Can I feed 2 recievers with same split source, run at same time?

electrocuted

electrocuted

Member
I ended up with 2 Pioneer sx 1250 amps/recievers. My question is can I split my feed of music source to each amp at same time to hear both amps at same time (of course with separate speaker pairs). Just not sure if something could back feed and cause harm. Why you ask do I want to do this? I just was wondering now that I have these 2 powerful monster amps in front of me....hmmmm what would this sound like?
 
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I have fed 6 pair of speakers, with 5 receivers, from a single source. Turn everything on, adjust volume on receivers to predetermined levels, then start source material and control the main volume control.

Sounded excellent outside the room, and outside the building. :rockon:
 
electrocuted said:
(...) Just not sure if something could back feed and cause harm. (...)
Click to expand...

Typically splitting a line-out up to two line-ins isn't really a problem. The combined load impedance just shouldn't be too low, in order to avoid a significant level drop, especially in combination with sources with pretty high output impedance. That's simply due to the output impedance and the combined load impedance forming a voltage divider - so the lower the combined load impedance gets, the more of the output voltage will already drop at the output impedance of the source. And mind you, that not only the input impedance of the pre-amp (or respectively pre-amp section of an integrated amp, receiver or whatever) itself may be relevant in that context, but the input impedances of the devices hooked to it may be too. That's because pretty often the tape-/record-outputs are unbuffered and also fed by unbuffered inputs, so that for example a receiver with two tape-decks hooked to it may very well already present itself to the source devices as the combined parallel load of itself and the two tape-decks.

And another thing to avoid would be long runs of high capacitance cabling, again in combination with a high source output impedance, as that can cause a roll-off in the highs. For example, if you'd have a source with an output impdance of 1 kOhm and two parallel 10 m runs of a cable type with 500 pF/m, the corner frequency (= -3 dB point) of the high pass filter, that the output impedance and the cable capacitances would form, would be at ca. 15.9 kHz.

Greetings from Munich!

Manfred / lini
 
Ok just checking. Lol I'm just glad I am not the only crazy here that wants to try it.
On a serious note hover my dad spent the last 15-20 years of his life deaf enough so he could not hear the deep tone of my voice in person at the dinner table....very sad. We could only communicate by his special phone. My good friend just yesterday confided in me that he has serious hearing issues at 67.....same as my dad. I'm 62 now and all though my eyes have turned to **** my hearing still is spot on. I want to use it while I have it......as I sit here rockin to Jethro Tull Aqualung typing.
 
Connect a CD player to the first 1250 with its own set of speakers, then just connect the second 1250 to the first 1250's "REC OUT" or "TAPE OUT" going in to the second 1250's aux or "TAPE IN" with its own set of speakers. Should work fine.

Just make sure both 1250's speakers are in phase with each other and you are now ready to rock out to your hearts content. :music:
Just remember with this set up, you will have 2 of everything to adjust (volume, bass, treble, etc.).

Also since both 1250's have "pre out" "main in" capabilities, you can use one to drive both amp sections while only using one 1250 for all controls.

Using either connection, there will be no "back feed" whatever that is. :rolleyes::D
 
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Not a problem with two of these.

RCASplitterAdditional1ZOOM.jpg
 
Seems like you might be able to get some kind of switcher box to direct the source into whatever amp that you happen to be using at the time... or into both amps.

Actually, this two amp thing might be a really nice way to run two sets of speakers and still be able to have them play nice an loud. I have two sets of speakers hooked up to my amp and everything works but I have to have them on protection circuit when I play them both together so that I don't stress the amp too much. The circuit robs some of the volume and the bass though and a two amp solution wouldn't have that problem. You could really crank it up, all throughout your house...
 
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If you want to use one 1250 to power both 1250's then a pair of these adapters are probably your best bet, then just use a regular pair of RCA interconnects to connect these to the other 1250.
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lini said:
Typically splitting a line-out up to two line-ins isn't really a problem. The combined load impedance just shouldn't be too low, in order to avoid a significant level drop, especially in combination with sources with pretty high output impedance. That's simply due to the output impedance and the combined load impedance forming a voltage divider - so the lower the combined load impedance gets, the more of the output voltage will already drop at the output impedance of the source. And mind you, that not only the input impedance of the pre-amp (or respectively pre-amp section of an integrated amp, receiver or whatever) itself may be relevant in that context, but the input impedances of the devices hooked to it may be too. That's because pretty often the tape-/record-outputs are unbuffered and also fed by unbuffered inputs, so that for example a receiver with two tape-decks hooked to it may very well already present itself to the source devices as the combined parallel load of itself and the two tape-decks.

And another thing to avoid would be long runs of high capacitance cabling, again in combination with a high source output impedance, as that can cause a roll-off in the highs. For example, if you'd have a source with an output impdance of 1 kOhm and two parallel 10 m runs of a cable type with 500 pF/m, the corner frequency (= -3 dB point) of the high pass filter, that the output impedance and the cable capacitances would form, would be at ca. 15.9 kHz.

Greetings from Munich!

Manfred / lini
Click to expand...
Hi Manfred, I'd like to read more about that.
Do you know of a good article on that? If not I'll search for cable capacitance or???
Thanks, Bob
 
Bob: Actually, that's pretty simple. Formula is: Corner frequency = 1 / (2 x pi x cable capacitance x output impedance)

Mind you, that you need to heed the magnitudes of the units, though - i.e., the cable capacitance should be in entered F(arad) and the impedance in Ohm to get a result in Hz. So if you had a specific capacitance value for the cable type in pF/m, you'd need to multiply that with 10^-12 (for the conversion from pF to F) and with the length in metres (to get the actual capacitance and get rid of the "/m").

Greetings from Munich!

Manfred / lini
 
lini said:
Bob: Actually, that's pretty simple. Formula is: Corner frequency = 1 / (2 x pi x cable capacitance x output impedance)

Mind you, that you need to heed the magnitudes of the units, though - i.e., the cable capacitance should be in entered F(arad) and the impedance in Ohm to get a result in Hz. So if you had a specific capacitance value for the cable type in pF/m, you'd need to multiply that with 10^-12 (for the conversion from pF to F) and with the length in metres (to get the actual capacitance and get rid of the "/m").

Greetings from Munich!

Manfred / lini
Click to expand...
Manfred, Got that. I work with RF regularly. There's so much to read about cable capacitance, sound, etc that it's hard to tell which articles are legit or... I know there are different beliefs on cables. It does make interesting reading. Personally I have not been able to hear differences in cables however I've never run or experimented with an input cable of 10 meters long either. The longest I believe I've used is about 2 meters or so.
Bob
 
the simplistic rule of thumb I've lived by is the input impedance should be about 10 X the combined output impedance.
 
BobbyN said:
(...) There's so much to read about cable capacitance, sound, etc that it's hard to tell which articles are legit or... I know there are different beliefs on cables. (...)
Click to expand...

Oh, I see. Well, as you might already have remembered in the meantime (so that the following explanation might very well be superfluous for you...), in this case it's not a matter of belief (or individual listening impression), but just a matter of electro-physics, as the output impedance and the cable capacitance form an RC series circuit, that acts as a low-pass filter.

Greetings from Munich!

Manfred / lini
 
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