SQLGuy

I went ahead and ordered the Sony XM-4S to try the under-the-passenger-seat install... will post pictures (if successful) and an update on how this approach works out.

I also bought a used Infinity BassLink sub, which is internally powered and much smaller in footprint than the sub that's in my car now (picutre of current sub below)... this should be a nice reallocation of cargo space.

Cheers,
Paul

Alan

Amps are certainly challenging to fit... I have no under dash trays, I have a full spare & compressor set up, under the seats is very challenging - impossible with dual 12 way memory seats.

I like to have the hatch area be functional for luggage... My car came with one custom seat back amp mount and I later made another to match...

So now I have 2 x 4 channel amps mounted on each of the rear seat backs... in custom built frames & in final guise they are covered in speaker cloth - airflow is good amps run cool - and if it works in Phoenix it will work anywhere. 2 x 4 x 40W capable - Although I have it configured as 6 x 40 + 1 x 80 with electronic & some passive cross overs. Doesn't compromise luggage area or access much and its pretty stealthy looking.

Alan

Darklands

A very good small amp is the eton 75.4 . The amp fits in the original location and has great reviews here in Germany.
300 € and I think I will order one for my 86.5.
This amp isn´t a class d circuit and the sound is superb say german car hifi publications.

http://www.etongmbh.de/en/products/c...754/1/pid/110/

SQLGuy

Wow. That is a nice amp for 928's. Eton makes some very good drivers as well... I wasn't aware that they made amps.

If the Sony doesn't work out, I'll probably be looking for one of those.

Thanks,
Paul

JoeTaylor

Hi Karsten,

I dont think there are any Class A or AB amplifiers anymore, except maybe some high end home audio equipment. Heat and power comsumption are big issues with both types.

Switching amplifiers are here for good, they are compact, use less power and are well made.

Joe

Don Carter

Here's a shot of my in-spare setup. 4 channel amp, 2 bridged to drive the sub, the other two driving front and rear speakers (no fader capability), nothing driven off the head unit.

S4ordie

Alan - That is a very nice stealth set up you have there. I like it a lot.

SQLGuy

For class A, where idle current is properly 1/2 of full current capacity, this is true (efficiency about 20%). However, to be considered class AB, there only needs to be a tiny bit of idle current, so their efficiency is typically more like 70%. Better class AB amps, and especially, better MOSFET class AB amps, have higher bias... but class AB car amps are normally going to be biased just barely over class B.

Both class AB and class D car amplifiers, unless they're really low power, are still going to need a switching power supply to step up the 12V to something like +/- 35V or more. The losses and heat dissipation in these power supplies are the same. So, the main difference between class AB and class D for a car amp is going to be about 20% extra efficiency in the class D output section. There are still a lot of class AB car amps being made. In fact, it's only for the dedicated sub amps where you currently see more class D than class AB.

On the other hand, in a couple of years, I expect that pretty much everything is typical consumer audio will be class D of some sort. The switching amps are getting to be pretty good and engineers are getting a lot more comfortable with these designs.

JoeTaylor

Smiles SQLGuy,

Yeah, they gave that Carver guy a lot of crap when he came out with his first switching home amplifier. One EE I was in school with call it "motor beater" amplifier and only a pure class A amp would be correct.

Those were the days...

Haha, I am too old now to hear the difference... no more "RCA Dog" ears, now!

Smiles,
Joe

Mike B

As do I...Thanks for the pics Alan...gets me to thinking.

SQLGuy

Here's a quick and dirty pick of the quick and dirty installation of the Basslink II. This is supposedly an upgrade from the original Basslink... but the original has the advantage, as far as I'm concerned, of being 2.5" narrower and about 2" thinner.

Regardless, this is a big improvement, space-wise, from the Pioneer setup (above).

I plan to add a single Molex or some such connector so I can easily disconnect it and remove it when needed.

Cheers,
Paul

jmrjames

You have much more air space in your setup than I will in mine.

SQLGuy

I got the Sony amp in yesterday and installed it today.

It comes with a kind of ugly (IMO) and unneccessary chromed "decorative" cover over it, which has to be removed in order to access mounting holes and such. I liked the look so much better without it that I just left it off.

Initially I had planned to mount it under the passenger seat from some steel brackets I was going to fab, but, out of curiousity, I first checked to see whether it would fit where the original Blaupunkt used to be. To my pleasant surprise, with the original brackets removed, the XM-4S fit just perfectly.

Along the way, I encountered evidence that the guy that installed the JL either was working on an ingenious scheme to fill the car with sound by randomly mixing phases of speakers, or he just didn't understand that you're supposed to match phase between right and left, front and back, etc. In any case, I put all the speakers back in phase. I also drilled a bunch of holes (from the back) through the side cover to allow for air flow for the amp. The holes are unnoticable with the black cover over the black amp, but hopefully will allow enough cooling (the amp has a small fan that comes on as needed, and I made a lot of holes over it).

Anyway, here are some pictures to show the before and after, etc. Sound, so far, seems fine, and correcting the phasing helped things. (Actually, the JL Audio originally had a carpet covered MDF board behind it, so it took up even more of the footwell room than this... a nicely built amp, though.)

Cheers,
Paul

jmrjames

Most Excellent Paul !!!!

I just wish there was a 6 channel Amp that would fit there.

Marine Blue

So how many of you with stereo mods are going to SITM?

Would love to listen to some of these systems!