[808MGuy]

Has anyone actually tested and verified the output voltage of the OEM hi-fi HU. Its been said before that its supposed to be 5V max but my experience with it so far makes me believe its not quite that high. I've been meaning to hook up my laptop with a software based o-scope to take a reading but I've never gotten around to making an adapter than I can plug into the factory wiring and plug into the 3.5mm jack on the laptop sound card.

I have the outputs tapped in the trunk and then going through a symbilink y-adapter and then sending the signal to 2 Zapco SLB-U line drivers which are set to +12dB gain. The clip lights are not even blinking which I find odd if the signal is supposed to be 5V max and the max voltage on a SLB-U is +15V. If the signal really was anywhere close to 5V, I should have seen the clip light at least flicker on the +6dB setting. After the SLB-Us I have those signals going into channels 1-2 and 5-6 of my Zapco DC650.6. The input signal for channels 3-4 is internally routed from channels 1-2. To get decent output from the system, I have set the input gain at about 4.5V for each set of input channels. For the output gain, it is set between -13 and -7 for each channel which is near max. That is very odd for the level of input signal that should be going into the amp. I'm starting to wonder if something is wrong with the amp or something is wrong with my signal tap into the factory wiring.

My main reason for concern is because I'm still having heat issues with this amp. The heat seems to build up on the side of the amp where channels 5-6 hook up which are the Earthquake subs. I have 2-4 ohm models running in parallel for a 2 ohm load and I have the low impedence switch on the amp engaged which should step the rail voltage down to prevent overheating. My amp will overheat after about an hour of pretty loud playback. Removing the false floor cover will help a little but I can still get it to overheat so it doesn't seem like its only related to a lack of airflow.

Any suggestions from the experienced ones here would be appreciated.

[Technic]

The HiFi outputs are indeed 5V (both in the E46 and in the E9x) balanced.

I think that you will need to get that big-ass amp out of that covered space and install it under your deck.

If I'm having intermittent overheating issues with a MS-8 in the same spot as yours and I'm not even using its built-in amps then it is more that enough to guess that your amp needs even much more air circulation that what is getting now in that place...

[808MGuy]

Originally Posted by Technic

The HiFi outputs are indeed 5V (both in the E46 and in the E9x) balanced.

I think that you will need to get that big-ass amp out of that covered space and install it under your deck.

If I'm having intermittent overheating issues with a MS-8 in the same spot as yours and I'm not even using its built-in amps then it is more that enough to guess that your amp needs even much more air circulation that what is getting now in that place...

MS-8 overheating? Wow! Never heard of a DSP overheating.

[Technic]

Originally Posted by 808MGuy

MS-8 overheating? Wow! Never heard of a DSP overheating.

My last bit one in the same place was extremelly hot to the touch as well, and the PDX amps have gone into heat protection several times in the CD Changer trim after long and loud use.

You Zapco amp is not designed to be in a closed/tight enclosure area (the same as the MS-8), that's for sure. You could try wiring a couple of fans with a relay to the remote signal, that will help a lot with the air circulation/heat transfer. That's what BMW does with the Sirius module in the same area.

[VP Electricity]

I have a customer with a DC650 mounted upside down in an E90 who is having heat issues as well. As a general rule, the DC series of amps, with multiple fans, do fine in enclosed spaces, upside down and right side up. I have my DC650 under the rear cargo floor in my E91 and I've been trying to get it to shut down with no luck.

We've also done a DC650 upside down in an E46 running an all-active system - tweeters, midwooofers, and a 10" - with no heat issues.

However, I will say this: The customer who is having heat issues with that amp is running 5/6 bridged into 2 ohms, and so are you. I know Zapco says it can handle it, but the instances where we have no heat issues here are all 4 ohm loads on 5/6.

So I would suggest TRYING 5/6 in stereo 4-channel and seeing how your amp does. That's what my amp is right now, and it isn't overheating.

I am not saying you will want to run it that way. You'd probably get xi's and run them 2 ohm stereo. But it's an easy test if your wiring is done in such a way that it's all configured at the amp.

I've heard of some DC amp fans failing, so I guess it's worth checking that out.

[808MGuy]

Originally Posted by Technic

My last bit one in the same place was extremelly hot to the touch as well, and the PDX amps have gone into heat protection several times in the CD Changer trim after long and loud use.

You Zapco amp is not designed to be in a closed/tight enclosure area (the same as the MS-8), that's for sure. You could try wiring a couple of fans with a relay to the remote signal, that will help a lot with the air circulation/heat transfer. That's what BMW does with the Sirius module in the same area.

I've thought about that but I'm at a loss as to where to put the fans. I figured for them to be useful I would have to cut holes in the floor cover so I could bring in cooler air and get the hot air out. I was thinking one fan on each side wired in push-pull configuration to bring air in from one side and pull air out the other. I'm just not sure I really want to cut two holes into the floor cover.

[808MGuy]

Originally Posted by VP Electricity

I have a customer with a DC650 mounted upside down in an E90 who is having heat issues as well. As a general rule, the DC series of amps, with multiple fans, do fine in enclosed spaces, upside down and right side up. I have my DC650 under the rear cargo floor in my E91 and I've been trying to get it to shut down with no luck.

We've also done a DC650 upside down in an E46 running an all-active system - tweeters, midwooofers, and a 10" - with no heat issues.

However, I will say this: The customer who is having heat issues with that amp is running 5/6 bridged into 2 ohms, and so are you. I know Zapco says it can handle it, but the instances where we have no heat issues here are all 4 ohm loads on 5/6.

So I would suggest TRYING 5/6 in stereo 4-channel and seeing how your amp does. That's what my amp is right now, and it isn't overheating.

I am not saying you will want to run it that way. You'd probably get xi's and run them 2 ohm stereo. But it's an easy test if your wiring is done in such a way that it's all configured at the amp.

I've heard of some DC amp fans failing, so I guess it's worth checking that out.

Thanks Ken. The 2 ohm SWS has crossed my mind and the system is wired where I could do that pretty easily. The overheat condition usually happens in the afternoon when its hot outside after about 1 hour of loud playback so I'm guessing the combination of hot ambient air and the heat generated by the amp is just too much. At night or in the morning, I have never got it to shut down. I'll try it at 4 ohms stereo for awhile just to see what happens.

[VP Electricity]

Originally Posted by VP Electricity

As a general rule, the DC series of amps, with multiple fans,

Poor phrasing on my part. Should have read:

...with multiple fans built in...

[Technic]

Originally Posted by 808MGuy

I've thought about that but I'm at a loss as to where to put the fans. I figured for them to be useful I would have to cut holes in the floor cover so I could bring in cooler air and get the hot air out. I was thinking one fan on each side wired in push-pull configuration to bring air in from one side and pull air out the other. I'm just not sure I really want to cut two holes into the floor cover.

I don't think that cutting holes in the trim is needed -or implied. Just more air circulation than what you have right now and keeping the front of the cover (closer to the bumper side) slightly open will help to expel some of the heat in that enclosure.

[kmarei]

wanna trade my 2ohm SWS-8s for your 4 ohms?

i have a similar situation
i am running the subs in series and although my amp can run at 1ohm
i think its making it too hot, i installed 2 14cm fans powered off a PAC relay, but it still overheats when i listen at loud volume.
so would love to run it at 2ohm, there will be no difference in power for my amp anyway
i'm not a fan of running in parallel
since i am using the OEM wires
the signal would have to travel all the way to one sub and back before going to the other sub
it might not make any audible difference, but i don't want to run them that way

[kmarei]

and i also have to turn up the gain on my amp to reach max power
and the gain on my amp is set to 5v at its lowest setting
so i think that confirms what you said about the 5v output

[VP Electricity]

Originally Posted by kmarei

and i also have to turn up the gain on my amp to reach max power
and the gain on my amp is set to 5v at its lowest setting
so i think that confirms what you said about the 5v output

Not really. "8V" capable aftermarket decks don't reach 8V very often.

[808MGuy]

Originally Posted by kmarei

wanna trade my 2ohm SWS-8s for your 4 ohms?

i have a similar situation
i am running the subs in series and although my amp can run at 1ohm
i think its making it too hot, i installed 2 14cm fans powered off a PAC relay, but it still overheats when i listen at loud volume.
so would love to run it at 2ohm, there will be no difference in power for my amp anyway
i'm not a fan of running in parallel
since i am using the OEM wires
the signal would have to travel all the way to one sub and back before going to the other sub
it might not make any audible difference, but i don't want to run them that way

I'm gonna play with it a bit more but I'll keep that in mind. But if you're running in series that means the 2-4 ohm subs would show the amp an 8 ohm load. Your amp runs the same power into 4 or 8 ohms? I know the PDX and JL HDs have regulation like that but I thought at 8 ohms the output does actually go down.