Re: Merging three Capsules on two Preamps?!
The ?OPA Alice is designed for capsules without a FET, to run off of Phantom power, and to drive balanced signals into a mic preamp or recorder. It really isn’t applicable for this application? Best Regards,
Jules Ryckebusch?
toggle quoted message
Show quoted text
On Feb 11, 2025, at 12:50, martenberger92 via groups.io <martenberger92@...> wrote:
? The FP33 looks indeed like the one device that I would need. But it's also on the heavy side. I had some slightly bigger Audio Development stuff, but mobility and lightweightedness are King for this project.
So thanks for pointing out my conflict, I am relaxing into just using three electret capsules and then merging them.
I assume the best way would be using the OPA Alice circuit on all three capsules and then merging on them right?
Would it be better to merge before the OPA Alice circuit on the capsules side, or after between the OPA circuit and the XLR Preamps?
It seems I could relatively easy add a attenuator Pad into the the Mid Mic so I would have some degree control in merging mode.
Thanks for the feedback!
|
Re: Merging three Capsules on two Preamps?!
The FP33 looks indeed like the one device that I would need. But it's also on the heavy side. I had some slightly bigger Audio Development stuff, but mobility and lightweightedness are King for this project.
So thanks for pointing out my conflict, I am relaxing into just using three electret capsules and then merging them.
I assume the best way would be using the OPA Alice circuit on all three capsules and then merging on them right?
Would it be better to merge before the OPA Alice circuit on the capsules side, or after between the OPA circuit and the XLR Preamps?
It seems I could relatively easy add a attenuator Pad into the the Mid Mic so I would have some degree control in merging mode.
Thanks for the feedback!
|
Re: Grounding Issue with TSB2590
#P48mems
That wouldn't be worth a try because it just wouldn't work.
Le 11/02/2025 à 18:18,
gerttreggertert223 via groups.io a écrit?:
toggle quoted message
Show quoted text
Would it be worth a try if i connected the cable shielding to
the ground of the capsule case? Or am I risking damaging
something by doing so?
|
Re: Merging three Capsules on two Preamps?!
On Tue, Feb 11, 2025 at 11:33 AM, kennjava wrote:
Opti-Alice
Sorry, the right project name is OPA-Alice
|
Re: Grounding Issue with TSB2590
#P48mems
On Tue, Feb 11, 2025 at 12:18 PM, @MusketenManfred wrote:
Would it be worth a try if i connected the cable shielding to the ground of the capsule case?
If you're using the simpleP48 powering scheme as specified in the Ambi-Alice instructable, grounding the capsule case will instantly and permanently damage the built-in FET. Don't ask me how I know this.
?
As mentioned, cardioid electrets are extremely sensitive to radiated hums and buzzes. You can test this by getting an empty soup can, ground the can, and carefully position it over your mic... you'll hear the buzz drop away.
?
So you need to come up with a metal mesh to shield the capsule and its wiring. Sometimes even two layers: something that shields each capsule, and then an overall mesh shield, like a metal mesh strainer.
|
Re: Grounding Issue with TSB2590
#P48mems
Would it be worth a try if i connected the cable shielding to the ground of the capsule case? Or am I risking damaging something by doing so?
|
Re: Merging three Capsules on two Preamps?!
On Tue, Feb 11, 2025 at 10:29 AM, <martenberger92@...> wrote:
I am aware that in a way I am describing a mixer yes. But I want this setup to be as small and light-weighted as possible and also battery powered.
It still seems that your goals are in conflict:
- XLR in with phantom power
- high performance
- mix controls or switching
- small, lightweight, simple, portable, battery-powered
?
But anyway. Off the top of my head, a first approach to DIY might look like this:
- crib some of the circuitry including opamp from the Opti-Alice project to buffer the raw capsules, to make one balanced mic preamp, and for post-mix makeup gain if necessary
- battery supply (6v or more) from alkalines or rechargeables for the opamps
- a charge pump, or 6x 9v (the rectangular PP3 type) for phantom power
besides I don't know any compact 3 channel XLR mixer with phantom power.
There are portable analog mixers available in the pro and semi-pro market. The Saramonic SR-PAX1 is a two-input mixer with phantom which might be a good starting point for modification, or combine two. Or their Smartrig+ mixer. I think Rolls offers similar mixers.
?
In the used market, the SHURE FP32 or FP33 can often be had for $200 or less. These are 3 mic in, stereo out, with phantom. Heavy little suckers.
?
|
Re: Merging three Capsules on two Preamps?!
No I want to Merge a Stereo AB with a Mono Mid/vocal mic.
I want to be able to switch between:
Stereo AB, Stereo AB + mono Mic, Mono Mic?
And if I can have some degree of balancing the mono mic with the stereo that be great too. Maybe just with an adjustable pad circuit.
|
Re: Merging three Capsules on two Preamps?!
Thanks for your view on this.
I have a Zoom, also a Sound Devices Mixpre10ii and many decent mics, so its not really about High fidelity or practicality here.
It's more about creating something playful and analog in nature just for the sake of it.
Yes I have been thinking also about using three electret capsules instead, too. However I would like the XLR input idea better.
I am aware that in a way I am describing a mixer yes. But I want this setup to be as small and light-weighted as possible and also battery powered.
besides I don't know any compact 3 channel XLR mixer with phantom power.
And the preamp quality of the tape recorder is really good, I dont want to decrease on quality...
Thats why I just want to switch between Stereo AB and Mid Mic or merge them.?
?
BTW: If you dont need your Sony walkman anymore, I'd happily take care of it and feed it with heartfelt music?
|
Re: Grounding Issue with TSB2590
#P48mems
Yes, but the case doesn't?connect to the circuit ground (Pin-1) of the XLR's. In my instructable I run it all the way up to shield?the inner?two wires of the Mogami cable. I am also making the three?terminal Capsule into a "two terminal" by connecting S and G (Source and Ground). I have not had issues with this method and have used the 2590 in multiple projects this way.?
Jules On Tue, Feb 11, 2025 at 9:18?AM gerttreggertert223 via <gerttreggertert223= [email protected]> wrote:
They look to be shielded. ive attached a photo so you can see what im talking about.
They have Mesh in front and the body is soldered to ground on the 4 pads in the right picture. They should be grounded.
-- Best Regards,
Jules Ryckebusch
214 399 0931
|
Re: Grounding Issue with TSB2590
#P48mems
They look to be shielded. ive attached a photo so you can see what im talking about.
They have Mesh in front and the body is soldered to ground on the 4 pads in the right picture. They should be grounded.
|
Re: Alctron MA-1 Schematic question
S1 would allow you to disconnect the input at pin 2 (dont know why anyone would want that...), S2 selects an input impedance (~3150 ohms or 150 ohms).? The MA1 preamp is powered by +48v phantom from the following mic preamp it's plugged into. Phantom is not passed through to the MA1's input.
|
Re: Merging three Capsules on two Preamps?!
There's a way to make a passive battery box that could bias 3 electret capsules and has the "mono" capsule feeding both the L and R outputs, but it would have a bit of loss from a resistive mix matrix, and it wouldn't really have the blend control you wanted. And it wouldn't provide any XLR input(s) with phantom.
?
You could build a mini mixer with 3 XLR mic inputs; there are many balanced mic preamp circuits out there, including with phantom... but since you can buy decent little mixers for not much more than it would cost to DIY one it, it would seem pointless.
?
And all this effort to feed a cassette recorder? (hey, i have a SONY Walkman Pro cassette recorder somewhere, but it had its day, and we've moved on)
?
Your best move is probably to put your money into a new (or used) digital recorder that will record from 4 mics, so no external box or mixer required. A starting point would be ZOOM - such as their H4n Pro, H4E,? H5, or H6E recorders. Also Tascam.
|
Re: Merging three Capsules on two Preamps?!
You are describing a mixer. There are small ones out there that would accomplish?this. And as has been mentioned, take the two ambience capsules pan one hard right one hard left and mix the vocal in the middle. Adding them in mono may not sound good.
Jules On Tue, Feb 11, 2025 at 7:27?AM martenberger92 via <martenberger92= [email protected]> wrote:
Hi all,
I would like to create a little circuit box that merges the signals of two ambient mics (L/R) with a single vocal mic (M) before entering the preamps.
So I can record stereo ambient and vocal simultaneously on my sony cassette 2 Track cassette recorder.
The recorder has two decent mic preamps without phantom power.
Is that possible? How would a circuit like this look like?
I was thinking of using two omni primo capsules for ambient and a XLR input for the extra vocal input (potentially condenser +48V).
Ideally there would be a single switch or potentiometer with which I can switch from only ambient, to only vocal mic, and some in between settings.
Is there someone that could help me out with a circuit sketch??
And what would be the easiest way to add phantom power to that device? The whole rig is intended to be used in the field and with batteries.
I could install 9V block batteries or also 3,7V Lipo batteries as power supply.
Any help is greatly appreciated!
Thanks?
M
-- Best Regards,
Jules Ryckebusch
214 399 0931
|
Re: Merging three Capsules on two Preamps?!
Merging two omnis down to mono might not sound that great. They generally don't downmix to mono very nicely.?
J
On Tue, 11 Feb 2025 at 13:27, martenberger92 via <martenberger92= [email protected]> wrote: Hi all,
I would like to create a little circuit box that merges the signals of two ambient mics (L/R) with a single vocal mic (M) before entering the preamps.
So I can record stereo ambient and vocal simultaneously on my sony cassette 2 Track cassette recorder.
The recorder has two decent mic preamps without phantom power.
Is that possible? How would a circuit like this look like?
I was thinking of using two omni primo capsules for ambient and a XLR input for the extra vocal input (potentially condenser +48V).
Ideally there would be a single switch or potentiometer with which I can switch from only ambient, to only vocal mic, and some in between settings.
Is there someone that could help me out with a circuit sketch??
And what would be the easiest way to add phantom power to that device? The whole rig is intended to be used in the field and with batteries.
I could install 9V block batteries or also 3,7V Lipo batteries as power supply.
Any help is greatly appreciated!
Thanks?
M
--
07889727365
02036861372
3 Swimmers Lane
Haggerston
London
E2 8FR
|
Merging three Capsules on two Preamps?!
Hi all,
I would like to create a little circuit box that merges the signals of two ambient mics (L/R) with a single vocal mic (M) before entering the preamps.
So I can record stereo ambient and vocal simultaneously on my sony cassette 2 Track cassette recorder.
The recorder has two decent mic preamps without phantom power.
Is that possible? How would a circuit like this look like?
I was thinking of using two omni primo capsules for ambient and a XLR input for the extra vocal input (potentially condenser +48V).
Ideally there would be a single switch or potentiometer with which I can switch from only ambient, to only vocal mic, and some in between settings.
Is there someone that could help me out with a circuit sketch??
And what would be the easiest way to add phantom power to that device? The whole rig is intended to be used in the field and with batteries.
I could install 9V block batteries or also 3,7V Lipo batteries as power supply.
Any help is greatly appreciated!
Thanks?
M
|
Alctron MA-1 Schematic question
I've recently seen the schematic for the Alctron MA-1. However, there are a couple of features that aren't clear and I hope to get some help from the group.
?
On the input side, after XLR1, there are two items labeled S1 and S2. They look like switches. S1 could be a mute switch. S2 looks like it connects XLR1-3 to either R1 or R2, perhaps to compensate for mic Zin.?
?
The other question I have is: where is power applied? Alctron's literature says it "operates on 48V, but does not pass phantom power to the mic." OK, but where is the power applied??
?
Dan
|
Re: Grounding Issue with TSB2590
#P48mems
Aah, OK! So the buzz is due to teh fact that the capsules are not
properly shielded.
The shield must extend as far as possible to cover most of the
capsule. Ideally, even the front of the capsule should be shieded.
Of course, a mesh should be used, to allow sund to hit the
diaphragm.
Le 11/02/2025 à 07:08,
gerttreggertert223 via groups.io a écrit?:
toggle quoted message
Show quoted text
They work great except for the buzzing. Im just using a
simple p48 circuit so 1 3.3uF cap and a 100k resistor on the xlr
plug.
|
Re: Grounding Issue with TSB2590
#P48mems
They work great except for the buzzing. Im just using a simple p48 circuit so 1 3.3uF cap and a 100k resistor on the xlr plug.
|
Re: Grounding Issue with TSB2590
#P48mems
The one on the left is a 3-wire capsule, when the one on the
right is a 2-wire.Depending on the circuit, they may be
incompatible.
Apart from the buzz, does it work?
Le 11/02/2025 à 03:45,
gerttreggertert223 via groups.io a écrit?:
toggle quoted message
Show quoted text
Maybe this is helpful. Ive attached both circuits of the
datasheets of the capsules. On the left is the JLI2590a and on
the right is the dr2501 I used. They look a bit different.?
Should i adjust the wiring?
?
?
|
