JBL PRX series auto-off disable?

Re: JBL PRX series auto-off disable?

He didn't say it would be his first choice, or what he would do - just that it happens.
Actually he said "Perfect scenario for that", which indicates he thinks it is a good idea.

He's suggesting that it's a neat failsafe for when people are being silly.
But it's not. It's pointless and can cause more problems without solving ANY.

Who knows, maybe it gives them an Energy Star rating or something like that which they get a tax credit for.
That's a very likely explanation actually. Or even more likely, there's a power controller chip already being made (taken from some home stereo piece) that's $0.05 cheaper and it has a power saving mode that's not defeatable.

I don't have as much issue with manufacturers getting their stuff built overseas than I do with them staying completely un-involved. I'm kinda shocked, really, that this is how JBL has become.
 

Steve Garris

Freshman
Mar 29, 2012
46
0
0
Seattle, WA
Re: JBL PRX series auto-off disable?

JBL has had a few head scratchers. I agree on the gate, which BTW has been around since at least the PRX 500 series - I was shopping 7 years ago or so, and hated the "feature" then. I ended up buying QSC HPR instead.

More recently in the fantastic sounding SRX-800P series, the default gain is 26dB rather than the more common 32dB, so the forums are filled with people saying the speakers are "underpowered" as they have to turn the gain knob higher than comparable products. Yes I know they did this to match the ITech defaults, but I don't like it on the ITechs either. BTW, there is a gate on by default in the SRX-800P series, but it's fast enough that I haven't been bothered by it, and I believe you can disable the "power saving mode" that turns it on.
Regarding the PRX gate feature, can you point me to some documentation on this? I've never heard it on the 500 and 600 series systems I use. It's documented in the 700 series spec's as a "power saving mode", but I can't find any reference in the 500 and 600 series manuals.

I was one of those scratching my head in the forums regarding the SRX output. I've learned now just to feed it more signal, but I'm hoping JBL will change this with a firmware update in the future.
 
Re: JBL PRX series auto-off disable?

Your argument that you have better control of the speakers by having separate amps together could be used as an argument for your portable situation as well. If so, then why are YOU using powered speakers?
Powered speakers are MOST useful in portable situations (weight, flexibility) and LEAST useful in an install (wiring, maintenance, control). Using a powered speaker that has controls on it's back in an installation is a terrible idea for SO many reasons.

At idle, a powered speaker probably draws 25-30 watts. While not much, that works out to about $30 in electrical consumption per year if the speaker sits idle 24X7. It adds up if you have multiple speakers in a room.
I assume that's a guess and not a measurement. If I get a chance, I'll see if I can measure the current draw of these speakers while idle and when in standby.

Yes, in an ideal world, you could put all of the speakers on a switch or a breaker. However, now you need to teach people how to find that breaker and turn on the speakers when they are needed. Believe it or not, in many situations, that's more difficult than it seems. If you can just pick up the mic and talk, that is much easier for many to understand. It's quite common in the install world to leave stuff powered on 24X7 because of this.
Leaving everything "hot" 24x7 sounds like a terrible idea and not safe at all. I do admit it's done all the time, but I don't think we should be building and installing equipment to encourage this.

The reason to keep things on 24X7 is answered in question 3. The same problems you describe, of people plugging things in, or amp failures, etc. could happen if you have an amp in a rack.
But, at least you can get to the amps and shut them off easily. A powered speaker flown or mounted somewhere might require a ladder or lift and a lot of effort to shut down. If they are on a breaker or remote switch, then it's easy. And again, with that external switch, you eliminate any need for a standby mode.

Yes, it would be nice if you could defeat the option, but that extra option would increase the cost of the speaker.
Not at all. If the circuitry was made that way, there would be no cost difference. Fixing it after the fact would be expensive, yes. This is why it's good for companies to DESIGN products rather than just re-branding existing crap. Chinese manufacturers rarely get the features right, and how could they? They don't know how the North American user uses these things.
 

Ivan Beaver

Graduate Student
Jan 11, 2011
2,300
10
0
Atlanta GA area
Re: JBL PRX series auto-off disable?

Who knows, maybe it gives them an Energy Star rating or something like that which they get a tax credit for.
ACTUALLY-that is EXACTLY the reason the Peavey IPR amps have the blue LEDs in them that you can see when it is OFF.

In order to get the energy star rating, the "idle current" must be very low-according to the way the "spec" is written.

Since you cannot divide the operating current by "zero" and have a number to put on the application, it HAD to draw some current.

So they put the LEDs in there to draw a small amount of current in the "off" position.

Blame it on the "government" and how specs are written.

It doesn't always make sense. Having a product waste energy in order to be called an "energy saver".
 
Re: JBL PRX series auto-off disable?

ACTUALLY-that is EXACTLY the reason the Peavey IPR amps have the blue LEDs in them that you can see when it is OFF.

In order to get the energy star rating, the "idle current" must be very low-according to the way the "spec" is written.

Since you cannot divide the operating current by "zero" and have a number to put on the application, it HAD to draw some current.

So they put the LEDs in there to draw a small amount of current in the "off" position.

Blame it on the "government" and how specs are written.

It doesn't always make sense. Having a product waste energy in order to be called an "energy saver".
No. The Energy Star requirements dictate only maximum power consumption, and a manufacturer is very much allowed to draw less than the maximum allowed. Take a look at the standard for yourself: http://www.energystar.gov/sites/def... AV Program Requirements (Rev Dec-2014)_0.pdf

Another salient point in that standard is the requirement for an automatic power-off function, which can allow the manufacturer to avoid having to meet other parts of the standard if it is permanently enabled with a timeout of less than 30 minutes. My guess is that JBL took that exception, instead of reducing their idle power and presenting an option to disable the auto-off functionality to the user (allowed by the standard).
 

Ivan Beaver

Graduate Student
Jan 11, 2011
2,300
10
0
Atlanta GA area
Re: JBL PRX series auto-off disable?

No. The Energy Star requirements dictate only maximum power consumption, and a manufacturer is very much allowed to draw less than the maximum allowed. Take a look at the standard for yourself: http://www.energystar.gov/sites/def... AV Program Requirements (Rev Dec-2014)_0.pdf

Another salient point in that standard is the requirement for an automatic power-off function, which can allow the manufacturer to avoid having to meet other parts of the standard if it is permanently enabled with a timeout of less than 30 minutes. My guess is that JBL took that exception, instead of reducing their idle power and presenting an option to disable the auto-off functionality to the user (allowed by the standard).
Well I can't say-since I have not read the particulars.

HOWEVER that is exactly what the designer (JD) told me in a phone call when we were discussing it.

So that is all I have to go on.
 

Carlos Mazuca

New member
Jul 7, 2019
3
0
1
50
USA
[QUOTE = "Andrew Broughton, publicación: 13543, miembro: 318"]
¿Alguien sabe si hay una manera de desactivar la función de ahorro de energía en los altavoces con alimentación de la serie JBL PRX?
[/CITAR]
Anyone know if there's a way to disable the power saving function on the JBL PRX series powered speakers?
there is .. I had that problem and managed to solve it ... in case someone still has it and wants to solve it
 

Pete Dunn

New member
Aug 17, 2020
3
0
1
77
Perth
On the PRX715 discontinued input/ control panel with the DSP card 'PRX700 Full Range V6' manufactured around mid 2013 and no longer available, there is a ribbon cable to a 26 way header; two rows of 13 pins. This carries + and - 15V DC from the power amp/ power supply, audio signal and ground also the centre pin nearest to the edge of the PCB is the enable/ disable line that turns the Class D amp on and off when the DSP thinks it should or if the card fails in service. When the amp is active and the LED is blue there is about 3.3V DC on this line. When the amp is 'killed' the line is pulled close to ground. A work-around for a faulty DSP card is to disable the track to this pin on the underside of the DSP PCB. Please note that the indicator LED will turn red indicating stand-by but the amp will continue to operate. The proper fix is, of course, to install the upgraded complete amp module ex. USA: JBL PRX715 Amplifier Assembly JBL 5046365 / 5058666. This including freight is about $AUD600.00 in Australia and is very difficult to obtain.
 

Pete Dunn

New member
Aug 17, 2020
3
0
1
77
Perth
This disables the auto off. One of the faults that I have had is that the amp switches off even with a signal applied. Stays on for a minute or so and then goes to sleep. Hearsay has it that JBL had endless problems with this unit: intermittent faults, noise etc. In Australia the warranty support is next to nothing. Sell and forget.
 

Pete Dunn

New member
Aug 17, 2020
3
0
1
77
Perth
I thought that I had better add a bit. On these units the actual muting part of the circuit is on the Class D amp/ power supply card. The front panel DSP card controls this via the ribbon cable, centre pin nearest the edge of the front panel input card. If the screws that hold the connectors to the front panel are removed, removing another 8 or so inside attaching the card to the stand-offs will let you hold the PCB in your hand. The small PCB track that goes to the centre pin carries the 'kill' signal. If the PCB track is cut the amp will stay on forever! Pete
 

Danny Avila

Freshman
Dec 8, 2012
5
2
3
Hi 🖖.

The input module has an OpAmp circuit that senses the signal level and translates it to a positive voltage in the correspondent CPU pin, so it can control the obnoxious power saving option of this particular batch of PRX700 Series. As I have not any one of these at hand by now, I can't measure the max voltage level necessary in the pin SDETECT to keep the system alive and performing, but doubling R44 and R48 resistor values to 220K Ohm and C57 to 0.33uF will improve sensibility in the OpAmp (+) input pin and it will keep its output on Hi level with smaller signal fed to the loudspeaker, so the CPU senses the audio input as active and keeps the amp enabled with lower levels of input signal.

I attached a section of that circuit to locate the parts in the Input board.

🎤
 

Attachments