I just went from powering my front component speakers via my Pioneer head unit (22 Wrms - not good) to using a JL 300/2v2 amp (and wow - it really performs!!).
I terminated the speaker leads from the head unit with a thick wrapping of electrical tape on each now-unconnected end. But, my Pioneer head unit is still getting quite warm. Warm as when its amps were driving speakers! No, I didn't create a short-circuit by twist-connecting the speaker leads, hehe.
Does having no speakers connected to the head unit's internal amplifiers turn them completely off or not? I want this head unit to last as long as possible so I want those internal amps off. Cool running is the goal, heh.
Thanks!
Joe
I terminated the speaker leads from the head unit with a thick wrapping of electrical tape on each now-unconnected end. But, my Pioneer head unit is still getting quite warm. Warm as when its amps were driving speakers! No, I didn't create a short-circuit by twist-connecting the speaker leads, hehe.
Does having no speakers connected to the head unit's internal amplifiers turn them completely off or not? I want this head unit to last as long as possible so I want those internal amps off. Cool running is the goal, heh.
Thanks!
Joe
Wow. That's a bummer... Not that I often use the system at 34 out of 40 on the volume gauge, I was really hoping the head unit wouldn't heat up like it did previously. With the new component drivers and JL amp, it can easily do the 34/40 cleanly but my SPL meter says danger, according to OSHA recommendations, heh. So, I keep it around 20 (or even less).
Maybe instead of the head unit failing completely, the amp chip will be the first to go and then the unit will keep functioning nice and cool, haha.
What IS really nice is that 1980's music, with a much lower average output, can now be played at a level equal to new CD's that are often horribly compressed to the limit. 150Wrms/ch into 125Wrms/ch drivers gives the proper amount of headroom!
Thanks for your knowledge there!
Joe
Maybe instead of the head unit failing completely, the amp chip will be the first to go and then the unit will keep functioning nice and cool, haha.
What IS really nice is that 1980's music, with a much lower average output, can now be played at a level equal to new CD's that are often horribly compressed to the limit. 150Wrms/ch into 125Wrms/ch drivers gives the proper amount of headroom!
Thanks for your knowledge there!
Joe
As stated before the audio amplifiers remain on even with no load connected. They still generate heat, but typically when the audio amps fail they kill the preamp output signal as well. I've removed the audio amplifiers in some of my decks that I don't plan to use without power amplifiers and they work just fine (and cool). I prefer decks without amplifiers anyways since the power output isn't that great.
So, if the amp chip dies, the pre-amp signal goes along with it? Arrrggghhh.
I will now consider taking the amp chip out of the loop as you have done. After moving to external power amplifiers, and noting how much the wattage headroom improves the quality of the sound (along with a 108.5dB SNR of the JL 300 amp), I'm not going to be using the internal HU amps again.
I may seem to be preoccupied with this HU (a Pioneer DEH-P8600MP) but it hasn't gone down in value at all over three years! Maybe $50 as it still sells for around $550. Compared to other technology depreciation, this one just doesn't depreciate! I'm sure there are better HU's out there but I really like this one.
Thanks!
Joe
I will now consider taking the amp chip out of the loop as you have done. After moving to external power amplifiers, and noting how much the wattage headroom improves the quality of the sound (along with a 108.5dB SNR of the JL 300 amp), I'm not going to be using the internal HU amps again.
I may seem to be preoccupied with this HU (a Pioneer DEH-P8600MP) but it hasn't gone down in value at all over three years! Maybe $50 as it still sells for around $550. Compared to other technology depreciation, this one just doesn't depreciate! I'm sure there are better HU's out there but I really like this one.
Thanks!
Joe
Hi AudioBahn:
Thanks for that bit of info there! I was thinking of locating the chip, looking-up who made it, getting a pin-out schematic, and then carefully cutting power to it (wire snip with option to resolder if need be, heh). Getting tech info on chips is pretty easy from the ADC and DAC chips I've done research on (AKM for example).
My model 8600 has so many crossover capabilities and other goodies that I really do love it (all functioning at lower than noticeable noise levels). The only thing I wish it could do is read/play a DVD with uncompressed WAV files stored on it (I don't listen to MP3 encoded stuff, not with the amps and drivers I now have). I also have the XM and RB20 aux input boxes, the latter I temporarily connected to a 'car PC' (vacation roadtrip) which stored my entire CD collection in uncomp WAV format (the sound from the PC's WT192X pro-audio card through the aux input was extremely accurate and uncolored).
I guess the one GOOD thing about the HU heating up is during cold Minnesota winters. The warm-up gets the deck's CD bearings up to proper use temperature nicely...
Thanks again all. I greatly appreciate your thoughts.
Joe
Thanks for that bit of info there! I was thinking of locating the chip, looking-up who made it, getting a pin-out schematic, and then carefully cutting power to it (wire snip with option to resolder if need be, heh). Getting tech info on chips is pretty easy from the ADC and DAC chips I've done research on (AKM for example).
My model 8600 has so many crossover capabilities and other goodies that I really do love it (all functioning at lower than noticeable noise levels). The only thing I wish it could do is read/play a DVD with uncompressed WAV files stored on it (I don't listen to MP3 encoded stuff, not with the amps and drivers I now have). I also have the XM and RB20 aux input boxes, the latter I temporarily connected to a 'car PC' (vacation roadtrip) which stored my entire CD collection in uncomp WAV format (the sound from the PC's WT192X pro-audio card through the aux input was extremely accurate and uncolored).
I guess the one GOOD thing about the HU heating up is during cold Minnesota winters. The warm-up gets the deck's CD bearings up to proper use temperature nicely...
Thanks again all. I greatly appreciate your thoughts.
Joe
I will double-check on that defeatable amp feature but I'm 99.9% sure my model 8600 doesn't have such a feature. I'm nerdy enough to have read the operation manual to the point of knowing it quite well along with all the configuration screens/pages that the HU provides via its display. 
It does sound like a perfectly reasonable feature to offer too.
Thanks!
Joe
It does sound like a perfectly reasonable feature to offer too.
Thanks!
Joe
My kenwood has a defeatable amp, I have it turned off, it makes the preamp signal cleaner according to kenwood.
That is a nice pioneer, but I'm pretty sure that one doesn't have a way to turn the amp off. I would just take it apart and find the lead that supplies 12v+. It will be easy and you can just cut the trace with a razor or desolde the pin(s) and pull them above the board a little. You could also solder two wires, one to the amp ic power pin(s) and another to the 12v+ source and have an external switch connected to be able to use the amp in the future if needed.
That is a nice pioneer, but I'm pretty sure that one doesn't have a way to turn the amp off. I would just take it apart and find the lead that supplies 12v+. It will be easy and you can just cut the trace with a razor or desolde the pin(s) and pull them above the board a little. You could also solder two wires, one to the amp ic power pin(s) and another to the 12v+ source and have an external switch connected to be able to use the amp in the future if needed.
Your Kenwood perhaps splits the pre-amp signal between the pre-outs and the internal amp inputs? Maybe that's why the signal should be better (stronger) when eliminating the internal amp input?
Yup, I was thinking of the razor blade or pin-up methods too for my Pioneer 8600.
I like the external switch idea too!
Thanks!
Joe
Yup, I was thinking of the razor blade or pin-up methods too for my Pioneer 8600.
I like the external switch idea too!
Thanks!
Joe
Just wondering...Which brands of headunits seem to overheat the most? I know Kenwoods do but now there is talk of Pioneer's units here...
I'm shopping around to replace mine and was looking at a Pioneer cause it had everything my Kenwood has but was just hoping it doesn't overheat but I'm not so sure on it now. How about Alpine players? They have low wattage for their output but do they overheat a lot?
I'm shopping around to replace mine and was looking at a Pioneer cause it had everything my Kenwood has but was just hoping it doesn't overheat but I'm not so sure on it now. How about Alpine players? They have low wattage for their output but do they overheat a lot?
ppia600:
Pin 4 turns on the power amp IC but it's driven directly by the microcontroller. The microcontroller can't drive a relay directly and the output is only 5v. I've used two transistors to restore the remote output when the IC was removed. You could also use one transistor and a relay.
jdgonko:
This head unit has a fan. Is the fan on yours operating?
Pin 4 turns on the power amp IC but it's driven directly by the microcontroller. The microcontroller can't drive a relay directly and the output is only 5v. I've used two transistors to restore the remote output when the IC was removed. You could also use one transistor and a relay.
jdgonko:
This head unit has a fan. Is the fan on yours operating?
The amp rating of the FET wouldn't be an issue.
If you wanted to use an N-channel FET to drive a relay, you'd connect the gate to pin 4 of the amplifier IC. Connect the source (leg 3 of the FET) to ground. Connect the drain of the FET (center leg) to the relay coil. The other side of the relay coil would go to 12v.
I'd suggest inserting a 10k ohm resistor in series between the microcontroller and the gate (inside the head unit, preferably) to protect the microcontroller in case of a wiring fault or in case the FET fails.
If you wanted to use an N-channel FET to drive a relay, you'd connect the gate to pin 4 of the amplifier IC. Connect the source (leg 3 of the FET) to ground. Connect the drain of the FET (center leg) to the relay coil. The other side of the relay coil would go to 12v.
I'd suggest inserting a 10k ohm resistor in series between the microcontroller and the gate (inside the head unit, preferably) to protect the microcontroller in case of a wiring fault or in case the FET fails.
Having just moved to all external amps, I'm not 100% sure how hot the Pioneer model 8600 HU will get in the future (but I'll keep tabs on it). From the above discussion, that amp chip is still trying to send a large signal to non-existent speakers...bummer.
For years up until about a week ago, when driving a pair of component speakers at 34/40 on the volume gauge, which would likely be it's 22Wrms/ch max, for say 20-30 minutes, the ejected CD (by me) would be quite hot to the touch. Enough that I wondered if one would maybe warp someday, heh. The HU only once in three years showed the OH (overheat) indicator and that was with no A/C in the cab, on a very hot day, and running the HU loud.
Hi Perry:
Yes, the 8600 does have a rear heatsink and small fan. Maybe the fan died? That's something I didn't think to check when I had the dash all apart. But, that rear area is so small and cramped with the wiring harness that I cannot see decent airflow happening anyway. With all my computer parts, including fans that size, I could likely replace it if I do find that it has failed. Thanks for the heads-up.
My two bits.
Joe
For years up until about a week ago, when driving a pair of component speakers at 34/40 on the volume gauge, which would likely be it's 22Wrms/ch max, for say 20-30 minutes, the ejected CD (by me) would be quite hot to the touch. Enough that I wondered if one would maybe warp someday, heh. The HU only once in three years showed the OH (overheat) indicator and that was with no A/C in the cab, on a very hot day, and running the HU loud.
Hi Perry:
Yes, the 8600 does have a rear heatsink and small fan. Maybe the fan died? That's something I didn't think to check when I had the dash all apart. But, that rear area is so small and cramped with the wiring harness that I cannot see decent airflow happening anyway. With all my computer parts, including fans that size, I could likely replace it if I do find that it has failed. Thanks for the heads-up.
My two bits.
Joe
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