Need to make 3 line outs from 1

Stream · 25th September 2009, 07:31 PM

Hello.

I'm planning to tweak one Car CD-player (Honda Accord 2008).

It hasn't pre outs, so I'll try to make some and get signal before power amp.

But I'm worrying about one problem. I need 2 or 3 line outs to make per-channel amplification (some kind of bi-amp).
And I think that paralleling 3 outs is not very good idea, right?

Can You please give me advice how can i make this? Maybe some kind of simple buffer based on opamp? I would be very pleased if someone share scheme of this...

Speedskater · 25th September 2009, 10:09 PM

If the pre-amp (really it's a line amp, as the output voltage stays the same) has a robust output stage and all the power amps have the same type input stage, than the pre-line-buffer-amp should have no problems driving several amps. Problems sometimes arise with amp inputs that but different demands on the buffer. Turning one of the amps off can cause high distortion in the other connected amps.

Stream · 26th September 2009, 07:31 AM

Thanks for answer.

It's actually not line-amp, but pre-amp-out because it is placed right before the amp stage...

I just worried about output resistance and signal level of pre amp stage. If normal out has x kiliohms, than 3 paralleled will have about three time lower, right? And normal output level is ~2V, than paralleling three out will have the same value or lower?

picowallspeaker · 26th September 2009, 07:45 AM

Go with a CF and a ECC82 ! Everybody would say " Ohhh! That's amazing ! Tubes in a car ! " if you put them in sight , otherwise nobody wouldn't say anything.

Stream · 26th September 2009, 11:21 AM

It's cool to have tubes in car, but i haven't work with them and it's not my car

I just need to know the best way to get 3 pre outs from stock (without factory pre-outs) system

picowallspeaker · 26th September 2009, 11:29 AM

Better if it's not your car ! You can ask a lot for charge and keep the rest..
I was posting you a simple schematic altough it would require a noiseless DC-DC converter to raise the voltage to 250 V. Better go with the simple applications of the TL061...and change from split supply to single supply ...or use two 9V batteries.
Sorry I threw off all my books!

Stream · 26th September 2009, 01:48 PM

No thanks, 250V without skills - it's very dangerous in car.

I need simple solution for 0...9V or +\-12...15V

Quote:

I was posting you a simple schematic

Sory, but where did you post that? : )

Quote:

Better if it's not your car ! You can ask a lot for charge and keep the rest..

It's not case of commercial, I just help someone to build SQ car and now we are thinking over future project, before buying amps and loudspeakers.

picowallspeaker · 26th September 2009, 02:09 PM

Hello Stream !Got rid of all my books 'cos everything is on the Web.
Here's the application note...Eeek! A mouse !
I was posting you a vacuum tube one , but you can easily find it..perhaps better if supplied with lower voltage ie. 80 V.

Stream · 26th September 2009, 02:59 PM

Thank You. It looks like subj

What is the "name" of this scheme? I would like to search addition info about this.

25th September 2009, 07:31 PM	#1
Stream diyAudio Member Join Date: Aug 2008	Need to make 3 line outs from 1 Hello. I'm planning to tweak one Car CD-player (Honda Accord 2008). It hasn't pre outs, so I'll try to make some and get signal before power amp. But I'm worrying about one problem. I need 2 or 3 line outs to make per-channel amplification (some kind of bi-amp). And I think that paralleling 3 outs is not very good idea, right? Can You please give me advice how can i make this? Maybe some kind of simple buffer based on opamp? I would be very pleased if someone share scheme of this...

25th September 2009, 10:09 PM	#2
Speedskater diyAudio Member Join Date: Sep 2002 Location: Lakewood, Ohio	If the pre-amp (really it's a line amp, as the output voltage stays the same) has a robust output stage and all the power amps have the same type input stage, than the pre-line-buffer-amp should have no problems driving several amps. Problems sometimes arise with amp inputs that but different demands on the buffer. Turning one of the amps off can cause high distortion in the other connected amps. __________________ Kevin

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26th September 2009, 07:31 AM	#3
Stream diyAudio Member Join Date: Aug 2008	Thanks for answer. It's actually not line-amp, but pre-amp-out because it is placed right before the amp stage... I just worried about output resistance and signal level of pre amp stage. If normal out has x kiliohms, than 3 paralleled will have about three time lower, right? And normal output level is ~2V, than paralleling three out will have the same value or lower?

26th September 2009, 07:45 AM	#4
picowallspeaker diyAudio Member Join Date: Apr 2007	Go with a CF and a ECC82 ! Everybody would say " Ohhh! That's amazing ! Tubes in a car ! " if you put them in sight , otherwise nobody wouldn't say anything.

26th September 2009, 11:21 AM	#5
Stream diyAudio Member Join Date: Aug 2008	It's cool to have tubes in car, but i haven't work with them and it's not my car I just need to know the best way to get 3 pre outs from stock (without factory pre-outs) system

26th September 2009, 11:29 AM	#6
picowallspeaker diyAudio Member Join Date: Apr 2007	Better if it's not your car ! You can ask a lot for charge and keep the rest.. I was posting you a simple schematic altough it would require a noiseless DC-DC converter to raise the voltage to 250 V. Better go with the simple applications of the TL061...and change from split supply to single supply ...or use two 9V batteries. Sorry I threw off all my books!

26th September 2009, 02:59 PM	#9
Stream diyAudio Member Join Date: Aug 2008	Thank You. It looks like subj What is the "name" of this scheme? I would like to search addition info about this.

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