AKG C3000B 5 min mod - Awesome mic!

[diddley]

Just a simple question : do i need à spécial soldering Iron for such à small cap or à regular one is good?

 

[Khron]

That sort of depends on how skilled you are, with whatever soldering iron you have

That cap looks like a 1206 package, so it should be easily removable even with a soldering gun

A few years ago, i had to troubleshoot a TV processor board, which involved removing and resoldering 0805 and 0603 sized ferrite beads in series with some supplies to one chip. I did that with my ancient soldering gun, with the tip being a shaped loop of 1mm copper wire ;D

Just a simple question : do i need à spécial soldering Iron for such à small cap or à regular one is good?

 

[Icantthinkofaname]

Just a simple question : do i need à spécial soldering Iron for such à small cap or à regular one is good?

Not much experience here, but you probably don't want too narrow a tip. I've just been practicing soldering on a cheap BM-700 mic since I don't mind if that gets trashed, but I find that too narrow a tip might make it difficult. I'm just using one of those cheap $20-something soldering kits from Amazon though.

 

[pelaxderelax]

Has anyone else tried this modification?

 

[Icantthinkofaname]

Why AKG did this is beyond me. The C3000 mics have a somewhat bad reputation because of this. Without that capacitor they'd be much better mics and people would actually want to use them. If they were 3 pattern omni/cardioid/figure 8 I'd be all over them.

Has anyone else tried this modification?

No but it's not really an uncommon mod. Usually you replace a capacitor to improve the negative feedback to make a K67 caspule work properly, not remove a capacitor that injects a ton of signal, but it's kind of the same idea. You just won't be adding another capacitor.

 

[pelaxderelax]

First, I want to apologize for my bad English.
I do not know anything about electronics and I would not like to damage the microphone, but I have a C3000b and this modification seems easy.
So, is this a usual and safe modification? Will this modification significantly improve the microphone response? Or is it a waste of time?

Do I just need to remove the c303? I do not have to do anything else?

 

[kingkorg]

There are measurements i have taken and posted here. So you can easilg draw the conclusion what the mod does. It is a boost in the circuit no one really needs.

Yes, you should just remove the capacitor. You do this at your own risk, and you have to decide for your self if it is worth it, just like with any mod. Technicaly, nothing wrong about removing that cap, it just makes the circuit flat.

 

[pelaxderelax]

Hello KingKorg, thanks for responding so fast.

If I understood correctly, in summary, this modification brings the c3000b to 414, when it works in cardioid polarity, is not it?

Please, don´t be angry with me, I don´t doubt your knowledge, I am Spanish and I have doubts about my English  :-[

Finally, I understand that it is my risk to modify the microphone. I have a friend who is an electronic technician and he will help me. Thank you for your concern.

 

[kingkorg]

Not mad of course, i hope i didnt give you that impression.

Well, yes that is true about the response. However if you dont like the mod, you can always put back the capacitor. It is a fairly big one.

 

[pelaxderelax]

I thought that the capacitor could not recover, it is good to know that it is possible.

I think I'll talk to my electronic friend to start working.

If possible, I will try to contribute conclusions to the forum

thank you very much again

 

[kingkorg]

You are welcome!

 

[mhelin]

Here a picture of the C3000 new version PCB. All components have been shrinked compared to image posted by kingkorg.

 

[mhelin]

If I still had the C3000 (sold it) I would strip the circuit board from all components except the connectors and switches and build some simple FET input circuit with transformer output on it. Either the one from Scott Dorsey mod without bias voltage supply components (that was a 2SK170BL source follower with 2k2 source resistor and LL1587 1+1:4 reversed, CT to capsule bias filtering circuit which can  be dropped,  phantom source 2x 1k resistors to 10uf filter to power the FET circuit, could be 2k2 from the CT or how much the FET needs current) or a circuit like FET847 (https://groupdiy.com/index.php?topic=61057.0) using KM84/U87 circuit (without the correction network)  with 2N3819 followed by BV13 or GZ-T87 transformer.

 

[RuudNL]

I just looked at the schematic, but I can't see why the gain of U300 can be 9 dB at high frequencies.
Maximum gain at high frequencies is (2700+2210/2210)  2,22x, or 6,9 dB.
Or is there extra HF gain elsewhere in the circuit?
(OK, 6,9 dB gain at HF is already as bad as it can get...)

 

[kingkorg]

My setup is not calibrated, so i can not claim it was precisely 9db boost. 6.9db is quite a lot to add to already brightish capsule anyways.

 

[RuudNL]

Yes, I fully agree with you!
But the strange thing is that it says on the schematic:  gain @ 6 KHz-20KHz: + 9dB.

 

[lampas]

Just mod it ... Incredible... Kingkorg f*****g great microphone... I owe you a beer 
Now I need to find another two...
I also put out a foam from the inside of the microphone ...

 

[kingkorg]

I am glad you like it!

One thing you should listen to is how well it preserves low mids at distance. This is the only mic i have ever owned that does this.

While most other mics lose a lot of low end moved further away, due to proximity effect, this one keeps delivering that range even at greater distance.

 

[electrisizer]

ive done the mod too,
now its a usable mic  ;D
thank you!!!!

 

[chefducuisine]

Good job!!!

I just had a look in my locker and only found the original C 3000 from the 90ies (two capsules inside: a CK12ish one and an electret).

A different beast...
I have uploaded the OM including a schematic to TechPubs:
https://groupdiy.com/index.php?topic=44737.20