Gus

Say you have a capsule and you want to build a microphone

What is the capsules response?

Then pick a grill environment or use what grill and body you have then think about what happens with the capsule and grill interaction

Then pick or design a circuit with corrections or without corrections

Nothing should stop you from trying a CK12 in a U47 body etc.

Don't get stuck thinking a capsule design goes with some circuit(s).

You do need to keep in mind the capsule charge voltage.


shabtek

ok but is there a BOM?
"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ

Recording Engineer

I’ve always wanted a friend, who always over-designs audio gear and has never studied the designs of classic mics, to design me a mic with a CK12 type in a 47 style body. I’d definitely go for a Beesneez body for it.

I also would like to do an M/S mic in a 47 style body with SD capsules, oriented for end-address and the fig-8 nulls at the grill rails. I was hoping to use Les Watts’ capsules, but he’s fallen off the map for years now. I’m also thinking transformer-based and fixed stereo output, even though neither one of those are popular.

Gus

I was hoping more people would post their ideas in this thread.

If you are going to DIY and you want to learn things and not just build a "clone" sometimes bad copy.

Here is one for you a U47 like grill with a k67 like capsule and a lowpass have you tried that compared to a 47 like China copy capsule?

shabtek I guess you are right where is the BOM and PCB?

wlinart

I think in the same vein is the fet847 project, km84 circuit with k47, ck12,... capsule in a cheap bm-800 body.

Gus

I think in the same vein is the fet847 project, km84 circuit with k47, ck12,... capsule in a cheap bm-800 body.

That circuit can be done a little different/better IMO

mjrippe

OK, I'll play!  I have never built a clone, but I did build prototypes for a mic company - both tube and HV solid state.  Plenty of tech and mechanical experience.  These are actual parts on hand:

Single sided 67 type capsule, not Chinese.
BV-8 Transformer
BM-800 body
Generic PSU 6V & 150V (I can mod for other voltages)
Most of the common sub-mini tubes: 5840, 5784, 6205, 7586, 6S6B-V, 6S31B-V

What I don't have is the knowledge of how all these elements will interact.  My goal?  A unique cardioid tube mic with the solid mids of a U67, gently rolled off highs, and a bit more bottom.  Is it possible?  Do we have the technology?  ;D

Mike

kingkorg

I've been thinking lately on how to avoid any kind of grille around the capsule. Had some success, and the results are really nice. ;)

Gus

OK, I'll play!  I have never built a clone, but I did build prototypes for a mic company - both tube and HV solid state.  Plenty of tech and mechanical experience.  These are actual parts on hand:

Single sided 67 type capsule, not Chinese.
BV-8 Transformer
BM-800 body
Generic PSU 6V & 150V (I can mod for other voltages)
Most of the common sub-mini tubes: 5840, 5784, 6205, 7586, 6S6B-V, 6S31B-V

What I don't have is the knowledge of how all these elements will interact.  My goal?  A unique cardioid tube mic with the solid mids of a U67, gently rolled off highs, and a bit more bottom.  Is it possible?  Do we have the technology?  ;D

Mike

I would post something but you posted you built prototypes for a microphone company

Delta Sigma

I would post something but you posted you built prototypes for a microphone company

I think he means past tense and as a tech. I'm curious what your idea with those parts would be.

I don't have the comprehension to start from scratch. I would probably start with an m269 and modify.
Neil Fitzpatrick


mjrippe

I think he means past tense and as a tech. I'm curious what your idea with those parts would be.

I don't have the comprehension to start from scratch. I would probably start with an m269 and modify.

Correct, I did not design the mics, simply built them. 

To be more specific, using the parts I have what would be the hurdles to overcome to reach my goals?  Is the body shape and size going to cause a particular change in frequency response?  Will it make a difference that I am going cardioid-only?  Which tube is a good match for the capsule and transformer?

Starting with the M269 sounds like a good idea to me.  Just pick a different tube and then adjust for the other factors.

rogs

For my first venture into a 'proper' mic experiment (as opposed to playing around with electrets ) I decided I would not take chance on an expensive kit, but would start with a cheap K.67 Chinese capsule and work from there.
I bought a couple of BM800s as donor bodies, and designed my own circuit - based on a 'standard' Schoeps  circuit - together with a CMOS voltage multiplier for the polarisation voltage.
Rather than waste money on a specific PCB outlay at the start, I built the circuitry onto stripboard. Cheap and easy to make changes!
Worked out way better than I though it would, for a first try..
 
(I've made some notes here: http://www.jp137.com/lts/LDCX2.notes.pdf )

Nice and simple to change things like LF and HF responses, and apply different polarisation voltages.

I then thought I'd try a different version with a K.47 style capsule, and a cheap U87 style body. (photos attached).
Interesting to compare that with my original BM800 results....
I also tried out an end address version in a BM800 body, for which I designed a 3D printed capsule mount.

And more recently I have tried out a figure of 8 version, using a double sided CK12 'style' (edge terminated) capsule, and my RF bias circuit.

All interesting experiments, the results of which I could hear and measure for myself, rather than relying on someone else's idea of what sounds 'good'.

What I did learn is that these kinds of mic experiments very quickly get into the realms of the 'law of diminishing returns'....
You can spend a LOT of extra money for very little actual improvement in performance.

It really is quite amazing just how good a result you can get, with a bit of experimentation.
Helps a lot if you're lucky enough to come across  a decent - cheap - capsule in the process! :)

 
« Last Edit: April 04, 2021, 05:44:28 PM by rogs »
www.amx.jp137.com - A DIY RF condenser mic project

mjrippe

Thanks for sharing that, rogs.  One of your ideas sparked a memory for me - the end address capsule.  I realized that the sound I was describing/looking for is very much that of the Lomo 19A19 that I used to own! Definitely a path to explore.

kingkorg

This might be a nice donor. Scroll through the images.

https://a.aliexpress.com/_mtrKnlh

rogs

Thanks for sharing that, rogs.  One of your ideas sparked a memory for me - the end address capsule.  I realized that the sound I was describing/looking for is very much that of the Lomo 19A19 that I used to own! Definitely a path to explore.

Here's a link to my end address LDC mount ... (mounting holes are for an BM800 body)...

https://www.shapeways.com/product/EFE6MUJYM/34mm-ldc-mic-bracket?optionId=123657963
www.amx.jp137.com - A DIY RF condenser mic project

rogs

This might be a nice donor. Scroll through the images.

https://a.aliexpress.com/_mtrKnlh

That's looks nice ---- bit pricier for a donor body than your typical BM800 though !  :)
www.amx.jp137.com - A DIY RF condenser mic project

shabtek

That's looks nice ---- bit pricier for a donor body than your typical BM800 though !  :)

that's the cost of complete disregard for I.P
"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ

kingkorg

Nady SPC10 is also a good alternative.

Recording Engineer

I’ve kept my eye out for one for years now. Have never been able to get my hands on one though.

rogs

I have a friend who performs as a singer/guitarist (or rather who DID perform before Covid! :)).
He had the opportunity to try out an LDC end address mic (I think it was with a borrowed KMS105? ) and had been pleased with the results.
 
Some of his gigs had been outside venues, and he had been advised that conventional LDC mics are not really recommended for outdoor use, due to possible problems with moisture...and that the only commercial condenser mics suitable for outdoors would be SDC Sennheiser or Rode shotguns.

I suggested that he might like to try out one of my end address RF bias mics....
A Lo-Z condenser mic with an LDC capsule - so should be OK outdoors.

He's looking forward to trying it out  - once the gigs start again!



www.amx.jp137.com - A DIY RF condenser mic project


 

Related Topics

  Subject / Started by Replies Last post
18 Replies
7329 Views
Last post June 06, 2004, 05:38:47 AM
by TheRealWaldo
2 Replies
1496 Views
Last post November 06, 2008, 05:30:37 PM
by Ptownkid
14 Replies
3018 Views
Last post June 30, 2010, 04:12:32 PM
by pucho812
24 Replies
1412 Views
Last post April 01, 2021, 05:29:19 PM
by bockaudio