Splitting one source signal into two Headphone Amps?
Mar 17, 2002 at 7:41 PM Thread Starter Post #1 of 7

Magic77

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I'd like to know if it is safe or possible to split the RCA outputs of a desktop CD Player into two different Headphone Amps? I was thinking of using the 1 RCA male to 2 RCA female adapters at each output, but I'm not sure if this is the right way to do it.

Will there be any significant signal loss? Can only one Amp be turned on at a time? or can both be on at the same time?

Thanks for any help.
 
Mar 18, 2002 at 12:18 AM Post #3 of 7

Dusty Chalk

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Single most important consideration: input impedances on the two headphone amps, output impedance on the source. The input impedances should be high enough that neither amp "sees" the other. (Someone else explain that, I'm not sure how to say it.) Also bear in mind, some things change when turned off -- make sure your device does not do that.

The other consideration is if the output of the CD player is enough to drive both players. mA is probably the most important spec for this.

Yeah -- why can't you just hook 'em up serially?
 
Mar 22, 2002 at 3:30 AM Post #4 of 7

rickcr42

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possible,but as mentioned above results could vary.You might consider using a distribution amp

update : since this is a DIY forum,a more detailed answer would be -
A simple device could be built using multiple op-ampsor monolithic buffers.One device for each desired output
 
Mar 24, 2002 at 11:39 PM Post #5 of 7

joensd

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Good question.
i´ve been looking for a while for the complete answer (and suitable circuits)
the only thing i found so far is a distribution amplifier like in the TL074 datasheet.
anyone seen this?
Isn´t it too complicate for that purpose?
Shouldn´t a simple unity gain buffer with a 100k resistor from pos.input to ground be enough?
Would a buffer capable of a few ma´s be enough to drive two amps if the pots of the amps are say 47k or higher? (for example power and headphone amp)
thanks
 
Mar 24, 2002 at 11:54 PM Post #6 of 7

rickcr42

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ideally you would use a gain of one (unity) op-amp as the input element and use either an individual buffer or op-amp stage for each output.In that way you would get zero interraction between source and outputs.
Not a hard build at all.Just pay careful attention to the supply bypasses per device , lay it out as you would visualize the usage and all should go well
Hope this helps

Rickmonster
 
Mar 30, 2002 at 6:03 AM Post #7 of 7

kwkarth

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Typically, you will not have a problem driving two amps from the same source. Use good quality Y adaptors and you should be fine. Double check by listening to one amp before and after connecting the second rig. Listen for volume changes and altered frequency response. I drove both the Creek OBH-11SE and SAC K1000 simultaneously from my CDP with no problem or perceived change in quality. I can now do the same thing driving both my Max and SAC from the same CDP, but prefer to drive the Max from the CDP and then use the pre-out from the Max to drive the SAC so I can use the crossfeed processor for both amps.

Typically, line outputs are on the order of 600 ohms to 2k ohms while typical line inputs are 10k ohms on average. You should have no loading problems, i.e. a buffer is completely unnecessary.
 

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