Good solid state donor mics for RK47?
« on: September 01, 2019, 11:49:08 PM »
What are some good solid state condensers for use with the RK47 (by which I mean all of the Chinese K47 capsules similar to iSK's)? I was looking at the Studio Projects B3, but I'd like some other suggestions too. Preferably things in the sub $200 price range. Ideally they'd have 3 polar patterns, a low cut filter, and a pad.

I'll also take suggestions for donor mics for the Chinese "CK12" capsules, since I still have a Maiku edge terminated capsule sitting around.

I also have one of iSK's K47 copies as well. Would like to find a use for them.

Ideally the end result would be at least as flat as the AT4050 if not flatter.


alexc

Re: Good solid state donor mics for RK47?
« Reply #1 on: September 02, 2019, 12:30:20 AM »
I liked the apex 480 mic with 'screwed-ring-mounted suspension mic-holder assembly   ...  as a donor mic in the 'large u47' type style on the super cheap.

It is a ldc fet head amp  type, which you can diy mods to as it is, or as I did, replace the internals with a tube+traffo based head amp.

Stock capsule in the original circuit is pretty good too I have to say, there are some mods out there ...

I changed the capsule to something sino but more comprehensively manu-tested, and stuck in a fab cinemag 2416nico with a ge 5 star 6072 tube ...

 [I powered my 'apex 480  tubified build'  with  a spare   cheap 'tube mic power supply+cable', that I modified to suit my purposes]

...

ANyway - Apex480 is a nice donor :)
I ping therefore I am

RuudNL

Re: Good solid state donor mics for RK47?
« Reply #2 on: September 02, 2019, 05:23:57 AM »
This is an ideal donor body for a U47 clone.
It even looks like a U47 FET!

https://www.thomann.de/nl/the_tbone_sct700_roehrenmikrofon.htm
There is a solution for every problem!

http://www.vansteenisaudio.nl

Re: Good solid state donor mics for RK47?
« Reply #3 on: September 02, 2019, 05:53:25 PM »
This is an ideal donor body for a U47 clone.
It even looks like a U47 FET!

https://www.thomann.de/nl/the_tbone_sct700_roehrenmikrofon.htm
I've got the PSU for that and the cable. I've even still got the body, and transformer, and a 6072a tube kicking around. I just have to find a tube mic with that body that doesn't have the tube soldered to the PCB.

Khron

Re: Good solid state donor mics for RK47?
« Reply #4 on: September 02, 2019, 06:34:50 PM »
... So just redesign the PCB (or PCB's) to fit a socketed tube? Or is the body too short to allow for that?

http://cdn.recordinghacks.com/images//mic_extras/tbone/SCT700-pcb.jpg

It does look kinda tight in there, after all. Buuuut not impossible.

If you can get the tube-board to sit on top of those "tangs" (as opposed to under them, as stock), and clip off the excess pins of a socket, you miiight just be able to fit the whole thing in there. I think...  ???

I've got the PSU for that and the cable. I've even still got the body, and transformer, and a 6072a tube kicking around. I just have to find a tube mic with that body that doesn't have the tube soldered to the PCB.
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans

Gus

Re: Good solid state donor mics for RK47?
« Reply #5 on: September 02, 2019, 07:59:49 PM »
Back in the 2000s Marik posted about using individual  sockets soldered in the PCB in a 1050 build that had the soldered in tube.
There was a picture IIRC.

Marik

Re: Good solid state donor mics for RK47?
« Reply #6 on: September 03, 2019, 02:02:49 AM »
Back in the 2000s Marik posted about using individual  sockets soldered in the PCB in a 1050 build that had the soldered in tube.
There was a picture IIRC.

Wow Gus--you remembered this one! Yes, that worked well for that barbaric practice of soldering those tubes. The sockets gave enough clearance for the circuit. Even though I don't remember the source for those individual sockets, if there is an interest please let me know--I think I know where I can find it out.

Best, M
Samar Audio & Microphone Design

www.samaraudiodesign.com

The Art of Ribbon Microphones

Re: Good solid state donor mics for RK47?
« Reply #7 on: September 03, 2019, 03:27:43 AM »
I found a cheap used Apex 460 on eBay for under $150, (no PSU afaik). Does the 460 have a proper tube socket?

RuudNL

Re: Good solid state donor mics for RK47?
« Reply #8 on: September 03, 2019, 03:34:13 AM »
Yes
There is a solution for every problem!

http://www.vansteenisaudio.nl

Khron

Re: Good solid state donor mics for RK47?
« Reply #9 on: September 03, 2019, 03:58:43 AM »
Hey, isn't that, like... cheating?  ???  ;D

I found a cheap used Apex 460 on eBay for under $150, (no PSU afaik). Does the 460 have a proper tube socket?
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans


Re: Good solid state donor mics for RK47?
« Reply #10 on: September 11, 2019, 09:16:29 AM »
What are some other flat DIY capsules? I know 3U Audio has a darker K67 for use in a flat circuit, AKG has the teflon capsule. Of course there's also the usual Chinese K67s as well.

I really like the sound of the Oktava MK219 and 319, but they're cardioid only, so I'd have to get 2 to make a multipattern mic. The MK-220 is a pretty different sounding mic I think, it's got a noticeable presence boost, and sounds similar to the AT4047 from demos I've heard.

I could always just order more iSK BM-600s again as well, and just do the normal capacitor swap as well. I'm thinking I'd like to get a decent pair of monitors and a measurement mic so I can start measuring my mics myself.

Re: Good solid state donor mics for RK47? New
« Reply #11 on: September 11, 2019, 12:23:50 PM »
Someone correct me if i am wrong, but as far as i understand physics of capsules 34mm cardioid capsules can not be flat. Due to dimensions and nature of cardioid pattern they just must have a resonant peak or dip somewhere in the upper mid range-high end.

The capsules we tend to call "flat" are usually flatter than k67 types, but neither k47 nor 3U audio's smooth k67 are anywhere near flat.

That is why measurement mics are tiny compared to ldc.

3U audio's does have very low peak, but it has a rather large dip before that peak. Its just one or the other.

Marik has new flat model, which i sadly never got to test.

My best bet for flat response is to find smoothest capsule with least crazy dips and peaks, and then eq them one way or another to get flattest response. Which is the thing Neumann went for with u67/87.  Or Townsend with Sphere.

Or simply smaller capsule like km84.

« Last Edit: September 11, 2019, 12:34:12 PM by kingkorg »


 

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