Low cost Class D pro plate amps.

Is this amp OK?
Message
Author
Grant Bunter
Posts: 5869
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: Low cost Class D pro plate amps.

#46 Post by Grant Bunter » Sun Jul 23, 2017 3:46 pm

chris_c_ wrote: Grant, about pricing and product, your feedback would be a help: Which features would you require? Which features would you like to have but not absolutely require? How much would you be interested in paying?
I've tried to say more than once elsewhere here in the forum I'm not interested.

Unless the plate amps have every feature under the sun, with enough power, and are free.
Even then, in a new build, I wouldn't want to be adding more material for a plate amp chamber, changing weight, or centre of gravity for each cab, buying a whole bunch of (my) standard outlet plug to IEC power cables, etc etc etc.

When I initially commented, I said I was only interested from a price point perspective.
And the reason I was interested in that perspective is I maintain one could buy a smaller amount of regular power amps vs plate amps, for the same, or less, cost. Some of that is also that I can run (with the right amp) at least 4 cabs per regular power amp.

Regardless of features, for the plate amps to be attractive as an option (for those that may be interested), they would need to cost 1/4 the price of a regular power amp that will do 4 cabs in order to be price competitive. Or, if they do have DSP including EQ etc, then they need to be the same price (or lower) as however many regular power amps and a driverack (for example) any given user will require otherwise...
Built:
DR 250: x 2 (melded array) with March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

chris_c_
Posts: 192
Joined: Thu Oct 28, 2010 5:48 pm
Location: Hartford, CT, US
Contact:

Re: Low cost Class D pro plate amps.

#47 Post by chris_c_ » Mon Aug 07, 2017 9:10 am

Grant Bunter wrote:
chris_c_ wrote: Grant, about pricing and product, your feedback would be a help: Which features would you require? Which features would you like to have but not absolutely require? How much would you be interested in paying?
I've tried to say more than once elsewhere here in the forum I'm not interested.

Unless the plate amps have every feature under the sun, with enough power, and are free.
Even then, in a new build, I wouldn't want to be adding more material for a plate amp chamber, changing weight, or centre of gravity for each cab, buying a whole bunch of (my) standard outlet plug to IEC power cables, etc etc etc.

When I initially commented, I said I was only interested from a price point perspective.
And the reason I was interested in that perspective is I maintain one could buy a smaller amount of regular power amps vs plate amps, for the same, or less, cost. Some of that is also that I can run (with the right amp) at least 4 cabs per regular power amp.

Regardless of features, for the plate amps to be attractive as an option (for those that may be interested), they would need to cost 1/4 the price of a regular power amp that will do 4 cabs in order to be price competitive. Or, if they do have DSP including EQ etc, then they need to be the same price (or lower) as however many regular power amps and a driverack (for example) any given user will require otherwise...
Trust me Grant you're with me on this, I'm interested in doing this plate amp such that its performance and cost per channel are exceptional.
Newest mix 8) https://facebook.com/BEATJACKERmusic "Like" appreciated :D

Grant Bunter
Posts: 5869
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: Low cost Class D pro plate amps.

#48 Post by Grant Bunter » Mon Aug 07, 2017 4:34 pm

chris_c_ wrote: Trust me Grant you're with me on this, I'm interested in doing this plate amp such that its performance and cost per channel are exceptional.
Chris,
Trust me, you're wrong on that assumption.
Even if you can do what you say, shipping from the USA would kill any potential for me (because I can buy regular power amps here in Australia right now with the specs I need), and, I'm not interested.

Still, get on it for your fellow country mates who are interested.
This thread is nearly 2 months old already, and all I can see is you waiting for people to tell you what they want are are willing to pay before you even get started.
Go the other way around. Talk to your manufacturer and work out pricing, get it made, sell them...
Built:
DR 250: x 2 (melded array) with March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

User avatar
MulletOver
Posts: 52
Joined: Fri Dec 14, 2012 9:02 pm
Location: Clinton, IN
Contact:

Re: Low cost Class D pro plate amps.

#49 Post by MulletOver » Mon Aug 28, 2017 10:02 pm

Enjoying the discussion so far! I was toying with the idea of a plate amp recently for my subs. I picked up a salvaged plate amp from a JBL SRX815P cabinet a few months ago for $50. I estimated that I could run up to (4) T39's off of it, but I can't install it in any of my current cabs.

So, if I built another T39, I know I would need to extend the cabinet somehow/somewhere - where would be the most practical place to mount the amp? (And Bruce, don't say 'the rack' ;-)
(8) 19" T39s (4xLab12, 4xDelta12LFA)
(4) SLA-PRO (4x6") Alpha6a
(1) Simplexx 10" wedge

Bruce Weldy
Posts: 6363
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Low cost Class D pro plate amps.

#50 Post by Bruce Weldy » Mon Aug 28, 2017 10:56 pm

MulletOver wrote: (And Bruce, don't say 'the rack' ;-)
In it's own little box? You could put it on top of the rack.

Pretty sure that JBL amp is rated at either 4 or 8 ohms, not 2.....so, 2 T39s would be the max on it. Hard to find the specs on the amps in the powered speakers. Typically the single driver boxes are 8 ohm and the double drivers are 4 ohm. They probably use the same plate amp in those, so I'd guess that it's 4 ohm.

You can bet that those amps have built-in DSP specific to that particular box - I kinda' doubt that you'd be able to re-program it to be just a naked power amp.....I could be wrong.

Of course, you'll still need a limiter....that will be in a rack......hmmmm.....back where we started.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Rich4349
Posts: 620
Joined: Wed Jul 30, 2008 10:18 am
Location: Kankakee, IL

Re: Low cost Class D pro plate amps.

#51 Post by Rich4349 » Tue Aug 29, 2017 8:39 am

Bruce Weldy wrote:
In it's own little box? You could put it on top of the rack.
Or maybe bolt it right onto the front face angle of the horn mouth? Sure, it'll disrupt 100% efficiency, but Bill's horns are so damn efficient- what's 3-4% lost? Vibrations? Yeah, there are going to be SOME, but again, these cabs are so damn well braced. Besides, it's a $50 amp- EXPERIMENT! Cabling could be a bit ugly, so... go Steampunk! Dress em up, paint em bronze? Add in a few superfluous cable coils? Idk.
Bruce Weldy wrote: Pretty sure that JBL amp is rated at either 4 or 8 ohms, not 2.....so, 2 T39s would be the max on it... Typically the single driver boxes are 8 ohm and the double drivers are 4 ohm.
So go series / parallel? Parallel 8/2=4, series them right back up to 8? Not much wattage split 4 ways (edit: 800w, so not *too* bad), but a fun cheap experiment.
2 DR250s, 2 27" Lab15 T-60s, 2 30" Neo Titan 39s, 1 Autotuba...and looking for more!

Bruce Weldy
Posts: 6363
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Low cost Class D pro plate amps.

#52 Post by Bruce Weldy » Tue Aug 29, 2017 11:19 am

Rich4349 wrote: So go series / parallel? Parallel 8/2=4, series them right back up to 8? Not much wattage split 4 ways (edit: 800w, so not *too* bad), but a fun cheap experiment.
Yep....more cables per box plus specialty cables/box to wire in series.....yep, those plate amps make everything easier..... :mrgreen:

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

chris_c_
Posts: 192
Joined: Thu Oct 28, 2010 5:48 pm
Location: Hartford, CT, US
Contact:

Re: Low cost Class D pro plate amps.

#53 Post by chris_c_ » Tue Aug 29, 2017 1:49 pm

MulletOver wrote:Enjoying the discussion so far! I was toying with the idea of a plate amp recently for my subs. I picked up a salvaged plate amp from a JBL SRX815P cabinet a few months ago for $50. I estimated that I could run up to (4) T39's off of it, but I can't install it in any of my current cabs.

So, if I built another T39, I know I would need to extend the cabinet somehow/somewhere - where would be the most practical place to mount the amp? (And Bruce, don't say 'the rack' ;-)
1. Measure the volume of the JBL SRX815P plate amp (the part that sits inside of the cab) in cubic inches.
2. Divide by the area of the back of the T39 cab in square inches.
3. Equals the number of inches of depth to add to the T39 cab.
4. Building the "deeper" T39.
5. Cut correct sized rectangle in the back of the T39 to hold the JBL plate amp.
6. Add 3 speakons to the back of this cab, series-parallel wired power amp outputs to the 3 other T39's.
Newest mix 8) https://facebook.com/BEATJACKERmusic "Like" appreciated :D

Rich4349
Posts: 620
Joined: Wed Jul 30, 2008 10:18 am
Location: Kankakee, IL

Re: Low cost Class D pro plate amps.

#54 Post by Rich4349 » Tue Aug 29, 2017 1:57 pm

chris_c_ wrote: 1. Measure the volume of the JBL SRX815P plate amp (the part that sits inside of the cab) in cubic inches.
2. Divide by the area of the back of the T39 cab in square inches.
3. Equals the number of inches of depth to add to the T39 cab.
4. Building the "deeper" T39.
5. Cut correct sized rectangle in the back of the T39 to hold the JBL plate amp.
6. Add 3 speakons to the back of this cab, series-parallel wired power amp outputs to the 3 other T39's.
EXCEPT, this accounts for *volume* used by the amp, but it also destroys the proportions of the horn in that 2nd to last fold.
2 DR250s, 2 27" Lab15 T-60s, 2 30" Neo Titan 39s, 1 Autotuba...and looking for more!

Rich4349
Posts: 620
Joined: Wed Jul 30, 2008 10:18 am
Location: Kankakee, IL

Re: Low cost Class D pro plate amps.

#55 Post by Rich4349 » Tue Aug 29, 2017 2:02 pm

Bruce Weldy wrote:
Rich4349 wrote: So go series / parallel? Parallel 8/2=4, series them right back up to 8? Not much wattage split 4 ways (edit: 800w, so not *too* bad), but a fun cheap experiment.
Yep....more cables per box plus specialty cables/box to wire in series.....yep, those plate amps make everything easier..... :mrgreen:
I follow your point, except you're going to run the amplified signal to a standard cabinet first, anyway, and S/P to the others, anyway, sooo...

For his idea you're running power from a nearby (hopefully) outlet, and an unamplified signal from the mixer etc to the first cabinet. I realize this isn't the optimal way, given ground loop hum, etc, so no need to :horse: any earlier points, but this guy seems hellbent on doing it, so let's give him all the rope he wants!

So Chris: how goes the relationship with the manufacturer you're contracting with? Get a unit price yet?
2 DR250s, 2 27" Lab15 T-60s, 2 30" Neo Titan 39s, 1 Autotuba...and looking for more!

Bruce Weldy
Posts: 6363
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Low cost Class D pro plate amps.

#56 Post by Bruce Weldy » Tue Aug 29, 2017 2:49 pm

Rich4349 wrote: but this guy seems hellbent on doing it, so let's give him all the rope he wants!
thus my :mrgreen:

I did do some research on the amp for him.....I still would run no more than two cabs off that amp. And you still have the problem of all the proprietary DSP that is most likely in that JBL amp. Most likely has a set EQ curve for that particular full-range box - might not be ideal for a BFM sub.

If you are going to go the powered route, get an amp that just produces clean power without the extra baggage of one coming out of an off-the-shelf speaker.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

David Raehn
Posts: 668
Joined: Tue Apr 30, 2013 5:56 pm
Location: Colonial Beach VA

Re: Low cost Class D pro plate amps.

#57 Post by David Raehn » Tue Aug 29, 2017 4:28 pm

Of course, Sommer Cable makes combo power-signal cabling:

http://shop.sommercable.com/en/Cables/B ... 051-1.html

so that will level the playing field.... :roll:

Bruce Weldy
Posts: 6363
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Low cost Class D pro plate amps.

#58 Post by Bruce Weldy » Tue Aug 29, 2017 4:42 pm

David Raehn wrote:Of course, Sommer Cable makes combo power-signal cabling:

http://shop.sommercable.com/en/Cables/B ... 051-1.html

so that will level the playing field.... :roll:

Yikes! Fine for lights.....not for audio. Don't want that power cable to run parallel to the signal cable for long of a distance that close together. While we all run our power and snake next to each other - at least they are in separate jackets and not living in that close a proximity.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

David Raehn
Posts: 668
Joined: Tue Apr 30, 2013 5:56 pm
Location: Colonial Beach VA

Re: Low cost Class D pro plate amps.

#59 Post by David Raehn » Wed Aug 30, 2017 6:14 am

They say it's rated for AES/EBU, DMX and balanced audio....

Bruce Weldy
Posts: 6363
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Low cost Class D pro plate amps.

#60 Post by Bruce Weldy » Wed Aug 30, 2017 9:31 am

David Raehn wrote:They say it's rated for AES/EBU, DMX and balanced audio....
Yeah, but do you really want a power cable running right up next to your signal cable? One of the first things I remember learning in audio was to try and cross power and signal at right angles when possible and try to stay away from then running alongside. May be an old wive's tale.....but, it would make sense that there could be some issues with hum interference running analog audio.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Post Reply