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Title: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Dan Courtney on March 31, 2019, 07:56:16 pm
I need to drive 2 mono FOH speakers and 2 daisy chained stage monitors.

Will a 2 channel power amplifier do?

If Yes, how would it be best to wire it?

Details:
2 Electro-voice EKX-12 - 350 Watt - FOH speakers - (Passive)
2 Stage Monitors - 250 - Watt (Emininence Beta 10A) plus -Pyramid TW44 1-Inch Tweeter
? Power Amp -- not purchased yet (but 2 channel seems cheaper)

Mixer -- SoundcraftUi24r
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: David Sturzenbecher on March 31, 2019, 07:57:46 pm
Depends on the amp and depends on the speakers.


Sent from my iPad using Tapatalk Pro
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Nathan Riddle on March 31, 2019, 08:04:18 pm
I need to drive 2 mono FOH speakers and 2 daisy chained stage monitors.

Will a 2 channel power amplifier do?

If Yes, how would it be best to wire it?

Reply with details such as make, model, modifications, quantity, etc. For all equipment.

We can help you out.
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Dan Courtney on March 31, 2019, 08:42:05 pm
Details:
2 Electro-voice EKX-12 - 350 Watt - FOH speakers - (Passive)
2 Stage Monitors - 250 - Watt (Emininence Beta 10A) plus -Pyramid TW44 1-Inch Tweeter
? Power Amp -- not purchased yet (but 2 channel seems cheaper)
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Dan Courtney on March 31, 2019, 08:42:31 pm
Details:
2 Electro-voice EKX-12 - 350 Watt - FOH speakers - (Passive)
2 Stage Monitors - 250 - Watt (Emininence Beta 10A) plus -Pyramid TW44 1-Inch Tweeter
? Power Amp -- not purchased yet (but 2 channel seems cheaper)
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Mike Caldwell on March 31, 2019, 10:38:37 pm
In general terms yes, one channel would run the mains the second would run the monitors.
Two speakers paralleled together would be a nominal four ohm load per channel.

An amp with something in 800 to 1000 watts at 4ohms would be safe for you mains but could be a little dangerous for you monitors.

Set the compressors on the main outs and the monitor aux out at a high ratio for some limiting and a little extra aggressive on the monitor aux out.

What amp are you looking at getting.

You will want some high pass filtering on your monitors, The
Ui24 does not have high pass filters on the outputs.

A budget amp that would be decent for your monitors would be a Crown XLS 1502 or 2002, they have a built in basic DSP you can set for high pass filtering. For your monitors I would have the high pass set around 110hz.

For that matter the largest XLS 2502 would work for your mains but maybe leave a little output of the speakers go unused.
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Marc Sibilia on April 01, 2019, 04:31:37 am
You will want some high pass filtering on your monitors, The
Ui24 does not have high pass filters on the outputs.

The Ui24R does have HPF and LPF on the Master L/R Outs and Aux 1 & 2.  But you can also use the matrix to patch through the 4 additional channels that they added on V.2 of the firmware to have more flexible (adjustable slope) HPF and LPF, if you need it, as well as parametric EQ.
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Mike Caldwell on April 01, 2019, 08:29:28 am
The Ui24R does have HPF and LPF on the Master L/R Outs and Aux 1 & 2.  But you can also use the matrix to patch through the 4 additional channels that they added on V.2 of the firmware to have more flexible (adjustable slope) HPF and LPF, if you need it, as well as parametric EQ.

I stand corrected, yes they do have HPF and LPF filters on the master and matrix outs.

So with that you could get something like a single QSC RMX and run the mains on one channel and the monitors on the other channel and do all the processing in the mixer.
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Dan Courtney on April 01, 2019, 10:09:05 am
Mike & Marc, thank you for your quick and detailed responses.

For a small church, we have a limited budget and your knowledgeable suggestions are appreciated.

Dan  :)
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Taylor Hall on April 01, 2019, 10:57:48 am
Mike & Marc, thank you for your quick and detailed responses.

For a small church, we have a limited budget and your knowledgeable suggestions are appreciated.

Dan  :)
What kind of budget are you working with? We could help with a few amplifier suggestions that fit your price range and give you some wiggle room for other upgrades.
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Dan Courtney on April 02, 2019, 11:27:08 am
What kind of budget are you working with? We could help with a few amplifier suggestions that fit your price range and give you some wiggle room for other upgrades.

I'm looking into Mike's suggestions noted above.
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Dan Courtney on April 04, 2019, 06:50:55 am
If I went with the Crown XLS 1502, how would it be best to wire it to the 2 FOH speakers and the  2 daisy-chained monitors (described above) ? That is how to connect? See back view of amp.

PS The reviews of the Crown XLS are quite impressive including the low fan noise :-)
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Bob Faulkner on April 04, 2019, 07:13:00 am
If I went with the Crown XLS 1502, how would it be best to wire it to the 2 FOH speakers and the  2 daisy-chained monitors (described above) ? That is how to connect? See back view of amp.

PS The reviews of the Crown XLS are quite impressive including the low fan noise :-)
Connect one of your FOH speakers to channel output "1" on the amp, and then daisy-chain the other FOH speaker from the first FOH speaker (using the second NL-4 on the back of the speaker).  Then, connect your daisy-chained monitor speakers to channel "2".
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Dan Courtney on April 04, 2019, 08:33:22 am
Connect one of your FOH speakers to channel output "1" on the amp, and then daisy-chain the other FOH speaker from the first FOH speaker (using the second NL-4 on the back of the speaker).  Then, connect your daisy-chained monitor speakers to channel "2".

Thanks, yes daisy-chaining the monitors will work easily. But daisy-chaining the FOH, wall mounted speakers would be a challenge. Could I add banana plugs to one of the FOH cables and use the other Ch 1 outlet on the back of the mixer? (Parallel ??) or a speakon Y adapter out of ch 1??
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Chris Grimshaw on April 04, 2019, 10:03:15 am
Thanks, yes daisy-chaining the monitors will work easily. But daisy-chaining the FOH, wall mounted speakers would be a challenge. Could I add banana plugs to one of the FOH cables and use the other Ch 1 outlet on the back of the mixer? (Parallel ??) or a speakon Y adapter out of ch 1??

Both of those ideas will work. I'm not a fan of banana plugs, although they have got me out of trouble before now, as they're too easy to have problems with. Either short-circuits or reverse polarity.

Chris
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Dan Courtney on April 19, 2019, 08:20:33 pm
Mike , I went with your suggestion and I'm happy with the Crown XLS 1502. We have lots of headroom for our setting.
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Scott Holtzman on April 20, 2019, 01:52:19 am
Mike , I went with your suggestion and I'm happy with the Crown XLS 1502. We have lots of headroom for our setting.
Why is the amp in the booth?  That seems like a lot of speaker cable.

Sent from my VS996 using Tapatalk

Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Dan Courtney on April 20, 2019, 10:33:33 am
Why is the amp in the booth?  That seems like a lot of speaker cable.

Sent from my VS996 using Tapatalk

Good questions, Scott.

Access to the amp allows for fine tuning (HPF) and gain adjustment. (You might notice the black tape over the knobs.) We've been trying different settings. It allows us to turn on the mixer first before the amp and the amp power cord goes into the power line conditioner. Having the amp close will us access to back so that we can quickly switch out the digital mixer for an analog mixer in case of an emergency. Our sound booth is at the back of sanctuary.

Yes, the end of the snake wires are messy. Maybe 90° ends would help. Maybe a digital snake to the stage in the future.
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Scott Holtzman on April 21, 2019, 12:46:54 am
Good questions, Scott.

Access to the amp allows for fine tuning (HPF) and gain adjustment. (You might notice the black tape over the knobs.) It allows us to turn on the mixer first before the amp and the amp power cord goes into the power line conditioner. Having the amp close will us access to back so that we can quickly switch out the digital mixer for an analog mixer in case of an emergency.

Yes, the end of the snake wires are messy. Maybe 90° ends would help.
I can't think of a reason you would touch the HPF during a production. 

My concern is all the loss of the speaker cable.  Power conditioner is worthless, especially for an amp.   Remote turn on from stage would be the way to go.

Sent from my VS996 using Tapatalk

Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Dan Courtney on April 21, 2019, 04:05:42 pm
I can't think of a reason you would touch the HPF during a production. 

My concern is all the loss of the speaker cable.  Power conditioner is worthless, especially for an amp.   Remote turn on from stage would be the way to go.

Sent from my VS996 using Tapatalk

Hi Scott, (GAVS) Your experience in audio is appreciated. Newbie here.

We wouldn’t be adjusting the HPF during a production but during setup as we trying to get the best sound out of the monitors without over powering them. (We also use the HPF in the Soundcraft mixer.)

I believe that the speaker cable loss is doable according to the charts I’ve looked at. Heavier gauge copper $$$ would always be better.)

The power bar we're using is the Furman M-8x2 Power Conditioner. It’s also a surge protector. (Sweetwater). I have the digital mixer on a UPS in case of any sudden utility power glitches.

I’ll look into that “remote turn on from stage” suggestion.

Actually our mixer could be on stage too … since we run it via Wi-Fi & ethernet.
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Scott Holtzman on April 22, 2019, 02:14:19 am
Hi Scott, (GAVS) Your experience in audio is appreciated. Newbie here.

We wouldn’t be adjusting the HPF during a production but during setup as we trying to get the best sound out of the monitors without over powering them. (We also use the HPF in the Soundcraft mixer.)

I believe that the speaker cable loss is doable according to the charts I’ve looked at. Heavier gauge copper $$$ would always be better.)

The power bar we're using is the Furman M-8x2 Power Conditioner. It’s also a surge protector. (Sweetwater). I have the digital mixer on a UPS in case of any sudden utility power glitches.

I’ll look into that “remote turn on from stage” suggestion.

Actually outer mixer could be on stage too … since we run it via Wi-Fi & ethernet.

What is GAVS?

So that amp is powering monitor not mains?

The UPS is always a good idea.  Surge suppressors and line filters don't add a lot of value over a  conventional power strip. 

The high pass should be set for the lowest frequency you want to ever send to the speaker and left alone.  The tweaks you speak of should be done in the board.  Frankly I don't ever think I have seen an amp at FOH,  in installs the amps are usually in locked racks or an amp room.  On tour all amps live on or right off the stage deck.

Hope this helps.

 
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Dan Courtney on April 22, 2019, 07:32:02 am
What is GAVS?

So that amp is powering monitor not mains?

The UPS is always a good idea.  Surge suppressors and line filters don't add a lot of value over a  conventional power strip. 

The high pass should be set for the lowest frequency you want to ever send to the speaker and left alone.  The tweaks you speak of should be done in the board.  Frankly I don't ever think I have seen an amp at FOH,  in installs the amps are usually in locked racks or an amp room.  On tour all amps live on or right off the stage deck.

Hope this helps.

GAVS is my short form for Ghost Audio Visual Solutions, your company, I believe.  I did read many of your previous posts - informative.

If you have time, read back through this posting and you will see how I'm using a 2 channel amp to power both the mains and monitors. (Perhaps a second amp in the future).

It was suggested on here to set the HPF to the monitors (used by vocals and guitar) to 110 dB Hz, but I've been dipping a little lower (90 dB Hz) trying to get a richer sound. (and still try to protect the monitors from too high a wattage.)
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Scott Holtzman on April 22, 2019, 09:23:14 pm
GAVS is my short form for Ghost Audio Visual Solutions, your company, I believe.  I did read many of your previous posts - informative.

If you have time, read back through this posting and you will see how I'm using a 2 channel amp to power both the mains and monitors. (Perhaps a second amp in the future).

It was suggested on here to set the HPF to the monitors (used by vocals and guitar) to 110 dB, but I've been dipping a little lower (90 dB) trying to get a richer sound. (and still try to protect the monitors from too high a wattage.)

I would stick with the 110hz, you are not trying for hifi.  The purpose of a monitor is for the musician to hear what they need to play.  90Hz is too much mud.

BTW you have dB instead of HZ.  dB is not a unit of measurement in itself but a scale, you have to have a variable after it setting the value you want to quantify on the dB scale IE: dB SPL or dB $$$ (my favorite)

Thanks for your kind words, some of my posts are obnoxious too!
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Nathan Riddle on April 24, 2019, 09:44:03 am
FWIW, I regularly see amp(s) at FOH in small churches. Not advocating the practice, but if they didn't install a sequencing system and the runs are for two bose panaray speakers in the front running 50w of power I doubt that 100ft of 16awg speaker cable is doing all that much. That and it's usually a single 2ch amp running mains and choir monitor off channels 1,2 respectively.

I'm actually currently working an estimate to bring the amps to the stage for a client.
Title: Re: Can I Replace a 4 Channel Amp with a 2 Channel Amplifier?
Post by: Nathan Riddle on April 24, 2019, 09:51:17 am
To be clear for power.

Any amps (or high-current devices) should be plugged directly into the wall outlet. There should be no surge protection going on. The only caveat is properly designed high-current remote relay switching systems that may/may not have built-in surge protection.

All electronics that require longer than ~1.5s bootup time (digital mixer, computer, digital snake, etc) should be on UPS that-is battery backup. Pure sinewave preferred.

I suggest having a surge protector for the UPS as they are usually only 600j and a Panamax MD2 is 1350 with other additional protections.

Lastly, a sequencing system that turns amps on last and off first (compared to the mixer/dsp) is a very good idea.


The power bar we're using is the Furman M-8x2 Power Conditioner. It’s also a surge protector. (Sweetwater). I have the digital mixer on a UPS in case of any sudden utility power glitches.

I’ll look into that “remote turn on from stage” suggestion.

That M-8x2 is not a surge protector by any stretch of the imagination. And your amp should not connect to it in any-way-shape-or-form.

The UPS is always a good idea.  Surge suppressors and line filters don't add a lot of value over a  conventional power strip. 
If the power strip is decent, I agree.