I research, though, I just simply can not understand the electronic aspect of rigging a cabinet to a PA amp. Please let me know what the loudest speaker cab(set)configuration would be for this amp.
I have no need for Stereo Mode. I would love to run two 12" cabs in Bridged/mono mode as this would be for vocals ONLY. Specs below.
I also do not understand the difference between series and parallel. Currently, I am using ONE single banana clip connected to(Mono/Bridged)which is clamping BOTH Speakon cables (one to each speaker). Would that be series or Parallel?
What are your speaker and rigging configuration recommendations for the following amp?
QSC USA 850
Stereo Output
4 Ohm, 1Khz - 425 watts
8 Ohm, 1Khz - 270 watts
8 Ohm, 20Hz - 20Khz - 240 watts
Bridged Mono
4 Ohm, 1Khz - 1100 watts
8 Ohm, 1Khz - 850 watts
Thank you all for your replies in advanced!
Need to match cabs to an amp
Need to match cabs to an amp
Last edited by Frank The Rabbit on Tue Jun 17, 2014 8:39 pm, edited 1 time in total.
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- Frank The Rabbit
- Posts: 2 Joined: Tue Jun 17, 2014 12:00 am
Re: Need to match cabs to an amp
Wow..
Nobody?..
Nothing?..
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- Frank The Rabbit
- Posts: 2 Joined: Tue Jun 17, 2014 12:00 am
Re: Need to match cabs to an amp
Given your lack of confidence regarding safe wiring of multiple speakers I'd suggest you buy a pair of 250 watt continuous rated, 4 ohm speakers. Connect one to each channel of the amp using shop bought speakon cables (the dealer may well be persuaded to include a pair). It is usually recommended that the amp has a power output (RMS) os between 1.5 and 2 times the speakers continuous rating to get the max out of the system. Just be careful that you don't overdrive the amp so that it distorts (use your ears) as that distortion can lead to speaker damage.
I'm not sure what you mean by this, one single banana plug won't complete a circuit, can you post a pic?
Ok found a pic of one of these on ebay. I'd guess the plugs go to the two red binding posts, this will be in parallel so you must use 16 ohm cabs (giving a resulting impedance of 8 ohms which is the minimum safe impedance in bridge mode. If you cabs are 8 ohm you must use them in stereo mode, though you can drive both channels with the same signal for mono.
I also do not understand the difference between series and parallel. Currently, I am using ONE single banana clip connected to(Mono/Bridged)which is clamping BOTH Speakon cables (one to each speaker). Would that be series or Parallel?
I'm not sure what you mean by this, one single banana plug won't complete a circuit, can you post a pic?
Ok found a pic of one of these on ebay. I'd guess the plugs go to the two red binding posts, this will be in parallel so you must use 16 ohm cabs (giving a resulting impedance of 8 ohms which is the minimum safe impedance in bridge mode. If you cabs are 8 ohm you must use them in stereo mode, though you can drive both channels with the same signal for mono.
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- Sam Spoons
Forum Aficionado - Posts: 22914 Joined: Thu Jan 23, 2003 12:00 am Location: Manchester UK
Still mourning the loss of my 'Jedi Poster" status 
People often mistake me for a grown-up because of my age.
People often mistake me for a grown-up because of my age.
Re: Need to match cabs to an amp
Found a manual!
Looks like the spec in the OP is correct, it will do 4 ohm bridged, (and 2ohm per channel) though there are warnings about overheating when running it this way, so it may not be wise given your quest for "loudest".
To be honest, I'd go with what Sam said.
Looks like the spec in the OP is correct, it will do 4 ohm bridged, (and 2ohm per channel) though there are warnings about overheating when running it this way, so it may not be wise given your quest for "loudest".
To be honest, I'd go with what Sam said.
Re: Need to match cabs to an amp
I'm pretty sure the red sticker on the 8th pic down (and below) http://www.ebay.co.uk/itm/QSC-Audio-Professional-Power-Ampli... says min 8 ohms in bridge mode.
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- Sam Spoons
Forum Aficionado - Posts: 22914 Joined: Thu Jan 23, 2003 12:00 am Location: Manchester UK
Still mourning the loss of my 'Jedi Poster" status
People often mistake me for a grown-up because of my age.
People often mistake me for a grown-up because of my age.
Re: Need to match cabs to an amp
You could be right - I can't tell. But there's no doubt about what the manual I linked to says page 8.
The warnings about overheating in 2ohm (which will apply to 4ohm bridged) mode are on page 5
The warnings about overheating in 2ohm (which will apply to 4ohm bridged) mode are on page 5
Re: Need to match cabs to an amp
Yup, no doubt about it, that's what the manual says 
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- Sam Spoons
Forum Aficionado - Posts: 22914 Joined: Thu Jan 23, 2003 12:00 am Location: Manchester UK
Still mourning the loss of my 'Jedi Poster" status
People often mistake me for a grown-up because of my age.
People often mistake me for a grown-up because of my age.
Re: Need to match cabs to an amp
The QSC USA850 will bridge into 4ohm. It'll get hot if you push it, but its a fairly heavy-duty thing and will cope.
Since this is for vocal use, I'd be confident that heating won't be an issue - there's rarely any long-term high power delivery like, for example, subwoofers sometimes need.
Find some decent 12" two-way tops. Anything worth spending some money on will do the job well, and stand up to the QSC amp. My tops are 350w continuous (as in, all-day pink noise), but since music is peaky, I used one of your QSC amps bridged to one of the tops, for a (rather loud) festival.
HTH
Chris
Since this is for vocal use, I'd be confident that heating won't be an issue - there's rarely any long-term high power delivery like, for example, subwoofers sometimes need.
Find some decent 12" two-way tops. Anything worth spending some money on will do the job well, and stand up to the QSC amp. My tops are 350w continuous (as in, all-day pink noise), but since music is peaky, I used one of your QSC amps bridged to one of the tops, for a (rather loud) festival.
HTH
Chris