New Amplifier time approaches

Technical Area Electrics & ICE
1
  1. My model of MX-5 is: PRHT 2008 NC1 with Bose

Current setup:
-Pioneer da250dab headunit
-Connects2 harness adapters
-Using Pioneer PreOut and not the resister pack to connect.
-Focal isu200 door speakers
-Standard rears
-Unplugged front

I am convinced a lot more musicality can be released by the Focals if I could feed them a few more horsepower. So in the spirit of nothing ventured, nothing gained, I plan to replace the Bose amp with an aftermarket unit.

I have seen various posts on this on miata forums, but just thought I would reach out here to see if anyone has been there and done that on European cars, and has any advice to offer.

1st question is where is the amp? On the Miata forum it is advised as being behind the passenger seat (remember PHRT is different to rag top). Does anyone know if this stays on the right hand side on a RH drive car, or if it swaps side?

Next - I am assuming the only cables I will need to cut/ splice are speaker out, line feed in, power and the blue switch on cable. There are going to be other cables, such as the connector to the roof opener, can all these just be taped up?

For amp selection, I was planning to take the bose out and measure it, then buy something that will easily fit - but again, anyone been there and done that? Any recommendations? Presuming a classD amp for heat control in small physical size.

Do amps come with suitable Jack’s that I can use to slice to, or do I need to think about that aswell.

Hoping for a budget of around £100 to £130 sort of money for this, including any Jack’s etc. Is reasonable? Can stretch if needed, but aware this is a fourteen year old car.

Thanks for any comments/help. I will try to document as I go and post a new thread as a “how to” if/when I do this.

2

I have answered many of my own questions, by just jumping in.

Getting the amp out is easy, five minute job.

Thinking about a £100 Pioneer GM-D1004 amp, there is a similar Focal one, but twice the money, and there are Sony and Alpine options between the two… but cannot find any reviews that compare sound quality… most seem to be written by someone comparing spec sheets ; ie a waste of time reading.

That said… does anyone know what the specs on the Bose unit were? Anyone got a Mazda brochure from 2008? If they claim 100w per channel I may well just waste money buying a Pioneer that claims the same.

Anyone any thoughts?

3

So I have found a 2008 brochure, would upload it if I could.

Anyhow, Bose upgrade is a “200 watt seven speaker…” system.

4

Hi mate, I’ve just installed a JL Audio JD400/4 into my 25th AE. I have 2 channels powering the standard door speakers (will upgrade later with JL Audio C3-650 components), and have bridged the other 2 channels to power a JL Audio 6W3v3, which is installed in a ported box in the passenger footwell. It’s only a 6.5 inch sub, but it plays down to about 25hz and doesn’t make the car rattle. I wanted it for quality rather than outright volume, and it sounds (IMHO) absolutely brilliant.
Amp is in the glovebox, wiring was tricky, but installed in about 2 hours. Spliced speaker wires for the fronts, and bought an Alpine INE-920w pre-out harness to provide clean rca signals for both fronts and stereo sub output. Retained factory AVN2 head unit, which was already flashed to standard Alpine GUI.
Well chuffed and highly recommended.
Amp was on offer for £230, harness and wiring kit was £50, Sub was £200 and box was built by me for about £30 in materials.
Think the standard speakers will blow eventually, but they sound okay with the amp crossover removing frequencies below 70hz.
Good luck with Bosectomy, I’ve read the Focal speakers are really great when amplified properly :ok_hand:t2:

5

Oohhh that is all a bit pricey for my blood, but respect to you. Really surprised you are still on the standard speakers though.

I am heavily leaning towards:
Pioneer GM-D1004, bridged to two channel driving the door Focal set. Connected to the PreOuts on the head unit.
Running the Rears directly from the head unit it.

Wiring should be relatively easy as the amp comes with connectors, so should be able to splice onto the existing loom, and there is space to have extra length to make the go easy. Also hopeful that Pioneer connectors should be readily available aftermarket if I want to try things.

Still trying to make up my mind whether I should bother running the rears. And if I do run them, should I upgrade the speakers? Hence the thought of maximising the potential of the fronts by bridging the amp, fitting and forgetting, then I can run the rears from the HU and worry about their quality later.

The Pioneer Amp, dinky though it is, is still about a centimetre taller than the Bose, so I need to double check there is enough room. (Edit correction - the Pioneer is actually shallower than the Bose, wrong info published somewhere).

6

Bosectomy complete.

I went with the pioneer amp GM-D1004 at £99 including the wiring. Set it up bridged to provide two channels with 90watt rms available per channel. Connected it to the head unit speaker level out, and running the rear speakers off the headunit.

It has achieved what I want - removes the muddy sound and gives greater clarity and openness.

Also really loud… with the bose amp, the headunit would sit at between 35 and 40 (40 is max) while on the open road. Now it is louder than before with the gauge showing volume of 20 or 21.

No sub woofer depths though, sounds deep and rich, but not the same base extension as a dedicated sub would bring. But I can live with that… for now…