Headunit Controller Idea

[TEKNOPUG 3]

Following my recent disappearing stereo, I've had an idea for a new one.

 

From my understanding, an amplifer is switched ON by the ign/output lead from the headunit. It's power comes from the battery. The music signals are sent from the headunit via the RCA leads.

 

Would it therfore be possible to wire the ON lead to an igntion ON lead from the loom or even just a switch on the dash. Then plug in an alternative music source (mp3 player, discman etc) into the RCA leads?

 

Thus doing away with a conventional head unit altogether and just mounting a pair of RCA sockets of similar in the dash?

 

I remember wiring a MD player direct to an amp and using the headuint to switch the amp on in an old 205 I had many moons ago.

 

Thoughts, ideas anyone?

[d-9 0]

Yeah that would work. Only issue with having it on when you turn the key is you might get a pop/bang from the speakers/sub when you start the car.

 

And obviously you would need a volume controlled output on your ipod or whatever your going to plug in.

[TEKNOPUG 3]

I would probably wire a switch up on the dash for a power on/off.

 

Would I need a dedictaed line out or could I run straight from a headphone output?

[d-9 0]

Headphone output would probably be better as that would have a volume control on it.

[Dream Weaver 2]

I posted similar a while back, but my idea was to have a Jack port fitted into the dash to plug an Ipod into - the internals for the "amp/headunit" would then be hidden with the fuses under the dash.

 

http://forum.205gtidrivers.com/index.php?showtopic=46877&hl=

[Guest Lil Black Pug]

That would work fine mate might have to look at supressors as I would imagine you will have the old engine whine. Its worth thinking about fuses etc to protect your stuff.

 

Headphone output will give you a signal that has already been amped, in order to set the system up correctly will take a lot of time playing with the gains because the signal will distort almosty immediatley. Though to be honest I doubt the sound quality will any good anyway.

 

Def look for a line out the qulaity of the signal will be far better, plug it through a line driver (they are worth the cash) and it should work fine. As for controlling the system good amp set ups come with bass controllers these days and that will give you your control?!!

 

Think there is a good chance you will get popping etc but if you take a bit extra time with the connections / connectors (a couple of quid for a connector is a bargain over tape when you blow a sub) and earths you should be ok.

[TEKNOPUG 3]

That would work fine mate might have to look at supressors as I would imagine you will have the old engine whine. Its worth thinking about fuses etc to protect your stuff.

 

Headphone output will give you a signal that has already been amped, in order to set the system up correctly will take a lot of time playing with the gains because the signal will distort almosty immediatley. Though to be honest I doubt the sound quality will any good anyway.

 

Def look for a line out the qulaity of the signal will be far better, plug it through a line driver (they are worth the cash) and it should work fine. As for controlling the system good amp set ups come with bass controllers these days and that will give you your control?!!

 

Think there is a good chance you will get popping etc but if you take a bit extra time with the connections / connectors (a couple of quid for a connector is a bargain over tape when you blow a sub) and earths you should be ok.

 

 

I'm thinking that it would be better to run an RCA to jack plug from the amp, under the carpet and then up into the bin by the gear stick. Keep it all stealthy then.

 

So I need to find and MP3 player with a line out and preferably a remote. Is it possible to get universal line-out converters? That would be best.

 

Also, how does the power ON to the amp work? On a HU it uses the electric aerial out. Does it need to be a constant feed or is it just an ON/OFF signal? I was thinking that I could use the feed from the switchgear for the rear wiper, as I don't have one on mine. I'm not sure how it works though?

[tom_m 0]

the power ON from the HU to the amp is just a constant low switching current. you would need to work out what the amp could handle you putting into it, or sort out a circuit that could deliver just the switching current to your amp or you'd risk damaging it i think.

 

you'd need a volume controlled output on your chosen player not line out, otherwise your music would always be the same volume.

 

just get yourself a louder exhaust and you'll not need a stereo

 

of course the ipod universal dock has a line out and its own volume control separate from the ipod and a remote control too!

 

doesn't look secure enough to use in a car tho, IMO

Edited February 14, 2006 by tom_m

[TEKNOPUG 3]

you'd need a volume controlled output on your chosen player not line out, otherwise your music would always be the same volume.

 

Would a line driver have it's own volume control? Or can I run a pre-amped headphone out through a line driver? It must be possible somehow?!

 

 

doesn't look secure enough to use in a car tho, IMO

 

 

Can't be any less secure than having a head unit on display???!!!! At least I can stick an MP3 player in my pocket and there would be no signs that I had any tunes in my car at all.

 

Guess I really need to speak to an auto-electrican or ICE expert.

[Guest Lil Black Pug]

A line driver will make the signal stronger so you wont have to crank up the gains and distort/stress the signal.

 

You would need some form of controll on the line out ie bass controller maybe get a fader?

 

As for switching the amp on, I just thought it was a small electric signal, you could probably use the wiper feed, id be thinking that its probably the only feed to the wiper and might be a bit OTT? Rip out the under side of the dash and test the wires from the ignition and it shouldnt take long to find the one you need.

 

As for security? Well you could always sing and then think of the weight you will save!

[TEKNOPUG 3]

A line driver will make the signal stronger so you wont have to crank up the gains and distort/stress the signal.

 

You would need some form of controll on the line out ie bass controller maybe get a fader?

 

As for switching the amp on, I just thought it was a small electric signal, you could probably use the wiper feed, id be thinking that its probably the only feed to the wiper and might be a bit OTT? Rip out the under side of the dash and test the wires from the ignition and it shouldnt take long to find the one you need.

 

As for security? Well you could always sing and then think of the weight you will save!

 

 

I could probably get some EQ on the actual amp, I would imagine.

 

So I need to find some way of controlling the volume through the lineout and sort out the switching feed. I would have thought that the wipers would have their own power supply and the signal from the switchgear is merely On/Off?

[Guest Lil Black Pug]

Wouldnt know mate, ive only been working on pugs since christams, frankly nothing would suprise me.

[d-9 0]

Right, this is really simple.

 

The amp needs:

+12V from the battery (big red wire in an amp wiring kit)

Ground to the body (big black wire in an amp wiring kit)

Signal in from the source (twin RCA plugs normally)

Remote turn-on

 

The Remote turn-on is a toggled 12v from the headunit in a normal setup. Put 12v onto that pin on the amp and the amp turns on, remove the 12v and the amp turns off. As this is a low currant feed you can use thinish wires and pull the feed off somewhere in the dash, my fave would be one of the power feeds to the radio as your not using them anymore, or from the fag lighter wiring. Run this through a switch onto the remote pin on the amp, flick the switch and it will turn on.

 

As discussed above you will need a volume control, if you take a line out of your ipod and put it onto the line in of the amp you will possibly blow your eardrums and almost certainly blow your speakers. I still think the easiest way to do this is with a volume controlled output on the ipod, if the sound quality sucks then worry about adding a fader. Dont think the remote bass knob from the amp would work, as *I think* theyre usually either a gain control or a bass control, not a volume control.

[Guest Lil Black Pug]

Agreed mate only thing I would say is that a signal amplified twice is gonna sound crap?! You wouldnt take the output from one amp and plug it into another one unless you drive a nova of course eh?

 

Wise of the bass controller i didnt mean PG bass cubes but thinking about it you are probably right the gain. Might have to be a fader then?

[TEKNOPUG 3]

Right, this is really simple.

 

The amp needs:

+12V from the battery (big red wire in an amp wiring kit)

Ground to the body (big black wire in an amp wiring kit)

Signal in from the source (twin RCA plugs normally)

Remote turn-on

 

The Remote turn-on is a toggled 12v from the headunit in a normal setup. Put 12v onto that pin on the amp and the amp turns on, remove the 12v and the amp turns off. As this is a low currant feed you can use thinish wires and pull the feed off somewhere in the dash, my fave would be one of the power feeds to the radio as your not using them anymore, or from the fag lighter wiring. Run this through a switch onto the remote pin on the amp, flick the switch and it will turn on.

 

As discussed above you will need a volume control, if you take a line out of your ipod and put it onto the line in of the amp you will possibly blow your eardrums and almost certainly blow your speakers. I still think the easiest way to do this is with a volume controlled output on the ipod, if the sound quality sucks then worry about adding a fader. Dont think the remote bass knob from the amp would work, as *I think* theyre usually either a gain control or a bass control, not a volume control.

 

That's all makes sense and seems pretty sensible. I deally then, I need to find a source unit with a volume controllerble line out - if such a thing exists? I was looking at a Sony HD5, they have a seperate line out form what I can see. If not, could I run it through a small 6 channel EQ/Fader, with it's own volume control?

 

Would I still benefit from a line driver? I've seen a Phoenix Gold one for £7!

 

 

Agreed mate only thing I would say is that a signal amplified twice is gonna sound crap?! You wouldnt take the output from one amp and plug it into another one unless you drive a nova of course eh?

 

 

Surely you can get amps with RCA outs as well as in's, so that you can daisy-chain them?

[d-9 0]

With headphone outputs its usually ok. I just plugged the headphone out of my sony ipod thing into a line-in on my power amp as a test and it was near indistinguishable from the same track from my cd player via the preamp. A little more bassy from the ipod thou due to the EQ settings on there.

 

Like I said, try it the simple way and if it sounds crap then get a fader or some such.

 

 

(HK power amp, marantz pre, arcam alpha7 cd player, spendor bc1s, sony hd3)

 

Surely you can get amps with RCA outs as well as in's, so that you can daisy-chain them?

 

they wont be amplified, just pass throughs.

 

That's all makes sense and seems pretty sensible. I deally then, I need to find a source unit with a volume controllerble line out - if such a thing exists?

 

Some HI-FI cd players, my old Marantz CD63 did. Havent seen any portable devices with a volume controlled line out thou, probably because headphone output is so close to line out anyway (usual way to connect a portable device to a hifi if it doesnt have a line out is just to turn the headphones vol all the way up)

[TEKNOPUG 3]

Vibe sell one of these:

 

"BC10 Level controller

Suitable for all amplifiers, our in dash level controller is designed for simple universal fitment between head unit and amplifier and enables amplifier control from the dash mounted lever. "

 

Could that be used to control the volume from a line out?

[Guest Lil Black Pug]

Thats the sort of thing I was thinking of but as D9 said its probably gonna control the gain

[tom_m 0]

What i meant by secure is it don't look secure enough to use while the car is in motion, i think the ipod would come out of the dock.

 

Look here and look at the universal dock and remote. The dock takes soundout of the ipods line level out and is volume controlled.

[TEKNOPUG 3]

What i meant by secure is it don't look secure enough to use while the car is in motion, i think the ipod would come out of the dock.

 

Look here and look at the universal dock and remote. The dock takes soundout of the ipods line level out and is volume controlled.

 

 

What ipod dock??? What are you chatting about Tom??!!!!

 

 

I'm just gonna stick the source plaeyr in the bin by the gearstick. I'll probably use a remote control if it's tricky to use manually.

 

(I won't be getting an iPod - they're unreliable, overpriced, fashion-tat)

[jim205GTI 3]

Slightly of topic but when my mate's car got broken into ( well had the rear screen removed ) he was talking with his dad about moving his head unit to another place in the car so all you see in its place was like a bin or blanking plate....... just wish i could remember where too though but it sounded like a good idea and would have worked as all that is being done is extending the cables

[tom_m 0]

tbh this sounds like an over complicated solution, why not try mounting you HU in the space under the ECU, thats a much less conspicuous place for it, you might even to be able to fasion a cover for the cubby to make it look like a fuse panel or sonething (if you have paintguy's skills anyway )

[d-9 0]

I dont see that it really is overcomplicated at all, you only need a amp wiring kit, amp, ipod (or similar) and mini-jack to phono lead, a lot of which most poeple have already.

 

Round our way they will break into your car to see if thers anything worth nicking, so hiding the headunit isnt really much use, plus it would be a pain not being able to see the display. Hence my amp is going under the carpet under one of the seats, my ipod will go in a phone holder up on the dash somewhere.

[Edd-XS 0]

Im pretty sure you can get phono volume supressors, which is basically a small block with a variable resistor in and two pairs of phono female leads coming out the back. You can then use the line out of anything you want and turn the nob on the front down and use it as a basic volume control. As it doesnt boost the signal at all, it only cuts it completely or at max, lets it through without resistance (which would give you your full line out volume). They are designed for audio and this is what i would do! Cant think where ive seen one, it might of been at work (halfords) of all places!

Thinking of moving my HU aswell as when ive got my harnesses on i dont think ill be able to reach it

Hope this helps?

Edd

[Maerten 0]

Thats just a regular volume knob, its used in almost the same way in amplifiers. Look for volume knobs for DIY amplifiers, they will be of audiograde quality.

 

My (non DIY) amp has an Alps "Blue velvet" You wont need this one because its motorised, but im sure Alps have lots of other models as well.

 

good luck