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Amps for Meyer UPA-1A system


Biskit

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Hi Guys,

The title says it all really, I'm looking for suitable amps for a system consisting of 4 x UPA-1A (2 per side) and 4 x USW subs (also 2 per side). I do have the correct Meyer processors for the cabs.

 

As you can probably guess from the fact I'm asking the question here rather than of Meyer... I'm looking for a 'value' solution. I know these cabs were designed for use with particular Crest or Crown amps 'back in the day' with the power output, gain and maximum output voltages carefully matched to the drivers. Unfortunately I don't have the luxury of the budget for such things, so...

 

Looking at the T-amp TSA 4-300 (intending to use a channel each for HF and mid per side on the UPAs, and a second unit with one channel for each sub, drivers linked in parallel). The spec sheet numbers seem to match the quoted requirements of the speakers quite well, apart from the voltage gain which is a bit higher than suggested, although I figured the Speaker Sense circuitry on the processors would take care of that? Only thing is they just 'feel' a bit underpowered for a PA of this size... perhaps that's just a bit of an old fashioned preconception, and I know the Meyer speakers are incredibly efficient... I also looked at the TSA 4-700 from the same range, but that seems way overpowered when looking at the manuals for the speakers. I just want to make sure I can get a decent performance from them without blowing up either the speakers or the bank balance! This is a 'reserve' system, doesn't need to be 'rider friendly', but application could be anything really so getting close to the design performance of the system is the aim, to allow for anything from theatre shows, to bands, to disco.

 

Any other suggestions?

Many thanks

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Just remember that the M-1 and B-2 processor outputs are quite hot at +26 dBv (max), so you need to adjust the signal path accordingly to set the correct gain into the amps.

 

Our "cheat" for this was to use an unbalanced link between the processors and amp inputs, which dropped the level a little. We had always meant to replace it with a proper attenuator but never got around to it, and in ~10yrs of use didn't experience any problems.

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Just remember that the M-1 and B-2 processor outputs are quite hot at +26 dBv (max), so you need to adjust the signal path accordingly to set the correct gain into the amps.

 

Our "cheat" for this was to use an unbalanced link between the processors and amp inputs, which dropped the level a little. We had always meant to replace it with a proper attenuator but never got around to it, and in ~10yrs of use didn't experience any problems.

That's a useful point to note, thanks I'll certainly bear it in mind. Is this possibly one of the reasons why the suggested amps for these speakers are relatively low in voltage gain compared to other similar power rated amps? And can the issue be mitigated by just attenuating at the amp input, or turning the processor output down? I'm not sure if/how this would affect the speaker sense feedback loop and hence the driver protection.

 

Any generally thoughts on if the amp I suggested could be suitable, or am I way off the mark?

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Just remember that the M-1 and B-2 processor outputs are quite hot at +26 dBv (max), so you need to adjust the signal path accordingly to set the correct gain into the amps.

 

Our "cheat" for this was to use an unbalanced link between the processors and amp inputs, which dropped the level a little. We had always meant to replace it with a proper attenuator but never got around to it, and in ~10yrs of use didn't experience any problems.

That's a useful point to note, thanks I'll certainly bear it in mind. Is this possibly one of the reasons why the suggested amps for these speakers are relatively low in voltage gain compared to other similar power rated amps? And can the issue be mitigated by just attenuating at the amp input, or turning the processor output down? I'm not sure if/how this would affect the speaker sense feedback loop and hence the driver protection.

 

Any generally thoughts on if the amp I suggested could be suitable, or am I way off the mark?

 

Yes, turning down the input gain changes the overall voltage gain from input to output of the amp. The sense lines are sensing the actual output voltage of the amp, so will continue to work as intended.

 

Mac

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We drive our Meyer UPAs with Lab Gruppen amps - it's been a very successful pairing for many years.

 

I suspect from what the OP said, he isn't going to have the budget for anything like Labs unfortunately. We used Powersoft Q4002 very successfully (and really enjoyed the huge reduction in weight and space) but that was for a primary rig that saw a lot of use, not a secondary one.

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We just retired our 1986 UPA-1A PA system in favour of an L'Acoustics WiFo rig. In fact, I thought you were describing our old system at first!

 

We were using QSC PLX3002 amps with them which seemed to work pretty well.

That's interesting to know, just out of interest what was the reason for retiring the UPA-1A system now, and how did you find its performance towards the end - was it still living up to expectations, or did you have issues with the audio performance compared to more modern systems?

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I took our UPA rig out for the first time in a while and was actually quite pleasantly surprised with the sound. My biggest complaint about the rig is that it does get quite harsh when run hard.

 

However compared to our newer kit it is far heavier and slower to set up.

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That's interesting to know, just out of interest what was the reason for retiring the UPA-1A system now, and how did you find its performance towards the end - was it still living up to expectations, or did you have issues with the audio performance compared to more modern systems?

 

It was basically an issue of accumulating faults - stuff like the rubber on the cones was starting to degrade, and once you replace one, you have to replace the lot as the replacement parts don't sound quite the same. We were also finding that it got a little harsh when run hard, and we were getting complaints from visiting engineers that each box sounded slightly different.

They didn't sound "bad" as much as they didn't match each other - and we didn't have (or want) box-by-box EQs to compensate.

 

Also, we'd had them since 1986, so it had exceeded our best-case scenario for lifespan by 5 years! The budget for replacement was ready to go so we went ahead and replaced them before a catastrophic failure occurred.

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