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Design me a 10 dB XLR Attenuator
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James Roper-Kum
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#1
31st January 2008
Old 31st January 2008
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Question Design me a 10 dB XLR Attenuator

Help!

I need 10dB of Attenuation for a K6 ME66 Mic going into a Sony Z1 as I have heard that the K6 has dangerously high output.

No time to purchase as the shoot is a last minute thing.

I know its gonna have something to do with resistance, but in what configuration?

Really should have done an electronics module at uni.

cheers

James
#2
31st January 2008
Old 31st January 2008
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PM me your email address and I will send you my attenuator calculator.
It's an Excel file and I could not upload it to this forum.

It calculates T, O, H, Pi, L and U type attenuators.
James Roper-Kum
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31st January 2008
Old 31st January 2008
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Sweet!

You are a star.

Have you built one before?

If so have you got any tips?

Thanks again

James
James Roper-Kum
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31st January 2008
Old 31st January 2008
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I just found this.

http://www.dplay.com/book/pgs2e/pads.pdf

Do you know if the XLR to XLR balanced +4dBU to -10 dBV line attenuator equals 10dB of reduction?

I am a bit confused?

Could anyone explain why the ME66 is so HOT and why a Z1 cant handle it?

I presume they are both balanced.

Is it impedance inconsistancy?

Thanksin you

James
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31st January 2008
Old 31st January 2008
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I just emailed you the calculator.

Did you get it?

Let us know how it worked out!!!
James Roper-Kum
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31st January 2008
Old 31st January 2008
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Hey man!

Got the e-mail and I am about to build.

But first...... is the Z value the Nominal impedance in Ohms?

And am I right in assuming I want the H Type Attenuator for an XLR to XLR?

I have seen some manufactured devices that quote 200 (Mic) 600 (Line) and the H types Z Value was set to 600 when I opened the document.

Thanks again

James
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31st January 2008
Old 31st January 2008
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James Roper-Kum
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31st January 2008
Old 31st January 2008
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Wow!

Thanks Matti!

Who need to go to college when you have the internet.

Cheers

James
James Roper-Kum
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31st January 2008
Old 31st January 2008
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Can you guys spot the problem?

ME66

Pick-up pattern super-cardioid/lobar
Frequency response 40–20,000 Hz ± 2.5 dB
Sensitivity (free field, no load) (1 kHz) 50 mV/Pa ± 2.5 dB
Nominal impedance 200
Ω (with K6)
Min. terminating impedance 1000
Ω (with K6)
Equivalent noise level
A-weighted (DIN IEC 651) 10 dB
CCIR-weighted (CCIR 468-3) 21 dB
Max. SPL (1 kHz) 125 dB (THD = 1 %)
Dimensions in inches .88 x 8.7

Weight 2.29 oz

Sony Z1

XLR audio input
XLR 3-pin female x 2, 327 mV, -60 dBu: 3 kΩ, +40 dBu: 10.8 kΩ, power supply: approx. 40 V

#10
31st January 2008
Old 31st January 2008
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Quote:
Originally Posted by James Roper-Kum View Post
Do you know if the XLR to XLR balanced +4dBU to -10 dBV line attenuator equals 10dB of reduction?

James
Hi James,

If memory serves the loss / gain with +4 <-> -10 is about 11.5 dB. [EDT: just saw the precise value in a table from Matt's links. its 11.79dB]

Best,
Silas
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James Roper-Kum
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5th February 2008
Old 5th February 2008
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Quote:
Originally Posted by Remoteness View Post
I just emailed you the calculator.

Did you get it?

Let us know how it worked out!!!
Hi Guys

I did it! With a little help from Jim the gardener (who used to be a physics teacher).

I used the closest to ideal resitors I could find. 4 x 54's and 1 x 120 gave me about 11 dB of attenuation.

I built an H-type balanced circuit on a piece of circuit board and inserted it at the Male end of the XLR. I then made a loop in that end of the XLR and cable tied the circuit into the loop so as to keep the joint as safe as possible.

It did the job well and I proceeded to make a good recording. If I hadn't built this pad in to the cable then the recording could quite easily have been a distorted one.

Thanks to everyone for their pointers.

Remember everyone: Sennheiser ME66 Mics are to hot for the Sony Z1. The Z1 just doesn't have the dynamic range.

Cheers

James
#12
19th July 2009
Old 19th July 2009
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I just bought a bunch of resistors from radioshack. I want to build a -15db pad for my API preamp. Does anyone have a detailed diagram and what resistors to use?
thanks
#13
19th July 2009
Old 19th July 2009
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