Behringer B1 mods

[kingkorg]

It is entire volume of air behind the diaphragm that counts. Not even replying, just informing the public.

 

[Dimon]

Thank you, will try! I would not increase the 15nf, but instead I have lowered it to 10nf, to reduce noise.

For now, inspired by this thread and your insistence on the importance of the acoustic resonance of the grille shape and so, I tried something in that way. And the result is WOW! That thing really changes the sound, in this case it help a lot to bring mids up. For sure this is not the best shape but it already makes me smile listening the microphone. Will investigate more

Yes, with such amplification, any internal distortions from air resonances against the grid, the body and the insides come out very audible, given that the vocalist sings with good support.

 

[LevinGuitar]

Improving my rubber "domes" in B1 and B2. The same rubber piece as I used before but using the lower part of the big one. Here I tried to imitate the NT2 dome. Works better than the previous attempts

 

[venusaudio]

I haven't used the B1 in a pro recording but can't be happier listening the test of the last experiment. Definately worth it, but also is a delicate work dealing with capsule diaphragm and the holes.
Even just dampening the grille resonance makes an improvement, but in a different way, flatter, for voices I prefer the capsule mod with the dampening too.

How much will you get for it? Make a good sounding mic instead

I am absolutely newbie in microphone mods but I own a Behringer B1 and I wish to upgrade its terrible high end to a flater direction. What would be the suggestions to change materials (resistors,diodes, caps) on the board, to change the capsule to a flat K47 or both? My goal is to get as flat as possible for easier equalizing later.
Thank you.

 

[LevinGuitar]

Well, you can try a the flat K47 an see if you like the result, maybe it would be similar to a TLM49, that circuit should be pretty close to this one. But if you find some lack of low end then you'll have to try that capsule in a different one, transformer coupled or tube.

To use the original capsule in the original circuit you have to use some kind of deemphasis in order to achieve a flatter response. There are different ways to do it described in this forum.

This one is probably the best, but you have to figure out how to implement that idea in your mic.
https://groupdiy.com/threads/stupid-or-clever-you-decide-u87-meets-schoeps.67148/

 

[venusaudio]

As a begining I have ordered a JLI TSC-1 which has some midhighs +4-5db from 3-5khz then falls down to 0db at 6-8khz and up again +4-5db on 10khz. It is about the same like the U87 frequency response diagram.
As far the most sibilants are around 6khz, I hope to get more balanced midhighs. If it will not sound as I wish I'll give a try to their RK47. In any case my goal is to get a flater high end and then to round it a bit with external EQing. I am also curius about the new capsule low end, the one in the B1 - type 797audio K103 I think - has a very impresive low end, I very often have to use the low cut filter.
I think hf deemphasis should be my last and final step. I'll do the capsule upgrade and I'll come back with the results.

 

[venusaudio]

If I manage this balance to my sibilance using the TSC-1, I will be very satisfied.

 

[LevinGuitar]

The original K67 style cardioid capsule in the B1 is not a K103. I can't recommend any chinese K47 and haven't tried their K103 recreation. Good luck!

 

[venusaudio]

Thank you.

 

[LevinGuitar]

I'm turning one of that B1 into a U87ish circuit and want to use the switch for different voicings. In order to place some deemphasis in the brightest setting, how bad would be adding more caps of same type in paralell in the deemphasis?

Already tried that few times and didn't hear any worse but have read many times to avoid caps in paralell in the audio path when possible (even some good mics have two caps in the output like the Sony C35/36p)

 

[kingkorg]

I'm turning one of that B1 into a U87ish circuit and want to use the switch for different voicings. In order to place some deemphasis in the brightest setting, how bad would be adding more caps of same type in paralell in the deemphasis?

Already tried that few times and didn't hear any worse but have read many times to avoid caps in paralell in the audio path when possible (even some good mics have two caps in the output like the Sony C35/36p)

I am not familiar with theory behind, but i see nothing wrong with doing that in this case. It is in audio path, but feedback path, it is feeding back the audio out of phase that is shaping the audio in phase you are hearing. Hope it makes sense.

 

[LevinGuitar]

I believe I understand how the deemphasis works (yet may not). So being in the sound path, any micro de-syncronizations? between charging/discharging times of the caps may increase the THD, but that would be more likely with different caps types I guess

 

[Mr. Moscode]

Noise sources:

The 2n5457 fets aren't the quietest fets around. There is or was a 2sk something 176 maybe? that is super lo noise. J310 is a higher gain and low noise jfet. I don't know how it would work in that circuit. It's a cascode so hi gain. Maybe a j310 for the lower jfet.
Also, there may be some zener noise is on the +15 rail so you should try a 100mfd or larger to ground on the oscillator board and the audio boards. It's worth a look. If you have a scope it's easier to find noise.

 

[LevinGuitar]

Yes, I tried other k67 capsule and the NTK went ok, today I briefly tried the NTK capsule in other mic and it almost did not work, sound came randomly when shaking the mic, like if there was bad connection somewhere, but it could be my fault also, will check the leads (I have checked for continuity between backplate and the frontring and there was none and the capacitance is around 100pf)

The capsule is in great looking condition btw

I tried that faulty capsule from a NTK in a NT1000 (NT1000 does not have an imput blocking voltage cap as the NT2a does) and at first it worked ok, but when applied some air pressure of close talking it took the bias off (up to twice the voltage difference), and with a bit harder air pressure it shut down completly the mic until phantom is disconnected. The stock NT1000 capsule did not had that issues.
So the capsule is leaky? How? :/

 

[Khron]

it took the bias off (up to twice the voltage difference)

Could you be any more specific / clear?

 

[LevinGuitar]

https://proxy.imagearchive.com/030/0309d57eb7ba25fe17e1be8f9e0ad431.png

I measured up to 15v in the source leg of the fet, when with stock capsule it is 7.8v