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zcasper · Jul 28, 2002, 10:14 PM

Hello everyone, got a question:

How can I get the analog sound out (headphone jack) and the internal speaker to work at the same time on a Quicksilver G4?

The only thing I can come up with is to disconnect the speaker from the mobo and splice it to the headphone jack.

Does anyone have a better idea or some suggestions before I try this?

Thanks,

Zach

Carl Norum · Jul 29, 2002, 12:10 PM

<blockquote>quote:<hr />Originally posted by zcasper:
How can I get the analog sound out (headphone jack) and the internal speaker to work at the same time on a Quicksilver G4?<hr /></blockquote>I have yet to hear a solution to this problem. The same question was asked not two weeks ago in this very forum. Check the back issues, so to speak.

 <blockquote>quote:<hr />The only thing I can come up with is to disconnect the speaker from the mobo and splice it to the headphone jack.<hr /></blockquote>I don't think this will work. I am pretty sure that the speaker output is not an analog output. I remember a bunch of comments at the time they were released about them being "digital", which probably means that they have a PWM signal sent to them from the computer. Read the other thread - I'm not going to write that same post over again.

Carl Norum · Jul 29, 2002, 12:12 PM

[Double post]

[ 07-29-2002, 04:30 PM: Message edited by: Carl Norum ]

zcasper · Jul 29, 2002, 12:22 PM

<blockquote>quote:<hr />Originally posted by Carl Norum:
 <blockquote>quote:<hr />Originally posted by zcasper:
How can I get the analog sound out (headphone jack) and the internal speaker to work at the same time on a Quicksilver G4?<hr /></blockquote>I have yet to hear a solution to this problem. The same question was asked not two weeks ago in this very forum. Check the back issues, so to speak.

 <blockquote>quote:<hr />The only thing I can come up with is to disconnect the speaker from the mobo and splice it to the headphone jack.<hr /></blockquote>I don't think this will work. I am pretty sure that the speaker output is not an analog output. I remember a bunch of comments at the time they were released about them being "digital", which probably means that they have a PWM signal sent to them from the computer. Read the other thread - I'm not going to write that same post over again.<hr /></blockquote>Your talking about the Pro Speaker out. I'm talking about the jack for the headphones.

Zach

Carl Norum · Jul 29, 2002, 03:33 PM

<blockquote>quote:<hr />Originally posted by zcasper:
Your talking about the Pro Speaker out. I'm talking about the jack for the headphones.<hr /></blockquote>Oooh - rainbooooows! <img border="0" title="" alt="[Wink]" src="wink.gif" />

Sorry about that. The internal speaker on a quicksilver looks a lot like the pro speakers - it probably works the same way. In either case it will be more work than just shorting the connections together - the speaker (if analog) will require a lot of amplification that the headphone jack does not. You will end up destroying one or the other if you aren't careful. Get a scope and see what the signals going to each are like... then plan your changes accordingly.

[edit: 1337 typing skillz]

[ 07-29-2002, 04:34 PM: Message edited by: Carl Norum ]

zcasper · Jul 29, 2002, 05:16 PM

That's true - I hadn't thought about it if the internal speaker was PWM or not. Now that I think about it, it probably is.

This spoils the whole idea.

So the quesion is now, what make the internal speaker turn off?

Carl Norum · Jul 30, 2002, 10:08 AM

There is a special-application chip made by National Semiconductor that has separate and switchable PWM and analog outputs. I expect something similar to that is what is controlling the audio on the Power Mac. The National chip can only handle one active output at a time without overheating, which explains the switching problem you're having.

I don't think a setup using a chip like this one will be easily bypassed. My old beige G3 tower could use the internal speaker at the same time as the analog output jack. I wonder why it was changed?

zcasper · Jul 30, 2002, 10:21 AM

<blockquote>quote:<hr />Originally posted by Carl Norum:
There is a special-application chip made by National Semiconductor that has separate and switchable PWM and analog outputs. I expect something similar to that is what is controlling the audio on the Power Mac. The National chip can only handle one active output at a time without overheating, which explains the switching problem you're having.

I don't think a setup using a chip like this one will be easily bypassed. My old beige G3 tower could use the internal speaker at the same time as the analog output jack. I wonder why it was changed?<hr /></blockquote>Because the G3's didn't have the PWM speaker.

Carl Norum · Jul 30, 2002, 11:39 AM

Well, no kidding. But you think they would try to at least match the functionality of the earlier product. Though I guess the NeXTstep-OS X transition left a lot of stuff by the wayside, too (useable font panel, anyone?).