Stupid pa system questions...

[jgcable]

I have a Soundtech PS802 power amp. Here are the specs below. I have a Mackie 14 channel mixing board and 2 Peavey 8 ohm PA cabs loaded with a 15 and a horn in each. They are 8 ohm cabs.
What would be the best way to hook this up to get maximum power. I currently have it hooked up in 8 ohm bridged 800w mono and I have the speakers plugged into the left and right sides of the power amp.
Would it be better to leave the amp in 400w 4 ohm stereo?

Power Amplifier – PS802

Following in the footsteps of the popularly acclaimed PS800, SoundTech is proud to offer a further refinement of its "smaller, lighter, and more powerful" Power Source Series. The PS802, which yields 800 Watts in a scant 1 space high, 15.8 lbs. rack mount package, is a heavyweight performer in a flyweight package. The SoundTech PS802 achieves its small size and light weight by using a highly efficient, hybrid switch mode power supply, which reduces the need for bulky mains transformers. Weight and size savings are especially important for portable sound applications; whereas smaller, lighter amplifiers yield daily savings in transportation and labor.
Specifications

• Specifications
• 8 ohms Stereo mode 230W + 230W
• 4 ohms Stereo mode 400W + 400W
• 8 ohms Bridged mode 800W
• Frequency Response: 5Hz - 65kHz ±3dB
• THD 0.05% @ 800W
• Damping Factor at 8 Ohms: >240
• Channel Separation: 85dB
• S/N: 120dB
• Input Sensitivity: 1.23 +4dBm
• Slew Rate: 42v/μsec
• Maximum Voltage Gain: 36.3dB
• Input Impendence: 7.5Kohm unbalanced, 15K ohms balanced
• Protection: In-rush current, output muting, DC sensing, Short circuit, thermal
• Indicators: Temp/Protect/Bridge/Power/Peak/dB cut
• Cooling Fan forced air cooling, dual variable speed control fan through a massive heat sink.
• Dimensions H x W x D: 1.72" x 19" x 15.4
• Weight: 15.8 (lbs.)

[markD]

if you run it stereo, with (2) 8 ohm speakers you would only get 230W per side. what is the power handling/specs on the speakers? those will go a long way in determining the most efficent setting on your amp.

in order to get 400W per side, the speaker load would have to be 4 ohm.

the way you are running the amp now, you are delivering a total 4 ohm load to an amp that wants to see 8 ohms. you are not getting the 800W rating.

it seems that the safest, most efficient hook up would be to have the amp set to stereo. but, since your cabs are rated at 8 ohms, you will only get 230W per side. you would need to add another pair of 8 ohm cabs to get the full 400W stereo rating.

hope that helps...

[jgcable]

if you run it stereo, with (2) 8 ohm speakers you would only get 230W per side. what is the power handling/specs on the speakers? those will go a long way in determining the most efficent setting on your amp.

in order to get 400W per side, the speaker load would have to be 4 ohm.

the way you are running the amp now, you are delivering a total 4 ohm load to an amp that wants to see 8 ohms. you are not getting the 800W rating.

it seems that the safest, most efficient hook up would be to have the amp set to stereo. but, since your cabs are rated at 8 ohms, you will only get 230W per side. you would need to add another pair of 8 ohm cabs to get the full 400W stereo rating.

hope that helps...

Hey Mark, I do have another pair of 8 ohm cabs. So.... if I took my Peavey 8 ohm main pa cabs and used the outs on the Peaveys and connected it to my yamaha 8 ohm main cabs ins on both sides I would have 4 ohms right?
If I did that would it be better to run the amp in stereo 400w per side or bridged 800w mono?

It sounds confusing but let me break it down again

Forget the mixer, that doesn't matter.

I have a Soundtech PS802 power amp. I posted the spec on it.
I have 2 Peavey main PA cabs that are rated at 400 watt program, 800w peak and are 8 ohms
I have 2 Yamaha main PA cabs that are rated at 300 watt program and 600w peak and are 8 ohms.

Whats the best way to hook this gear up for maximum power?

Thanks! JG

[Franx]

If you connect the Yamahas to the Peaveys (parallel), you get 4 ohms on each side.
Now you set the amp to 400W stereo and connect the parallelled Peavey/Yamaha right/left !
So you have 400W/4ohms per side (basically what Mark said)

[markD]

does the amp have different jacks for bridged vs. stereo operation?

assuming that it doesn't, daisy-chain the cabs like you said and set the amp for 800W mono, or just do what Franx said. either way you are getting 800W.

if the amp has different jacks let me know...

[jgcable]

does the amp have different jacks for bridged vs. stereo operation?

assuming that it doesn't, daisy-chain the cabs like you said and set the amp for 800W mono, or just do what Franx said. either way you are getting 800W.

if the amp has different jacks let me know...

The amp has binding posts (bannana jacks) both left and right. It also has a bridging switch on the back.

[markD]

ok. then use one of the hook-up methods already mentioned by franx or myself and you will get 100% power from the amp.

i ran into the same issue with my pa amp. i have a 2000 watt peavey. it is a 4 rack space beast....but the vocals were getting lost in rehearsal. eventually, i figured out that to get max power from the amp, it had to run at 2 ohms. we daisy-chained (3) 8 ohm cabs together per side, and we got a LOUD vocal system. now i am running a pair of 2X15 + horn cabs and a pair of 1X12 + horn cabs per side to get the 2 ohms. it is a great vocal system!!

[jgcable]

I am on the lookout for another power amp too. Currently we have a 400 watt power amp for the monitors and the 800 watt Soundtech for the mains. The problem I see is the Soundtech is only 1 rack space and I just don't see how it could handle a 2 guitar rock band that plays fairly loud. In regards to mics, we run one guitar direct (its a Line 6 Flextone combo), we have 4 vocals, and we mic the kick drum and an overhead thats placed over the snare and tom toms. It seems to clip fairly easily.

[Rsmacker]

Peavey do amps now that run happily into 2 ohms? Well, wonders will never cease, that used to be a recipe for a fucked amplifier. Only PROPER* amps used to go down to 2 ohms and not go tits up, 3 months down the line.


* Like QSC/Crown/Powersoft etc

[Rsmacker]

I am on the lookout for another power amp too. Currently we have a 400 watt power amp for the monitors and the 800 watt Soundtech for the mains. The problem I see is the Soundtech is only 1 rack space and I just don't see how it could handle a 2 guitar rock band that plays fairly loud. In regards to mics, we run one guitar direct (its a Line 6 Flextone combo), we have 4 vocals, and we mic the kick drum and an overhead thats placed over the snare and tom toms. It seems to clip fairly easily.

As I just posted, spending a few quid on a decent amplifier really does pay. You'll look around, compare prices and see something like the Soundtech and it will be way cheaper than even a second hand Crown (Amcron over there?), and will seem similar spec. Don't be fooled though, spend your money wisely, avoid Peavey, Yamaha, Soundtech or anything made in China.

When you put one of the previously mentioned amplifiers, head to head with a QSC or Crown (go for a Macrotech) you will be astonished at the difference in sound quality, it will blow your tits off, I assure you. There will be some cracking deals on old technology, amps with big fuck-off toroidal transformers in, because everyone wants a 1u digital switch mode amp that is light as a feather. These cheap switch-mode things are absolutely shite though, unless you are spending serious wonga on a Powersoft or similar. Again, try one right next to an old Macro-tech, wound to full and you will see (and hear) I'm right!


It doesn't matter how good every other bit of your kit is, a shit amplifier will let it all down, it's a totally false economy to buy a cheap one.
(It was one of the lessons I learned many years ago, setting up my Hire Co, and would never have believed it, all amps are kinda similar, surely? Not a bit of it. I bought some decent amps, they cost me an arm and a leg, but have never looked back - they were worth every penny.)

[jgcable]

As I just posted, spending a few quid on a decent amplifier really does pay. You'll look around, compare prices and see something like the Soundtech and it will be way cheaper than even a second hand Crown (Amcron over there?), and will seem similar spec. Don't be fooled though, spend your money wisely, avoid Peavey, Yamaha, Soundtech or anything made in China.

When you put one of the previously mentioned amplifiers, head to head with a QSC or Crown (go for a Macrotech) you will be astonished at the difference in sound quality, it will blow your tits off, I assure you. There will be some cracking deals on old technology, amps with big fuck-off toroidal transformers in, because everyone wants a 1u digital switch mode amp that is light as a feather. These cheap switch-mode things are absolutely shite though, unless you are spending serious wonga on a Powersoft or similar. Again, try one right next to an old Macro-tech, wound to full and you will see (and hear) I'm right!


It doesn't matter how good every other bit of your kit is, a shit amplifier will let it all down, it's a totally false economy to buy a cheap one.
(It was one of the lessons I learned many years ago, setting up my Hire Co, and would never have believed it, all amps are kinda similar, surely? Not a bit of it. I bought some decent amps, they cost me an arm and a leg, but have never looked back - they were worth every penny.)

Thanks for the response. My other band.. Fools Faith has all Mackie and JBL equipment. It has been bullet proof for years.
I totally understand about the quality of the power amps thing you mention. I have been looking at QSC and Crown.
Looking for something around 1200 watts.

[markD]

Peavey do amps now that run happily into 2 ohms? Well, wonders will never cease, that used to be a recipe for a fucked amplifier. Only PROPER* amps used to go down to 2 ohms and not go tits up, 3 months down the line.


* Like QSC/Crown/Powersoft etc

hahahahaha, yeah. my peavey is older one - USA made. i have been running 2 ohms for about 6 years now - no fuckage yet!!!!

[roodyrocker]

The QSC power amps would be nice but just as an FYI, even QSC power amps are made in China these days. I have a couple QSC RMX2450 power amps for mains and a Crown for the monitors that my band used. They sound good! About a year ago we went to powered QSC speakers and a Presonus digital board We're using the QSC HPR 118i's for subs and QSC HPR 153i's for top boxes. nice stuff! QSC discontinued the HPR line and replaced it with the K series so I look for good deals on used HPR's or new old stock ones.

[jgcable]

More stupid questions. Obviously, I wasn't in charge of the PA in most of my bands!

How do I hook this up and more importantly... can I? I want the maximum power I can get.

Here is what I have...

QSC USA 900 power amp. Its 450w per side at 4 ohms stereo or 900w bridged mono at 8 ohms. It has banana jack outputs.
2 Peavey 8 ohm main PA cabinets rated at 400w peak and 2 Yamaha 8 ohm main PA cabinets rated at 300w peak.

[markD]

you are pretty much going to do the same thing as with the soundtech. daisy-chain the cabs: one yamaha into one peavey and then hook it up to one side of the amp. repeat. end result? you will be running the amp at 450W perside stereo into 4ohms!!