km@emory.UUCP (Ken Mandelberg) (02/16/86)
I recently got a Sony portable CD player, and have wondered about using
it in my car. I tried powering it from the cigarette lighter with a
Radio Shack adapter, and this seems to work fine. (By the way is there
any point in using Sony's adapter instead? The few dealers I called
didn't have one, and I was impatient).
The real question is about getting it to use the car's speakers. I
have a Toyota Camry with a factory Toyota radio. Toyota sells a
separate cassette player which also mounts in the dash, and is
connected to the radio through a multipin (DIN?) connector on the back
of the radio. I don't know this for sure but I presume that the
cassette uses the amplifier in the radio.
Does it seem likely that I could rig a (passive) adapter to send the CD
player's line output into the radio? So far I don't have any info on
the pinouts of the connector. The Toyota maintainance manuals do not
address the issue. Any ideas where to get electrical info about the
radio?
Please no flames suggesting that quality of the radio's amplifier and
speakers are a bad match for the CD. I appreciate that already.
Incidentally, I noticed that is some press reports of the Winter CES in
Las Vegas, that several manufacturers announced after market dash
mountable radio/amplifier/cassete units with an easy connect
arrangement for portable CD players. I didn't keep track of which
manufacturers, and haven't seen them advertised retail yet.
--
Ken Mandelberg
Emory University
Dept of Math and CS
Atlanta, Ga 30322
{akgua,sb1,gatech,decvax}!emory!km USENET
km@emory CSNET
km.emory@csnet-relay ARPANEThsu@eneevax.UUCP (Dave Hsu) (02/17/86)
In article <1582@emory.UUCP> km@emory.UUCP writes: >I recently got a Sony portable CD player, and have wondered about using >it in my car. I tried powering it from the cigarette lighter with a >Radio Shack adapter, and this seems to work fine. (By the way is there >any point in using Sony's adapter instead? The few dealers I called >didn't have one, and I was impatient). > >The real question is about getting it to use the car's speakers. I >have a Toyota Camry with a factory Toyota radio. Toyota sells a >separate cassette player which also mounts in the dash, and is >connected to the radio through a multipin (DIN?) connector on the back >of the radio. I don't know this for sure but I presume that the >cassette uses the amplifier in the radio. > >-- >Ken Mandelberg I saw one of those el-cheapo units on sale here in the DC area last weekend (soundesign? one of those) for around $14 (reg. $27, methinks), which basically included the cigarette adapter and some peculiar circuit you connect to your car antenna. Wow, does this mean that if I hop up the parts, I can broadcast glorious music to neighboring cars? :-) -dave -- David Hsu Communication & Signal Processing Lab, EE Department <disclaimer> University of Maryland, College Park, MD 20742 hsu@eneevax.umd.edu {seismo,allegra}!umcp-cs!eneevax!hsu "Godzilla has been spotted in Sector 5!"
dsi@unccvax.UUCP (02/19/86)
> > I saw one of those el-cheapo units on sale here in the DC area last > weekend (soundesign? one of those) for around $14 (reg. $27, methinks), > which basically included the cigarette adapter and some peculiar circuit > you connect to your car antenna. Wow, does this mean that if I hop up > the parts, I can broadcast glorious music to neighboring cars? :-) > Not to change the subject (exactly) but we have a peculiar problem in the Charlotte radio market with respect to FM radios and a desired station. When some cars equipped with el-cheapo FM sets are tuned to 96.9 mHz (WLVK) and they pass by you while you are listening to WKZL (107.5) in many cases, the local oscillator from the WLVK-tuned receiver is able to completely overtake WKZL. The effect in many cases is bad multipath -like interference and the other usual flup-flup noises, with properly shielded and designed receivers. Back to the original point, though: why on earth would anyone want to play a CD player through a very poorly designed FM or AM modulator. I doubt seriously that the circuitry exists for either stereophonic FM or AM in a $27 box; you can be assured that in the FM case, the differential distortion in the modulator will make CD's sound horrible. (In fact, the differential distortion in most commercial FM transmitters makes a CD sound horrible....) It is entirely possible that leakage and the right circumstances would result in cars around you at a stoplight would receive an interfering signal of your CD player. If I were going to do this, I'd simply open up the Toyota radio and interrupt the audio at an appropriate place, bring coaxial cable out to a switch and jacks, etc. Then again, the last Toyota radio I tried this with had DC controls for volume and so on, and it was somewhat more difficult to find the appropriate point in the radio chassis. You could always find the "common point" where the AM tuner feeds the power amplifier circuitry, and use that; if you aren't committed to AM radio listening. (The Toyota AM radio in question here wasn't worth listening to, anyway....) I've played my CD player through the usual 3.5 watt car radio type amplifier (used as a monitor amp on our earth station) driving BIC Formula 1 (hack, cough, wheeze) speakers. It wasn't that bad at low volume. However, most car stereo amplifiers have gross phase distortion (pull out your Ford factory radio and run a proof on it) as well as a frequency response similar to that funny thing on your desk with 12 buttons on it.... The Toyota radio I modified (for roughly the same purpose) had more tilt at 100 Hz than my 1948 Collins 20-T AM transmitter at 100% modulation. If you are really interested in doing this, find a decent radio chassis to start with. David Anthony DataSpan, Inc