AKG genuine CK12 Brass capsule: building DIY mic with a single Jfet-transistor
- Thread starter Schertler
- Start date
A very quick update.... after picking a correct B index FET LSK170 transistor and wiring both sides of the capsule, so the figures are getting even higher specs of THD=0.000088% and Noise: 998.04nV in Omni pattern, Cardioid pattern does offer the previous figures of THD=0.000247%, Noise: 1.8971µV.
This is the complete version of the mic. The Switch X1 is a micro-toggle which should be installed on to the mic saddle's round panel under the basket-grill because TLM 103 fuselage does not feature any cutout for mounting such a pattern-switch button , so the basket-grill has to be unscrewed for selecting between Omni and Cardioid, and this does not seem to be a hard task, however I am going to replace TLM 103 fuselage by some larger mic body later......
This is the complete version of the mic. The Switch X1 is a micro-toggle which should be installed on to the mic saddle's round panel under the basket-grill because TLM 103 fuselage does not feature any cutout for mounting such a pattern-switch button , so the basket-grill has to be unscrewed for selecting between Omni and Cardioid, and this does not seem to be a hard task, however I am going to replace TLM 103 fuselage by some larger mic body later......
chinhnguyen
- Joined Aug 23, 2021
- 1
Hi. i'm trying to mod my noisy usb mic by replace the capsule and jfet. I wonder if i adding a resistor like you mentioned above will help the usb mic get low noise ?
I'm using fifine K669 , it has 2sk660 included
I'm using fifine K669 , it has 2sk660 included
Audioguru again
- Joined Oct 21, 2019
- 6,710
Please define the noise:
1) Random hiss?
2) Random rumble?
3) Mains hum?
4) Acoustical feedback howling or squealing?
5) Electronic oscillation?
1) Random hiss?
2) Random rumble?
3) Mains hum?
4) Acoustical feedback howling or squealing?
5) Electronic oscillation?
Greetings!
Yesterday, my microphone project was completed, got it assembled after some basic tests, it took me one year of searching, purchasing parts, designing etc....
More detailed results can be found on Vegalab (Russian forum) where I started the initial project, this is the link to the latest updates!
The final stage of the project in brief......
The FIN schematic given above is designed by Russian guy Paul, no significant changes were done, just using different transistors and incorporating a choke oscillator (Meisner/Armstrong Oscillator) on to the mic's PCB, 60V polarization voltage is what you should consider with such an older model condenser capsules.
So the following are the basic specs of the real mic which was just assembled yesterday. I have to note on to the nearly 100% similarity matches of the real mic's characteristics with its simulation in LTSpice software (just 2-3% of mismatch!), this is almost universal and unique software you must have, use and trust.
1) CK12 capsule: 84pF/80pF capacitances of membranes (standard is 72-86pF)
2) Self-Noise: Cardioid 1.388µV (single membrane), Omni 765.98nV (both membranes), LTSpice simulated 1.332µV/704.13nV
3) THD: 0.000018% based on LTspice, will be measured later
The final schematics of the mic and choke oscillator:
The microphone:
Good luck with your mic projects! Merry Christmas and a very Happy 2022 Year!
Yesterday, my microphone project was completed, got it assembled after some basic tests, it took me one year of searching, purchasing parts, designing etc....
More detailed results can be found on Vegalab (Russian forum) where I started the initial project, this is the link to the latest updates!
The final stage of the project in brief......
The FIN schematic given above is designed by Russian guy Paul, no significant changes were done, just using different transistors and incorporating a choke oscillator (Meisner/Armstrong Oscillator) on to the mic's PCB, 60V polarization voltage is what you should consider with such an older model condenser capsules.
So the following are the basic specs of the real mic which was just assembled yesterday. I have to note on to the nearly 100% similarity matches of the real mic's characteristics with its simulation in LTSpice software (just 2-3% of mismatch!), this is almost universal and unique software you must have, use and trust.
1) CK12 capsule: 84pF/80pF capacitances of membranes (standard is 72-86pF)
2) Self-Noise: Cardioid 1.388µV (single membrane), Omni 765.98nV (both membranes), LTSpice simulated 1.332µV/704.13nV
3) THD: 0.000018% based on LTspice, will be measured later
The final schematics of the mic and choke oscillator:
The microphone:
Good luck with your mic projects! Merry Christmas and a very Happy 2022 Year!
I am late but I have tried and got an amazing experience! https://forum.allaboutcircuits.com/...ser-capsule-repair-and-diy-microphone.158053/
Hi there, lot of work and done nicely!
Have you built/measured the accurate characteristics in the LTSpice ?? This should help to realize the real qualities......
My approach was very simple, I was looking for the highest specs with the most lower number of components and overall dimensions of PCB .......
Good luck!
Have you built/measured the accurate characteristics in the LTSpice ?? This should help to realize the real qualities......
My approach was very simple, I was looking for the highest specs with the most lower number of components and overall dimensions of PCB .......
Good luck!
