Behringer B2 Pro mods?
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Icantthinkofaname
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Ah that makes a lot more sense since the f8 is two cardioids in opposite phase.
Icantthinkofaname
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Behringer did get back to me confirming the current B2 Pro uses the 797 CY002. I have to say kudos to Behringer for actually disclosing the capsule origin.
EatsMicrophones
Member
Just to clarify, the B1 uses the CY037 and the B2 uses the CY002? Which one is going to get me closer to a C800 sort of sound?
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Icantthinkofaname
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The CY002 is a U87 style capsule. Same EQ curve, just higher. The C800 capsule follows a similar lift but the there's a little boost at 3K, it drops to neutral around 5K, then rises starting at 6K to be around +5 dB. The K67 and the copies have a boost from 3K on without a dip, and the boost is bigger than the C800G.Just to clarify, the B1 uses the CY038 and the B2 uses the CY002? Which one is going to get me closer to a C800 sort of sound?
This is a measurement by Kingkorg,yhe green is the C800G style capsule from 797, the blue is 797's CY002 amd the purple is Takstar's K67. The latter two follow the same shape as the real K67s but the high frequency boost is bigger,I believe the real K67s have a +4 dB boost.
I don't actually know the part number for the C800G style capsule. You could probably get pretty close with the CY002 if you notch out 5K. It won't be identical because the peak of the C800 style capsules HF boost is at 13 or 14K, and the K67 copy (CY002)'s peak is at 11K. The green curve is scary close to what Sony's published C800G frequency response is, it's just maybe 1 or 2 dB brighter right at the peak.
To my knowledge every C800G clone is just using an unattenuated K67 (or attenuated to be about +5 dB at 11K if it's a brighter capsule like Microphone-Parts RK87 or Advanced Audio or Peluso's capsules). I'm not too sure about the one Stam Audio made, but I have reason to believe it's the same since Stam apparently now uses 3U Audio capsules.
You could also ask Guosheng at 3U Audio to sell you the capsule used for the Warbler MKVID. It has a very similar (advertised) curve to the C800G. You'll probably be paying 2 or 3x what you'd pay for the 797 capsule if you go that route.
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EatsMicrophones
Member
Didn't even realize the 797 had their own C800G capsule. Currently emailing them about capsules, what model number should I be asking for?
Icantthinkofaname
Well-known member
I think it's the CY037.
Guosheng of 3U will probably sell you the Warbler MKVID capsule as well. It'll be more expensive but you'll probably receive it within a couple days. Then you can throw it in a tube mic with a cylindrical headbasket and it should work pretty well (of course tube selection and the circuit will have some impact on the sound).
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LevinGuitar
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Can anyone tell why they use the 2N5551 (Q3) after the main J305 fet (Q5) instead of leaving it alone as the Schoeps circuit does?
I'm turning my B2pro into the B2 removing the output caps, rewiring and adjusting R7, and like it a bit more, but wonder if it's worth to go further into schoeps original way removing also Q3
I'm turning my B2pro into the B2 removing the output caps, rewiring and adjusting R7, and like it a bit more, but wonder if it's worth to go further into schoeps original way removing also Q3
The Schoeps circuit has equal value resistors connected to the drain and the source of the JFET, so it pulls double-duty, both as impedance converter and "phase splitter".
Behringer seems to have gone the route of using the JFET as a source follower (unity-gain buffer), and use a separate NPN as the phase splitter.
If you just skip the NPN and leave the drain connected to the positive rail, you'll... get a less-than-ideal signal out of it, let's just say.
Q1 has the emitter arrow pointing the wrong way in that schematic, btw. As well as D1? That's weird.....
Behringer seems to have gone the route of using the JFET as a source follower (unity-gain buffer), and use a separate NPN as the phase splitter.
If you just skip the NPN and leave the drain connected to the positive rail, you'll... get a less-than-ideal signal out of it, let's just say.
Q1 has the emitter arrow pointing the wrong way in that schematic, btw. As well as D1? That's weird.....
LevinGuitar
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The idea is to rewire all as in the schoeps circuit, of course, but will it make an audible difference to use the J305 as phase splitter also and skip one transistor in audio path?
In the other hand, having the J305 used only for buffer, before splitting the phase, is there a way to implement any kind of deemphasis in the U87 way? I tried something but haven't succeed
In the other hand, having the J305 used only for buffer, before splitting the phase, is there a way to implement any kind of deemphasis in the U87 way? I tried something but haven't succeed
There are several differences. Output pair is npn/pnp combo for example.
Edit:
See the attachment for deemphasis in schoeps. B2 uses deemphasis for HPF.
Courtesy of @RuudNL
https://groupdiy.com/threads/stupid-or-clever-you-decide-u87-meets-schoeps.67148/post-852987
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Notice also the C9 and the whole bias arrangement. Overall lower THD, and different saturation curve. Also r6 c4 jumper.
LevinGuitar
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What does C9?
Lower THD in the B2pro than in the original Schoeps because of the bias?
The way i see it c9 is for bootstraping. It "actively" shifts the gate bias point depending on the signal. And as Khron mentioned the jFet is in source follower arrangement which has intrinsically lower thd.
I gut them completely ,install tube innerds instead ,
still good usable film resistances on the board in the hi Meg range ,
never thought about reusing the fets , but I kept the boards .
I like the headbasket shape, the quality of the casework and nickel plating ,
As I said over on Rocks thread , with a little buffing it gleams .
I definately think the broad hump in the uppermids and highs in the standard Behringer needs pulling back a notch or two , Im not sure how much the capsule has to do with that bump vs the circuitry ,
Ive got very usable results with tube circuits without equalisastion with the behringer capsules .
The other thing is they can be had for small money nowadays used.
still good usable film resistances on the board in the hi Meg range ,
never thought about reusing the fets , but I kept the boards .
I like the headbasket shape, the quality of the casework and nickel plating ,
As I said over on Rocks thread , with a little buffing it gleams .
I definately think the broad hump in the uppermids and highs in the standard Behringer needs pulling back a notch or two , Im not sure how much the capsule has to do with that bump vs the circuitry ,
Ive got very usable results with tube circuits without equalisastion with the behringer capsules .
The other thing is they can be had for small money nowadays used.
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ubxf
Well-known member
I'm trying to figure out the value of the 2 ceramic caps inside the black box under the capsule from the schematics it looks like
capacitor CC1-160V-102-K 2 C23,24
160V = voltage rating (a bit much, but i guess it's ceramic?)
102 = "10" followed by "2" zeroes, so "1000", in pF, thus 1nF
K = tolerance rating, +/-10% (J is 5%, M is 20%)
ubxf
Well-known member
Thank you so much
Where would be the best place to sell two B2-Pro microphones manufactured around 2002? I wanted to mod them but fact is I have zero time. Was thinking of listing them on Reverb, but maybe there are better places, especially for enthusiasts intent on making mods.
