Lab Gruppen FP14000 clone amplifiers - Page 82

It is a very rare day when I would get 97v. 99% of the time I get 103v.

Japan has a voltage of 100V.

Not sure if you're agreeing or disagreeing. If he's only hitting the -4dB mark then it's less than 50% of the amp's power, and the Itech is +3dB more than the 10Q, you're 7dB difference. Excursion nor sound are going to be the same. Is there something missing in that equation?

Not sure if you're serious.

He's in Japan. Power there is 100Vrms (AC). It's not like the US where it's 120V.

I am amazed JapanD did not put 220 or 240vac in his HT room. Everything else is top rate stuff.

Here's what my voltage meter says.

As you can see, the difference between -10db and a full -4db is large. 255 volts, 70 vs 325.
Interestly enough, the amp manages to squeak out another 50 volts into the VPL circuit... but it sounds distorted and nasty at this point, even though the subs are only moving an inch (35% of their xmech).

That voltage seems quite high to me, even considering it's unloaded. Is that known to be a characteristic of this type of amp?

@whoaru99, no, that sounds right.

FYI, i am not intimately familiar with the internals of this amp but I measured a 190V DC on the amp capacitor circuit when I was doing some diagnostics a while ago.

Just doing some simple math:
190v into an 4ohm load is 9025watts assuming all the links in the output chain can handle that kind of power.

now as for output voltage as measured by BassThatHz:
190+190=380

Am I wrong to assume that the switching amplifier design can make 190+ on the positive hump of a sine wave and -190 on the negative hump?
this explains why we see that measurement from BassThatHz.

Hope I didn't confuse anyone. I may be confused myself.

That means the 14k should output about 800volts. Just over double this.

The circuit breakers limits us to 30amps, thus 3600watts / 4 = 900watts rms. Assuming 100% efficiency (which it's not).
So I'm sure if you connected four water-cooled 4-ohm loads though it would drop to about 58V rms per channel.

rather unhappy with my latest sanway purchase, amp works, but definitely not the sunon fans that johnson promised.

how do i know? it is noisier then my fp14000 from 2011!

also the new packaging is bad, bubble wrap galore!

no reply from johnson either after purchase

they are just trying to give you the full jet engine background noise experience.

if the negative rail also run on 190V DC, in which most dual rail amps do, you'll have the supply at 190V-0V-190V.
which means that the amp could swing the output from -190V to 190V sine.

which mean the amp have a Vrms of 134V.
which mean at 100% efficiency (and no limitation at the current), the amp could do
P = V^2/R
P = (134^2)/R

say the load is 4 ohm, you'll have P=(134^2)/4 = 4489Wrms.

it's class D, the efficiency could be in the high 90%. and with a huge enough capacitor bank, the amp could be made to sustain enough current that it wouldn't be current limited, especially with music signal.

Breakers don't pop instantly so you can easily have transients that exceed those wattages.

Thanks @Paskal9

I was not going to attempt that math with the flu so glad someone did.

I am currently using only one channel of my 14K @ 4Ohm so assuming i was using both theoretically I can achieve 4489Wrms for each channel or 8978W rms total. Pretty decent.

~4000 Wrms max is a more realistic number considering there's gonna be switching loss, inductor loss.
i've seen quite a few class d design that are capable of rail to rail output swing (unloaded), so measuring that much voltage output like bassthathz did without any load isn't surprising.

But I thought these amps are class A/B with an SMPS, not Class D...

I think they are actually Class H with tracking SMPS.

Yes, that's what they are. A variation on class A/B. Too many classes!

the original FP14000 is a class TD. supposedly a tracking class D. that is, if the wiki could be trusted.
from wikipedia: from the original FP14000 product page:
there's a whole bunch of new classes that manufacturer tend to create to help differentiate their products from the traditional class. class T, TD, S, Z, W, and a collection of marriages between them.
well if it's a switched waveform, however fancy the design is, is still a switching amp. essentially still a class D.
though i might be wrong. feel free to correct.

anyway power output is true to all and every amp design. there's no way an amp would be able to swing the output more than its power rail. it's physics.

Not in example presented. Once you hit the PS rail voltage the amp can't put out any more power to a given load regardless of what it has available from the AC mains.

The Wiki is not to be trusted. It's wrong. I certainly agree on the limitations of physics in its output

I've had my two fp14k clones for well over a year now and they still run flawlessly.

The 5400 is relatively inefficient and is known to require gobs of power to really get going. Watching a single clone completely manhandle TWO 5400 in a SEALED box made me a believer.

Comparing the 4ohm output of a single channel of the fp14k to the bridged output of a single ep4000 is laughable. My .02 cents from hands-on experience with both amps.

I agree entirely. My set up used to be 2 EP4000's and 2 Ultra 5400's now I just have one clone and A LOT more power... I could clip both EP4000s easily.

^^^

This!!

As I currently have a pair of Ultra 5400's and two ep4000 for power, I wonder if it would be worthwhile to get the clone while still on a 15a dedicated line. I won't be upgrading the line any time soon, as we are considering a move... but still wonder what I'm leaving on the table with the ep4000's.

I have each of my clones on their own 15 amp circuit and I've had ZERO problems running them this way.

Thanks for the heads up

Have you ever ran the LMS on just an ep4000? I know it is underpowered compared to the clones, just curious if you have any insight into the upgrade.

I'm not really sure where all this talk continues from about the LMS-U being 'inefficient'. Everyone keeps saying that or that it needs/requires a ton of power. It's actually tremendously more efficient that most high excursion 18's. It just so happens to be able to soak up a lot of power.