Hey guys,

Dad and I are going to start work on a Car PC for his Mini Cooper S in a few weeks, and I'll need an amplifier to replace the original Harmon Kardon unit since it only works with the original stereo (which is being removed).

Since it's such a small car, can anyone recommend a good quality amp that is also quite small? It will probably need to be able to fit under the passenger seat.

Cheers

JL Audio slash series (300/4) very small footprint

Alpine PDX - 4.100

DLS RA series

Audio SRx series

All amps are quite small

I would also give a thumbs up to the Alpine PDX stuff, great size and they don't get too hot.

Take a look at digital amps that are on offer from a range of manufactures. Digital amps are far more compact, and give off less heat. You also have versitile mounting solutions.
What kind of amp did you want? Monoblock (http://www.jvc-australia.com/JVC/client/c_products_details.jsp?catID=32&prodID=375)? 2ch (http://www.jvc-australia.com/JVC/client/c_products_details.jsp?catID=32&prodID=373)? 4ch (http://www.jvc-australia.com/JVC/client/c_products_details.jsp?catID=32&prodID=374)? All those are 182mm(D) x 250mm(W) x 62mm(H)

Wow, I am simply stunned at how pricey that compact amps are :O They do look good though.

Did a bit more searching around and came across this:

http://indashpc.org/new/adapters/car2pc-bmw.html

Thinking it might solve the problem in more ways that one. Let me keep the stock H/K amplifier, and use the steering wheel controls to control various car PC functions. Just not quite sure what they mean by "non DSP stereo", need to drop them an email.

Most amps are small, the compact ones are more expensive

If you had problems with size, you could always go the floating floor effect? Looks good as

Wow, I am simply stunned at how pricey that compact amps are :O They do look good though.
They cost more because they're generally a higher quality amp also, you will get much better sound from a digital amp, as there is less conversion processes going on

True dat. I recognise they are better quality but still, damn!!

It's for my dad's car so it will be him making the decision anyway. Spent $680 on a screen today thanks to the appalling exchange rate :rant:

They cost more because they're generally a higher quality amp also, you will get much better sound from a digital amp, as there is less conversion processes going on

Got a bone to pick here :-P

They are not digital amps, they are 'Class D' :P

But yes - Class D amps I personally prefer, they should in theory have a flat response.

wow you guys like going against the grain. D class are generally considered to be 'the worst' sounding amplifiers. Personally i couldnt give a crap if an amp is A, AB, D, F, E, G, H or valve, you can make any sound good.

As for small amps, if you still find yourself needing one, I regard the new little Rockford Fosgate amps quite highly, fantastic little units.

I guess it would also depend on what quality or level of oomph (watts, etc) you want.
I guy at my work just had a complete system (Alpine headunit, focal speakers, sound deadening, etc.). He didn't want to lose any space for an amp or sub so the shop fitted an (Alpine?) amp which attached directly to the rear of the Alpine headunit (behind the dash).

I don't think it was anything hardcore, but enough to give the Focals a bit more grunt.

You can do anything with a customer install. A guy in QLD is running a mini with 2 Audiosystem F2 amps ( huge amps ) and Focal speakers / sub and it doesn't take up much room considering.

I have also seen old Alpine V12 amps mounted into spare wheel areas with mini fans for cooling in hatchbacks.

If your clever you can do anything.

Got a bone to pick here :-P

They are not digital amps, they are 'Class D' :P

But yes - Class D amps I personally prefer, they should in theory have a flat response.

Depends on which amp you are talking about :P The Alpine PDX are definately digital. They have a superb dampening factor.
They are also Class-D. Class D is more efficient than A/B but generally not as sonically pure. Being digital though and with the fairly recent advances in technology, you would be pushed hard to tell the difference between these and the Class A/B Focal amps.

Check out the link below. I was VERY impressed when I was looking at them, but got married instead and bought a house :cry:
http://www.alpine.com.au/technology/pdx.asp

Being digital do they produce less heat?

Whether its being digital or not I would have to do the research, but they definately produce amazingly low levels of heat for their power and size. You can safely mount their 1x1000W amp under your seat.

Edit: See my post below. So digital has nothing to do with the size, but how the amp is controlled. The Class D aspect is responsible for the smaller size.

Depends on which amp you are talking about :P The Alpine PDX are definately digital. They have a superb dampening factor.
They are also Class-D. Class D is more efficient than A/B but generally not as sonically pure. Being digital though and with the fairly recent advances in technology, you would be pushed hard to tell the difference between these and the Class A/B Focal amps.

2nd this comment.

There are Class D amp, and there are Digital Class D amps. The JVC ones i mentioned and the Alpine PDX are both Digital Amps using the Class D Circuit

For those who have no idea what Class D means, read here:

http://en.wikipedia.org/wiki/Switching_amplifier

Still confused, but slightly more knowledgable now lol

Sounds like Class D is the way to go for size and heat reasons, due to better efficiency.

A bit of info which might help: (see wikipedia for more info)

Class A - Analogue Design
100% of the input signal is used. Efficiency is not really a consideration. The output devices (MOSFETs) are always on. Much more linear and less complex than other classes but shockingly inefficient. Generally used for small signal amplifiers (i.e. headphones). The output is an exact but larger replica of the input. The output is conducting all the time, even when there is no input.

Class B - Analogue Design
50% of the input signal is used. Class B amplifiers only amplify half of the input wave cycle. As such they create a large amount of distortion, but their efficiency is greatly improved and is much better than Class A. There are 2 sets of output devices which conduct in a push pull arrangement. The problem is the distortion which is introduced at the change over point. Not very common at all.

Class A/B - Analogue Design
The most common amplifier... An improvement over Class B is made by biasing the devices so they are not completely off when they're not in use.
In Class AB operation, each device operates the same way as in Class B over half the waveform, but also conducts a small amount on the other half. As a result, the region where both devices simultaneously are nearly off (the "dead zone") is reduced. The result is that when the waveforms from the two devices are combined, the crossover is greatly minimised or eliminated altogether. Class AB sacrifices some efficiency over class B in favour of linearity, so will always be less efficient (below 78.5%). It is typically much more efficient than class A.

Class D - Switching Design
Otherwise known as a switching amplifier. Because it is switching (i.e. not 'ON' all the time), it much more efficient than Class A/B which helps eliminate heatsinks (not all the time) and means that the physical size of the amplifier is much smaller.
Class D does NOT mean it is a digital amp, this is totally separate idea.
The analogue input signal from the source (headunit) is converted into a sequence of pulses. The average value of these pulses is directly proportional to the amplitude of the input signal.
The output contains unwanted noise from the pulse frequency (generally 10x or more than the input frequency) and its harmonics. These are removed with a theoretically lossless passive filter of capacitors and inductors.
The Pulses switch MOSFETs on and off. The trick is keeping the dead time (crossover point between the ON or OFF phase) as short as possible to minimise distortion.
Advantages:
* Reduction in size and weight of the amplifier,
* Reduced power waste as heat dissipation and hence smaller (or no) heatsinks,
* Reduction in cost due to smaller heat sink and compact circuitry,
* Very high power conversion efficiency, usually ≥ 90%.

Bang and Olufsen's ICEPower Class D system has been used in the Alpine PDX range. Reviews of this system say that it rivals traditional Class A/B amps in quality.

2nd this comment.

There are Class D amp, and there are Digital Class D amps. The JVC ones i mentioned and the Alpine PDX are both Digital Amps using the Class D Circuit

3rd'd.

Yes some now also use digital switching, like alpine (didnt know about JVC)

As for sound quality - they used to be thought of as low quality and were used mainly for monoblocks - technology is improving every year. Class D is the future :P

For those who have no idea what Class D means, read here:

http://en.wikipedia.org/wiki/Switching_amplifier

Still confused, but slightly more knowledgable now lol

Sounds like Class D is the way to go for size and heat reasons, due to better efficiency.

Pretty much.

More efficient, less heat.

Great for compact installs :cool: