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Two X9000's audio output in parallel

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N9LLO
Posts: 788
Joined: Sat Sep 08, 2001 4:00 pm

Two X9000's audio output in parallel

Postby N9LLO » Tue Jun 25, 2013 5:34 am

Has anyone tried parallelling the audio out on 2 x9000's to drive one 4 ohm speaker?

Chris
N9LLO

Will
Posts: 6823
Joined: Tue Sep 04, 2001 4:00 pm

Re: Two X9000's audio output in parallel

Postby Will » Tue Jun 25, 2013 1:04 pm

NO.
You would have to use two isolation transformers, one on each radio's audio/speaker output.
Last edited by Will on Thu Jun 27, 2013 3:12 pm, edited 1 time in total.

N9LLO
Posts: 788
Joined: Sat Sep 08, 2001 4:00 pm

Re: Two X9000's audio output in parallel

Postby N9LLO » Tue Jun 25, 2013 4:56 pm

I guess I should have asked has anyone but me tried it. The x9000 audio amps ARE transformer coupled and completly isolated. My dual drawer setup works fine with the audio leads in parallel driving a 4 ohm speaker.

Chris
N9LLO

Al
Posts: 1045
Joined: Tue Sep 04, 2001 4:00 pm

Re: Two X9000's audio output in parallel

Postby Al » Tue Jun 25, 2013 7:43 pm

If it works, it works. But not a great idea because you're backfeeding the opposing radio with audio from the active one. A transformer hybrid between the two radios and the speaker would have prevented that from occurring.

N9LLO
Posts: 788
Joined: Sat Sep 08, 2001 4:00 pm

Re: Two X9000's audio output in parallel

Postby N9LLO » Wed Jun 26, 2013 3:51 am

The only hybrid transformers I have seen were designed for two wire telephony circuits (600 ohms).
Probably too expensive for me even if avaliable for lo z circuits. I know there will be increased current in the amps under certain conditions but at typical volume levels I dont think it will be a problem. I seem to remember a lengthy discussion of this a long time ago but it may have been on the old board before the move to PHPbb. My search turned up nothing. Mabye someone else remembers or was involved in that discussion.

Chris
N9LLO

Al
Posts: 1045
Joined: Tue Sep 04, 2001 4:00 pm

Re: Two X9000's audio output in parallel

Postby Al » Wed Jun 26, 2013 4:37 am

The hybrid that I spoke of would have to be a custom one because I've not seen a commercially available low impedance one. A less expensive idea involves using an external power amp in inverting configuration with summing resistors on its inverting input fed from the audio outputs of both X9000s. Gives you the isolation between radios to prevent the backfeed situation while summing the outputs.

George
Posts: 265
Joined: Wed Apr 16, 2003 11:14 am
What radios do you own?: X9000, HT1550XLS, MTS2000, etc

Re: Two X9000's audio output in parallel

Postby George » Wed Jun 26, 2013 10:21 am

Hook them up and go to it. Nothing bad will happen.


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