Behringer Truth B2032A auto-standby annoyance...

[Ald-777]

Good day, all. I recently acquired a pair of Behringer Truth B2031A studio monitors. While I like these speakers for many reasons, there is one thing that bugs me: the auto-standby feature (when enabled) has annoying behaviour. The speakers go into standby mode too quickly and easily, (e.g, when I'm actually playing audio). They are also too reluctant to be knocked back out of standby. To knock them out of standby status, I keep having to crank up the volume control on my audio interface. I use these monitors at low volumes (near-field), which doesn't help. Ideally, I'd like them to go into standby mode only when there has been almost complete silence, re the input signal, for a minute or more. I'd also like it if a much lower level of input signal would knock them out of standby. Can anyone suggest a solution? I'm wondering if there is a sensitivity trim pot on the circuit board, or something. If there is no solution to this, I'll probably have to disable auto-standby and leave the Class AB amps running in normal mode during working hours. But I'm guessing they will then consume a lot more power, and might end up with a reduced lifespan, correct? Thank you for any suggestions!

 

[Ktacos]

I think the solution is to just turn off the stand by. I turn it off on all my powered speakers.

 

[Ald-777]

I think the solution is to just turn off the stand by. I turn it off on all my powered speakers.

Thanks, Ktacos. I wondered if that was a sensible option. I'm partly concerned about how much my electricity bills would likely increase! (Electricity is expensive, where I live.) I'm unfamiliar with Class AB powered monitors, as I've been using passive monitors until now. I'm also not too savvy about the kWh such amps use, so I'd be interested if someone could give me an estimate of the power/kWh consumed (a) in standby mode and (b) when full on. As mentioned, I usually have the speakers at low volume (I don't know if that makes a difference, does it?) The Class AB amp specs, per speaker, are:

 

[Mister T.]

Anyway, even when the B2031s are in stand-by mode the amplifiers stay powered on and they draw as much current as when the speakers isn't in stand-by. You can check this by letting the speakers in stand-by and touch the rear panel, you'll feel the warmth. Not the smartest design

If you want to keep your electricity bills low, just use the ON/OFF switch when you don't use them.

 

[Davey]

Anyway, even when the B2031s are in stand-by mode the amplifiers stay powered on and they draw as much current as when the speakers isn't in stand-by. You can check this by letting the speakers in stand-by and touch the rear panel, you'll feel the warmth. Not the smartest design

If you want to keep your electricity bills low, just use the ON/OFF switch when you don't use them.

Uh, no.
They draw about 15 watts when turned on and not playing music.
They draw about 5 watts when the standby mode is activated.
They draw 0 watts when the main switch is turned off.

The three TDA7293 standby and mute pins are ganged together in this design.

So, you do get 'some' of the power reduction feature.

 

[Mister T.]

Ah, mine have the LM3886.

 

[Davey]

Ah, mine have the LM3886.

Yep, that's a different muting scheme.....and one of the reasons they changed to the TDA7293 chips.
Most of these speakers still in the field (I suspect) are the newer TDA7293 design.

For the OP, you can determine which version B2031 you have by monitoring with a Kill-A-Watt meter, or similar.

Modification of the standby operation timing/threshold would require surgery on the speakers. Probably not worth it, in my opinion.

 

[Ald-777]

They draw about 15 watts when turned on and not playing music.
They draw about 5 watts when the standby mode is activated.

That's just what I wanted to know - thank you! 15W (plus somewhat more when playing music) sounds affordable, so I suspect I'll probaby leave them in 'on' mode and then use the on/off switch on an extension lead, to switch them off when not needed. It's a shame that the auto-standby feature doesn't work well (for me, at least).

 

[NEUTRINO]

That's just what I wanted to know - thank you! 15W (plus somewhat more when playing music) sounds affordable, so I suspect I'll probaby leave them in 'on' mode and then use the on/off switch on an extension lead, to switch them off when not needed. It's a shame that the auto-standby feature doesn't work well (for me, at least).

Hello, I don't have much knowledge of electrical and electronic engineering, so I'm afraid I might be giving you the wrong information.

The photo shows part of the B2031A's "power mode" circuit.

I think changing the 2.2K ohm resistor in R82 to around 1.1K would be more effective!

 

[DVDdoug]

You've probably already got your answer but the "Kill-A-Watt" is a popular, inexpensive gizmo for measuring power consumption.

I'd just leave it on like an amplifier or anything else and then turn it off when you're not using it.

...I don't actually have anything with auto-standby. Only my stuff with remote controls is in standby while waiting for a signal from the remote to turn-on.

I'll probably have to disable auto-standby and leave the Class AB amps running in normal mode during working hours. But I'm guessing they will then consume a lot more power, and might end up with a reduced lifespan, correct?

It's probably not going to hurt the lifespan. Sometimes it's better to leave things running than to switch them on & off, which usually creates a momentary current surge when they are switched-on. But electronics failures are mostly "random" anyway unless you let it overheat by playing it full blast outside in the sun in the summer, or something like that...