TK-730 PA Speaker Question..

Forts · #1 (**permalink**) 10-06-2012, 7:13 PM

I've been trying to hook up a PA speaker to my TK-730 and I'm not having any luck. Radio is currently setup with a remote head and on the 15 pin accessory connector pin 9 is jumpered to 12. Speaker audio then comes off the 6 pin connector on the back of the control head. According to the pinout, pins 13 & 14 should be PA... Yet with my external speaker connected there, and PA activated on the head unit.. I get no audio. Am I missing something here? Also, I'd like to use the PA speaker as an external speaker (which I have programmed to one of the other buttons). Can the same output be used for external speaker and PA?

Thanks!!

mmckenna · #2 (**permalink**) 10-06-2012, 9:16 PM

The "PA" output on the Kenwood radios is a low level output. You need to have an external amplifier to make it work. Connecting a speaker directly to those pins won't work. The output level is too low to drive a speaker directly.

Forts · #3 (**permalink**) 10-06-2012, 11:32 PM

Ahhhh! Thank you! All the stuff I read, nowhere did it mention that is a low level output and that an amp is required. The pinout from the service manual simply shows 'PA Speaker - 13W'.

Am I correct in assuming I can't use the external speaker option either, since it's driving the audio to the remote head?

ramal121 · #4 (**permalink**) 10-07-2012, 12:40 PM

No, not the case. There is a relay (K501 I believe) that will switch speaker output. It should be installed, don't think it was an option (as with other earlier radios). The speaker output will appear on the 15 connector on pins 6 and 12, and with the relay activated the speaker will now be on 13 and 14. The relay only switches one side of the speaker, the other side is common and tied together inside the radio. You cannot have both on at once. Check that you have the relay in and maybe hear it click when you press a button.

Now on the buttons, PA will kill the radio receive and connect the mic to the audio amp for hailing. If you want to switch radio receive to an outside speaker use "SP" speaker switch. Two different functions
and separate buttons need to be programmed. If both are used and activated at the same time the PA function will take precedence I think.

Forts · #5 (**permalink**) 10-07-2012, 3:49 PM

Thanks ramal121... I have both the SP and PA buttons programmed, and had a horn speaker attached to 13 and 14... no audio from either function. I will double check on the presence of the relay, but from what I recall I think I did hear a 'click' when I was playing with it earlier.

ramal121 · #6 (**permalink**) 10-07-2012, 4:28 PM

OK. Other than the relay, there are no jumpers or anything to set to complete the path to the rear 15 pin connector. It should just work. If you still have probs then I'd be ohm'n the path out with the schematic in hand.

On a side note newer Kenwoods (like a TK-790) use a dual output (stereo) audio amp. Both outputs appear on the accessory connector. The radio switches between inputs to output to either one (left) or two (right). Since the 730 is only a single ended audio amp, it uses a relay to switch the output to one of two output ports.

Good luck to your troubleshooting.

mmckenna · #7 (**permalink**) 10-08-2012, 11:15 PM

Sorry, screwed the pooch on that answer. The newer Kenwood's I've been working with only seem to have the low level outputs for the PA. I'll have to keep my eyes open for one of these.

ramal121 · #8 (**permalink**) 10-08-2012, 11:27 PM

Quote:

Originally Posted by mmckenna

Sorry, screwed the pooch on that answer. The newer Kenwood's I've been working with only seem to have the low level outputs for the PA. I'll have to keep my eyes open for one of these.

Obviously a 790 guy! I too get turned around with trying to get radios hooked to speakers, remotes, headsets, etc. The one thing that erked me was the lack of a low level output from the 730, only switched speaker. Gotta keep good notes to keep on top of things!

Forts · #9 (**permalink**) 10-09-2012, 8:22 AM

Ok... so if I'm following along correctly, when I activate the PA *or* SP function, audio should be switched to pins 13 & 14? Is this affected at all by the fact that I currently have the jumper in place from 9 to 12 to feed the audio to the remote head output?

Thanks for your help on this guys, I really appreciate it!

ramal121 · #10 (**permalink**) 10-09-2012, 9:50 AM

Although different functions, PA and SP both use the secondary speaker path so yes the relay should fire and speaker output will be on 13 & 14 for either.

The 9/12 jumper only routes speaker up to the control head, but since it's in the primary speaker path and is switched out during PA or SP it has no effect on what you're trying to do.

Forts · #11 (**permalink**) 10-09-2012, 9:56 AM

Great, thanks so much for clarifying that for me. I'll take another look at it this week and see if I can't get it working.