JVC to Sony?

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Simpo Two

Original Poster:

87,089 posts

272 months

Monday 12th October 2020
quotequote all
Afternoon all.

This is actually for a boat, but it's a car stereo so hopefully someone will know the answer.

My boat was fitted from new with a JVC KD-R331 CD/radio, and hence has a bunch of wires sticking out of a bulkhead that end in a JVC-shaped plug. 8 are for speakers, plus black and red (power I deduce) and yellow. Don't know at the yellow one is - earth?

Anyway, I hate the JVC unit, and want to replace it with a Sony MDX-C5970R because that's what I happen to have going spare and I like it. Naturally it has a Sony-shaped socket at the back. I have an adaptor cable for it which ends in two ISO plugs.

Can I get a JVC line socket to Sony plug, or do I need to go via ISO, in which case I'd need JVC line socket to ISO plugs?

Help required please smile

oilslick

937 posts

193 months

Monday 12th October 2020
quotequote all
I know nothing about how they wire radios on boats, but if you trace the cabling back a bit from your JVC shaped connector, is there an ISO connector block with a JVC adapter plugged into it? I have no clue if boat builders will use an ISO connecter as standard plus an adapter for whatever radio gets fitted.

If there is, it'll make fitting your new one somewhat simpler!

Simpo Two

Original Poster:

87,089 posts

272 months

Monday 12th October 2020
quotequote all
Thanks. At present there's about two feet of mixed wiring emerging from a hole in the wall between saloon and cockpit. It looks like they chopped the ISO sockets off the cable that came with the JVC unit and wired it directly into the boat's electrics with bullet connectors.

I have Sony to ISO male adapter, and I can find JVC to ISO male... is there an ISO female-female adapter to join them that way?

If necessary I can join bare wires with a soldering iron. Speakers are easy to work out but the others I'm not sure of. I could take the Sony cable and chop the ISO sockets off, like they did, but the Sony has extra wires which presents options for mistakes.

Edited by Simpo Two on Monday 12th October 17:49

oilslick

937 posts

193 months

Monday 12th October 2020
quotequote all
I'm not aware of their existence, but you could make one with two female ISO harnesses.

However, it's a rather messy solution. If it were me I'd be looking for a wiring diagram for the JVC connector then chopping it out (probably at the bullet connectors that are already there) and wiring in a proper ISO block. Then if at any point in the future you want to change radios, it's a much simpler job, just plug and play with a new adapter for whichever manufacturer you've bought.

Wouldn't have thought it'd be more than an hours labour for an auto/boat electrician (I'm assuming that boat electricians exist biggrin)

Simpo Two

Original Poster:

87,089 posts

272 months

Monday 12th October 2020
quotequote all
oilslick said:
I'm not aware of their existence, but you could make one with two female ISO harnesses.
That's a good idea!

oilslick said:
However, it's a rather messy solution. If it were me I'd be looking for a wiring diagram for the JVC connector then chopping it out (probably at the bullet connectors that are already there) and wiring in a proper ISO block. Then if at any point in the future you want to change radios, it's a much simpler job, just plug and play with a new adapter for whichever manufacturer you've bought.
I was reaching the same conclusion - found these: https://www.amazon.co.uk/dp/B07DK5WMFD and also https://www.ebay.co.uk/itm/Car-Stereo-Radio-headun... - not sure which is easiest.

Luckily I still have the installation guide for the Sony. Any idea what the yellow wire on the JVC is?

It's not really a boat issue, just a car stereo issue. I can do it, I just need to close the knowledge gap...

defblade

7,624 posts

220 months

Monday 12th October 2020
quotequote all
The red wire and yellow wire are both +12v, the black one is the earth.
Either the red or the yellow will be permanently live with +12v, the other will be switched live by the ignition/starter/"on" button/whatever boats have.
But there's no telling which way around without a multimeter, or wiring up the new stereo and seeing it it loses all it's radio pre-sets etc every time you turn the boat off.

It's really pretty much that easy; I'd be tempted to make up the Sony harness with bullet connectors that match what you've already got... it'll be easy to swap the red and yellow if you need to!

I'd guess the other wires coming out of the Sony harness will be a mix of orange (for the illumination dimmer control), blue (remote on for amps), possibly white or blue/white (+12v for power antenna/aerials)... you can easily ignore those, just make sure you tape up the ends.

Simpo Two

Original Poster:

87,089 posts

272 months

Tuesday 13th October 2020
quotequote all
Very helpful, thanks. I can work out which lead is which from the JVC plug, and the Sony installation instructions tell me which lead is which for the Sony (and says Red is the switched 12V).

There are three extra leads in the Sony plug over the JVC which I don't think have anywhere to go. Light blue marked 'ATT', blue/white which is connected via bullet to 'power aerial control', and an orange/white one not mentioned in the instructions, perhaps the illumination dimmer you mentioned. Hopefully it will work without those.

I'd like the Sony to be easily removable so will probably get the bare-ended ISO set, wire that into the boat, then it should be easy from there. Does that make sense?

Edited by Simpo Two on Tuesday 13th October 10:39

jakesmith

9,463 posts

178 months

Tuesday 13th October 2020
quotequote all
Buy a cheap multimeter for £10 to be sure which power feeds are the perminant / switched lives & the ground.
I would just chop the harness for you new radio off at the end & crimp new bullit connectors on for the boat, 15 mins work
Work out which speakers are which through trial & error cant take long

Simpo Two

Original Poster:

87,089 posts

272 months

Tuesday 13th October 2020
quotequote all
jakesmith said:
Buy a cheap multimeter...
Yep, got one smile

By perusing both the JVC and Sony instructions I've got every lead worked out, and by 'reverse thinking' I can identify the wires in the boat. I considered buying a crimper and bullet connectors but in the end decided to solder in an ISO system. Then if I sell the boat it's easy to retrieve the unit.

I was almost there on my own but PH filled in the missing bits smile

jakesmith

9,463 posts

178 months

Tuesday 13th October 2020
quotequote all
Simpo Two said:
jakesmith said:
Buy a cheap multimeter...
Yep, got one smile

By perusing both the JVC and Sony instructions I've got every lead worked out, and by 'reverse thinking' I can identify the wires in the boat. I considered buying a crimper and bullet connectors but in the end decided to solder in an ISO system. Then if I sell the boat it's easy to retrieve the unit.

I was almost there on my own but PH filled in the missing bits smile
I've just started soldering & heat-wrapping wires rather than crimping. It's incredibly satisfying for some reason & looks much more pro.

defblade

7,624 posts

220 months

Tuesday 13th October 2020
quotequote all
Simpo Two said:
Does that make sense?
Yep biggrin