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Author Topic: Yorkville LS808 and QSC1850HD  (Read 5405 times)

Troy Ritchison

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Yorkville LS808 and QSC1850HD
« on: September 16, 2013, 03:09:13 pm »

Quick story, I have been running this combo for 1.5 yrs with no problem.  A month or so ago I noticed the amp had gone into protect while I was lightly (speaking volume) playing music during set up.  I shut it down for a few minutes and everything came back fine.  This has happened 4-5 times since then but once I shut it off it comes back and gets through the show.  This past weekend it didn't make it through the first set before it went into protect (both limit lights stayed red)  I shut it off for the rest of the set, fired it back up on break and it hit 2/3 times the limit lights flickered twice then it hit protect again.  Wouldn't fire up the rest of the night unless I left the gain dials halfway down or more.

Called QSC this morning and was told that the amp is fine, my speakers are just vastly being under powered and that I should be running a PLX3102 bridged mono into these speakers.  The 1850hd is just working to hard.

Keep in mind that the clip lights rarely if ever flicker when I'm running the system, so somehow that doesn't make sense to me at all.  Plus I know these speakers do not need 1550 watts per to provide the volume I need.
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Ryan Fontenot

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Re: Yorkville LS808 and QSC1850HD
« Reply #1 on: September 16, 2013, 09:45:35 pm »

Hi, I noticed that you stated you had to turn the volume attenuators halfway down for the amp to work.  This is because of a gain structure problem.  You can receive full power out of an amp with the volume knobs at 9 and have proper gain structure or you can turn the knobs all the way up and get the same volume but with distortion, hiss, and overloading of the amp. 

It sounds to me like you need to properly set the gains on the entire system.  The knobs on the amp do not have to be all the way up.  There is a lot of information about how to properly set the gain in a system, if you Google it.

Thanks,
Ryan




Quick story, I have been running this combo for 1.5 yrs with no problem.  A month or so ago I noticed the amp had gone into protect while I was lightly (speaking volume) playing music during set up.  I shut it down for a few minutes and everything came back fine.  This has happened 4-5 times since then but once I shut it off it comes back and gets through the show.  This past weekend it didn't make it through the first set before it went into protect (both limit lights stayed red)  I shut it off for the rest of the set, fired it back up on break and it hit 2/3 times the limit lights flickered twice then it hit protect again.  Wouldn't fire up the rest of the night unless I left the gain dials halfway down or more.

Called QSC this morning and was told that the amp is fine, my speakers are just vastly being under powered and that I should be running a PLX3102 bridged mono into these speakers.  The 1850hd is just working to hard.

Keep in mind that the clip lights rarely if ever flicker when I'm running the system, so somehow that doesn't make sense to me at all.  Plus I know these speakers do not need 1550 watts per to provide the volume I need.
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Richard Turner

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Re: Yorkville LS808 and QSC1850HD
« Reply #2 on: September 16, 2013, 10:28:39 pm »

Hi, I noticed that you stated you had to turn the volume attenuators halfway down for the amp to work.  This is because of a gain structure problem.  You can receive full power out of an amp with the volume knobs at 9 and have proper gain structure or you can turn the knobs all the way up and get the same volume but with distortion, hiss, and overloading of the amp. 

It sounds to me like you need to properly set the gains on the entire system.  The knobs on the amp do not have to be all the way up.  There is a lot of information about how to properly set the gain in a system, if you Google it.

Thanks,
Ryan

QSC RMX1850HD is rated 300w/ch clean @ 8 ohm, unsure where you get the 1500 watt per box?

How would QSC know the amp is fine with a phone call?

Does the fan still work in it?  dust bunnies evicted lately?
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Ryan Fontenot

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Re: Yorkville LS808 and QSC1850HD
« Reply #3 on: September 16, 2013, 10:45:14 pm »

I never stated anything about wattage what so ever.  Doing this as long as I have, I have seen this same issue which is what brought me to this conclusion.  I do not have the need to call the manufacturer to ask them because I can tell what the problem is.

Dust bunnies are not going to make an amp cut on and off unless it is entirely stopped up.  I would think since he keeps walking up to the amp that it is not dirty and just has a bad signal or too much signal going in.

Please do your research before you go mouthing off about something someone else said. 



QSC RMX1850HD is rated 300w/ch clean @ 8 ohm, unsure where you get the 1500 watt per box?

How would QSC know the amp is fine with a phone call?

Does the fan still work in it?  dust bunnies evicted lately?
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Richard Turner

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Re: Yorkville LS808 and QSC1850HD
« Reply #4 on: September 17, 2013, 01:11:35 am »

I never stated anything about wattage what so ever.  Doing this as long as I have, I have seen this same issue which is what brought me to this conclusion.  I do not have the need to call the manufacturer to ask them because I can tell what the problem is.

Dust bunnies are not going to make an amp cut on and off unless it is entirely stopped up.  I would think since he keeps walking up to the amp that it is not dirty and just has a bad signal or too much signal going in.

Please do your research before you go mouthing off about something someone else said.

Yup I know nothing,,,,, thats for sure. Stuck fan and heat sinks plugged would never cause an amp to go into thermal protection, never ever.
 Its not likr the RMX 2450's I ran for a few years never had thermal issues either when pushed or ever had failure in the input board circuts, nope never ever happened.

OP stated not needing 1550 watts. , the ls808p uses a800 watt rms 8 ohm voice coil woofer from either RCF for older ones or B&C for more recent ones but I wouldn't know anything about that either having 8 of them oon the warehouse, nope not at all.
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Looking at retiring. Local PA market has shrank to 2 guys with guitars and bose l1 compacts or expecting full line array and 16 movers on stage for $300... no middle left going back to event DJ stuff, half the work for twice the pay.

Troy Ritchison

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Re: Yorkville LS808 and QSC1850HD
« Reply #5 on: September 17, 2013, 07:54:20 am »

I will go through the gain structure's again but I really don't I have that problem (but I am by no means an expert). 

The fan does work and the dust doesn't appear to be very bad looking through the grill.

QSC rep told me I needed to be running a PLX3102 bridged into these speakers (that's where the 1550 wattage came from). 
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Paul G. OBrien

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Re: Yorkville LS808 and QSC1850HD
« Reply #6 on: September 17, 2013, 07:10:05 pm »

It sounds to me like you need to properly set the gains on the entire system.

Gain structure is irrelevant here, unless there is something wrong with the speaker in question or the cable between it and the amp the amp should not repeatedly go into protection... period. This is a robust amp that will drive a 2 ohm stereo(4ohm bridged) load all day long so there has to be something seriously wrong to be triggering the protection circuitry.
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Troy Ritchison

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Re: Yorkville LS808 and QSC1850HD
« Reply #7 on: September 18, 2013, 10:07:53 am »

That's been my thoughts all along but I can't get QSC to agree.  This has happened more than once while I was playing a IPod during actual set up through the system (at lower than talking volumes)  This weekend was the second time its happened while being pushed.  I always use the same cables and the rack is never unplugged so I am at a loss.  Nothing in the system does more than a slight flicker of clip on the kick channel (Mixwiz board), the output strips on the board are barely into the yellow, and nothing down the line even hits the yellow.  The clip light on the amp doesn't come on at all during a show so I really have a hard time believing its not a faulty amp.  Below is QSC's last response to the situation.  In the previous email he states I need to be running a QSC PLX3102 bridged into these speakers.



Yes, the amplifier can run into 4ohms. That's not the issue. But running two Yorkville LS808 subwoofers in parallel requires an amplifier with at least 2800 W @ 4ohms in bridge mode. The RMX only has 1800 W @ 4ohms, which is severely under-powering your loudspeakers and making the amplifier work hard, therefore going into a thermal mode.


Bryan

Technical Support

QSC Audio Products, LLC

1675 MacArthur Blvd

Costa Mesa, CA  92626
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Ivan Beaver

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Re: Yorkville LS808 and QSC1850HD
« Reply #8 on: September 18, 2013, 10:28:22 am »


Yes, the amplifier can run into 4ohms. That's not the issue. But running two Yorkville LS808 subwoofers in parallel requires an amplifier with at least 2800 W @ 4ohms in bridge mode. The RMX only has 1800 W @ 4ohms, which is severely under-powering your loudspeakers and making the amplifier work hard, therefore going into a thermal mode.


Bryan

Technical Support

QSC Audio Products, LLC

1675 MacArthur Blvd

Costa Mesa, CA  92626
Sorry-but I disagree.

Speakers only "need" 1 watt (or so ) to operate.  Now how much they can handle and produce full output is a totally different issue.

The OP said the amp was not clipping and he also stated that he does not need full power to do the jobs that he is doing.

So having the extra power is not useful to him.

There is no way the amp is "working to hard" if he is not pushing it.  And since it is not clipping-I would not say that he is pushing it to hard.

Underpowering is never an issue-unless the amp is clipping.  Yet another audio myth.
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Ivan Beaver
Danley Sound Labs

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Ivan Beaver

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Re: Yorkville LS808 and QSC1850HD
« Reply #9 on: September 18, 2013, 10:33:01 am »

Quick story, I have been running this combo for 1.5 yrs with no problem.  A month or so ago I noticed the amp had gone into protect while I was lightly (speaking volume) playing music during set up.  I shut it down for a few minutes and everything came back fine.  This has happened 4-5 times since then but once I shut it off it comes back and gets through the show.  This past weekend it didn't make it through the first set before it went into protect (both limit lights stayed red)  I shut it off for the rest of the set, fired it back up on break and it hit 2/3 times the limit lights flickered twice then it hit protect again.  Wouldn't fire up the rest of the night unless I left the gain dials halfway down or more.

Called QSC this morning and was told that the amp is fine, my speakers are just vastly being under powered and that I should be running a PLX3102 bridged mono into these speakers.  The 1850hd is just working to hard.

Keep in mind that the clip lights rarely if ever flicker when I'm running the system, so somehow that doesn't make sense to me at all.  Plus I know these speakers do not need 1550 watts per to provide the volume I need.
Here are my couple of thoughts.

1: There could a an intermittant short somewhere in the speaker cable-the connections or inside the cabinet.  Any of which would cause the amp to shut down at times and not at other times.

2: I would flip the switches on the rear of the amp (SPECIFICALLY the input stereo-bridge ones).

I have run into cases where these are not "fully seated" and will cause the amp to do all sorts of weird things-like shut down-distort/clip early and so forth.

Just be careful and move them back and forth a couple of times AND MAKE SURE you put ALL of them in the proper positions for your operation.  The input/bridge switches HAVE TO ALL be in the correct position.

Have you tried other speakers AND CABLES on the amp?  It could possibly be a slightly defective amp.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!
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