I know DEAD HORSE.. but if you feel like it,.. Help me with Class A/B vs Class D.

[VWBobby 10+ year member]

Technology has improved drastically in the electronics industry and because of that, the downsides of class D circuits have been all but removed... especially with respect to the limits of human hearing. But of course, there are those die hards who will never like something new because their something old seemed so wonderful.

And of course, those die hards indoctrinate their progeny into believing the old is the only good and that's why you can still buy a $30,000.00 class A amp that produces 10 watts per channel. And, you can connect your $25,000.00 record player to that amplifier so they can listen to the wonderful 250-10,000 Hz frequency response of your aged vinyl... complete with all the original hissing and scratching they think they always loved so much.

I could not disagree with you more. I have customers with those $20,000+ systems, and trust me, you can hear a HUGE difference between that, and a

I'm not saying you can't design and build your own stereo/theater system for less than $2,000 that can compare in SQ to those $20,000 systems. Knowing where to source raw drivers, I could easily build some

I own a PPI Ion 650, Discus DSC1500.1D, and many other class D amps and I would put them on a par with other I have a $700 Kenwood 5 channel amp that I bought new in 2002 that sounds as good as some of the McIntosh, Audison and Treo amps I have heard. Kenwood had a solid design in the Excelon KAC line.

The one exception I have heard in the Class D, G, Gh or T technology in SQ is the JL Audio HD and XD amps. I have demo'd those amps A-B with about 10 other amps on a well stocked demo wall. This was playing through a set of $1100 Focal 3-ways and a few other sets (brands) for comparison. The JL amps sounded at least 95% as nice as the other high end A/B amps. There was a very small difference in SQ that I was not able to pinpoint, other than "hollow" midrange.

This same pissing match happens in the guitar and pro audio world. You can not achieve the same SQ with a $200 amp, that you will get with a $600 - 2000 amp. It just isn't going to happen. Otherwise Mesa-Boogie, Marshall, and many others could not charge as much as they do for the quality or tone.

Measuring frequency response on an RTA will tell you one thing....that the amp can reproduce "A" signal between 20-20khz. Is it flat or wavy? Will your ears discern the lack of reproduction at CERTAIN frequencies? Maybe. I know my failing ears can hear spots that certain amps or speakers will not reproduce accurately. I am not an audiophile snob, but I do know SQ. This is why most people do not like a system that is set by RTA for "SQ" comps and will usually EQ their signal to their own personal preference, or to make up for a lack of certain frequency reproductions.

Don't take this as a personal attack. I encourage you to A-B amps on the same set of your favorite comps, with no sub, and tell me you can not hear a difference between a high end A/B and your typical I have spent many hours in the car and home audio shops doing just this, so I could choose what sounded best to me, and typically it was surprising what cheaper equipment sounded on par with the high end. This is why some models outshine others, within the same brand. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[VWBobby 10+ year member]

not good to drop to 20hz subsonic

You're kidding right? You don't want your sub to play

 

[bbeljefe]

I could not disagree with you more. I have customers with those $20,000+ systems, and trust me, you can hear a HUGE difference between that, and a
I'm not saying you can't design and build your own stereo/theater system for less than $2,000 that can compare in SQ to those $20,000 systems. Knowing where to source raw drivers, I could easily build some

I own a PPI Ion 650, Discus DSC1500.1D, and many other class D amps and I would put them on a par with other I have a $700 Kenwood 5 channel amp that I bought new in 2002 that sounds as good as some of the McIntosh, Audison and Treo amps I have heard. Kenwood had a solid design in the Excelon KAC line.

The one exception I have heard in the Class D, G, Gh or T technology in SQ is the JL Audio HD and XD amps. I have demo'd those amps A-B with about 10 other amps on a well stocked demo wall. This was playing through a set of $1100 Focal 3-ways and a few other sets (brands) for comparison. The JL amps sounded at least 95% as nice as the other high end A/B amps. There was a very small difference in SQ that I was not able to pinpoint, other than "hollow" midrange.

This same pissing match happens in the guitar and pro audio world. You can not achieve the same SQ with a $200 amp, that you will get with a $600 - 2000 amp. It just isn't going to happen. Otherwise Mesa-Boogie, Marshall, and many others could not charge as much as they do for the quality or tone.

Measuring frequency response on an RTA will tell you one thing....that the amp can reproduce "A" signal between 20-20khz. Is it flat or wavy? Will your ears discern the lack of reproduction at CERTAIN frequencies? Maybe. I know my failing ears can hear spots that certain amps or speakers will not reproduce accurately. I am not an audiophile snob, but I do know SQ. This is why most people do not like a system that is set by RTA for "SQ" comps and will usually EQ their signal to their own personal preference, or to make up for a lack of certain frequency reproductions.

Don't take this as a personal attack. I encourage you to A-B amps on the same set of your favorite comps, with no sub, and tell me you can not hear a difference between a high end A/B and your typical I have spent many hours in the car and home audio shops doing just this, so I could choose what sounded best to me, and typically it was surprising what cheaper equipment sounded on par with the high end. This is why some models outshine others, within the same brand. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

First of all... no offense taken. Second, what are you disagreeing with? Everything I said? With the claim that technology has improved? Something else?

I agree with you that there's a difference between a $1K theater and a $20K theater. I used to sell & install the latter back when home theater was new and a cheap DVD player would set you back $600.00. Parasound was my flagship line and I paired that with Denon, Jamo loudspeakers, OMB projectors and signal cabling from XLO Electric.

I'd still put my $2500.00 HCA-1206 up against anything McIntosh, Adcom or Krell makes. But then, it was designed by John Curl, the same guy who designed the old Mark Levinson amps that still today fetch more than Parasound's Curl designed amplifiers. And I've listened to a Parasound 2 channel amp side by side with one of the Curl designed MLs and there is no difference in clarity, timbre, sibilant control or any of the other cool sounding audio reviewer adjectives.

There's also another thing to consider in the world of audio and that's the listening area. How is it prepared for audio? Well, the likelihood is that the $1K listening room isn't as acoustically dead as the $20K listening room. After all, there isn't much money left after equipment to go toward sound deadening in the former. Not to mention that the person with a $1K budget obviously isn't going to be as mindful of those things as the buyer of a $20K setup.

But in the end, the context of my post here was the difference between class AB & class D amplifiers in car audio. And my point is that between a $200.00 class D amp and a $500.00 class AB amp, any audible differences in sound quality will surely be lost in the absence of proper staging, deadening, processing, et al.

But then there are still those who insist that vinyl records sound better than digital recordings. Even in the face of empirical evidence proving that vinyl has a much narrower bandwidth than digital. Not to mention the inherent noise produced by dragging a hard, pointed surface through a jagged ditch.

 

[n2audio 5,000+ posts]

there is no difference in clarity, timbre, sibilant control or any of the other cool sounding audio reviewer adjectives.

//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[Chromatic]

Read you two guys debate over the A/B v D.. First bbeljefe has been very tactful in his choice of phrasing,.. indicating that he thinks a $200 ish Class D amp... (most people) aren't going to hear a noticeable difference in say a comparable Class A/B amp that may be another $100 or so. BUT, says some people just might. He, nor I, are disagreeing with the likliehood that some people (not the majority, imo), do hear a large difference between them. But, for a mid range budget build.. say keeping it under $1000 on parts.. Class D really offers advantages.

The smaller form factor and cooler running can't be dismissed. My setup sounds absolutely amazing with the PPI 900.5 Class D amp. I don't regret buying it one bit.

I don't think anyone here is really arguing any definitive stance.. ie: Class D = A/B in quality no questions asked.. and anyone who says otherwise is experiencing a placebo effect //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif -- A/B is technically a cleaner amp .. If you buy a decent one as goes with all equipment. BUT,.. just there mere fact that Class D tech has been around for a while now.. it's improved every 6months or so as new tech does.. given it's switching tech, and internals that involve processing there is a lot of room for improvement, and many improvements have been made by leaps and bounds since they were introduced due to our advanced knowledge with this technology already. I do think they are the future for your low to mid range install.. and who knows.. D amp tech. may become "good enough" to rival the high end A/B amps.. time will tell.

Speaking of Class D. My PPI 900.5, Class D amp -- I'm curious at what point I need to do something about active cooling where it's located. A big reason for the class D amp was because it runs cooler than A/B.. I put it in an enclosed (no ventilation) area.. and after watching a Movie in my car (parked) for 2 hours .. (I was just testing the DVD player and got hooked on the movie.. go figure.) -- The Amp was quite hot to the touch. Not too hot to keep my hand on the amp.. but quite hot.

At what point in amp temp (by feel) do I need to try to figure out taking more of the car apart and running some sort of fan setup in that compartment.

I'm hoping the answer is, your amp being Class D is fine at those temps.. and don't worry about it. I Just don't know what's dangerous, or normal for the Class D PPI 900.5 amp in terms of how hot it gets.

Here's the amp again in it's location:



That Door you see closes, and stays closed. Hence no air flow -- Just to be thorough here it is closed:



I know how to cool things.. I design computer systems,.. and cooling is a big part of it with some of the higher end stuff I design. But I really don't want to even run another thing to it if things are ok as they are. Not out of laziness so much, but because I don't want to introduce anymore current draws (I know the fan(s) I'd use would be 0.12amps or something similarly as small..) but if I went in to "cool" it (which was a large reason to buy that D amp instead of A/B in the first place) I'd be hacking up that door and probably putting a large 200mm or large fan at low rpm to push air in there mounted INTO that door.

Come on.. please tell me it's normal for that amp to get fairly hot to the touch.. (again, hot after 2+ hours of being on... put I could keep my hand on it without pulling it off, if that gives you any gauge of the heat.)

Thanks

 

[bbeljefe]

Read you two guys debate over the A/B v D.. First bbeljefe has been very tactful in his choice of phrasing,.. indicating that he thinks a $200 ish Class D amp... (most people) aren't going to hear a noticeable difference in say a comparable Class A/B amp that may be another $100 or so. BUT, says some people just might. He, nor I, are disagreeing with the likliehood that some people (not the majority, imo), do hear a large difference between them. But, for a mid range budget build.. say keeping it under $1000 on parts.. Class D really offers advantages.
The smaller form factor and cooler running can't be dismissed. My setup sounds absolutely amazing with the PPI 900.5 Class D amp. I don't regret buying it one bit.

I don't think anyone here is really arguing any definitive stance.. ie: Class D = A/B in quality no questions asked.. and anyone who says otherwise is experiencing a placebo effect //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif -- A/B is technically a cleaner amp .. If you buy a decent one as goes with all equipment. BUT,.. just there mere fact that Class D tech has been around for a while now.. it's improved every 6months or so as new tech does.. given it's switching tech, and internals that involve processing there is a lot of room for improvement, and many improvements have been made by leaps and bounds since they were introduced due to our advanced knowledge with this technology already. I do think they are the future for your low to mid range install.. and who knows.. D amp tech. may become "good enough" to rival the high end A/B amps.. time will tell.

Speaking of Class D. My PPI 900.5, Class D amp -- I'm curious at what point I need to do something about active cooling where it's located. A big reason for the class D amp was because it runs cooler than A/B.. I put it in an enclosed (no ventilation) area.. and after watching a Movie in my car (parked) for 2 hours .. (I was just testing the DVD player and got hooked on the movie.. go figure.) -- The Amp was quite hot to the touch. Not too hot to keep my hand on the amp.. but quite hot.

At what point in amp temp (by feel) do I need to try to figure out taking more of the car apart and running some sort of fan setup in that compartment.

I'm hoping the answer is, your amp being Class D is fine at those temps.. and don't worry about it. I Just don't know what's dangerous, or normal for the Class D PPI 900.5 amp in terms of how hot it gets.

Here's the amp again in it's location:



That Door you see closes, and stays closed. Hence no air flow -- Just to be thorough here it is closed:



I know how to cool things.. I design computer systems,.. and cooling is a big part of it with some of the higher end stuff I design. But I really don't want to even run another thing to it if things are ok as they are. Not out of laziness so much, but because I don't want to introduce anymore current draws (I know the fan(s) I'd use would be 0.12amps or something similarly as small..) but if I went in to "cool" it (which was a large reason to buy that D amp instead of A/B in the first place) I'd be hacking up that door and probably putting a large 200mm or large fan at low rpm to push air in there mounted INTO that door.

Come on.. please tell me it's normal for that amp to get fairly hot to the touch.. (again, hot after 2+ hours of being on... put I could keep my hand on it without pulling it off, if that gives you any gauge of the heat.)

Thanks

You're not likely to harm the amp running at those temperatures but it wouldn't be a bad idea to cool it off some. But in reality, that largely depends on how long your in car listening sessions are. If you seldom drive more than 15 minutes at a time, it might not be worth it. But if you have an hour long commute two ways a day, it just might be necessary.

As for the amount of heat you had... it's nothing to worry much over. That amp will get a lot hotter before you reach the point of possible damage. But since you have access to the fans, why not just install one inside the compartment and have it recirculate the air inside there? Obviously it would be best to introduce cool are or evacuate hot air but just circulating the air in there will make a considerable difference and it won't cause you to have to alter the interior.

And if you do add a fan, make sure you install a relay. Your head unit remote lead only supplies ~250mA and if that circuit is ever put in an overcurrent situation, it can do expensive or, even, irreparable damage to the head unit.

 

[VWBobby 10+ year member]

First of all... no offense taken. Second, what are you disagreeing with? Everything I said? With the claim that technology has improved? Something else?

Glad to see we are in agreement. The tone of your post made it sound like anyone who 'can' hear a difference in SQ is either a nutcase or a delusional audiophile. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif I agree that the "install" will usually kill any audible difference in comparison from one amp to another. Most people run their speakers off-axis, out of phase, or with a ton of cancellation or "beaming" from reverberant sound. I HATE that. I sit in the divers seat and position my speakers aimed at my head, using temporary mounts and tweaking small adjustments until "correct". When the axis is to my liking, I mold MDF rings into fiberglass door panels. I have built at least 3-4 cars in this manner, in recent years, and have made some cheap installs (

I cannot stress enough the differences that can be heard on a loaded sound wall in a moderately dampened room. Using the same sets of speakers, head unit, and only A-B'ing amps back and forth.......now I'm sounding really geeky here, but you can hear a difference. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Reminds me of the old coat hanger verses monster cable..... Short runs of less than 1 foot? Sure, coat hanger will be fine. Try 20+ feet and tell me that some crappy pot metal solid wire, loaded with oxygen, is going to sound the same. (head explodes) //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Chromatic]

You're not likely to harm the amp running at those temperatures but it wouldn't be a bad idea to cool it off some. But in reality, that largely depends on how long your in car listening sessions are. If you seldom drive more than 15 minutes at a time, it might not be worth it. But if you have an hour long commute two ways a day, it just might be necessary.
As for the amount of heat you had... it's nothing to worry much over. That amp will get a lot hotter before you reach the point of possible damage. But since you have access to the fans, why not just install one inside the compartment and have it recirculate the air inside there? Obviously it would be best to introduce cool are or evacuate hot air but just circulating the air in there will make a considerable difference and it won't cause you to have to alter the interior.

And if you do add a fan, make sure you install a relay. Your head unit remote lead only supplies ~250mA and if that circuit is ever put in an overcurrent situation, it can do expensive or, even, irreparable damage to the head unit.

Sounds good. Did a 15 minute drive today.. and the amp was literally COLD when I touched it .. go figure. What got the amp the hottest was a 2+ hour DVD movie, with the car stationary (not that being stationary is really any different to driving INSIDE the car).

Yes.. I work with fans from 20mm to 400mm every day.. so I'm well versed in working with those, eliminating any noise from the fans, amp draw etc. However, I have never put a fan in a car.. I won't lie.

So if I were to just mount a nice extra Noctua 200mm fan I have here doing nothing in the car.. What's the best way to wire it to eliminate adding any extra noise to the system,.. and powering it , et al.

You mentioned the remote,.. which makes sense to power up when the amp kicks on, and off when amp is off -- then a relay. I'm assuming this means I would tap into the remote wire from the amp itself (which will make installing the fan MUCH easier than running a new power source across the vehicle).. and the relay would be also attached to what? Another power supply/ground? Would I fuse the power line going into the fan with like a 1amp "inline" fuse? I trust your advice very much, so if you could describe the basic wiring hookup to the relay - fan - remote (and any other wires.. I know I would at least need to run a ground based on the way the circuitry of the fan I would use works of course)..

Can I essentially run remote as power from amp remote wire, and the ground from fan back to the ground terminal on the amp? With the relay it makes me think I need to be adding another wire, like an additional power source letting the remote wire be the "on/off" switch, relay then allow the other "power" wire feed current through relay.. and ground there because , well, everything needs a ground.

But this is just off the top of my head speculation,.. I'm sure you can clear this up in a sentence or two. If there is any specific relay that works best and if any extra fuse would be wise inline to fan or back to amp from fan let me know what rating you would use -- and of course the basic route X wire Y wire, and Z wire to relay at point 1, 2, and 3.. and I can take it from there.

Appreciate your advice!

 

[bbeljefe]

Sounds good. Did a 15 minute drive today.. and the amp was literally COLD when I touched it .. go figure. What got the amp the hottest was a 2+ hour DVD movie, with the car stationary (not that being stationary is really any different to driving INSIDE the car).
Yes.. I work with fans from 20mm to 400mm every day.. so I'm well versed in working with those, eliminating any noise from the fans, amp draw etc. However, I have never put a fan in a car.. I won't lie.

So if I were to just mount a nice extra Noctua 200mm fan I have here doing nothing in the car.. What's the best way to wire it to eliminate adding any extra noise to the system,.. and powering it , et al.

You mentioned the remote,.. which makes sense to power up when the amp kicks on, and off when amp is off -- then a relay. I'm assuming this means I would tap into the remote wire from the amp itself (which will make installing the fan MUCH easier than running a new power source across the vehicle).. and the relay would be also attached to what? Another power supply/ground? Would I fuse the power line going into the fan with like a 1amp "inline" fuse? I trust your advice very much, so if you could describe the basic wiring hookup to the relay - fan - remote (and any other wires.. I know I would at least need to run a ground based on the way the circuitry of the fan I would use works of course)..

Can I essentially run remote as power from amp remote wire, and the ground from fan back to the ground terminal on the amp? With the relay it makes me think I need to be adding another wire, like an additional power source letting the remote wire be the "on/off" switch, relay then allow the other "power" wire feed current through relay.. and ground there because , well, everything needs a ground.

But this is just off the top of my head speculation,.. I'm sure you can clear this up in a sentence or two. If there is any specific relay that works best and if any extra fuse would be wise inline to fan or back to amp from fan let me know what rating you would use -- and of course the basic route X wire Y wire, and Z wire to relay at point 1, 2, and 3.. and I can take it from there.

Appreciate your advice!

You can power the fan entirely from the amplifier's power inputs, using its battery & negative plus the remotes turn on wire. You can use any readily available 20 or 30 amp SPST (single pole single throw) automotive relay like this on from Parts Express and, I'd fuse it at no more than 3 amps.

No need to worry much about noise being introduced because computer fans don't create much noise and from what I've learned of you, your wiring isn't willy nilly laying around in such a way that it's susceptible to accepting noise. ;-)

The head unit remote will be disconnected from the amp and connected to the relay's coil (pin 86). Then, the other end of the coil will go to ground (85). The fused battery positive will go to the relay's common lead (30) and then, the normally open relay lead (87) will go to both the fan positive and the amplifier's remote terminal.

Here's a short primer on Automotive relays in case you'd like to be familiarized with them:



And here's a diagram of the relay connections:

Most of these relays have a tab on top with a screw hole that allows you to mount the relay pretty much anywhere you want. Just keep it & the fan on the power input side of the amp and you should have zero chance of introducing noise. Also, you can buy a relay harness that has pig tails on it so that you don't have to use individual female spade connectors. I prefer the latter but either way will work.

 

[bbeljefe]

Glad to see we are in agreement. The tone of your post made it sound like anyone who 'can' hear a difference in SQ is either a nutcase or a delusional audiophile.

No worries man. It's hard to convey subtle emotions through text and I'm pretty blunt in my writing so I get that a lot. I also use a lot of tongue in cheek sarcasm that may seem like I'm bashing people when in fact, I'm just poking fun. But yeah, slight differences can be heard by some (not most) people and yeah... there are a lot of delusional audiophiles out there. My sarcasm was directed at the latter.

Oh and, I couldn't agree more with on axis driver placement. That has to be the single most common mistake I've seen people make in both home and car audio system setup throughout the years. But try as I have, people still insist upon placing their home audio speakers in the far corners of their listening room or, they want to build expensive fiberglass door panels with 4 bullet tweeters pointing directly at one another at chest level or lower.

 

[VWBobby 10+ year member]

OP, a regular 80mm or 120mm PC fan is PLENTY for a relatively small amp as that. The heat does concern me. My PPI 650.1 is powering a Dayton HO 10" and rarely gets over lukewarm to the touch. My head unit doesn't put out a lot of power, so I have the gain around 75-80% (a big no-no), and it still doesn't get hot. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif Of course, most of my travel is 30-60 mins. Next time I am in a 2+ hour commute, I will check how hot the amp gets. I have it mounted upside-down to the parcel shelf in my trunk, to save space.

No worries man. It's hard to convey subtle emotions through text and I'm pretty blunt in my writing so I get that a lot. I also use a lot of tongue in cheek sarcasm that may seem like I'm bashing people when in fact, I'm just poking fun. ...

But try as I have, people still insist upon placing their home audio speakers in the far corners of their listening room or, they want to build expensive fiberglass door panels with 4 bullet tweeters pointing directly at one another at chest level or lower.

I know what you mean about subtle humor getting lost or people taking offense. That is the problem with the internet....No verbal tone, facial expressions or anything "human" can be conveyed so someone comes off sounding like a douche when they were just making a joke. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif This forum lacks good emoticons, making it even harder.

LOL, don't get me started on the multiple sets of bullet tweets and the dudes with the walls of pro audio speakers in their doors. I hope they like the sound of a baseball stadium PA, because that must be the effect they are going for with all that beaming. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

You have a lot more patience than I do. Good job hooking him up with the wiring diagrams for a proper relay install. That is another pet peeve of mine....Nobody knows how to wire a relay or build a simple logic circuit for making motorized amp racks or something cool anymore. //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif (NOT directed at the OP) The really cool installs of the late 90's and early 2000's seem to have gone by the wayside for the 30,000+ watt Meade type systems. (rolls eyes)

 

[Chromatic]

You can power the fan entirely from the amplifier's power inputs, using its battery & negative plus the remotes turn on wire. You can use any readily available 20 or 30 amp SPST (single pole single throw) automotive relay like this on from Parts Express and, I'd fuse it at no more than 3 amps.

Ok, that's nice.. No running wires more than a few inches.

No need to worry much about noise being introduced because computer fans don't create much noise and from what I've learned of you, your wiring isn't willy nilly laying around in such a way that it's susceptible to accepting noise. ;-)

Yeah,.. you never know sometimes -- but it's just a motor on a ball bearing generally.. Depending on the fan type.. Further I'll be using low RPM , larger fans for more CFM but without noise.

The head unit remote will be disconnected from the amp and connected to the relay's coil (pin 86). Then, the other end of the coil will go to ground (85). The fused battery positive will go to the relay's common lead (30) and then, the normally open relay lead (87) will go to both the fan positive and the amplifier's remote terminal.

Ok so the remote will run through relay before it hits the amp,... The rest of the wires will remain as they are IN the amp... And I will tap into the 4 Gauge power wire.. just by , I suppose, using a 14-16 gauge speaker wire screwed in WITH the fat 4g power wire in the amp terminal,..and putting an inline 3amp fuse on the wire which will end up hitting the relay,.. and the ground wire the same way..minus a fuse... All sounds straight forward as long as I'm correct on just screwing the power and ground 14 gauge (just because that's what I have a ton of left..) directly in the amp slots with the 4 gauge power and ground wires -- and remote wire will not be going to amp, it will go to relay, and relay will feed the remote back to amp.

Here's a short primer on Automotive relays in case you'd like to be familiarized with them:

Pig tails are easiest.. I'll likely actually use Crimps with this due to the area I will be working in (don't want to burn the carpet in there hehe).. and I've used crimps a little more after the big install as I've been rigging relays and switches in the car.. and the new crimps and tool I have really are impressing me on how good the connections are. But, who knows I may end up soldering the dam.n things lol.

Speaking of shoddy wiring... I JUST noticed this (got this car a little over a month ago).. I was redoing the ground.. and it was getting dark.. and this is what I suddenly saw as I was ducking my head down to remove a panel ...



Heh.. the dude didn't even hide the wire! Ughh..

The white leds.. are actually a bit useful in there and not hideous -- but the Blue led in the middle? Really? That's getting chopped. The white leds are adhesive, but he used what looks like hot glue to hold them (and they are coming off on the ends).. At least I hope it's hot glue and not superglue lol.. But,.. I think I'll keep the white ones.. But I'll take it all down and rewire the whole thing so It's "clean" -- and I'm going to snip and remove the Blue LED.

The hatch really has **** poor lighting.. and I know the original owner put those LEDS in to look "cool".. but they actually give off some reasonably light and are wired into the light that comes on when the hatch is opened,.. So it works out well. I keep getting surprised by stuff on or in this car lol. Especially when it has 26k miles.. The dude really started going after it quickly (I'm the third owner). But, if I listed all the work I've done on the car in the last month it'd be a little more ridiculous.. but most of it is fixing minor issues that the previous owner obviously has zero mechanical "knowledge".. but I digress.

Thanks for the info -- Let me know if I'm right about those connections in the amp,.. And mind linking a decent inline fuse to use? I don't particularly like those typical square ones you see people running off cigarette lighters and such.. Do they make some cylinder ones like the 80amp fuse the Amp 4g power wire uses, but obviously going to be MUCH smaller? It would be a cleaner look.

 

[Chromatic]

OP, a regular 80mm or 120mm PC fan is PLENTY for a relatively small amp as that. The heat does concern me. My PPI 650.1 is powering a Dayton HO 10" and rarely gets over lukewarm to the touch. My head unit doesn't put out a lot of power, so I have the gain around 75-80% (a big no-no), and it still doesn't get hot. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif Of course, most of my travel is 30-60 mins. Next time I am in a 2+ hour commute, I will check how hot the amp gets. I have it mounted upside-down to the parcel shelf in my trunk, to save space.

PC Fans (or Computer anything I am the expert on.. unlike being the noob here //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif ) -- I'm running fans I have on hand that are not being utilized,.. I have a great 140mm Noctua NF-F12 that runs at 28dBa.. and I can suppress it further with an ULNA if need be,.. but won't be needed. It also runs on a mere 0.05amps @ 6watts,.. If you were to categorize "PC fans" like you do speakers -- Noctua would be like Focal Utopia's //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif -- Ugly as sin , but of course made in Germany ,.. and run forever with SSO2 Metal Bearing Shells...

As for your amp temp vs. mine -- Well,.. I'm not so sure they can be compared as equals.. a one channel amp compared to a 5 channel amp is going to have different properties thermally. But, I think moreover it's location/location/location -- Where this amp is is just hot. It's Padded completely (so all the metal that was exposed is no more that would have helped a bit with heat dispersion) -- Further it's fully carpeted,.. and to top it off is closed and has a seal.. While it's not WATER tight.. it's much hotter than putting it under a seat even with the carpet all up on the amp. The "glovebox" as it's called this amp is in is really the anti-thesis of an ideal Amp location thermally -- It is a bit of an oven I suppose. Airflow is the biggest issue here as there is absolutely zero. I believe the fan will do wonders in this spot. The designer in me wants to Fabricate the door a bit and have it pulling in air from the cabin directly onto the amp.. But, I'm just going to start with it off to the side blowing horizontally across the amp just to keep some airflow going.

The amp isn't defective,.. my setup is good,.. and my gains are set actually a touch below the v=sqrt(rmsWxohms). The gains on this amp are set at 50% for the front, 50% for the rears, and 60% for the sub. So it's not jacked up on the gains,.. I was actually a bit surprised I had this much headroom given I'm pressing all the amps rated RMS power (well besides the 1-2v I dropped the gains as a safety net).

Really the only time it got HOT was when I was sitting in the car, with it off,.. in the garage,.. watching a Movie (dvd) for nearly 3 hours straight. On a 10-15minute trip last night to the post office.. I felt of the amp when I stopped and it was literally cold! So it really varies. For whatever reason the Video/DVD/Movie heated it up the most -- and I think much of that was merely due to the sheer amount of time and the CONSTANT current a movie has... A movie isn't even as dynamic as music -- which has varying levels of power as the song goes through it's own peaks and valleys.. then your pauses between songs.. different song types etc.

I do remember the A/B amps I had a decade ago... They were only pushing 100watts a piece RMS each on a single JL W1 12" (insane SPL).. but they got frying pan hot.. You'd get literal burns on your hand(s) if you held it there for more than a quick touch after being on for 20+ mins. I ran them 4-5 years, then sold them when I traded vehicles.

You have a lot more patience than I do. Good job hooking him up with the wiring diagrams for a proper rlay install. That is another pet peeve of mine....Nobody knows how to wire a relay or build a simple logic circuit for making motorized amp racks or something cool anymore. //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif (NOT directed at the OP) The really cool installs of the late 90's and early 2000's seem to have gone by the wayside for the 30,000+ watt Meade type systems. (rolls eyes)

@bbeljefe has been great! He is a wealth of knowledge and has a great disposition. As for me not knowing how to wire a relay, etc.. well.. thing with me, is I learn it, and learn it thoroughly and do it myself! Now in order to do so it does take gathering the information,.. which it really helps to have people like jefe who will at least point you in the right direction.. like with the links to more in depth explanation of the actual functions of the relays, etc. (While most people would just say,.. yah yah.. so I put those wires there.. ok .. ) -- And they never bother to go read up on what the relay, etc is actually doing. -- Actually the "Majority" of people wouldn't even be bothering to check how hot this amp was .. they'd have it shutup in that slot I do and wouldn't look at it unless something died/broke! That's the majority (Which isn't represented by the people on this forum. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif ).

I also enjoy this type of stuff.. learning,.. working with my hands -- This isn't a chore figuring out solutions to "Safeguard" to potential issues that could crop up.. I enjoy this type of work/small project.

Appreciate all your replies.

 

[SamIam71]

Could a mosfet transistor be used in place of the relay?

 

[bbeljefe]

Ok, that's nice.. No running wires more than a few inches.

Yes, you're correct. And yes, there are small glass fuses available but I'm not sire how easy it would be to find an inline holder for them as they're almost exclusively used on commercial and industrial electronics... which makes them both hard to find and abnormally expensive. I'd use what's readily available. After all, it's not something you have to look at daily. ;-)