated breath for ioaudio's PCB/tranny kits to become available...

Thanks,
Chris

 

[linguisticat]

Skylar,

Thank you very much. This is exactly the info I was looking for too - very informative post(s). Thanks again. I will keep my eyes open for ioaudio's tranny kit and dale116dot7's capsule.

Thank you,
Nathan

 

[Jonkan]

Has anyone experimented with the output coupling caps used when using Dales m7 clones in this design yet?

I ordered 0.33uf mundorf mcaps to atleast have something to put in my mics to get them working, but im pretty sure i want to try some experimenting after all.

What do you think about paper in oil caps vs regular polypropylene? I have no clue what difference, if any to expect.

Anyone besides e.oelberg, who posted earlier in this thread who has a preference to what value with dales m7 capsules they like?
Perhaps it is too early to ask, im not sure how many of you have actually finished building your mics.

Having never used PIO caps before, I figured id definately like to try some...problem is, they seem to be pretty expensive to buy, so if possible id like to atleast get in the right ballpark before i order. It seems they are liked by the hifi crowd, and are many times priced accordingly.

Would it be a good idea to try some cheaper polyester caps in different values to try and pin down what value i like the most, and then order a "better" cap with the same value after that? Or would the difference in sound due to the capacitors being of different make and material make that kind of thinking invalid?

What should i listen for in such a comparison if indeed a good approach to choosing the "correct" value? Overall response, or mainly bass response, how things like proximity effect affects the sound etc?
/J

 

[Gus]

http://uk.geocities.com/[email protected]/downloads_4.html

Claude posted this link some time ago.  Good read on caps.  No easy answer for caps because it depends on a few things.

 

[Davo]

You've got the right idea... experiment with some polyprops to find the value you like, then if you want, upgrade the cap.
I've used Jensen PIO's in a couple of projects and I think they sound great, they're damn expensive though.

cheers,
dave