Re: OPA for 34mm capsule?
Capsules arrived.
Are these true condenser type? They look like typical Chinese K67 style capsules. You will want to implement some aggressive high-frequency rolloff in the circuit to correct the response of these capsules. Otherwise the microphones will (most likely) have a harsh top end. You will also want to test the low frequency response. Many cheap K67s are thin below 300 Hz.? 1st time on pcbway, they do 5 pcs by default? I believe 5 pieces is the minimum.? ?Do they include the components with the pcb? Board houses rarely supply components. Components are definitely not included in the cost of manufacturing the PCB.? ¡ª matt.
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Re: OPA for 34mm capsule?
Capsules arrived.?
Are these true condenser type?
I was thinking going the pcbway and buy your pcb's, the Dual Alice and the Hex Inverter.?
1st time on pcbway, they do 5 pcs by default? Do they include the components with the pcb?
I am using single capsule per microphone.?
Thanks for your work!
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Re: Padding a TSSB2555B for drums (or other loud source)
This is great. And verifies what I was seeing with 220pF I had about 15-16db padding. You are showing 20db with 270pF. Thanks for doing this!
Danke!
mit freundlichen Gr¨¹?en,
Jules
On Wed, Jun 15, 2022 at 10:11 AM Mic Scharf < micscharf@...> wrote: ok, the picture turned out pretty small, try it now as a pdf
the cap values are 0, 100pF and 270pF?
-- Best Regards,
Jules Ryckebusch
214 399 0931
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Re: Padding a TSSB2555B for drums (or other loud source)
ok, the picture turned out pretty small, try it now as a pdf
the cap values are 0, 100pF and 270pF?
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Re: Padding a TSSB2555B for drums (or other loud source)
Thank you!!!! This is great? Best Regards,
Jules Ryckebusch?
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On Jun 15, 2022, at 09:14, Mic Scharf <micscharf@...> wrote:
?I measured the freq-response of a mic with Jules OPA circuit, TSB2555 and different values of the pad cap. 
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Re: Padding a TSSB2555B for drums (or other loud source)
I measured the freq-response of a mic with Jules OPA circuit, TSB2555 and different values of the pad cap. 
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Re: Padding a TSSB2555B for drums (or other loud source)
As Jules said above, I made some mics with a switch, but I also made some with headers (is this the right english term?) so I can change the caps pretty easy and experiment with different values and types. 
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Re: SDC capsule recommendation? (UK)
I love the simpleP48. As Roger mentions the downside is the case is not at ground potential. ?Checkout out files area for R values of the various capsules we have tried. ?I¡¯ve done the EM200. I have some 204¡¯s but don¡¯t like them as much as the 200¡¯s most of my builds with the this circuit are AOM 5024¡¯s and TSB 2590¡¯s? Best Regards,
Jules Ryckebusch?
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On Jun 13, 2022, at 07:47, Arjay 1949 <info@...> wrote:
?Further to my post above, I should mention that if you need to interface an unbalanced electret - as used with TRS mini jacks for? PIP inputs - then I've found works well.
Not balanced of course, but quite usable with PIP 2 terminal electrets, connected with a screened cable, and a 3.5mm jack plug (....and 'shortish' cable runs? - say 5m or less)
Commercial versions of that type of interface are available - like this one:?https://rode.com/en/accessories/adaptors-cables/vxlr-plus
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Re: SDC capsule recommendation? (UK)
Further to my post above, I should mention that if you need to interface an unbalanced electret - as used with TRS mini jacks for? PIP inputs - then I've found works well.
Not balanced of course, but quite usable with PIP 2 terminal electrets, connected with a screened cable, and a 3.5mm jack plug (....and 'shortish' cable runs? - say 5m or less)
Commercial versions of that type of interface are available - like this one:?https://rode.com/en/accessories/adaptors-cables/vxlr-plus
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Re: SDC capsule recommendation? (UK)
On Mon, Jun 13, 2022 at 10:18 AM, @seymourisland wrote:
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
Two aspects of the 'Simple P48'? I had problems with when using it with an EM204 were: ? The EM204 is a 2 terminal electret. It's not possible to get at the FET source. As result the microphone 'case' becomes an active terminal of a balanced phantom power interface. The case needs to be isolated from ground, and made not easy to touch! ? I had trouble trying to calculate the value of the series feed resistor accurately, before plugging the capsule in.? I'm not sure how sensitive the EM204 is to higher DC voltages, but I have had 2 x EM258 Primo capsules fail when more than 8V DC were applied to them. You could of course use an EM200 instead - which does have access to the FET source - if you are keen to use the Simple P48 circuit? I preferred to go for a more orthodox? 'Schoeps style' fully balanced type interface, even though it does cost a few extra pennies. ( I need to update that example schematic you've linked to -- those transistors are now hard to find, and the schematic has no 'hot plug' protection zeners. ? ??deals with those issues.... )
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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
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Re: Cardioid capsule with flat response? Primo EM204 or better alternatives?
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.  Best Regards,
Jules Ryckebusch?
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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
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Re: Cardioid capsule with flat response? Primo EM204 or better alternatives?
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
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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.
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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.
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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.
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Re: Padding a TSSB2555B for drums (or other loud source)
section 3.9.1 and especially figure 3.7
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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.
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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
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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.
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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.
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Re: Padding a TSSB2555B for drums (or other loud source)
What section are you referring to?
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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.
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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?
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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.
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Mic Scharf
Sey