I opened up a pair of Dan computer speakers.
The "ON/OFF" switch only interrupted the secondary feed to the PSU.
The 9-0-9Vac 1.2A mains transformer is permanently connected to mains supply, whether the switch is ON or OFF. There is a thermal fuse inside the transformer.
Is the ON/OFF switch usually not in the mains feed?
Before powering up I used the bulb tester just in case I had done anything wrong in the reassembly.
Surprise !!!!
the speaker consumes more power when OFF, than it does when ON
These are described on the label as "active" speakers.
Nonsense.
There are one pair of TDA2030 chipamps inside one speaker box.
One chip drives the bass/mid directly and the treble via a 4u7F electrolytic.
The other chip drives a cable feeding the other almost empty box. Again the bass mid has no crossover components and the treble has the 4u7F.
These are passive speakers with an inbuilt stereo amplifier to make them "self powered".
Is this a common mis description of "active" computer speakers?
The "ON/OFF" switch only interrupted the secondary feed to the PSU.
The 9-0-9Vac 1.2A mains transformer is permanently connected to mains supply, whether the switch is ON or OFF. There is a thermal fuse inside the transformer.
Is the ON/OFF switch usually not in the mains feed?
Before powering up I used the bulb tester just in case I had done anything wrong in the reassembly.
Surprise !!!!
the speaker consumes more power when OFF, than it does when ON
These are described on the label as "active" speakers.
Nonsense.
There are one pair of TDA2030 chipamps inside one speaker box.
One chip drives the bass/mid directly and the treble via a 4u7F electrolytic.
The other chip drives a cable feeding the other almost empty box. Again the bass mid has no crossover components and the treble has the 4u7F.
These are passive speakers with an inbuilt stereo amplifier to make them "self powered".
Is this a common mis description of "active" computer speakers?
Switching the secondaries has been common for many years in a lot of equipment. Reputable manufacturers (and I'm going back a while) used to put labelling of "standby/on rather than off/on but I'm not surprised if thats not the case for a lot of stuff these days. Why do they do it... cost I guess. Its cheaper and means a cheap non mains rated (i.e. a safety component) switch can be used.
Current consumption will be low but these things all add up as you know. Could be a project there, a small PCB thats say nicad powered to detect audio and turn on a mains relay.
Current consumption will be low but these things all add up as you know. Could be a project there, a small PCB thats say nicad powered to detect audio and turn on a mains relay.
That might explain what I am seeing.
Since the transformer is stamped 230Vac and I am on a nominal 240Vac supply then further up the saturation curve is possible.
It seems that drawing a small load to power up the quiescent chip is enough to reduce the saturation AND to reduce the total current consumption.
That is a surprise to me.
Since the transformer is stamped 230Vac and I am on a nominal 240Vac supply then further up the saturation curve is possible.
It seems that drawing a small load to power up the quiescent chip is enough to reduce the saturation AND to reduce the total current consumption.
That is a surprise to me.
Sorry about your bogus transformer. If you can't have half decent true power measurements as through something like a Kill A Watt, there's always the heat test. (Does it actually get warm, or not?) It doesn't sound like the system is really worth upgrading, but switching wall warts have come a Long way and now have very high efficiency, extraordinarily high in standby / no load with the use of chirp mode capable controllers. You could always get two wall wart switchers for your +/- supply, but you might do just as well shopping for a better product.
Last edited:
To also get the printer and monitor turned off, there's a device commonly referred to as a "Smart Stick" and those are recognizable by having a "Master" outlet that detects whether or not the PC is on, plus several switched outlets for those pesky computer peripherals that never turn off.
For example, this:
Amazon.com : ZuniDigital ZG7000B-15 7 Outlet Digital Smart Green Surge Protector (Black) : Electronics
It is also useful for the home entertainment center, for example, if the TV is "Master" then turning off the TV also knocks out power to 4 more devices so they can't consume electricity around the clock.
Those smarts sticks are also entertaining with lamps, whereby turning off the one you can reach, turns off 4 more.
For example, this:
Amazon.com : ZuniDigital ZG7000B-15 7 Outlet Digital Smart Green Surge Protector (Black) : Electronics
It is also useful for the home entertainment center, for example, if the TV is "Master" then turning off the TV also knocks out power to 4 more devices so they can't consume electricity around the clock.
Those smarts sticks are also entertaining with lamps, whereby turning off the one you can reach, turns off 4 more.
Hahaha i measured wattage of my sisters Defender MK35 speakers...
There is switch at the back of the amplified speaker but no one will never reach that far...
So ive been keeping them plugged 24/7...
The bad thing is that it sucks 20-22W when its idle! Thats alot id say but the chipamp is oscillating like a boss and generates alot of heat, the heatsink inside reaches temperature near 80°C!
When listening at normal level (1W) Now sure how hot will it get at its max output power, Hahaha that would be impossible the supply voltage of the amp is below +-16V DC and has only 36VA transformer that is made in china, which means, most of the power turns out as heat-.- But the amplifier max output power is 20Wx2 (Woofers 8 ohms and tweeters 4 ohms) NASTY COMBINATION IF CRAP CROSSOVER LIKE SINGLE CAPACITOR..
and chip is LM1876 I might change the transformer for higher voltage one but it would heat the heatsink to the limit and SpiKe would go full retard..
Anyway, I made new PCB for the amp... Rubbish design but i was able to eliminate oscillations now the heatsink is cool and transformer changed. When idle it draws normally below 5W as i still use cheap but russian made transformer.
There is switch at the back of the amplified speaker but no one will never reach that far...
So ive been keeping them plugged 24/7...
The bad thing is that it sucks 20-22W when its idle! Thats alot id say but the chipamp is oscillating like a boss and generates alot of heat, the heatsink inside reaches temperature near 80°C!
When listening at normal level (1W) Now sure how hot will it get at its max output power, Hahaha that would be impossible the supply voltage of the amp is below +-16V DC and has only 36VA transformer that is made in china, which means, most of the power turns out as heat-.- But the amplifier max output power is 20Wx2 (Woofers 8 ohms and tweeters 4 ohms) NASTY COMBINATION IF CRAP CROSSOVER LIKE SINGLE CAPACITOR..
and chip is LM1876 I might change the transformer for higher voltage one but it would heat the heatsink to the limit and SpiKe would go full retard..
Anyway, I made new PCB for the amp... Rubbish design but i was able to eliminate oscillations now the heatsink is cool and transformer changed. When idle it draws normally below 5W as i still use cheap but russian made transformer.
to use those in HT set up is scary. the slave outputs often have a very limited output current. they are designed for smal current devices such as printers monitors and pc speakersystems. they can not handle HT amps and poweramps.
Dat relay! Relay is one hell of a device! I will now go and do it but... I will use usb port and 5V relay, haha!
are you sure it can be done ? (LOL)
actualy if one would add up the standby consumption of a printer, amplifier, DAC, active xo, the monitor etc..etc.. whatever.... it may actualy someday return the investment.
not absolute realted, but many phone chargers allso consume more when no phone is connected.
a nother noteworthy thing is the pc psu it self, as some modells have considerable standby power cunsumption.
actualy if one would add up the standby consumption of a printer, amplifier, DAC, active xo, the monitor etc..etc.. whatever.... it may actualy someday return the investment.
not absolute realted, but many phone chargers allso consume more when no phone is connected.
a nother noteworthy thing is the pc psu it self, as some modells have considerable standby power cunsumption.
Simple fix:
Turn on your desk lamp, and then cut off the switch so the desk lamp cannot be turned off. This makes a desk light, indicator lamp combo function. Plug the desk lamp into a switched power strip along with the computer and peripherals. Use the power strip's switch.
Remember, 10% of an average power bill is standby waste.
P.S.
I'm not heating water while sleeping--the kitchen light switch is a heavy duty dpst model which also operates the water heater (it is highly insulated to retain heat well and so are the pipes). There's another case of room lighting serving dual-duty as indicator lamp.
Turn on your desk lamp, and then cut off the switch so the desk lamp cannot be turned off. This makes a desk light, indicator lamp combo function. Plug the desk lamp into a switched power strip along with the computer and peripherals. Use the power strip's switch.
Remember, 10% of an average power bill is standby waste.
P.S.
I'm not heating water while sleeping--the kitchen light switch is a heavy duty dpst model which also operates the water heater (it is highly insulated to retain heat well and so are the pipes). There's another case of room lighting serving dual-duty as indicator lamp.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.