[jmilleril]

Bear with me on a dumb question.. Multiple people run a FP20k on a 120v, 30A line. Doesn't it stand to reason that a single 20k would be just fine on a 240v 20A (or even 15A for that matter)

The AC to DC power supply in that amplifier is designed to draw up to 240volts and 30 amps or about 7000 watts. So either you bought an amp far larger than you needed, or you are going to be popping breakers / overheating wires and limiting it's output during anything beyond instantaneous burst sounds. Wire and a proper outlet is pretty cheap compared to the price of that amp, and doing it right could substantially improve it's performance. Can you do it, yes, but in general you shouldn't, and for best performance you wouldn't want to.

 

[Jk7.2]

Bear with me on a dumb question.. Multiple people run a FP20k on a 120v, 30A line. Doesn't it stand to reason that a single 20k would be just fine on a 240v 20A (or even 15A for that matter)

I have success running my 20k’s on 120V, 30A lines. As far as I’ve pushed the amps, I’ve never popped a breaker. (I used to all the time with Inukes on a 120v 15a) But my room is small, I have way too many subs that are high efficiency. Ported for even more spl. But I have pushed the amps to clipping and not had an issue with the breakers.
I’d still go 240v if you can. Why the heck not? Like already mentioned, it’s relatively not expensive compared to the cost of each amp. And if it helps the amp run smoothly and not upset the power lines, do it. Plus you’ll get more maximum output.

 

[mcallister]

Same as Jk, I’m running two 20k’s on dedicated 120v 30A lines and I can’t even get mine to clipping.

 

[jmilleril]

Same as Jk, I’m running two 20k’s on dedicated 120v 30A lines and I can’t even get mine to clipping.

Due to the extreme amount of capacitance in these things you can technically get it into clipping even if it's unplugged.
The supply side only matters for content that has longer duration and high intensity causing you to start seriously depleting it's reserves. That content exists, but you may not listen to it. In the old days we had discussions around peak power versus continuous. This amp is rated in peak power, but it has enough capacitance that it's peak can last pretty long. It's continuous rating is limited by it's power supply. My preference (as in my opinion) is to have an amp that can do most of it's power continuously, but I am showing my age there.

In general if you have something that works, awesome! If you want to build it once, then build it right the first time.

 

[Eskimo1]

The AC to DC power supply in that amplifier is designed to draw up to 240volts and 30 amps or about 7000 watts... Wire and a proper outlet is pretty cheap compared to the price of that amp, and doing it right could substantially improve it's performance.

Thanks for the clear explanation. I have a 240v 20A line available (shared with baseboard heaters that we don't use while using the theater), so while that's better than a 120v 30A, it's not optimal. Gotcha!
(My breaker box is absolutely full, so to add another 240V circuit in there would mean a sub-panel or freeing up space by swapping out a bunch of breakers for those doubled-up ones - additional PITA/cost)

 

[Jk7.2]

Thanks for the clear explanation. I have a 240v 20A line available (shared with baseboard heaters that we don't use while using the theater), so while that's better than a 120v 30A, it's not optimal. Gotcha!
(My breaker box is absolutely full, so to add another 240V circuit in there would mean a sub-panel or freeing up space by swapping out a bunch of breakers for those doubled-up ones - additional PITA/cost)

I had my panel replaced. With one for additional breakers. But I also have an Electriction buddy.

 

[Jefro6996]

Thanks for the clear explanation. I have a 240v 20A line available (shared with baseboard heaters that we don't use while using the theater), so while that's better than a 120v 30A, it's not optimal. Gotcha!
(My breaker box is absolutely full, so to add another 240V circuit in there would mean a sub-panel or freeing up space by swapping out a bunch of breakers for those doubled-up ones - additional PITA/cost)

Not sure how handy you are but a sub panel was actually pretty cheap. I already had 200A service on my main panel and the sub panel ran around $60. My main panel was pretty full, so I opted to have an electrician wire the sub panel and it only ran me $200, which was well worth it. That was wiring the sub panel off the main and adding all the basement circuits into the sub panel. I now have 3 dedicated 240v 30A circuits in my AV closet and 5 dedicated 120V 20A amp circuits so I should be future proofed. I ran all 10/2 for the 30A circuits since I had plenty of 120v circuits available already.

Sent from my SM-N975U using Tapatalk

 

[jmilleril]

So long as you have the physical space, a big subpanel is the way to go. As long as the existing main panel is a good design I do matching panels so I can move breakers around without challenges. Never pay retail for breaker panels! Retail for a decent large breaker panel may be $1000, but you can often get them for 20% of their retail price, and sometimes 10% of it.

240V and 20Amps is 4800 watts, or as we say around here, a good start

 

[Jk7.2]

So one of mine is dead?
No power at all. Won’t power on. Anyone had this issue? Is it a fuse? I am posting here instead of actually taking the amp apart and finding out for myself. Forgive me. Lol

 

[johnson636]

So one of mine is dead?
No power at all. Won’t power on. Anyone had this issue? Is it a fuse? I am posting here instead of actually taking the amp apart and finding out for myself. Forgive me. Lol

Have you checked the breaker for that circuit?

 

[Jk7.2]

Have you checked the breaker for that circuit?

Yes. I have many circuits in the area. I plugged it into one that was working for sure, and nothing.
Also just double checked, another amp worked on that circuit.

 

[EndersShadow]

I am posting here instead of actually taking the amp apart and finding out for myself. Forgive me. Lol

Sounds like a solid plan. I goggle photos of the back of my equipment rather than turning it around and disconnecting it lol


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[Pradeep2]

Just be careful my understanding is they can hold a significant charge well after they are unplugged from the wall.

 

[Randy_J]

So long as you have the physical space, a big subpanel is the way to go. As long as the existing main panel is a good design I do matching panels so I can move breakers around without challenges. Never pay retail for breaker panels! Retail for a decent large breaker panel may be $1000, but you can often get them for 20% of their retail price, and sometimes 10% of it.

240V and 20Amps is 4800 watts, or as we say around here, a good start

I agree that a sub pannel is the best way to go. If you go to a big box store you can get one for 60$ to 150$. When we were doing our addition on our new house it had a 200amp 32 slot pannel that was completely full. I had the space next to it so i matched what was there and put a second 32 slot pannel in. I only needed 7 more breakers but knew i wanted to be able to add whatever i needed for my someday theater build. It truly is not a hard thing to do. But i am a electrician so i may be a bit biased.

 

[Jk7.2]

I’m kinda stumped with this dead amp. I took the top and bottom covers off, and I don’t see anything that looks blown. Any ideas?
Edit:
It’s just these fuses. I did the dumb thing of jumping them. But amp powered on.

Now, where can I get these?

 

[johnson636]

Are both fuses blown? Do you smell anything? Did it suddenly loose power during heavy and extended bass song/movie scene? As you may know, a fuse is an overcurrent protection device, so unless the culprit of the overcurrent is located, the problem will still exist.

 

[Jk7.2]

Are both fuses blown? Do you smell anything? Did it suddenly loose power during heavy and extended bass song/movie scene? As you may know, a fuse is an overcurrent protection device, so unless the culprit of the overcurrent is located, the problem will still exist.

That’s the thing with having amps in a different room. I have no idea when it blew. My amp for the 4 NSW’s was working all along. So I had bass. I didn’t notice the other wasn’t working. Nothing smells. Everything is clean.

 

[BassThatHz]

Jumping the fuse holder is a good way to ensure that the amp is either fully-dead now, or not fully-dead yet. It will definitely clear the fault. 😅

You can get them at any HW store, but definitely online.
I believe they are just generic 30A 240V quick blow fuses.

You'll want to take each one out and test it with an ohm meter. If it reads 0-ohms then it is working, reinstall the working ones back where you took them out from.

You'll want to buy a pack of them because it might blow another set.

Yours appears to be fused at 60A, I assume you have the 120V model.
Drawing over 60A @ 240V would be quite the feat, even for a FP20k.
What were you powering with it?
Were you trying to weld IPAL-21's at 0-ohms at 194db... or what?

In any case, if you need a beefier amp you could get a pair of FP14k's, they run cooler, handle lower ohms better, and output slightly more power (6db bridged and 1-3db unbridged).
Or better yet: a used Gruppen PLM20k, those at least have PFC, 70-265v uni-supplies, legit trip protection, protection circuitry, load monitoring, DSP, (and more...)

Sounds like you clipped it to death and/or overheated it to death, perhaps.
Amps this powerful are capable of sagging the power grid, which can cause additional problems for the amp.
Did your UPS record any sag events by chance?
I run a dozen clones at 120V, and even though the line is 2awg I still manage to sag it from 120V to 105V and that still isn't anywhere near clipping yet. I probably should convert them all to 240V at some point, I'm sure the pole transformers and power company would be happier if I did. 😅

 

[Jk7.2]

Jumping the fuse holder is a good way to ensure that the amp is either fully-dead now, or not fully-dead yet. It will definitely clear the fault.

You can get them at any HW store, but definitely online.
I believe they are just generic 30A 240V quick blow fuses.

You'll want to take each one out and test it with an ohm meter. If it reads 0-ohms then it is working, reinstall the working ones back where you took them out from.

You'll want to buy a pack of them because it might blow another set.

Yours appears to be fused at 60A, I assume you have the 120V model.
Drawing over 60A @ 240V would be quite the feat, even for a FP20k.
What were you powering with it?
Were you trying to weld IPAL-21's at 0-ohms at 194db... or what?

In any case, if you need a beefier amp you could get a pair of FP14k's, they run cooler, handle lower ohms better, and output slightly more power (6db bridged and 1-3db unbridged).
Or better yet: a used Gruppen PLM20k, those at least have PFC, 70-265v uni-supplies, legit trip protection, protection circuitry, load monitoring, DSP, (and more...)

Sounds like you clipped it to death and/or overheated it to death, perhaps.
Amps this powerful are capable of sagging the power grid, which can cause additional problems for the amp.
Did your UPS record any sag events by chance?
I run a dozen clones at 120V, and even though the line is 2awg I still manage to sag it from 120V to 105V and that still isn't anywhere near clipping yet. I probably should convert them all to 240V at some point, I'm sure the pole transformers and power company would be happier if I did.

I just jumped the fuses to be sure it would turn on. Hopefully with no load at all there wouldn’t be a disaster. This amp has a history. It’s the one that got a new output board when it was doa. I did that replacement and it’s worked well ever since. But this probably is my fault. I’ve been pushing things because my room is a new remodel just to test out what’s changed. I did clip the piss out of the amps unknowingly a few times. Finally I decided to go see how they were during during the barrel roll scene. They were clipping.
The amp is powering my rear hst-18’s and nearfield ds4’s.
I’m prepared to just buy a new amp. We will see.
Also, it’s a 120V amp, on a 30A dedicated circuit.

 

[Vince_B]

Did it suddenly loose power during heavy and extended bass song/movie scene?

Meanwhile, outside....