Line driver? - diyAudio
Go Back   Home > Forums > General Interest > Car Audio

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 20th July 2007, 02:35 PM   #1
diyAudio Member
 
Join Date: Mar 2007
Default Line driver?

Is there anyway to build just a RCA line driver to take one input signal and have it put out 4 or 5V output on 3 outputs? Has to operate off of car voltage.
  Reply With Quote
Old 20th July 2007, 05:24 PM   #2
diyAudio Member
 
theAnonymous1's Avatar
 
Join Date: Feb 2004
Location: Anonymityville
Forget the "line driver" car audio mumbo jumbo. What you want is called a preamp.

Here is a circuit designed specifically for use in a car....

http://sound.westhost.com/project32.htm

If you don't like that circuit you can build nearly any preamp and use it. There are plenty of them around if you do a search.

The power supply for a preamp in a car is probably more complicated then the preamp itself. If your up to building your own you can try this one.....

http://sound.westhost.com/project95.htm

I've taken the easy way out for some Linkwitz Transform circuits I'm building. I went ahead and bought some DC-DC converters.

If you find a project that you feel confident building and need a supply, I can sell you one of mine (I have extras).

These sell for $70 new, but I can sell you one for $10.....

DATEL BWR-15/330-D12

http://www.newark.com/jsp/Power+Prod...sp?sku=18C3387

http://www.datel.com/data/power/bwr7-10wa-series.pdf

OR, you can just BUY a "line driver".

http://cgi.ebay.com/Pac-Turbo-1-Turb...QQcmdZViewItem
  Reply With Quote
Old 14th August 2007, 12:10 PM   #3
diyAudio Member
 
Join Date: Aug 2007
Default Datel DC-DC Converter

Do you still have any of the Datel DC-DC converters? I would -love- to get my hands on one for an equalizer project I've been working on. I prototyped the equalizer and was almost ready to solder everything together when I realized that supplying power wouldn't be straightforward in a car. I found the Datel units after a lot of research but was turned off by the $70! $10 is a lot more in the range of what I was thinking

As an alternative, would it be possible to use a PWM to regulate the battery voltage down to 5V and then upconvert again using the following from TI:

http://focus.ti.com/docs/prod/folder...ch010512d.html
http://focus.ti.com/lit/ds/symlink/dch010512d.pdf

or:

http://focus.ti.com/docs/prod/folder...cp021212d.html
http://focus.ti.com/lit/ds/symlink/dcp021212d.pdf

I was hoping that the output from such a pairing would give me a steady power supply since the fluctuating battery V is regulated upfront.

I'm really interested in the Datel units regardless, but also curious if the strategy I have proposed would work for low-power devices. Thanks for any insight!
  Reply With Quote
Old 14th August 2007, 01:11 PM   #4
diyAudio Member
 
theAnonymous1's Avatar
 
Join Date: Feb 2004
Location: Anonymityville
I've already let a few go and would like to keep most of whats left, but I can spare another I guess.
  Reply With Quote
Old 15th August 2007, 03:15 AM   #5
dangus is offline dangus  Canada
diyAudio Member
 
Join Date: May 2004
Location: Vancouver Island
There's little DC-DC converters at Mouser and Digikey... they start at around $15 and up. I'd suggest getting one that does +/-15V and regulating down to 12V with 3-terminal regulators if you're fussy.
  Reply With Quote
Old 15th August 2007, 04:53 AM   #6
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
cl_chemie:

If you don't find anything else, you can have this one for the price of shipping (~$7).

http://www.bmpt1.com/temp/psboard01.jpg
  Reply With Quote
Old 15th August 2007, 10:34 AM   #7
diyAudio Member
 
Join Date: Aug 2007
Default DC-DC converters

Anonymous1: A few other alternatives seem to have opened up so let me explore those before I request one of your Datel units. Thanks very much for the offer though!

Dangus: If I'm thinking of the same units that you are referring to, I had one major concern that held me back from using those. Namely, the given input range is either 12V or 15V +/- 10%. This gives me a range of 10.8-13.2V or 13.5-16.5V. I'm expecting the car battery to fluctuate between 12-14V conservatively (although I thought it would be better to account for at least 10-14V). Thus, a 12V version will be overloaded when the car is on (14V) and a 15V version will be under-volted when the car is off.

I'm guessing that the 12V version uses components that cannot tolerate >10% input. However, from what I understand, an underpowered component can still be functional but will not always give predictable results. If this is true, I can use a 15V version and then regulate down to 12V as you suggest in order to smooth out irregularities brought on by voltage drops . Am I on the right track here?

This was also the thinking behind the solution I posted above, except that I figured a PWM could regulate a very wide range of V very efficiently. If anyone has comments on that setup vs. the above they would be appreciated!


Perry: That's a very kind offer and I am definitely interested depending on the validity of my statements above. The only thing that I'm a bit worried about is that your solution is a full-strength PS for higher-wattage projects and I'm afraid it would be wasted on my little equalizer. Also, should I decide to produce a couple more of these equalizers it would be nice to have something that is readily available vs. a custom one-off solution. I will definitely get back to you though regarding your board. Thanks!
  Reply With Quote
Old 15th August 2007, 12:23 PM   #8
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Default Re: Line driver?

Quote:
Originally posted by audiobahnkid592
Is there anyway to build just a RCA line driver to take one input signal and have it put out 4 or 5V output on 3 outputs? Has to operate off of car voltage.
In an automotive environment you have to contend with noise and (potentially) long cable lengths. The line driver chip takes a single-ended output, converts it to a balanced output -- then the line receiver does the opposite -- in this way you avoid noise pickup over the cable.

You don'thave to use the specialist chips like the Analog Devices SSM2141 and 2142 shown in the attachment -- the same thing can be cobbled together with discrete opamps and some resistors -- and ADI shows how on their website.

With respect to bipolar power for the line driver -- the transistors in inexpensive PWM chips like the SG3524 and SG3525 are sufficient to drive a push-pull DC-DC converter -- you can get the transformer core you need from a busted PC power supply.

Take a look at the SSM2142 data sheet on Analog Devices website.
Attached Images
File Type: gif driver.gif (7.9 KB, 192 views)
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Line Array with PHY Driver jpetek Multi-Way 6 9th December 2012 01:35 PM
building a line driver fosgate3 Analog Line Level 2 10th May 2007 10:57 PM
Sub Line Driver rampage101 Car Audio 9 18th October 2006 06:39 AM
anyone care to help on a line driver??? JOE DIRT® Solid State 3 4th July 2003 06:29 PM
Balanced Line Driver Jerry Parker Everything Else 1 1st April 2003 05:32 PM


New To Site? Need Help?

All times are GMT. The time now is 11:40 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2