What's the better option and how (Balanced in/outputs) - diyAudio
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Old 3rd December 2002, 05:33 PM   #1
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Default What's the better option and how (Balanced in/outputs)

I am in the process of building Scott Dixon's DacKit and I am also on the list to get the Aleph X boards. The problem is that the Dackit does not have balanced outputs. So what is the best/easiest way to get these guys connected? Do I convert the inputs on the AX to unblanced or convert the out's on the Dackit to balanced? Or is there an adapter I can purchase to do this for me.

Thanks...Lee
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Old 3rd December 2002, 06:00 PM   #2
tiroth is offline tiroth  United States
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Better to add single-ended to balanced at the transmitter side, and reap all the benefits of balanced interconnects. (no ground loops, reduce interference)

Favored tool: BJT long tailed pair. Or opamps, tubes, etc. Sound.au.com has opamp converters, or the the LTP tube circuit on my site could be a starting point.
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Old 3rd December 2002, 06:59 PM   #3
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Default Found this circut...

My assumption would be that I would pull the signal off of the RCA Output on the Dac and move it over to the "+In" on the circuit below. I would then need two of these for the left and right signals.

Also any suggestions for better Opamps?



Click the image to open in full size.
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Old 3rd December 2002, 07:31 PM   #4
tiroth is offline tiroth  United States
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ne5532 will be a big jump. After that you will need to assess the flavor of the week for yourself.

I wouldn't use that circuit personally. It isn't really balanced at all.

Use either the more complex p87 transmitter or the old p51 one. There are tradeoffs with every topology. This is what makes for such great debates. ^_^

http://sound.westhost.com/project51.htm
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Old 3rd December 2002, 07:55 PM   #5
Bob2 is offline Bob2  Canada
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Default Balanced in/outputs

Lee

There was a big discussion about this already.
Balanced line

Bob2
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Old 3rd December 2002, 08:20 PM   #6
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Default Re: Found this circut...

Quote:
Originally posted by king30
My assumption would be that I would pull the signal off of the RCA Output on the Dac and move it over to the "+In" on the circuit below. I would then need two of these for the left and right signals.

Also any suggestions for better Opamps?



Click the image to open in full size.
King, you DO realise that the Gnd of the output CANNOT be connected to the input Gnd, right?

Jan Didden
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Old 4th December 2002, 12:57 AM   #7
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Just wanted to check if I have this right. Here is the schematic a took from the other thread.

Click the image to open in full size.

Here is my representation of how I would convert the output (top) of the DAC to balanced (bottom). Please let me know if you find any errors. Also suggestions for free websites that let you link directly to images would be great.

http://www.geocities.com/lee_king_99
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Old 4th December 2002, 08:07 AM   #8
Mad_K is offline Mad_K  Norway
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how about a nice BZLS?
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Old 4th December 2002, 09:51 AM   #9
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Quote:
Originally posted by king30
Just wanted to check if I have this right. Here is the schematic a took from the other thread.

Click the image to open in full size.

Here is my representation of how I would convert the output (top) of the DAC to balanced (bottom). Please let me know if you find any errors. Also suggestions for free websites that let you link directly to images would be great.

http://www.geocities.com/lee_king_99
There are (literally) two ways to look to this:
- from the input of the aleph it sees a balanced source as far as source impedance balancing is concerned. that is good;
- from the conversion circuit it is really just an unbalanced signal to pin 2 of the xlr. The other hot pin, pin 3, has a zero signal only.

This circuit is IMO OK for interfacing the CD player to the aleph, but it does not give the advantages of fully balanced interconnection. But then again, if your cabling to the aleph is not too long, it probably wouldn't make a difference anyway. I would say, try it.

The opamp can be any good one as advertised on this forum. You probably don't need any gain, the CD player will output at least 2V RMS. Where is your vol control? I don't know the aleph, being a Pass product it may need more input voltage and then the opamp can give the extra gain (gain = (Rfeedback/Rtoground)+1)


Jan Didden
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Old 4th December 2002, 10:45 AM   #10
SDF is offline SDF  France
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Hello King30, You don't need converter. The AlephX doesn't need because it works like the Bal Zen Pre and converts 'itself'.

Ask to Nelson Pass, you will see...
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