How can pcb's in amps handle so much current?

[ssh 924]

Couple weekends ago I was at a car show and a hertz sales rep was talking massive trash about sundown amps (and other non-mainstream companies).

He stated that it is impossible for sundown amps and other amps of similar build to do rated power on strictly pcb board. he said hertz amps had a solid copper plate underneath the circuitry to deal with producing high current (1000watts+ or whatever).

So my question is, do sundown amps (and others) have any plating underneath the boards? If not, then how do they handle all the current without frying?

I'm not in any way, shape or form questioning sundown quality (as I have a saz-1500d myself , but just interested in how all this works.

[inkfx 3]

PCB is like fiberglass material. It isn't the PCB that carries any kind of current, it's the metal traces within the PCB that route the electricity.

[ssh 924]

PCB is like fiberglass material. It isn't the PCB that carries any kind of current, it's the metal traces within the PCB that route the electricity.

then tell me how these small metal traces can carry such high current.

[todd.brust 29]

Where you need most power is in your outputs transitors and power supply. The power supply gets power straight from the battery and power wire. The output stage gets power from solid copper rails coming from the power supply and those rails feed the positive and negative parts of the output stage. And since most amps will use multiple output transistors the current is divided between accordingly so the traces can handle the current.

I don't know if I am dead on, but close. Anyone else car to elaborate?

[inkfx 3]

PCB is like fiberglass material. It isn't the PCB that carries any kind of current, it's the metal traces within the PCB that route the electricity.

then tell me how these small metal traces can carry such high current.

I don't exactly know how it works in amps but I'd guess with the help of all the transistors and capacitors on the board. The little traces in the PCB most likely don't care huge amounts of power.

[Duran 387]

That's funny that he says they are solid copper boards, he'd have a dead short

[ssh 924]

That's funny that he says they are solid copper boards, he'd have a dead short

they still had pcb but he stated there was copper plating underneath it, idk if they were strips perhaps?

[Duran 387]

That's funny that he says they are solid copper boards, he'd have a dead short

they still had pcb but he stated there was copper plating underneath it, idk if they were strips perhaps?

Hopefully he meant strips

[Kanaworm$ 292]

Couple weekends ago I was at a car show and a hertz sales rep was talking massive trash about sundown amps (and other non-mainstream companies).

He stated that it is impossible for sundown amps and other amps of similar build to do rated power on strictly pcb board. he said hertz amps had a solid copper plate underneath the circuitry to deal with producing high current (1000watts+ or whatever).

So my question is, do sundown amps (and others) have any plating underneath the boards? If not, then how do they handle all the current without frying?

I'm not in any way, shape or form questioning sundown quality (as I have a saz-1500d myself , but just interested in how all this works.

He meant copper traces!

Sundown and other quality non mainstream companies utilize double sided circuit boards or through hole mounting along with SMT (Surface Mount Technology).

Jake can answer this alot better than I can or maybe Chris from db-R can offer some insight!

[ssh 924]

I'm looking to bash anyone, I'm just curious and would like a good answer. That way if he's at the next show I can atleast defend sundown instead of being shut down if ya know what I mean

[GlassWolf 5]

Where you need most power is in your outputs transitors and power supply. The power supply gets power straight from the battery and power wire. The output stage gets power from solid copper rails coming from the power supply and those rails feed the positive and negative parts of the output stage. And since most amps will use multiple output transistors the current is divided between accordingly so the traces can handle the current.

I don't know if I am dead on, but close. Anyone else car to elaborate?

pretty well put.

the transformer (toroid if it's a good amp) gets the power straight from the 4+AWG wire that runs to the amp, and usually directly to the power supply. (I have some pics of the guts of my Orion 2250SX amps if needed to illustrate this)

The power supply converts high current 12VDC input power to what's usually 70 volt, or multistage output to the output FETs, which are where your heat comes from (at elast in a class AB amp anyway) which are generally bolted directly to massive bus bars that run the length of the amp (I can provide pics of these as well if you like) to soak that heat and transfer it to the heat sink or case of the amplifier (this is why big amps have big heatsink fins running their length, although with class T and D amps, these aren't as necessary since they are about 80-86% efficient vs an older class AB amp with like 60% efficiency) The power traces on the internals of amplifiers are suually huge, and very wide on a PCB, and higher end amps tend to stick with the old tried and true "through-hole" technology which tends to allow for a lot more power flow than smaller SMT boards and components could. That's why we still see big caps and transistor packages in amplifiers, whereas head units are all 4+ layer SMT boards these days to cram more into less space.

Anyway in short, the guy was feeding you a line of crap. I can disprove him in a matter of moments with an oscilloscope, a tone generator, a dummy load, a regulated power converter/supply (110VAC to 12VDC high current) and a DMM.. or in other words, my test bench.

If the amplifiers couldn't produce their rated power, sustained, they wouldn't get a CEA2006 rating that states they produce their rated power under very specific standards.

Now what you could argue is that the rated power can't be produced in a car because you have an inductive load in an environment subject to impedance rise, transfer function, cabin gain, dynamic input source, and other factors like that.. but that really is a different argument, and not directly related to what the sales rep was trying to feed you.

In truth, most sales people aren't electrical engineers, or even certified installers so what they tell you is what their marketing people cook up and feed them to regurgitate to buyers who aren't educated enough to shoot holes in their BS.

When I worked for a shop in the early 90s, we had a PG rep come by and try to talk us into selling his stuff. Now, I like Phoenix Gold, or I did back then anyway, but he started spouting off about hte amp having no minimum load spec, so just to see if his claim was true, we wired the amp up to the test board, then proceeded to wire up 8 2-ohm 12" Orion 12" subs to the amp, in straight parallel.

We cranked the volume and turned on the Alpine CD player.. The amp played!

....for about 2 seconds, then smoke poured out of it.

We unplugged the amp, returned it to the sales person, and tahnked him for his time, and his new door stop, and sent him packing.

[ssh 924]

Glasswolf thanks for clearing this up and making some sense out of it for me

[todd.brust 29]

Glasswolf.....that seems familiar. Were you or are you on CACentral.ent?

[GlassWolf 5]

Glasswolf.....that seems familiar. Were you or are you on CACentral.ent?

yeah I'm one of the admins of CAC.

[todd.brust 29]

Thought so. Nice to see you around these parts! Your knowledge could be used here!

[GlassWolf 5]

thank you.

[carampsguru 0]

Hello,

Actually the short and accurate answer to the question is:The PCB copper traces can handle higher current densities,because their surface area is bigger and

can dissipate the heat better(with lower temperature rise).This of course ,depends on the airflow and will be probably different for top and bottom layers.In multilayer

PCBs the internal layers can't cool off as good and lower current density is allowed.

For example: 50mm long and 30mm wide 2oz PCB copper trace can handle 83A of current with 80C temperature rise.For internal trace is half of that - 41.5A

Also the fusing current(when it opens) will be 266A with time for melting of 5.47s