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Re: SDC capsule recommendation? (UK)

 

On Sat, Aug 15, 2020 at 05:30 PM, Arjay 1949 wrote:
(PDF of that schematic here:??)
Hi Jon

I know the question can be redundant but what's the difference between your schematic?and the Simple P48 circuit to put an EM204 running?

I see there is a lot more of components there
Re: Cardioid capsule with flat response? Primo EM204 or better alternatives?

 

¿ªÔÆÌåÓý

They have a data sheet for it and it just lists S/N ratio as greater than 72db. ?I¡¯m testing this head to head with the TSB2590 on Thursday. Will post results. Both are mounted in line on top
of each other.image0.jpeg

Best Regards,

Jules Ryckebusch?

On Jun 12, 2022, at 17:10, a45porhora@... wrote:

?

[Edited Message Follows]

As always, thanks to Jules and all to share and help others in this nice Group :)

?

I will try the?JLI-160A11UC680, but I don't see any info about the Noise Levels/self-noise. The primo EM200/204 is only 16db, Pretty good for that range of price

Does anyone here know that info or should I write directly to JLI? :)

Cheers
Re: Cardioid capsule with flat response? Primo EM204 or better alternatives?

 
Edited

As always, thanks to Jules and all to share and help others in this nice Group :)

?

I will try the?JLI-160A11UC680, but I don't see any info about the Noise Levels/self-noise. The primo EM200/204 is only 16db, Pretty good for that range of price

Does anyone here know that info or should I write directly to JLI? :)

Cheers
Padding a TSSB2555B for drums (or other loud source)

 

Le 12/06/2022 ¨¤ 23:09, thet a ¨¦crit?:
What isn't clear is why the frequency affected is around 8k rather than some other frequency, and what characteristics of the capsule might lead the effect to be smaller or larger or the frequency to be different.
Indeed. Also I would have liked to have an explanation why teh capacitance changes non linearly.
Of course, increasing bias voltage tends to bring the diaphragm closer to the backplate, which increases capacitance, but why not so at frequencies above 8k or so?
Non linearity of capacitance vs frequency is hardly understandable since the dielectric is air, which is almost perfectly linear.
Re: Padding a TSSB2555B for drums (or other loud source)

 

Not so much misleading as just not very relevant to the sort of mics we usually build here, for all the reasons you say.

What isn't clear is why the frequency affected is around 8k rather than some other frequency, and what characteristics of the capsule might lead the effect to be smaller or larger or the frequency to be different.

I quite agree that it is irrelevant to a typical LDC though, and certainly AKG didn't think it a problem to drop the polarisation voltage on the 414B-ULS from 60v to 20v when the pad is engaged, even though the whole deal with the ULS mic is flat response. Which completely supports your experience that it isn't an issue with normal LDCs.

On 12/06/2022 18:45, recordinghacks wrote:
That graph is misleading. The voltages pictured are 28, 150, 250. Those values might be appropriate for a small diaphragm measurement capsule. Large-diaphragm capsules such as most people here would be using would collapse at any voltage higher than 70-80V. The actual range of polarization values you might actually use in practice ranges from about 20V to 70V, not 28-250.
Re: Padding a TSSB2555B for drums (or other loud source)

 

section 3.9.1 and especially figure 3.7

On 12/06/2022 18:39, Jerry Lee Marcel wrote:
What section are you referring to?

Le 12/06/2022 ¨¤ 18:46, thet a ¨¦crit?:
hmm that info in that book raises more questions than it answers! Such as what determines the size of the frequency effect for a particular capsule, and what determines the frequency that is affected.

I'm guessing some capsules are more affected than others with the frequency response change.


On 12/06/2022 16:21, Jules Ryckebusch wrote:
There is a debate?on padding with polarising voltage vs capacitance?addition. See page 96 of this: They show about?+/- 2-3db for a pretty wide range.
Re: Padding a TSSB2555B for drums (or other loud source)

 

So right Matt. They do say that graph is for a 1/2¡± microphone. And that it varies with diameter. But we are not doing 28V to 200V either.

Best Regards,

Jules Ryckebusch

On Jun 12, 2022, at 12:45, recordinghacks <matt@...> wrote:

?


On June 12, 2022 at 9:46:30 AM, thet (parenthetical@...) wrote:
There is a debate on padding with polarising voltage vs > capacitance
addition. See page 96 of this: > bksv.com/media/doc/be1447.pdf
They show about +/- 2-3db > for a pretty wide range.
That graph is misleading. The voltages pictured are 28, 150, 250. Those values might be appropriate for a small diaphragm measurement capsule. Large-diaphragm capsules such as most people here would be using would collapse at any voltage higher than 70-80V. The actual range of polarization values you might actually use in practice ranges from about 20V to 70V, not 28-250.

Further, most large-diaphragm capsules vary in response by more than 2dB from one capsule to the next. As an example, Neumann¡¯s spec on the U87 Ai ($3200) is plus or minus 2dB (which is to say, a 4dB delta from one mic to the next).

Therefore it doesn¡¯t make sense to focus on a potential 2dB shift in a single capsule¡¯s performance when the second mic you build would by 2dB if not 4-6dB different anyway. (Cheap capsules from Ali Baba definitely differ by more than 2dB from one to the next.)

But more to the point, you are not likely to see even a 2dB delta when changing polarization voltage within the range of 30-60V, at least not in my testing.

¡ª
matt.
Re: Padding a TSSB2555B for drums (or other loud source)

 

On June 12, 2022 at 9:46:30 AM, thet (parenthetical@...) wrote:
There is a debate on padding with polarising voltage vs > capacitance
addition. See page 96 of this: > bksv.com/media/doc/be1447.pdf
They show about +/- 2-3db > for a pretty wide range.
That graph is misleading. The voltages pictured are 28, 150, 250. Those values might be appropriate for a small diaphragm measurement capsule. Large-diaphragm capsules such as most people here would be using would collapse at any voltage higher than 70-80V. The actual range of polarization values you might actually use in practice ranges from about 20V to 70V, not 28-250.

Further, most large-diaphragm capsules vary in response by more than 2dB from one capsule to the next. As an example, Neumann¡¯s spec on the U87 Ai ($3200) is plus or minus 2dB (which is to say, a 4dB delta from one mic to the next).

Therefore it doesn¡¯t make sense to focus on a potential 2dB shift in a single capsule¡¯s performance when the second mic you build would by 2dB if not 4-6dB different anyway. (Cheap capsules from Ali Baba definitely differ by more than 2dB from one to the next.)

But more to the point, you are not likely to see even a 2dB delta when changing polarization voltage within the range of 30-60V, at least not in my testing.

¡ª
matt.
Re: Padding a TSSB2555B for drums (or other loud source)

 

What section are you referring to?

Le 12/06/2022 ¨¤ 18:46, thet a ¨¦crit?:
hmm that info in that book raises more questions than it answers! Such as what determines the size of the frequency effect for a particular capsule, and what determines the frequency that is affected.

I'm guessing some capsules are more affected than others with the frequency response change.


On 12/06/2022 16:21, Jules Ryckebusch wrote:
There is a debate?on padding with polarising voltage vs capacitance?addition. See page 96 of this: They show about?+/- 2-3db for a pretty wide range.
Re: capsules for close micing drums - suggestions?

 

I've almost always received something that basically met the description, though sometimes faulty or poor quality. Fingers crossed i'll get something usable. In this case there was no description beyond the photo - so we'll see.

I wonder what the fake sm57s on aliX are like, anyone tried one? for parts or entire?

On 12/06/2022 15:40, Jerry Lee Marcel wrote:
The problem with chinese is that you know what your order but you don't know what you'll receive.
Re: Padding a TSSB2555B for drums (or other loud source)

 

hmm that info in that book raises more questions than it answers! Such as what determines the size of the frequency effect for a particular capsule, and what determines the frequency that is affected.

I'm guessing some capsules are more affected than others with the frequency response change.

On 12/06/2022 16:21, Jules Ryckebusch wrote:
There is a debate?on padding with polarising voltage vs capacitance?addition. See page 96 of this: They show about?+/- 2-3db for a pretty wide range.
Re: Padding a TSSB2555B for drums (or other loud source)

 

Some mics (such as the C414B) seem to implement a pad by reducing?
the polarisation voltage instead or as well as adding a parallel
capacitor. I'm not sure of the relative merits of the two methods.
Most TSB-2555 circuits do not use any polarization voltage, because the capsule is pre-polarized. That is, in most TSB-2555 mics, there is no polarization voltage to reduce, so the only easy way to attenuate sensitivity is with a capacitor from JFET gate to ground.

Condenser mics with externally polarized capsules can use voltage based pads. Reducing capsule DC polarization voltage from 60V to 30V will reduce the mic¡¯s output level by 6dB. Cutting in half again to 15V produces a total attenuation of 12dB.?

I have seen some debate that the frequency response of the capsule changes with polarization voltage, but I have not measured any significant effect in my own testing, at least not between ~40V and ~65V. Very low polarization voltages such as 6-15V might well alter the sound of the capsule.

Strapping a capacitor from JFET gate to ground, as has been discussed here, is definitely effective, but can add distortion (which might be good or bad depending on your application).?

¡ª
matt.
Re: Padding a TSSB2555B for drums (or other loud source)

 

There is a debate?on padding with polarising voltage vs capacitance?addition. See page 96 of this:?? They show about?+/- 2-3db for a pretty wide range. We have one member who builds RF mics that don't?use a polarizing?voltage, just?changes in capacitance?to change the resonant frequency of an oscillator.?

I hear you on the switches. I don't?plan on changing them once the pad is in place. They will be my "drum mics"?lol.?

Jules

On Sun, Jun 12, 2022 at 9:26 AM thet <parenthetical@...> wrote:

regarding condenser pads.

A compromise solution in a large condenser is to use a dip switch or other small switch internally.? Then you can defeat the pad by taking the cover off and switching - which is still quicker than soldering. I do pattern selection with internal dip switches like that.

Some mics (such as the C414B) seem to implement a pad by reducing the polarisation voltage instead or as well as adding a parallel capacitor. I'm not sure of the relative merits of the two methods.


On 12/06/2022 15:14, Jules Ryckebusch wrote:
I've been tinkering with this for a bit and wanted to share. I padded my OPA Board with a 220pF cap across?the 1Gig resistor and measured. I am getting?about 15db padding and it works great on drums and other loud sources. I close miked a snare and Hi-Hat with them. Working on a front facing one to put in a kick drum see how that goes. I guess I could put in a switch?like Mic Sharf has but then I have to file a slot in the BM-800 body lol. I have enough that I am making four permanently?padded ones. Hey: Build your Own Mic Locker!




--
Best Regards,

Jules Ryckebusch

214 399 0931
Re: capsules for close micing drums - suggestions?

 

The problem with chinese is that you know what your order but you don't know what you'll receive.

Le 12/06/2022 ¨¤ 16:13, thet a ¨¦crit?:
The cheap chinese dynamic capsule I have is 450 ohms. Presumably designed for use without a transformer. So the ones you mention are significantly different. Definitely worth a try for the price. I will order a couple.

On 12/06/2022 12:13, Jerry Lee Marcel wrote:
I forgot to mention, quite often these capsules are low impedance (about 10-20 ohms) because they are generally paired with transformer, so the output level is lower than a standard SM57, but since the spl inside a tom is very high, it results in a perfectly compatibe level with a standard mic pre.
Re: capsules for close micing drums - suggestions?

 

Le 12/06/2022 ¨¤ 13:31, thet a ¨¦crit?:
Rather like removing the transformer from a SM57 then? I
Yes.
have heard about that mod as one that may be good for drums, but I don't actually have a SM57, and maybe I should.
I can't say the difference is spectacular, but rather good.

On 12/06/2022 12:13, Jerry Lee Marcel wrote:
I forgot to mention, quite often these capsules are low impedance (about 10-20 ohms) because they are generally paired with transformer, so the output level is lower than a standard SM57, but since the spl inside a tom is very high, it results in a perfectly compatibe level with a standard mic pre.
Re: Padding a TSSB2555B for drums (or other loud source)

 

¿ªÔÆÌåÓý

regarding condenser pads.

A compromise solution in a large condenser is to use a dip switch or other small switch internally.? Then you can defeat the pad by taking the cover off and switching - which is still quicker than soldering. I do pattern selection with internal dip switches like that.

Some mics (such as the C414B) seem to implement a pad by reducing the polarisation voltage instead or as well as adding a parallel capacitor. I'm not sure of the relative merits of the two methods.


On 12/06/2022 15:14, Jules Ryckebusch wrote:

I've been tinkering with this for a bit and wanted to share. I padded my OPA Board with a 220pF cap across?the 1Gig resistor and measured. I am getting?about 15db padding and it works great on drums and other loud sources. I close miked a snare and Hi-Hat with them. Working on a front facing one to put in a kick drum see how that goes. I guess I could put in a switch?like Mic Sharf has but then I have to file a slot in the BM-800 body lol. I have enough that I am making four permanently?padded ones. Hey: Build your Own Mic Locker!
Padding a TSSB2555B for drums (or other loud source)

 

I've been tinkering with this for a bit and wanted to share. I padded my OPA Board with a 220pF cap across?the 1Gig resistor and measured. I am getting?about 15db padding and it works great on drums and other loud sources. I close miked a snare and Hi-Hat with them. Working on a front facing one to put in a kick drum see how that goes. I guess I could put in a switch?like Mic Sharf has but then I have to file a slot in the BM-800 body lol. I have enough that I am making four permanently?padded ones. Hey: Build your Own Mic Locker!



--
Best Regards,

Jules Ryckebusch

214 399 0931
Re: capsules for close micing drums - suggestions?

 

The cheap chinese dynamic capsule I have is 450 ohms. Presumably designed for use without a transformer. So the ones you mention are significantly different. Definitely worth a try for the price. I will order a couple.

On 12/06/2022 12:13, Jerry Lee Marcel wrote:
I forgot to mention, quite often these capsules are low impedance (about 10-20 ohms) because they are generally paired with transformer, so the output level is lower than a standard SM57, but since the spl inside a tom is very high, it results in a perfectly compatibe level with a standard mic pre.
Re: capsules for close micing drums - suggestions?

 

¿ªÔÆÌåÓý

Very true. I¡¯m going to try and do some testing. ?I¡¯m thinking for the 25mm ones the chance is less for bottoming out but¡­

?Neumann claims 147db max SPL in one their LDC¡¯s with pad engaged. ?

Best Regards,

Jules Ryckebusch?

On Jun 12, 2022, at 07:36, thet <parenthetical@...> wrote:

?

yes I'm also wondering which of my many existing condenser mics would make good drum mics with a pad added. Or that i can build from the spares I have on hand.

Those cheap 25mm OD brass electrets from aliX might be interesting if they can handle the SPL.

the issue with condensers is whether the membrane will actually bottom out against the backplate... I would think that is a risk inside a tom or especially a kick. A capacitative pad can't protect against that.

On 12/06/2022 12:45, Jules Ryckebusch wrote:


The other thing I started doing is using a capacitor to pad my TSB2555B mics. Neumann does it on their U87 and U87 ai mics they use a 560pF on one and a 270pF on the other. For High Hat and snare 220pF on the TSB2555B works great. Im building a front facing mic with this capsule next week and will try and stick it in a kick drum soon. WIll let you know how it comes out.?
Re: capsules for close micing drums - suggestions?

 

¿ªÔÆÌåÓý

yes I'm also wondering which of my many existing condenser mics would make good drum mics with a pad added. Or that i can build from the spares I have on hand.

Those cheap 25mm OD brass electrets from aliX might be interesting if they can handle the SPL.

the issue with condensers is whether the membrane will actually bottom out against the backplate... I would think that is a risk inside a tom or especially a kick. A capacitative pad can't protect against that.

On 12/06/2022 12:45, Jules Ryckebusch wrote:



The other thing I started doing is using a capacitor to pad my TSB2555B mics. Neumann does it on their U87 and U87 ai mics they use a 560pF on one and a 270pF on the other. For High Hat and snare 220pF on the TSB2555B works great. Im building a front facing mic with this capsule next week and will try and stick it in a kick drum soon. WIll let you know how it comes out.?
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