pre out with HPF?

[kalel1975]

Hopefully someone out there knows a lot about In Car Entertainment. I've recently fitted an amplifier to the car and a massive sub etc. The amp. is a Mos Fet js4090p. Intermittantly a green protection l.e.d. comes on and the amp is switched off. This can happen from cold, so it's not as if the amp is over heating! Anyone know why this is? Next question... on my amp i have two low voltage mono leads from my head unit (a left and right channel supply).If I buy a cd/radio with one pre out with HPF, can i attatch both of these mono leads to this head unit output?Does one pre out stand for a pair or just one connection point? What is an RCA pre out? And.. what does HPF stand for? Please excuse my ignorance, new to all this amp and crossover wiring! Cheers people.

[Fish]

OK, let's start from the top. What is the brand and model of both the amp and the head unit? I tried a Google search on 'js4090p' and it drew a blank. A 'Mos Fet' is a type of electronic component, not a brand name. RCA outputs from the head unit are the preferable way to connect to an amp. HPF = High Pass Filter (only allows sounds over a certain frequency, normally either > ~500Hz or >5000Hz). Your problem with the amp cutting out (protection cut-out) could be due to an inadequate earth. Any earth connection to the car should ideally be with a woven cable onto the bare metal of the car's bodywork (WARNING - Don't go drilling into your fuel tank!!!). Alternatively it may be because you are connecting the wrong outputs from the head unit to the amp. Need to know more about what you've got there.

[kalel1975]

The amp.make is a Jet Sound, hence the JS in the js4090p model name. The earth connection is a constant earth although I haven't tested the resistance. I have fitted a switch to the remote wire which should more than cope with the voltage from the head unit. If the switch is turned off for a few seconds and on again, the amp and sub will jump back into life. Had a ride home from work tonight for 35 mins with no problem at all. I think the concern lies within the amp rather than good supplies and earths etc. I was concidering getting a Sony CDX-L410 because it has a good bass equaliser for getting good sound from my 6x9's. Getting back to the earth connection, I've used a Halfords 600 watt Amp kit, and fitted the earth lead as in the kit... but i feel the earth isn't the problem as I've explained above. The head unit fitted at the moment is a JVC mask something or other. This has two pairs of pre amp outputs. I am using the rear outputs (2) to send a supply to the amp.