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[Alex Jolly]

Hi i recently bought a set of 4 meyer upa's and 2 USW subs. The amp rack that came with is old and very heavy (2x QSC ex1250's and 1x H&H VX900. I've been looking at a pre-owned powersoft M28Q to run the 4 upa's or 2 upa's and 2 USW's depending on requirements. Although i've worked in sound for a while this is my first system so i'm a bit new to this.

Firstly is it possible to connect the sense outputs from the M1A processor to the M28Q as without this I guess it's possible to damage the speakers. I've studied the documentation for the M28Q and can't see this option. If not should I forget the M28Q for this purpose and go for crown XTi1000? I like that the M28Q is only 1U.

Also could I potentially run my whole system from this amp. i.e., 1 channel per sub and 2 channels for 4 speakers (pairs linked with splitter boxes that came with the system)

Finally I have the option of buying the same system again although with Crown XTi1000 amps. As I haven't had a chance to put it thru it's paces yet I was wondering roughly what size rooms/events/number of people I can hope to accomplish with what I have so far. Would twice the system be more appropriate for say outdoor band events this summer.

Thanks for any help you can provide. Much obliged.

[Mac Kerr]

Firstly is it possible to connect the sense outputs from the M1A processor to the M28Q as without this I guess it's possible to damage the speakers. I've studied the documentation for the M28Q and can't see this option. If not should I forget the M28Q for this purpose and go for crown XTi1000? I like that the M28Q is only 1U.

The M28Q should be fine, but you will have to build some custom cables to connect the amp outs to the sense ins of the processor. You will need an NL4 to dual banana plug from the amp to the processor, and another one stacked on the banana plug to feed the speakers.

If you want stereo you will need 2 M1 processors as they are mono devices. You also need a B1 or B2 processor for the USWs.

Mac

[Alex Jolly]

The M28Q should be fine, but you will have to build some custom cables to connect the amp outs to the sense ins of the processor. You will need an NL4 to dual banana plug from the amp to the processor, and another one stacked on the banana plug to feed the speakers.

If you want stereo you will need 2 M1 processors as they are mono devices. You also need a B1 or B2 processor for the USWs.

Mac

Thanks Mac,

I think I understand correctly but to clarify the powersoft M28Q doesn't have a dedicated sensor input function like say the crown xti1000 but by splitting the feed from the amp output positive & negative back to the processor sensor input (while also feeding the UPA) the same effect is achieved and the processor will limit the amp as required. Is this pretty much standard procedure in PA world when using amps without sensor input?

Thanks again. Alex

[gordonmcgregor]

Thanks Mac,

I think I understand correctly but to clarify the powersoft M28Q doesn't have a dedicated sensor input function like say the crown xti1000 but by splitting the feed from the amp output positive & negative back to the processor sensor input (while also feeding the UPA) the same effect is achieved and the processor will limit the amp as required. Is this pretty much standard procedure in PA world when using amps without sensor input?

That is exactly what I have done with my UPAs I have 2 m1s, a patchbay and a Powersoft amp in 1 4U rack the sense inputs for the speakers are split off the back of the speaker outputs in the patchbay, we used cheap Radio Shack multimeter cables just cut the probes off and solder the ends ono the speake connecrion the plug the correct banana plug in to the processor. G

[Brian Bolly]

Thanks Mac,

I think I understand correctly but to clarify the powersoft M28Q doesn't have a dedicated sensor input function like say the crown xti1000 but by splitting the feed from the amp output positive & negative back to the processor sensor input (while also feeding the UPA) the same effect is achieved and the processor will limit the amp as required. Is this pretty much standard procedure in PA world when using amps without sensor input?

Thanks again. Alex

Alex,

The Crown amp doesn't necessarily have "dedicated sensor inputs", it just has its 2 sets of paralleled outputs per channel - binding post (banana plug), and NL4 speakons.  You are correct though - if you want to use the Powersoft you can just split the output of the amp to go to both the speaker and the processor.  You might find that an easy way to do this is to build a small I/O panel for your rack and do the Y soldered onto the back of the panel instead of inside the NL4 plugged into the amp.

Keep in mind that since the UPA is a biamped box you will be running a mono system - 2 channels for subs (1 sub per channel, as the M28Q isn't rated for 2 ohms), and mids and highs for the other 2 channels.  Also, as Mac mentioned there is an appropriate processor for the subs - a B2 or B2EX.

[Alex Jolly]

Thanks guys.

The mists have cleared. I have 2x M1A's and 1x B2A. Following all you're brilliant advice I think i'll run the UPA's 1 or 2 per side (depending on requirements) from the M28Q in stereo using an I/O panel and use one of the QSC ex1250's that came with the system to run the subs. Getting rid of the H&H beast will be a blessing. That thing weighs a ton.

On a different note (Gordon), how does the M28Q perform. Are you happy with it in your system? I know it's very slightly overpowered for the UPA's but does it follow the same idea as a lower powered amp, ie., turn amp volume up full and let the processor warn you when it's the level gets too much?

If you are running the same system as me (4 tops 2 subs) what capacity venues would you use the system for? And what kind of jobs do you cover in terms of speech/music etc.

Thanks for all the help everyone. Very happy to be here and problem solved!

[Steve Anderson]

[...] turn amp volume up full and let the processor warn you when it's the level gets too much?

From memory with the Meyer processors, you're supposed to set amps to 26dB gain (20x)... someone will correct if Im wrong

[Mac Kerr]

From memory with the Meyer processors, you're supposed to set amps to 26dB gain (20x)... someone will correct if Im wrong

You are not wrong.

Mac