I’ve got an amp for a car audio system to try and make my missus’ MX5 stereo a bit more audible over the wind noise. Wired up with +12V direct from battery, IGN from same feed as stereo ignition +ve and GND direct to chassis using a seat mounting bolt. It works absolutely fine the first time it’s switched on, but if I turn the ignition off and on again it doesn’t work. If I disconnect from the battery and reconnect, it works again but only for the first time the ignition is switched on.

My question is, is it a cheap/easy fix? Not a problem if not, seeing as it only cost me a tenner, but it seems to be a reasonable amp (Vibe Black Box stereo 4, iirc) so I’d like to get it going.

you fitted a vibe to the car for your missus? 😯

if you run a feed direct from a 12v source to the REM terminal does the same symptom occur?

Hehe. What can I say? She seems to have been enjoying driving a lot more recently.

if you run a feed direct from a 12v source to the REM terminal does the same symptom occur?

Erm… No? If I do that, surely the amp will never switch off? I won’t have the problem with the amp not working, but the battery will be flat.
I’ve also thought of running switched power to both +12V and REM, but I really need 8 or 10 gauge cable to power the amp, hence taking direct from battery. It’ll just melt the wires otherwise.

go nuclear. It is the only way.

Failing that a REL Studio ought to do it.

REL Studio

That costs more than the car 😯

I like the idea of a nuclear MX5 though. I’ll get right on it.

just run direct supply for the purposes of testing, if the symptoms persist using a direct 12v supply then you’ve got yourself a faulty amp

if the symptoms disappear then the issue is either some kind of ignition switchery gubbins specific to the car manufacturer or you’ve wired the REM to the wrong connection

Right. Gotcha. It’s definitely amp-related, cos for the sake of a quiet life I got another cheapy amp from Maplins which works just fine when wired up the same way. I was just wondering if from my description of the fault it’s possible to tell if it’s something that I could take to a local electronics place and say “fix me the capacitors in this please” or not.

(I don’t even know what capacitors do)