XTi 4000 on a genset, some problems

[Robin_Larsson]

Hi everyone,

So, I´ve done three, one indoor 2 outdoor, gigs with my XTi 4000 and T48s, of only minimal testingtime before both of them, but atleast the drivers were burned in and the cabs airleak tested, but I´m gonna test them more as soon as I can.

Yeah, I´m very pleased with the T48s! More on that in some other thread when I´ve had more setup/trim time, but it sure is looking good!

The problem I´ve had is: The XTi amp is a bit unstable running of a cheaper genset, and yes, I´ve seen that others have had this problem also, I didnt really see that before I ordered mine sadly..
The setups have been: two different, but very similar, rather cheap 2.2 and 2.5kW gasoline gensets, driving the XTi, the DJ stuff and between 30 and 100W of LEDlights and Lasers. The first gig we use only one T48, and ran my two old single 15" tops, at the second we used 2 T48s, same tops. During the second gig we had a full DJ setup with both vinyls and cdplayers and a Pioneer DJM 600 mixer, at the first we ran with a laptop and MIDI DJ controller.
The second gig also had one of our 600W smokemachines on the same genset.

The problems I´ve had is:
1. Sometimes I get very much clipping, both on inputs and out, sometimes only on one side.
2. A few momentary dropouts of the output, it simply shut down the output, but amp still running and working in Bandmanager, sometimes both channels at the same time, sometimes only one, then mainly the sub channel.
3. After a few bassbeats the output drops by about 6db on both top and sub channel, after a pass of no bass in the music, it goes back up, only to drop again when the bass gets going, with the audience complaining a bit..

I´ve found that the genset we used on the first gig have a problem with the RPM regulator, it simply revs to much, so gave something like 245V and 70-75Hz (We have 230V/50Hz here in Sweden) until I regulated it down manually, but before getting it down, we had enormous clipping and could not get any good output at all, not so surprisning.

So for the second gig we first tested with our old genset, regulated as close to good power as we could, but music is dynamic, so it doesnt work very good. The we switched to the newer, 2.5KW genset I´d borrowed, it worked better, but still not good, problem number 3 was very prominent. But I couldnt really measure any drop in either voltage or frequency when it happens, and we cant be maxing out the genset with that setup, the amp should be running something like max 1000-1200W, if even that, sub channel running to the -6db limiter now and then and driving two T48s.
But I found that when the smokemachine started heating its 600W element, the amp ran perfectly! No drops in output or anything! I still couldnt measure any real differns with my multimeter, still showing like 234V/53Hz. But I guess that the smokemachine evened out the load on the genset, and maybe acting as a kind of buffer or so, being a purely resistive load and all.
But of course, when the smokemachine was warm, it turns of the heater, and the output on the amp dropped.
So we tried hooking up our two Geni Shiva 200R scanners, 200W discharge lamps, 250W total powerdraw each. The thinking was to get a constant load in the same region as the smokemachine, but it didnt work at all! That was the only time at this gig were we got problem 2, total dropout, and some hard clipping on the amp. I thought that was a bit strange, but likely have something to do with powerfactors and such, I guess the ballast in the scanners arent very pure resistive.

Long post, sorry, but here comes a question, I was thinking of buying a power conditioner, one that stabilises the voltage and filters out disturbances and powerspikes, likely this one: http://www.thomann.de/gb/phonic_ppc_9000_e.htm or maybe the cheaper Furmans, like the M-10 X E.
Would you say that it could help with some of my problems? I have a feeling it could, even if not as good as an Inverter genset or a UPS would, but should be better, more so with the Phonic PPC 9000, since it regulates the voltage to the right level, doesnt seem to me that the Furman does that?

Of course I should buy a better genset, but its simply to expensive for just a few outdoor partys each summer, likely only one or maybe 2-3 more this summer, summer is short and gives alot of rain in Sweden:P Sure, we could rent one, but these parties are small and almost for free( we´re trying to rebuild Gothenburgs Hardcorerave scene again:P)
Is there any other amps that run better on bad power/gensets? I think I´ve heard that the Peavy IPR does? or even some old iron ones like the EP 4000?
I really like the XTi in other respects, and really dont feel like selling it, even if I must say that if feels alot cheaper than it was... mainly the switches in the front panel feel/look and sound like cheap crap:P

Hope someone read it all and have a good response:D

//Robin

[RayAbbitt]

Bite the bullet and get a decent generator. Getting a real regulator will cost a lot more than the Phonic you suggested. (It is nothing more than a powerstrip with "surge suppresion" and can't do anything to adjust the voltage.

Buying a different amp won't fix your problems either. An unregulated generator is good for nothing but lighting. You need to accept that and get something that won't end up destroying your equipment.

-ray

[Robin_Larsson]

well, sadly its not biting the bullet, there is simply no way we can but a generator for around 1500 euro or more for a long while, we just dont have that money to spend on that.

Are you really sure that the Phonic doesnt regulate the voltage? they say that it does on their website, phonics, not thomann that is.

Any theories as to why it work more or less perfectly with the additional load? It´s after all only the XTi that seems to have a problem, of all our eqiupment, and we have used one of those generators with and old amp before, with good results, even if that had a lot less power, but it cant really be that the generator dont give enough power, must be to uneven or so..

//Robin

[el_ingeniero]

Try a line conditioner. The Tripplite LR2000 should output a steady 230V with input voltages of 175V-253V. It sells for a little over $200 in the US. Of course, run the light system directly off the generator.

[Robin_Larsson]

Okey guys, I was wrong on the phonic, it does not regulate the voltage, their salestext made me think so, but the manual set me straight:p that's why I always read the manual before I buy stuff, if its available online:p

So I didnt buy the phonic. I loked at the tripplite, would cost me over 700dollars here.. also, it looks like it only regulates in thee steps, and only promises 230v +-10% and my generators are better than that, they only been of by about 5-10 volt, kess than 5%. So, I dont think that the issue really is the wrong voltage, atleast not if +-10% is considered good for sensitive electronics! Perhaps the frequency is more of a problem? But the better of the two gensets were at about 53hz, so should be good?

Can it be that the generator simply cant react fast enough to deliver enough snorte? And that when its loaded more with a static load, it just works better?

Anyone think that the phonics RF filters and such can help to prevent excessive clipping? Although I dont think we had that problem when the smokemachine ran:p

How do you guys do it when running on generators?

Any thoughts as to why it worked with the smokemachine running, but not at all with the equal power discharge scanners?

Cheers!
Robin

[camrynekai]

Anything less then 117v a/c in on a XTI4000 and < will have issues producing 65hz and lower(sustained)@ 4ohm per ch. load. For stable sub duty the XTI6000 is a much better choice. Granted it has way more balls then needed...but it will not fail to deliver enough power for ANY of Bills designs and can do so down to about 109v a/c with a 2ohm load.

[el_ingeniero]

I guess you are hozered: http://www.ustpower.com/Files/Small%20G ... %80%A6.pdf

[Robin_Larsson]

el_ingeniero, that was some interesting reading, although its a bit on the negative side:P After all, it actually works alot of times to run stuff on electronics:P But it does better explain the problem with the changing load, that I was getting at, and yes, thats most likely why it works better with more load than just the amp on the generator, the dynamic part of the load is then a much smaller part of the total load, easier for the generator to handle.

But still its a bit of shame, and I think a bit strange, that this specific amp that can handle from 110 to 240V have more problems dealing with the power from a generator than some other switchmode amps, as that seems to be the opinion here? No other of our electronics showed any signs of problems with the generator power. But yes, the amp is the only electronic load that changes alot:P

And the main problem is most likely that the generator just cant deliver enough power fast enough.

Yeah, we´ll see how we´ll solve it the 27e of august, maybe run a small electrical heater on the same genset as the audiosystem:P And run the bigger lights and smokemachines on the other generator.

camrynekai, dont you guys run 110V in America? I wonder what the lower limit for the XTi 4000 perfomance is when running on 230V.. After all, it does do both 110 and 230V without changing any settings as far as I know, so it really should be able to work good anywhere between, as long as the freguency is between 50 and 60Hz. I guessing that the unstable frequency might be more of a problem for the amp than the voltage.

But does anyone know if any other amp works better on generators/bad power?

//Robin

[Tom Smit]

Probably be a good case for old iron. Won't be as noticeable, I would think.

[camrynekai]

With the new style amps...it is a new world...ya really need to buy bigger and use less to get the benefits of SMPS.

[el_ingeniero]

+1.

Gensets are a terrible environment for switch mode power supplies, unless the genset incorporates a massive flywheel to keep the speed (and hence the output) steady.

You need one of those amps with massive transformer based power supplies, the bigger the transformer the better.

[matt996]

Why not just get a small electric heater to run as a dummy load, to keep the generator's throttle open a bit. If the frequency issues are arising when the load is reactive and dynamic, adding a constant resistive load to the generator should help to smooth things out a bit especially when you're dealing with a relatively slow acting mechanical governer/throttle controlling the engine speed. If your generator has enough kW to run everything then I'd think this would be the cheapest solution though it means you'll burn a bit more gas.

[Robin_Larsson]

Matt996, that's a good idea, and exactly what i was planning to test:) t
Thats what the smokemachine did really, added a constant resistive load, just not constant all the time:p should have had a smokemachine that could run on low powwr continius output:p or some lights that could work, but I only have LED and discharge lights so.

Clearly worth to use a bit more gas:p

Thanks guys! I'll let you know how i worked out, next part is the 27th of august:(
Now, back to cutting fibreglass for my boatbuilding project! Oh, the bot needs a kickass subwoofer later, a Yacht-Tuba?:p really need an efficient hornsub on a sailingboat:)

//Robin