Low cost Class D pro plate amps.

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chris_c_
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Low cost Class D pro plate amps.

#1 Post by chris_c_ »

Has anyone seen or got any idea where one might be able to look for a plate amp like this:

* Low Cost
* Class D topology
* Plate Amp 400 - 800W
* Voltage Limiter DSP
* XLR/ 1/4 combo ins
* World SMPS power supply 240/120V AC

For use on subs and tops.

1. Sub version should drive a single or dual 12 @ 8 ohm pro sub driver such as Lab 12. DSP limit to any voltage in range.

2. Top version should DSP to limit voltage and crossover the input then biamp drive a pro 12 bass/mid driver plus peizo array or dual compression horns as in the DR280 etc.

I see 700W plate amps, low cost, class D, yet they're lacking pro balanced inputs, power supply, and simple cheap DSP voltage limiter/crossover, probably due to lack of organized demand.

If these WERE made available,
1. How much would you be willing to pay, and
2. How many would you buy??
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Re: Low cost Class D pro plate amps.

#2 Post by Bruce Weldy »

chris_c_ wrote: If these WERE made available,
1. How much would you be willing to pay, and
2. How many would you buy??
My answer to both questions is zero.

Powered speakers require twice to number of cables per speaker to operate. If you lose an amp in a powered speaker, the speaker is rendered useless....with separate amps, you can re-configure on the fly and get through the gig.

The manufacturers have made it easier to put together a system via powered speakers, but it's also dumbed down the users. Sure, it's simple to hook 'em up, but nowhere along the way does the end user ever have to actually learn how things work......that's a vital part of learning how to make a system sound good, not just how to hook it up.

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chris_c_
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Re: Low cost Class D pro plate amps.

#3 Post by chris_c_ »

Bruce Weldy wrote:Powered speakers require twice to number of cables per speaker to operate. If you lose an amp in a powered speaker, the speaker is rendered useless....with separate amps, you can re-configure on the fly and get through the gig.

Thanks for your reply Bruce! I appreciate your opinion and comments, on this topic of basic pro plate amps for use by us the DIY sub and top builders.

I understand the cons you bring up - the risk of losing a plate amp - however, isn't there more than the one possible failure scenarios for amp-rack centric setups than just losing a rack amp during the gig??

Let's weigh ALL the pros and cons of BOTH plate amps AND rack amps.

1. "twice the number of cables per speaker to operate" - Yes maybe this is a con for plate amp systems and a pro for rack amp systems - but you can reduce total footage of AC power cable runs by having plate amps with a power-out to daisy chain these IEC power cables (or neutrik powercon) between the powered boxes - the tops or small subs which require half or less the max power from a single 15 Amp AC circuit - that'd be 800W.

2. "If you lose an amp in a powered speaker, the speaker is rendered useless." - Maybe, unless you also install a backup Speakon speaker input - so that in the event of losing the plate amp, you have the option to run a spare rack amp to power that speaker. Or just whip out a spare powered speaker. Or spare plate amp. Anyone here ever replace a blown speaker driver with a spare during a gig? Same concept - replace the plate amp live during the gig with your spare plate amp.

3. One thing you gotta like is having the sub push air past a Class D plate amp's heatsink in the horn path - this helps cool those transistors even more and make them extra comfortable, now you need a smaller cooling fan.

4. Really like the idea of having one less big piece of critical gear - the amp rack box, this is a "single point of failure" in the sense that, just one unlucky misstep involving the amp rack - whether it gets dropped, falls out of a truck, rained on, falls into a body of water - no more amplification, the show's over, or it never even begins.

5. When you have a pro plate amp in each box, this means, when you drop/water-damage/otherwise lose one box, that's OK, there's 7, or 11, or 19 other boxes in the sound system, each with its own independent amp, and the show will go on! Most likely hardly anyone will notice - except maybe the audiophiles and sound techs in the audience!

6. Last but not least, many many pro line array systems are class D plate amp based. If they can do it successfully, then why not us DIY people?? Pro line arrays often daisy chain the power, up to the point where the power circuit can handle it, then run a new power circuit, every 2 or 3 boxes. And they also daisy chain the audio signal in. Some line array plate amps are even individually addressable from the Front of House, with a daisy chained Ethernet port to allow individual timing delays and power volumes adjustment of the drivers to permit a finely tuned dispersion of the sound to cover only the audience and not a meter/foot beyond the edge of the general spectator area. And some also provide data back to FOH about driver power soak, or when a driver is getting close to blow, or has blown.
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Re: Low cost Class D pro plate amps.

#4 Post by Bruce Weldy »

1. "twice the number of cables per speaker to operate" - Yes maybe this is a con for plate amp systems and a pro for rack amp systems - but you can reduce total footage of AC power cable runs by having plate amps with a power-out to daisy chain these IEC power cables (or neutrik powercon) between the powered boxes - the tops or small subs which require half or less the max power from a single 15 Amp AC circuit - that'd be 800W.
Other than on the back of high-end line arrays, I haven't noticed any power outs or pass-thrus on off the shelf powered speakers (there may be some, I just haven't seen 'em). You'd still have to run at least one power cable to each stack and each monitor will have a cable even if daisy chained....the number of cables is the same....they are just shorter. As far as power consumption, I regularly run 6 subs, 4 tops, 6 monitors - driven by 4 driveracks and 6 power amps on a single 15v circuit and have never blown a fuse....and this is outside on ageing GFI outlets.

So, I'd say power consumption would be equal.


2. "If you lose an amp in a powered speaker, the speaker is rendered useless." - Maybe, unless you also install a backup Speakon speaker input - so that in the event of losing the plate amp, you have the option to run a spare rack amp to power that speaker. Or just whip out a spare powered speaker. Or spare plate amp. Anyone here ever replace a blown speaker driver with a spare during a gig? Same concept - replace the plate amp live during the gig with your spare plate amp.
Have you ever seen a Speakon on a powered cab? Certainly, you can do it, but you are adding extra expense and work on every cab.

Oh, and if you are using an amp with DSP - I'd assume you be using an active crossover in the DSP - if so, then you'd need two speakons to cover highs and lows in a top cab...which would also mean an outboard processor and two amp channels.....

As far as whipping out a spare speaker....isn't that kinda defeating the purpose? You'd have to invest in another cab and another plate amp.

Actually, because I always run two tops per side and multiple subs at every gig, I've never had to replace a driver at a gig. I've lost diaphragms, but was able to limp home on one speaker per side.

3. One thing you gotta like is having the sub push air past a Class D plate amp's heatsink in the horn path - this helps cool those transistors even more and make them extra comfortable, now you need a smaller cooling fan.
I'm sure that's true....but amps in a rack have fans.
4. Really like the idea of having one less big piece of critical gear - the amp rack box, this is a "single point of failure" in the sense that, just one unlucky misstep involving the amp rack - whether it gets dropped, falls out of a truck, rained on, falls into a body of water - no more amplification, the show's over, or it never even begins.
:loler: Yep, that chance of falling in a body of water is always a possibility - thus, I NEVER accept a gig on a barge....or a rowboat. Any piece of gear can be abused, but my amp rack is solid, lives in a trailer, is on wheels and doesn't get beat about. Rain is not an issue unless it's coming sideways - but, I always have plastic available and on-station if there is any chance of rain.

5. When you have a pro plate amp in each box, this means, when you drop/water-damage/otherwise lose one box, that's OK, there's 7, or 11, or 19 other boxes in the sound system, each with its own independent amp, and the show will go on! Most likely hardly anyone will notice - except maybe the audiophiles and sound techs in the audience!
Unless you are building a touring-sized system, I just don't see this as being applicable to 99% of the folks on this forum. I can power 16 cabs with 6 amps. I'm sure my 6 amps would cost way less than 16 plate amps. Plus, my BFMs are lighter without the amp onboard.
6. Last but not least, many many pro line array systems are class D plate amp based. If they can do it successfully, then why not us DIY people?? Pro line arrays often daisy chain the power, up to the point where the power circuit can handle it, then run a new power circuit, every 2 or 3 boxes. And they also daisy chain the audio signal in. Some line array plate amps are even individually addressable from the Front of House, with a daisy chained Ethernet port to allow individual timing delays and power volumes adjustment of the drivers to permit a finely tuned dispersion of the sound to cover only the audience and not a meter/foot beyond the edge of the general spectator area. And some also provide data back to FOH about driver power soak, or when a driver is getting close to blow, or has blown.
You are absolutely correct (and I have had the opportunity to mix on some large line arrays - it is definitely fun!). Like anything, you should use the right tool for the job. Touring line arrays are a whole different world from the typical weekend warrior....even those with large systems. Those touring systems have techs to help set it all up and they typically arrive the morning of the event that starts that night. And they only use powered arrays - the subs are almost always run from an amp rack.

Should we take some ideas from the big boys? Sure. But, I just don't feel this is one that makes sense in the world in which most of us live. I have a friend with a "powered" system. One sub, two tops, four monitors....I routinely set up my system in half the time it takes them. They have to get power cables all over the stage, then run mic cables to every piece of gear. Then they have to make sure every cab is turned on and all the settings are correct on each one....oh, and make sure the volume knob is turned up....and on and on and on......

Is it easier to design and build a system around powered boxes? Yep. But, it will also take you longer to set it up every time you take it out. I'd rather spend time up front in my leisure to build a proper rack, a well thought-out rack panel and have it wired so that it is plug and play every time it comes off the trailer.

Do powered speakers have a place? Certainly. If you are an acoustic player and just need to carry around a single or pair of small powered speakers and a 2-pound mixer, then go for it. But, once you add subs and monitors, it's time to do it right.

All that said, everyone gets to decide for themselves - especially in the DIY world. But, just because you can do something, doesn't necessarily mean you should.

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Re: Low cost Class D pro plate amps.

#5 Post by Grant Bunter »

Errr, the one thing you can't do is put a plate amp in the horn path.
That's been said by the designer more than once.

It occupies space/volume, alters flare rates, and consequently affects expected performance.
You would need to fit a false chamber to each cab to fit a plate amp.
So, up goes pack space, build material, time...
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Re: Low cost Class D pro plate amps.

#6 Post by Rich4349 »

As for "pushing air past the amp...": isn't the air really just vibrating back and forth mainly? Unless you're locating the amp very near the throat, where air pressure and speed are higher, the air speed slows down dramatically (exponentially) toward the mouth, no?

(I think the op has this "bonus / free" feature stuck in his head. I know: I have the same problem with my own hare-brained ideas.) I mean the hare-brained part toward myself; no offense intended!
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Re: Low cost Class D pro plate amps.

#7 Post by Grant Bunter »

I got a bit intrigued about your idea. Not because I want to do it, just because of what it would cost.
So I did some searching.

What satisfies your criteria of cheap?
Park Audio (?Ukraine) do some high power plate amps but the dual channel units seem to have set crossover points that don't work as per Bill's plan specs.
Same for Dayton's versions. Again, different/incorrect crossover point or inadequate and set slopes.

DSP in these units is better described as EQ shaping

Sub suitable:
http://www.ebay.com.au/itm/PLATE-AMPLIF ... SwMmBV6RTF

At 365US per, needing one per cab, I think you'd do better pocket wise with rack mounted power amps (and run more cabs of that same amp, eg 4 tops not 1).

I didn't spend a lot of time looking.

I think you'd struggle to find exactly what you need in terms of the requirements your looking for, at least at a cost that would make it worthwhile...
Built:
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Re: Low cost Class D pro plate amps.

#8 Post by BrentEvans »

Ok... so here's the opposing opinion.

I switched to powered cabs (4 RCF HDL10As per side) within the last year for various reasons, all out of necessity. Despite having to run two cables (which I usually can run at the same time) my setup time is lower than when I had all passive cabs. This includes taking them up on a flying frame. Instead of running a NL8 out to each side (which is heavy and stiff) I can run a 14 gauge power line and a mic line and I'm done. The NL8 was necessary to get Biamped tops and two subs. while I still use passive subs, I can run a single NL4 out to that, but If I had the active subs, I could run a single Mic cable for those and daisy chain them, as well as hooking on to the power already run from the tops. IF I wanted to power shade my tops, I'd have to run a cable per cab, which would be two more NL8s and a breakout. all that cable takes up much more space on the trailer, not to mention the amp rack.

All that means that active takes LESS cabling which is easier to run for my rig to get the same flexibility. While it's true that I could get away with a single nl8 trunk, there is still the amp rack that has to be hauled and loaded in and out. If I was all active, I could eliminate two racks and a cable trunk from my trailer, and by looming together the power and signal cables for monitors, setup is the same. It's all about how you design your rig to work.

So... can we once and for all put to bed the concept that active takes more time and effort? It doesn't. In general it's more efficient and easier to work with. If you're worried about an amp blowing (something that has happened to me only twice in 20 years of working with sound equipment) then CARRY A SPARE. The same goes for active or Passive cabs on that one. The only downside to active is cost. That said, I have saved enough in labor in less than a year to realize that they will pay for themselves very soon.
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Re: Low cost Class D pro plate amps.

#9 Post by Bruce Weldy »

BrentEvans wrote: So... can we once and for all put to bed the concept that active takes more time and effort? .
What would be the fun in that?

As I said, it's all a matter of scale....you are running a much bigger rig that most of the weekend warriors. You have the proper cabling built to your specs and lengths. And you made no mention of monitors, where every one of 'em gets two cables. Which means running more power boxes to the front of the stage. Again, in your situation where you are doing big shows, you are probably putting AC drops all over the stage, so it's not as big a deal. For most of us, that is just additional work.

Plus, the pro-line stuff like you have has the through-put receptacles for AC - off the shelf stuff that most people use don't. That means more IEC cords that don't roll up worth a darn and are only 6 feet long - thus extension cords and power strips everywhere.

In your world, I'd have everything custom-designed and it would be fairly simple too. But, most of the guys in my world are buying off the shelf cables and running Wal-Mart power strips. The stages look like spaghetti and there are trip hazards everywhere with those stiff, crappy cables sticking up in the air to grab a toe.

I still vote for passive boxes in the size stuff I'm doing. It's clean and easy to set up. I can have my entire outdoor rig (everything I've got) from trailer to making noise in about 15-20 minutes. I could never pull that off with powered speakers.

But, I totally understand your world. It's just not the norm for BFMers.

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Re: Low cost Class D pro plate amps.

#10 Post by BrentEvans »

Bruce Weldy wrote:
BrentEvans wrote: So... can we once and for all put to bed the concept that active takes more time and effort? .
What would be the fun in that?

As I said, it's all a matter of scale....you are running a much bigger rig that most of the weekend warriors. You have the proper cabling built to your specs and lengths. And you made no mention of monitors, where every one of 'em gets two cables. Which means running more power boxes to the front of the stage. Again, in your situation where you are doing big shows, you are probably putting AC drops all over the stage, so it's not as big a deal. For most of us, that is just additional work.

Plus, the pro-line stuff like you have has the through-put receptacles for AC - off the shelf stuff that most people use don't. That means more IEC cords that don't roll up worth a darn and are only 6 feet long - thus extension cords and power strips everywhere.

In your world, I'd have everything custom-designed and it would be fairly simple too. But, most of the guys in my world are buying off the shelf cables and running Wal-Mart power strips. The stages look like spaghetti and there are trip hazards everywhere with those stiff, crappy cables sticking up in the air to grab a toe.

I still vote for passive boxes in the size stuff I'm doing. It's clean and easy to set up. I can have my entire outdoor rig (everything I've got) from trailer to making noise in about 15-20 minutes. I could never pull that off with powered speakers.

But, I totally understand your world. It's just not the norm for BFMers.
I did mention monitors... loomed power cables with the signal cables and a small power strip in the stage box takes care of that. I also bought 25ft iecs for all my powered monitors and they roll up and are tied to the handles for transport, with spares available.

I do have a small SOS active system too. Rcf Evox 8. Amp is in the sub with a speak on to the top, It sets up WAY easier and faster than my other small systems with similar parts. I can throw that system up with two of them and a couple of powered monitors in 15 minutes with an X18 and a couple of wireless that stay in a box with cords and mics.

ANY SYSTEM can be simplified with a little thought and planning. I still have a bunch of wal-mart and harbor freight power strips in my system too. It's just a matter of thinking it through and figuring out a simple setup that will work for 90% of the things you do. There are lots of weekend warriors using active stuff these days... that's why it's so popular.

I really think that finding an active solution for BF cabs would be great. Unfortunately, most of the current solutions are fairly expensive and the cabs really aren't designed for it.
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Re: Low cost Class D pro plate amps.

#11 Post by Bruce Weldy »

BrentEvans wrote:
ANY SYSTEM can be simplified with a little thought and planning.
Amen to that!

I just like that all of my settings are safely handled in a rack and don't change. All the knobs and push button EQ settings on the off the shelf JBLs, QSCs, etc. are just more things to go wrong and have to be dealt with.

And as I said earlier, so many people that buy that stuff don't bother to address EQ for the mains and think it is just plug and play...... anyway, like you, I can make anything work, I just still like the "one cab/one cable" approach. Call me old school.....or old man....or old fat bastard.....I answer to most anything as long as there's a free meal involved.

Good discussion. We've laid out both cases pretty succinctly. Wish I could get out your way and work a show with you someday.

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Re: Low cost Class D pro plate amps.

#12 Post by Bill Fitzmaurice »

BrentEvans wrote:[ most of the current solutions are fairly expensive
They are.
and the cabs really aren't designed for it.
For the above reason.

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Re: Low cost Class D pro plate amps.

#13 Post by Think »

IMHO active can be very handy for smaller systems. Something like https://www.mivoc.com/gs/product_info.p ... -watt.html can be very usefull, but for a little more you buy a complete sub https://www.mivoc.com/gs/product_info.p ... oofer.html

For mobile use, you can screw a car amp on the back or on top.

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Re: Low cost Class D pro plate amps.

#14 Post by DJPhatman »

Think wrote:IMHO active can be very handy for smaller systems. Something like https://www.mivoc.com/gs/product_info.p ... -watt.html can be very usefull, but for a little more you buy a complete sub https://www.mivoc.com/gs/product_info.p ... oofer.html

For mobile use, you can screw a car amp on the back or on top.
Except that the 2 links you provide take us to home use grade amps. No balanced input/through-put = no good for us.

These 2 might be better: https://www.mivoc.com/gs/product_info.p ... k-iii.html and https://www.mivoc.com/gs/product_info.p ... k-iii.html

But, sadly, they give absolutely no specs... :roll:
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Re: Low cost Class D pro plate amps.

#15 Post by chris_c_ »

Here's some specs:
https://www.amazon.de/MPA-M-I-L-L-Y-Kom ... B007P3Q3Y2

A test video:


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