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#1
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audio da info needed
I would like to build a passive balaned da with 4 outs. Does anyone
have a link that would give me the resistor values needed? Approx loss? I will be using a +4 or +8 input. Thanks Joe |
#2
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On 21 Apr 2005 20:38:18 -0700, "Joe" wrote:
I would like to build a passive balaned da with 4 outs. Does anyone have a link that would give me the resistor values needed? Approx loss? I will be using a +4 or +8 input. This looks like award-winning material. Has Googoo instituted some contest that I've missed? Brilliant, Chris Hornbeck |
#3
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"Joe" I would like to build a passive balaned da with 4 outs. Does anyone have a link that would give me the resistor values needed? Approx loss? I will be using a +4 or +8 input. ** A typical balanced output can drive many inputs - 10 at least. Most power amps have male and female input connectors to allow chaining - if this is not possible them just make a box with one female and 4 male XLRs with all pin 1s linked, all pin 2s linked and all pin 3s linked. ................ Phil |
#4
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"Joe" wrote in message oups.com... I would like to build a passive balaned da with 4 outs. Does anyone have a link that would give me the resistor values needed? Approx loss? I will be using a +4 or +8 input. Thanks Joe One very simple way is to use "build out" resistors. If it is nominally 600 ohms balanced in and out to everything, you can use 600/4=150 ohms in series with each plus or minus "leg". If you were only driving 2 devices you'd use 300 ohm. Julian |
#5
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Julian Adamaitis wrote: "Joe" wrote in message oups.com... I would like to build a passive balaned da with 4 outs. Does anyone have a link that would give me the resistor values needed? Approx loss? I will be using a +4 or +8 input. Thanks Joe One very simple way is to use "build out" resistors. If it is nominally 600 ohms balanced in and out to everything, you can use 600/4=150 ohms in series with each plus or minus "leg". If you were only driving 2 devices you'd use 300 ohm. Julian Be careful about loading in a situation like this. When working with a unknown load, or a transformer I would use no more than 100 ohms, typically 50 ohms. rd |
#6
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"RD Jones" wrote Be careful about loading in a situation like this. When working with a unknown load, or a transformer I would use no more than 100 ohms, typically 50 ohms. I'd usally rather have too much resistance at an output rather than too little. Why do you warn against too much? Julian |
#7
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"Julian Adamaitis" wrote in message ... "RD Jones" wrote Be careful about loading in a situation like this. When working with a unknown load, or a transformer I would use no more than 100 ohms, typically 50 ohms. I'd usally rather have too much resistance at an output rather than too little. Why do you warn against too much? Julian Poof !! |
#8
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On Thu, 21 Apr 2005 23:33:10 -0700, in rec.audio.pro "Julian
Adamaitis" wrote: "RD Jones" wrote Be careful about loading in a situation like this. When working with a unknown load, or a transformer I would use no more than 100 ohms, typically 50 ohms. I'd usally rather have too much resistance at an output rather than too little. Why do you warn against too much? Julian If your output Z is too high, it means that a load will drop the level, and if you need to parallel two or more devices from one DA out, you will get levels drops, so a low source Z is "a Good thing" try http://www.canford.co.uk/commerce/re...tails/2742.pdf martin After the first death, there is no other. (Dylan Thomas) |
#9
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Cheapo DA
Agreed, a low Z o/p (1 to 100 ohms) can feed lots of 10k Z inputs without level/reponse drop. I usually add a 51 to 75 ohm resistor in each o/p leg from either bus of the bal i/p pair. You can run long feeding leads easily. Best keep the o/ps in phase with i/p. Assuming source is reference of around 1mW, you could even add switchable 50dB bal'd pads in one or two o/ps for deriving mic level. Ground the (metal) audio distribution box via input XLR pin1, assuming provider screen is grounded! But float those multi-output XLRs' pin 1. The receiving gear will usually provide the grounded screen for its signal lead (unless it's battery-powered - in which case you *would* link it to Source pin1) Or to be more flexible, add an Earth/Ground Lift/Make spdt mini-toggle per o/p XLR interrupting its pin1 to common ground bus (from i/p XLR pin1). "Phil Allison" wrote in message ... "Joe" I would like to build a passive balaned da with 4 outs. Does anyone have a link that would give me the resistor values needed? Approx loss? I will be using a +4 or +8 input. ** A typical balanced output can drive many inputs - 10 at least. Most power amps have male and female input connectors to allow chaining - if this is not possible them just make a box with one female and 4 male XLRs with all pin 1s linked, all pin 2s linked and all pin 3s linked. ............... Phil |
#11
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"Julian Adamaitis" wrote in message ... "David Morgan (MAMS)" wrote Poof !! Naw, if you short the output, then poof. Quite right.... |
#12
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Thanks for all the responces to my question
Joe |
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