GR86 Puzu Amp, harness tap, full range rear signal.

[Road_trip]

I've been planning on doing this for a while, adding an amp and using a full range signal for the rear speakers.
It's not worth doing if you're still using the standard fit rears, there's a reason why the bass was cut to them, they won't handle it.
I have previously upgraded the rear to Pioneer 4" 2-way, as detailed in this thread:

GR86 - Rear Speakers

I've previously fitted the Focal kit to the front and was very happy with the improvement over standard, but that was always going to be a first step upgrade. An amplifier, rear speakers and / or a sub was the longer term plan. With this car an unobtrusive build that could be put back to...

www.gr-zoo.com

I had originally wanted to do it with a Pioneer or Kenwood 4 channel amp. As I discovered more about the factory system, it became apparent that the DSP in the Puzu would be better to help overcome the awful factory sound equalisation in the radio, that was tuned to suit the original cr@p speakers.
I've just acquired a Puzu Amp from a forum member, so modified the harness before fitting it to my car.

What this does, it splits the front speaker outputs (left and right) from the radio and sends them to the Front and Rear inputs of the Puzu.
You loose the Front/Rear fader control on the headunit, but all the levels can be controlled and adjusted in the Puzu. The User Presets can have different levels Front to Rear if you want to vary it that way.

First, strip back the harness wrap from the radio end of the harness. I cut the adhesive wrap to stop it getting stuck to everything while working.

Remove the white and grey wire terminals from the 10 pin socket. A micro screwdriver pushed in from the front will release the retainer.


Cut the green and purple wires in the 6 pin plug. I cut at 3.5" and 4" to stagger the cut.

 

[Road_trip]

Insulate 2 wires, one of each colour with heat shrink.

Then heat shrink 4 wires together to tidy up the loose ends. The staggered cut avoids the need to insulate all 4 individually.
I left these wires in the loom just in case I ever want to connect them up at anytime.

Cut back the insulation from the 4 ends in the harness. I cut back 8mm, be careful the wire strands are very fine.

Cut a section of insulation from the white and grey wires, corresponding with the lengths of the green and purple.

Twist the wires together.
White + Green
White/blk + Green/blk
Grey + Purple
Grey/blk + Purple/blk

 

[Road_trip]

Solder the 4 twisted joints.

Heat shrink insulate the 4 soldered joints individually.

Push the 4 terminals (white and grey wires) back into the plug, in the correct positions.
Re-wrap the harness. I also used zip ties on the ends of the wrap for security.

Plug it in, full range sound to both front and rear speakers.

Now start adjusting everything on the laptop for the Puzu set up. Seems easy to do.

 

[callahan]

Very impressive! Glad you're getting so much out of the Puzu, they're great little amps.

 

[Road_trip]

Thanks, I'm very happy with it even on the first try set up. Will tune it a bit, then look at time delays.
I'm a convert to the Puzu, the tuning and the extra power in one box are great.
Thanks again

 

[qajteq]

Hey @Road_trip
Thanks for sharing, nice catch.
I plan to do the rears as well, just different speakers, and was wondering, if it's still doable to bypass the high filter on stock headunit/radio once rears are replaced? What do you think? Is it doable? Any disadvantages you are aware of?

 

[Road_trip]

Hi, as far as I know, it is not possible to bypass the filter and sound EQ settings inside the headunit.

The only way to get a full signal to the Rear was to split the Front speaker output and amplify it, all done outside of the headunit.

The downside is losing the Front/Rear fader control within the headunit.
Vocal Image Control can be used to reduce the vocal levels, or shift it Left to Right, but not move it Front to Rear.
When splitting the signal, an amplifier with 'gain adjustment' (level controls) is essential to allow independent setting of the Font and Rear volume.

The DSP in the Puzu Amp allows for a very flexible set up of levels and equalisation to all 4 channels. (or upto 6 channels if you use the full capacity of the Puzu for a Sub and Centre speaker)

Be careful with your choice of Rear speakers. The Pioneers I used are very close to the body pillar flange when fitted. The depth and diameter combination of the magnet is close to the limit of what will fit.

 

[Road_trip]

Just to round this off, the supplied Puzu harness (Number 7) has wires coloured to the ISO standard.
They don't correspond to the Subaru or Toyota colours, but these pictures show what goes where in the plugs.

 

[Gibbo78]

Thanks for the wiring info Road_Trip, helped when I needed to make the mod to the wiring loom.

 

[Gibbo78]

If anyone is using an iPhone or Mac (with M1 or later chip), there is an app for the PZ-C7. Checked it on the iPhone and it works. Not sure when it appeared as the instruction I had when the amp arrived last year was only PC Laptop and Android phone app.