AKG C3000B 5 min mod - Awesome mic!

[kingkorg]

Thanks, good to know. Akgs tend to change without notice, big time.

I had latest edition of 535eb with pcb that had nothing to do with schematic posted on the site. It sounded so bad that i thought it had to be broken. But no, that was the sound of latest edition.

To be honest c3000b stock sounds like broken too.

 

[mhelin]

Just ordered this mic as it's in sale now in many places (about 129 EUR).  It seems the capsule uses the front capsule of the C414 dual-capsule system and the "AKG Back-Plate Technology" electret back-plate as in C214. The current version is again named C3000, the B was dropped from the name in 2012 I think. S.D. didn't mention the electret nature of the capsule in the article and seemed to think the bias voltage was mandatory for the capsule to work. Got me thinking would it be possible to take the front and back apart and maybe put two fronts together to make the C414 style capsule, or just use another DIY back-plate. Maybe the  latter is no necessary if you apply extra bias voltage which could also make the FR even more linear and lower the noise level. Could this method be used with other electret capsules to improve the SNR and FR? Maybe if you get a one  without the integrated FET? How about the BM800?

 

[ln76d]

C4000 and C314 use double sided electret version of these capsules.
You can apply polarisation voltage for these capsules, but in original circuits (without factory set polarisation voltage) it only do the worse effect.
SNR isn't problem with these microphones. AKG from the 90's focused mostly on the noise specs but rather not the sound of their products...
FR will change with extra bias -  some of these capsules work decent some will loose a little bit of low end and bump hi freq.
FR of the capsules is rather linear (not in original circuit!), even more linear than many other capsules.
I should have C4000 capsule without diaphragms, want to experiment with double sided? Cover the shipping and its yours

 

[kingkorg]

Just ordered this mic as it's in sale now in many places (about 129 EUR).  It seems the capsule uses the front capsule of the C414 dual-capsule system and the "AKG Back-Plate Technology" electret back-plate as in C214. The current version is again named C3000, the B was dropped from the name in 2012 I think. S.D. didn't mention the electret nature of the capsule in the article and seemed to think the bias voltage was mandatory for the capsule to work. Got me thinking would it be possible to take the front and back apart and maybe put two fronts together to make the C414 style capsule, or just use another DIY back-plate. Maybe the  latter is no necessary if you apply extra bias voltage which could also make the FR even more linear and lower the noise level. Could this method be used with other electret capsules to improve the SNR and FR? Maybe if you get a one  without the integrated FET? How about the BM800?

I dont think you need it flatter after removing eq, it's an excellent capsule as is, dont let the fact that it's electret fool you.

Not 100% sure, but c214 has eq circuit as well. Modded c3000b sounds much better than c214 imho.

One thing i am thinking about now is to make tube version of it, without polarisation voltage.

 

[ln76d]

I dont think you need it flatter after removing eq, it's an excellent capsule as is, dont let the fact that it's electret fool you.

Not 100% sure, but c214 has eq circuit as well. Modded c3000b sounds much better than c214 imho.

One thing i am thinking about now is to make tube version of it, without polarisation voltage.

Still the circuit can be tweaked for better response

Grab for cheap used Solidtube  - it's great microphone to improve - capsule, transformer and body are excellent!
After rework trully ****** CCDA circuit you can have real deal hi-end microphone!
I love it for many sources, these weekend used for kick and violin recording

 

[kingkorg]

Will do, thanks!

 

[Kat]

This is the cap that should be removed.

File isn't available. Can you repost it, please?

 

[ilfungo]

Repost it!
Thanks!!!

 

[kingkorg]

There is someting wrong with the server. No files are available anywhere on the groupdiy. I hope they will fix it soon.

Anyway, here is link to schematic. You should remove c 303

https://www.google.no/url?q=http://cloud.akg.com/7770/c3000_b_service.pdf&sa=U&ved=0ahUKEwi57fHMotrZAhVKOJoKHd_iBRUQFggTMAM&usg=AOvVaw30YYapgArkx7QDs7aJG7M0

 

[kingkorg]

It is grey smd capacitor just beside black electrolytic cap in the left upper corner on this pic.

http://www.saturn-sound.com/images/akg%20c3000b%20-%20pcb.jpg

 

[Kat]

Thank you very much!!

 

[mhelin]

On my (current generation) C3000 (no "B" in name anymore) the C303 is a tiny 0201 SMD capacitor and the larger black electrolytic is replaced with a ceramic 0805 sized one. You can't desolder the 0201 one, it's too small, you have to destroy it!

 

[kingkorg]

I am not sure if it's the same mic, you have to make sure that its the right capacitor and same schematic.

I managed to change twelve 68pf smd capacitors with regular Weller soldering station on Shure ksm44, so it is possible. That one is huge compared to them. There are tweezers for that stuff, but i do just fine with regular soldering iron.

 

[ilfungo]

Thanks kingkorg!!!
Just remove C303 or need to be jumpered?
Thanks for great info I've 3 of this microphones.

 

[kingkorg]

No, just remove them. Do not add jumper!

 

[ilfungo]

Hi kingkorg
Just to be sure is C303 is in red circle?
thanks!

 

[kingkorg]

No, that is transistor. Just a second!

 

[kingkorg]

This one

 

[ilfungo]

THANKS!!!

 

[diddley]

Hello!
I'm a newbie here!

I have a C3000b and i'm gonna test your mod soon!
I'll test it  and compare with an AT4033 (my best mic).

Thanks a lot, it's a great job you've done !