Impatience got the better of me and I've ordered one of these:

http://www.fnac.pt/mp3002190/Huawei-MediaPad-T1-7-0-8GB-3G-Prateado

Only 1gB ram but it does everything.

My only doubt now is cutting the cubby hole to fit it .....

I have a Samsung S5 Galaxy which I use for satnav ...... attached by a sucker holder on the windscreen. Nice big clear high res screen and voice commands. I can't speak too highly of it. I also use it for Amazon prime music ........ but not for music in the car at the moment until I sort my head unit out.
I run google maps for normal road driving and the UK ordinance survey maps for any exploring, either on foot or driving. I previously used TomTom then more recently Miomaps. but Google is better. More informative and up todate.
Ordinance survey maps use the memory map program to run them on a pc, but if anybody has the maps and wants to run them on their Android there is another prog to run them (wink wink, can't do smileys). pm me.
```

Riddlemethis mentioned Here maps from Nokia. I've got it on my phone as it's a Nokia Windows phone but it's now been released for Android too (see http://www.androidcentral.com/here-maps-android-drives-google-play-free). The main advantage over Google Maps is that you can download maps to your device and the only thing it needs data for is the real time traffic. So if you don't have a data connection it'll still work and it doesn't cost you a fortune in roaming charges when out of the country. I've got most of Europe downloaded to my phone but when I did some contract work for Formula One Management, I downloaded the extra countries and used it very successfully in India, Canada, Korea and Malaysia. From what I've seen of Google Maps on Dina's Android phone, it is far better in many ways.

Brilliant, thanks, downloading now.

Orangebean wrote:

What sort of line level booster are you using for your sub Marty? Mine is fed at line level from my Sony head unit and seems a bit gutless. <br>
I'm thinking one of these http://www.ebay.co.uk/itm/Autoleads-Car-RCA-Phono-level-line-level-signal-booster-1v-upto-4v-PC9-460-/381245838120 <br>
Always happy to find a cheaper solution, as long as I can have it delivered yesterday :-)

Yes, that is the one i'm using for my sub - it works OK (i opened it up and soldered wires directly to the board instead of using RCA connections). The only problem I have from my android unit now is the low pop when it turns off - but I think that is more coming from the head unit than the fact it's got a booster in it - the booster now just boosts everything!

Definitely gets the sub level back to being on par with the door speakers - before it was working, but just comparatively very low, so you couldn't tell it was doing anything until you turned it up really loud

Thanks Marty, I'll give one of those a try. <br>
After a day of messing around under the dash yesterday, removing and binning little filter boxes, pre-amps, mystery electronic components and repairing various bodges to the loom, I can confirm that the Ray Ambler attenuators were the solution to my ever-present low level buzz. <br>
I now have a fully functioning, hum free and satisfyingly ballsy sound system, just gutless in the sub department. <br>
Back to the Android tablet in the dash now...

I have the same low output sub problem.

My first P38 is the only one (I'm on number 4) where the sub worked properly and was good enough for me.

Marty .... did you test for low line level to the sub amp from the DSP amp?

I got a mono pre-amp from Maplin (one of the kits), and it had the same pop problem. In my case, it was definitely the amp causing the issue - it would do it with no source connected. Gave up on that idea and went with the aftermarket amp/sub route after ruining my dual driver factory sub with the vacuum cleaner :)

Right, tablet has arrived and is really nice, good screen and solid.

Whilst I fret about how to cut up the dash part carefully (it is not a sat nav one), what do I do if the battery goes flat and I can't access the on off button?

Is there an app or utility which always boots the system up when power is connected?

Go to the settings - display and see if there is a tap to wake option.This will allow you to double tap the screen to wake it up.
There are other apps out there like wave unlock but not sure if that will work after a flat battery.

There are also bluetooth buttons you can buy. They are stick on buttons that you could place on the dash say, They can be programmed to do different controls via bluetooth. So you might be able to set it as an on button when it connects to the tablets bluetooth.

Also look up NFC tags, they are similar to the bluetooth providing your tablet has NFC of course.

SpiggyTopes wrote:

I have the same low output sub problem.

My first P38 is the only one (I'm on number 4) where the sub worked properly and was good enough for me.

Marty .... did you test for low line level to the sub amp from the DSP amp?

I haven't tested the amp level coming from the DSP amp as I haven't ever had a RR with a working DSP amp!
I just remember reading that the RR system uses a fairly high line level signal, whereas most standard RCA pre-outs are a max of about 2V.. I seem to recall reading that the P38 system uses 4V, hence why the booster helps.

The only other BIG difference between the P38 system and most aftermarket systems is that the RCA Pre-outs are all unbalanced audio signals, whereas the P38 sound system uses a balanced audio signal, which means that it is a lot less susceptible to noise and interference as it effectively cancels itself out. Most aftermarket systems are all unbalanced as it's cheaper and easier to produce - which is where the ground is tied to the radio/chassis ground and then there is a single audio signal wire.

I believe this is also the reason that the level is lower as the peak-peak values of the balanced system will be bigger than the peak-ground value of an unbalanced system.

I think replacing the sub amp with an aftermarket one (and even keeping the P38 sub enclosure) would probably work better as the line level input would be unbalanced, low level and it would amplify from there - that would probably sort out the popping and the need for a booster if you have an aftermarket head unit. It's something I'm going to look at trying at some point when I get time again (probably after sorting out my engine problems!!)

I think that's the basics of the system - there is a whole science and theory around audio signals that I learnt a long time ago!! but a google search will probably bring up a tonne of other info about balanced vs unbalanced signals...

Marty

Marty,

I read through you posts on the other forum about pulling the eBay special Android unit apart to make it fit and wanted to do the same in mine.

You mentioned that your car was missing the DSP amp though.

My car is a 2001/51-plate Vogue and has the factory fitted sat nav and Harman Kardon audio.

Would it be pretty simple to hook this all up would it take a lot of wiring work?

It would be possible, yes.

It seems a bit backwards, but I would probably remove the DSP amp and retrofit individual door amps in the loadspace (as per my DSP amp removal/replacement thread) and then use attenuator circuits to come from the amplified output of the Android unit to drive the speakers.

It might seem a bit backwards to ditch the DSP amp - but a) if it's working, then you can sell it for a decent price and it would probably cover the cost of the Android unit, and swapping to individual amps etc. and b) the DSP system only takes a Left/Right feed which the amp then splits to each door - which if you do away with the factory head unit, then you lose that control.

The other way would be to output from the android unit and input that to the factory head unit - but that's a bit of a double-up on equipment.

It sounds like a lot of extra work and rewiring to do it, but in reality it took me an afternoon to install my DSP replacement in my other restoration P38 which has a dead DSP amp. The additional wiring for the inputs for Rear Left/Right didn't take long to run up to the dash either, and given how good it sounded - I am looking at swapping my current crossover system I made years ago to fit a DSP replacement unit into my own P38.

If you wanted to go the route of Android unit, plus DSP replacement - then I would be happy to do the install for you, or at least help with the amp/wiring/attenuator side - as I have all the parts to be make attenuators - and should hopefully (within a month or so when they arrive from China) have the required connectors to make DSP replacement cable looms to connect to door amp units.

I guess at the end of the day, it will depend on how integrated you and the system to be (eg an addition to the factory system, or a complete replacement nav/radio system) and I guess how much you want to spend on it.

I am sure that between the cost of the unit and swapping the DSP amp out - if you have a working DSP amp, and factory navigation computer, then you would get reasonable money for them - I would conservatively say that you would probably break even and the overall cost of swapping everything wouldn't be that much.

I'm happy with how my setup is, but think I will retrofit a DSP replacement unit to my vehicle at some point when I have enough connectors spare to make one for my p38, as I am sure it will sound a LOT nicer than the integrated amp chip is in the Android unit - though it isn't a BAD sound - I was just blown away by hearing the HK amps in my restoration P38!

You're right, that does sound like a lot of work!

What's actually involved in your DSP replacement system?

Running it through the standard head unit doesn't appeal all that much - I was planning on taking that out and filling the space with a single DIN CB radio unit for off road trips.

I was hoping for a fairly straight forward plug and play option.

I've been poking around online this afternoon and found this.

If I'm reading it right, my system is in their section 2 and if I set the volume to max using the standard head unit and connect the new one using this adapter it should work.

Can you see any reason this wouldn't work?

The DSP replacement system is basically 4 door amps mounted to a sheet of aluminium which then bolts where the DSP amps sits.

It then gets wired in instead of the DSP amp, and an extra piece of loom is run to the head unit end to provide signal feeds for the Rear Left/Right doors. There is some re-wiring needed, but when I do the kits, (assuming my connectors arrive and are the correct ones) the wiring will all be labelled to join it to the vehicle wiring correctly.

Yes, I think you can use something like the adapter they show - or you could just make a pair of attenuator circuits for a lot less than that to connect to the current feeds.

There isn't any reason to start with that it wouldn't work - I have heard of people having trouble connecting to the DSP amp before with aftermarket solutions - but maybe they didn't turn the volume all the way up first. The only other thing I see is that with the number of people who have DSP amp problems and the fact they fail and are generally unrepairable.

It's your vehicle and your choice at the end of the day. If it were my vehicle and I was going to the extent of replacing the whole front end of the system, I'd swap out the DSP amp to start with to get rid of what is known to be a problem part. That and what they are worth WORKING as second hand is a lot more than what it's worth as a massive paperweight if/when it does fail and you need to find another solution.

Up to you, but yes, I don't see why the H2L adapter and turning it all the way up before disconnecting it won't work. I would make attenuator circuits rather than the adapter though, but that's just me aswell!

+1 on making the attenuators. Enough components from RS to make 4 would only cost around £6 delivered with loads of resistors left over!

I think it sounds like a much bigger job than it is to me as I'm not used to doing electronics work.

It sounds similar to what I tried to do a couple of years ago.My other car is a Focus ST170 with the factory fit sub and amp, the Audiophile system.

I wanted to connect my Parrot kit to the amp but it didn't work in the same way as aftermarket kits. There was a thread on a Focus forum detailing how to make some kind of box of tricks involving stripboard and resistors to connect an aftermarket head unit to the Ford amp. I tried that but never got it working - all I got was a horrible series of pops and bangs form the sub and disconnected it.

For the P38 door amps, are they all the same or were there standard ones and uprated/Harman Kardon ones?

Door amps are all the same. There were 4 different levels of audio system fitted to the P38, low and mid line that only had speakers in the doors fed directly from the head unit, early HK high line with amps in each door and later HK high line with just the DSP amp in the boot. The DSP amps die and cost an arm and both legs, which is why Marty looked into replacing it with four door amps (as this system was fitted to the majority of cars). The kit he's proposing to produce, (when he gets the plugs) will be as plug and play as possible. The only wiring that will need adding will be a feed for the rear speakers from the head unit to the amp in the boot. Wait until he's back in the country and if you ask him nicely he'll probably install it for you.....

Sorry for all the questions - this audio system is all new to me!

My last one had the bog standard system and I did nothing with it, besides connect a 3.5mm jack adapter to the CD changer port.

This one has the little tweeters up by the mirrors, would the door amps power these too or would they just do the drivers in the doors themselves? I'm coming around to this DSP replacement idea but I think it will ultimately be decided the lady of the house and the more info I have the more likely it will be that I can convince her it's worthwhile :P

What kind of price do working DSP amps fetch? I've tried to find one on eBay but all I seem to find is the one from the L322 - are they the same?

There's a number of different DSP amps but they are just that, different. The one fitted to a Disco looks the same as a P38 one but only drives the front door speakers, not the rears or sub, the L322 one is completely different again.

On a standard car audio system, the three (or two on the really basic low line system) speakers in each front door, are paralleled up so whatever is feeding them will feed all of them. On a basic, conventional, system you'd have 4 outputs from a head unit, going to front left, front right, rear left and rear right. Each of these outputs will feed all speakers in the four doors. So there will be a pair of wires from each door that go up to the head unit.

The original high line system had a head unit that delivers a lower level (not high enough to feed the speakers directly) output to the amps in the doors which then feed the speakers. I suspect this was because the high power levels the system runs would have made the head unit too big and run too hot if the output amps had been in the head unit itself. Modern amps are much smaller and run much cooler so modern systems can run 50+Watts without melting the dashboard.

The DSP system only has left and right channels, and a data signal from the head unit which go to the DSP amp in the boot. The data signal deals with splitting the signals between the front and rear speaker and the bass, treble, etc which is all done in the DSP amp. So instead of the cables form the speakers in each door going to the head unit, they all go to the DSP amp.

This means that, unlike the earlier systems, you can't just slap a modern head unit in the dash and expect it to work because they will have 4 (or five if you include a sub) outputs that are expecting to go directly to loudspeakers. Some modern units can have the output switched between speaker level or line level so can be used with the earlier system with external amps. If they can't, then that is when you need the attenuators to drop the speaker level down to something that the amps can handle.