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Author Topic: AT8531 RCA mod (completed w/ pics)  (Read 13140 times)

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Offline Chuck

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Re: AT8531 mod (wiring question)
« Reply #15 on: March 22, 2011, 02:36:34 PM »
If you replace the full sized XLR jack with an RCA jack you will not be able to run them using phantom power from a pre-amp, which according to that thread is the best way to run them.
Reality is merely an illusion, albeit a very persistent one.

Microphones: Microtech Gefell M300, AKG C 480 B comb-ULS/ CK 61/ CK 63, Sennheiser MKE 2 elements, CAD GXL1200 (cardioid and mod-cardioid capsule & electronics mod), Audix M1290-o, Micro capsule active cables w/ Naiant PFA's, Naiant MSH-1O, Naiant AKG Active cables, Church CA-11 (cardioid), (1) Nady SCM-1000 (mod)
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Offline darktrain

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Re: AT8531 mod (wiring question)
« Reply #16 on: March 22, 2011, 02:46:48 PM »
If you replace the full sized XLR jack with an RCA jack you will not be able to run them using phantom power from a pre-amp, which according to that thread is the best way to run them.

You are correct, he can run em that way but you would be taking them from a 3 wire to 2 wire mic, then you might as well get a 4.7k mod and just use the mic in power or small battery box

Offline Chuck

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Re: AT8531 mod (wiring question)
« Reply #17 on: March 22, 2011, 02:47:49 PM »
If you replace the full sized XLR jack with an RCA jack you will not be able to run them using phantom power from a pre-amp, which according to that thread is the best way to run them.

You are correct, he can run em that way but you would be taking them from a 3 wire to 2 wire mic, then you might as well get a 4.7k mod and just use the mic in power or small battery box

Agreed.
Reality is merely an illusion, albeit a very persistent one.

Microphones: Microtech Gefell M300, AKG C 480 B comb-ULS/ CK 61/ CK 63, Sennheiser MKE 2 elements, CAD GXL1200 (cardioid and mod-cardioid capsule & electronics mod), Audix M1290-o, Micro capsule active cables w/ Naiant PFA's, Naiant MSH-1O, Naiant AKG Active cables, Church CA-11 (cardioid), (1) Nady SCM-1000 (mod)
Pre-amps: Naiant littlebox, Naiant littlekit v2.0, BM2p+ Edirol UA-5, Church STC-9000
Recorders: Sound Devices MixPre-6, Tascam DR-680, iRiver iHP-120 (Rockboxed & RTC mod)

Recordings on the LMA: http://www.archive.org/bookmarks/ChuckM
Recording website & blog: http://www.timebetweenthenotes.com

Offline igene

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Re: AT8531 mod (wiring question)
« Reply #18 on: March 22, 2011, 02:54:41 PM »
so running these after a preamp is kind of like adding a rolloff and a buffer ?

are you saying to leave them as is, and add the 4.7K resistor to the XLR in the box and run these inline w/ a pre or power supply?

not sure.
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Offline darktrain

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Re: AT8531 mod (wiring question)
« Reply #19 on: March 22, 2011, 03:03:16 PM »
so running these after a preamp is kind of like adding a rolloff and a buffer ?

are you saying to leave them as is, and add the 4.7K resistor to the XLR in the box and run these inline w/ a pre or power supply?

not sure.

actually after thinking about that for a second, the output shouldn't matter, whether you run 2 xlr's into a single mini plug or rca's to mini plug, either way they are coming to a single mini plug, i think we got sidetracked but you are only talking about outs right, you are leaving the mini xlrs intact correct

Offline Chuck

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Re: AT8531 mod (wiring question)
« Reply #20 on: March 22, 2011, 03:13:20 PM »
I was just pointing out that the best use for that device is to turn 48v phantom power into ~9v for electret condenser microphones.
If he needs a battery box, he should buy or build a simple battery box. From my way of thinking if you're going to buy or build a battery box, you may as well get one that's a pre-amp too. For example the pre-amps that Chris Church makes. I believe it was Chris that pointed out that the AT boxes have a low cut filter built into them, which I don't think is a good thing necessarily.
Reality is merely an illusion, albeit a very persistent one.

Microphones: Microtech Gefell M300, AKG C 480 B comb-ULS/ CK 61/ CK 63, Sennheiser MKE 2 elements, CAD GXL1200 (cardioid and mod-cardioid capsule & electronics mod), Audix M1290-o, Micro capsule active cables w/ Naiant PFA's, Naiant MSH-1O, Naiant AKG Active cables, Church CA-11 (cardioid), (1) Nady SCM-1000 (mod)
Pre-amps: Naiant littlebox, Naiant littlekit v2.0, BM2p+ Edirol UA-5, Church STC-9000
Recorders: Sound Devices MixPre-6, Tascam DR-680, iRiver iHP-120 (Rockboxed & RTC mod)

Recordings on the LMA: http://www.archive.org/bookmarks/ChuckM
Recording website & blog: http://www.timebetweenthenotes.com

Offline igene

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Re: AT8531 mod (wiring question)
« Reply #21 on: March 22, 2011, 03:17:31 PM »
correct.

I just want the outputs easier to handle.

miniXLR in > RCA panel out.
recessed nicely, making it more secure.

I have a couple of panel connectors ready to go...
and some rubber isolation too.


I have another question.
What is the max voltage this circuit can handle ?

3V ? 6v ?  9V ? 12v ?




I'd also like to add that as I do this I'm learning as well feeding my creative needs.
I have a CA-9100 and other pre's. That's not what this is about.
« Last Edit: March 22, 2011, 03:36:04 PM by igene »
Leela : ...what are we going to do ?
the Doctor : Should we try using our Intelligence ?
Leela : Well, if you think it's a good idea.
--------------------------------------------------------------------------
Gallifreyan Guard : But you do have access to the greatest source of knowledge in the Universe.
the Doctor : Well, I do talk to myself sometimes, Yes...

Offline igene

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Re: AT8531 mod (wiring question)
« Reply #22 on: March 22, 2011, 04:14:45 PM »
couldn't wait.
I'm testing w/ a 9v and everything is cold to the touch, no smell or smoke.
the 9v side is just a bit hotter. running one side AA and 1 side  9v

I also tested the pins w/ a DMM, I'm putting out 9v from the miniXLR output.


« Last Edit: March 22, 2011, 04:19:31 PM by igene »
Leela : ...what are we going to do ?
the Doctor : Should we try using our Intelligence ?
Leela : Well, if you think it's a good idea.
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Gallifreyan Guard : But you do have access to the greatest source of knowledge in the Universe.
the Doctor : Well, I do talk to myself sometimes, Yes...

Offline igene

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Re: AT8531 mod (wiring question)
« Reply #23 on: March 22, 2011, 04:41:54 PM »
what is that circuit on the back of the XLR connector ?




better shot >

« Last Edit: March 22, 2011, 04:48:44 PM by igene »
Leela : ...what are we going to do ?
the Doctor : Should we try using our Intelligence ?
Leela : Well, if you think it's a good idea.
--------------------------------------------------------------------------
Gallifreyan Guard : But you do have access to the greatest source of knowledge in the Universe.
the Doctor : Well, I do talk to myself sometimes, Yes...

Offline igene

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Re: AT8531 mod (wiring question)
« Reply #24 on: March 22, 2011, 05:51:37 PM »
first one finished and tested.
Works great.



Leela : ...what are we going to do ?
the Doctor : Should we try using our Intelligence ?
Leela : Well, if you think it's a good idea.
--------------------------------------------------------------------------
Gallifreyan Guard : But you do have access to the greatest source of knowledge in the Universe.
the Doctor : Well, I do talk to myself sometimes, Yes...

Offline kinglerxst

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Re: AT8531 mod (wiring question)
« Reply #25 on: March 22, 2011, 06:08:36 PM »
What was the difference in powering between the one running the single AA and the one running the 9V?

The 8531 was the "replacement" for the 8532 and the 8532 runs a 9V battery, so curious as to how much the powering difference was, I was figuring the 8531 used the 1.5V and then stepped it up to 9V internally so it ran the same as the 8532. I was never able to locate any spec info for the modules though......

Offline igene

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Re: AT8531 mod (wiring question)
« Reply #26 on: March 22, 2011, 06:36:16 PM »
there was maybe 10% more signal and a bit more clarity.
I put it all back the way it was - with the AA sled all soldered back.

I completed both boxes and tested. They work fine.
Actually, they may be a bit louder.
I have a suspicion that the circuit on the output XLR may be some kind of resistor
reducing output...but I'm just guessing.

Here's the completed mod >



Leela : ...what are we going to do ?
the Doctor : Should we try using our Intelligence ?
Leela : Well, if you think it's a good idea.
--------------------------------------------------------------------------
Gallifreyan Guard : But you do have access to the greatest source of knowledge in the Universe.
the Doctor : Well, I do talk to myself sometimes, Yes...

Offline kinglerxst

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Re: AT8531 mod (wiring question)
« Reply #27 on: March 22, 2011, 06:42:47 PM »
>turn 48v phantom power into ~9v for electret condenser microphones.

That's always had me curious since if the power module by itself was to give 9V to a mic, then why would phantom power of 48V be needed additionally if the module is just going to tone the 48V back down to 9V anyways?

>I believe it was Chris that pointed out that the AT boxes have a low cut filter built into them, which I don't think is a
>good thing necessarily.

Some of the AT modules that may be the case, however the 8531 (and 8532 before it) both have switches for off/flat/roll-off, so you don't have to run roll-off. I always run them at flat response.

Offline kinglerxst

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Re: AT8531 RCA mod (completed w/ pics)
« Reply #28 on: March 22, 2011, 06:54:23 PM »
>I have a suspicion that the circuit on the output XLR may be some kind of resistor
>reducing output...but I'm just guessing.

Can you measure the resistor values?

Would be curious as to what the difference would be taking out the resistors and running straight across the circuits instead......

Offline igene

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Re: AT8531 RCA mod (completed w/ pics)
« Reply #29 on: March 22, 2011, 06:57:10 PM »
I don't know.
I can guess though.
Perhaps it has something to do with amps.

It just occurred to me, if people are pumping 48V into this module, then 9V is totally OK.
All you have to do is take the bottom off, remove the battery sled for the AA and solder on a 9V clip.
Then the 9v battery sits in the space, and you just use gaffer's tape to hold it in place.
9V battery box, no problem. No extra anything needed.


I'll take a measurement now...of the resistor (?)
Leela : ...what are we going to do ?
the Doctor : Should we try using our Intelligence ?
Leela : Well, if you think it's a good idea.
--------------------------------------------------------------------------
Gallifreyan Guard : But you do have access to the greatest source of knowledge in the Universe.
the Doctor : Well, I do talk to myself sometimes, Yes...

 

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