Is it ok to keep a cheap mini class-D amp turned on?

[Deleted member 9685]

I'd like to hook any of these to Raspberry Pi and keep it turned on.

• A cheap chinese generic TPA3251 amplifier
• A cheap chinese generic TPA3255 amplifier
• HiFiBerry Amp2

How does keeping a cheap mini class-D amp turned on affect its lifespan and sound quality over the course of years?

 

[RayDunzl]

I wouldn't worry about it too much...

I leave the stuff that I use turned on.

Audio Buddy turns his stuff off.

Mine gets more use, like, all the time.

 

[Willem]

But it is unnecessary power consumption, even if small. I recently replaced a power hungry set top box with a modern one that has about 50 watt per hour lower electricity consumption: 25 watt, down from 75 watt. That is 1.2 kilowatt per day or some 430 kilowatt per year. That is about 8% of our total energy consumption. The cost difference at our local electricity prices is 85 euro per annum. And there is the ecological argument in this day and age of climate change.

 

[Deleted member 9685]

@Willem According to my measurement device, my amplifier consumes ~4.8W when there is no sound.
When I listen to quiet music, it still consumes ~4.8W.
However, I don't know whether it's 4.8W per second or 4.8W per hour. It just reads ~4.8W

 

[0bs3rv3r]

@Willem According to my measurement device, my amplifier consumes ~4.8W when there is no sound.
When I listen to quiet music, it still consumes ~4.8W.
However, I don't know whether it's 4.8W per second or 4.8W per hour. It just reads ~4.8W

It is consuming 4.8W continuously. If you want to know the actual energy consumed, and hence what you'll pay for it, you need to measure something like watt-hours (or kilowatt-hours). e.g. 1000 watts used for one hour, burns one kilowatt-hour of electricity.

 

[Willem]

4.8 watt is not much, but more than some other units in sleep mode. Anyway, it is wasted energy. I am making a quite extensive energy saving effort at home, and the seemingly invisible consumption of all sorts of gear does add up quite a bit. Since we have solar panels, I am particularly interested in reducing electricity consumption during the dark hours/days.
Apart from excess electricity consumption, there is also the fire risk, and particularly from gear that may not meet proper safety standards. My late father was an electrical engineer by training and a long career in industry - he would always turn off all gear before he went to bed since he did not trust the low technical quality of much consumer grade stuff. With that and Amir's frequent criticism of the safety of cheap audio gear in mind, I would be concerned about keeping such cheap chip amplifiers permenently turned on.

 

[RayDunzl]

I don't know whether it's 4.8W per second or 4.8W per hour. It just reads ~4.8W

multiply 4.8 W x 1hour and it consumes 4.8watt hours.

That's 0.0048kWh

A year has 8760 hours.

The device will consume 8760 x 0.0048 = 42.48 kWh in a year.

Around here, a kWh costs about $0.12, so it would cost 42.48 kWh x 0.12 = $5.09 to run full time for a year.

According to my measurement device, my amplifier consumes ~4.8W when there is no sound.
When I listen to quiet music, it still consumes ~4.8W.

It will consume a little more if you turn up the volume.

On average, moderate listening, we probably only give the speakers a watt or two of power,

 

[gattaca]

^^^^ Ditto. I hinted at some of this in another thread "With that and Amir's frequent criticism of the safety of cheap audio gear in mind, I would be concerned about keeping such cheap chip amplifiers permanently turned on. " When the Buttkicker AMPs first came out, just because they could switch on from standby modes based on signals, people left them on all the time. A lot of sub amps do this today as well - scary for me at least.

But now, if you read their instructions, they added some lines saying, "Unplug this unit during lightning storms or when it is unused for an extended period of time. This device may be plugged into a surge protector or power strip, but should NOT be plugged into a UPS (uninterruptible power supply). DO NOT LEAVE THIS AMPLIFIER IN ‘STAND BY MODE’ WHEN NO ONE IS IN ATTENDANCE. For safety and to ensure long life, turn the amplifier power switch to the OFF position when unit is not being used."

Why? Hmm outside of the low but vampire power use, see -> https://www.avsforum.com/forum/113-...holy-smoke-my-buttkicker-amp-caught-fire.html

Today, I switch everything off via a series of SurgeX sequencers. The only things which remain on in low/standby are:
a) the main AV Pre-AMP b/c it controls the main 12V trigger,
b) the cable box,
c) Logitech Harmony + IR/Remote control setups,
d) 12V Kepco PSU (designed to run 24/7 for decades) which drives the thermostatically controlled Noctua fans exhausting the cabinets.

YMMV. For the KWH used google around but here's one to help you decide the $ to keep things on:
https://www.rapidtables.com/calc/electric/energy-consumption-calculator.html

Have a good one! Later.

 

[Deleted member 9685]

We keep our routers and phones and alarm clocks on for years without a single incident.

 

[gattaca]

^^^ no argument there b/c those have been designed and tested to run 24/7/365. Many consumer electronics and some of these "throw it in a box ICE-based amps" give me great pause. Is my house or the lives of my family worth the risks? Each buyer has to ask and answer it for themselves. Live and Let Live.

That statement I highlighted from the current buttkicker AMP manual I'm pretty sure appeared after their recall/problems of nearly burning down people's houses. I know, I have an original printing and it's not present.

Like my comment about the US-made Kepco's vs. most Chinese-designed and sourced PSU. It's a totally different design focus between as low-costs as possible vs. long-term reliable and safe(r). Those elements are not even in the same league. I'm not saying you cannot find some good Chinese designs at all. BUT.. you have to be trained to know what to look for and hope they did not take short cuts in manufacturing.

For instance, what BRAND capacitors are they using and what are their thermal and voltage ratings? I know Amir has called this out before. We should all remember the fake Chinese capacitor fiasco which has caused so many issues for the past many years in everything from computers to AV electronics (and Buttkicker AMPS)...

BTW, I toured the Kepco factory about a year ago. I met the owner as well as their design engineers. I only use Kepco's now and make damn sure if it's not a Kepco, then it is UL/ETL certified from a reliable source. Yeah they are more expensive but if you are patient, you can pick up eBayed units for much less. They last/run nearly forever. There are also a few other brands I'd use but you get the picture. Caveat Emptor. Peace.

 

[Deleted member 9685]

Does this look good enough to you? If you knew a better 32V 5A adapter on the markets, let me know.

 

[gattaca]

Interesting.. That's a perfect representation of the challenges with many imports. They look neatly made and tidy. But without testing and/or seeing the PCB's there's no way to know for instance how much current those copper traces are designed for or can carry safely before burning the board or arching thru the layers.

Also, just because a cap says "Panasonic," "Rubycon" or "Nippon" does not mean that's what they indeed are... Real Rubycon, Nipons, and Panasonic caps are VERY well made. But the fun fact is I recall it being a Rubycon engineer that swiped the formulas that lead to the now infamous "cap-gate". Knowing the chain of custody for those components is important as well as trusting but verifying the component suppliers. I found this listing about the different makers in the cap market -> https://www.tomshardware.com/reviews/power-supplies-101,4193-5.html

The other thing I learned with when I spoke with those engineers is he said they spot test the spooled products before assembly even when they are from known suppliers. They test the beginning, middle and end of the reels b/c they've seen parts early in the spool be fine..and parts later on not be to spec - trust but verify.

The only thing I can comment on WRT the 32V unit is is not ETL or UL listed. Also, do NOT assume the "CE" mark is the real "CE" for mark for European conformity. It can also mean literally marked for "Chinese Export" and nothing more.

FWIW, these are the marks I often look for but YMMV: It's best and safest to buy only from known reliable suppliers who've been in business for a while. Unless you are a EE, trained in PSU designs, especially SMPS, it's difficult / impossible to discern what you are seeing.

The only thing I can state about the open box is I see no evidence of any fusing or electrical breakers in that open unit. Only a licensed EE could comment further.

I piped up in this thread b/c I'm trying to educate fellow AVers about the gotchas of this tread. When purchasing cheap chinese-made PSU or other such items, you may not be purchasing something thoroughly tested, designed or safe under all operating conditions. OTOH, I'm sure some of the stuff may be well designed. Separating the wheat from the chaff can be very difficult. Caveat Emptor.

The above is from the Kepco page -> https://www.kepcopower.com/decmsaf.htm
Peace.

 

[NTomokawa]

Hey a fellow certification-o-phile! You know, I never understood why UL chose to use "ЯJ".

Meanwhile if your mini class-D isn't warm at idle then you can most likely leave it on and forget about it. I'd do that with my Yamaha monitors but their heatsinks radiate significant warmth even when idling. I wonder what the amps are doing in there...

 

[Deleted member 9685]

if your mini class-D isn't warm at idle then you can most likely leave it on and forget about it.

My body temperature // My right fingers < My left fingers < My arms

When I touch the amp with my right fingers, it feels warm.
When I touch the amp with my arm, it feels a bit cool.
According to my right fingers, the amp enclosure is cooler than my left arm.
My core body temperature is supposed to be 37 degrees celcius.
So, the amp enclosure's temperature is below 37 degrees ceclius.

I can either leave it on or send it to standby mode when I don't use it.
There's no off switch. There's only a standby mode switch.

 

[RayDunzl]

My body temperature // My right fingers < My left fingers < My arms

These are real handy:

That seems to be the left-handed version, though.

 

[Blumlein 88]

These are real handy:

View attachment 42971

That seems to be the left-handed version, though.

Do you need the right handed version for the read out in fahrenheit?

 

[solderdude]

Lifespan of capacitors is measured in hours at a certain temperature.
When one leaves it on when not in use the hours keep ticking.
When one only switches it on when needed this will prolong life.
There is another advantage of powering the device (so the power supply off) and that is the chance of damaging the amplifier after several years of usage increases over the years. This is the reason why the so called 'start capacitor' is always situated near a heatsink.
This preventive trick only works when the power is actually switched off frequently.

The most problems will come from the SMPS and not the amp itself most likely.

So there is a technical advantage (and financial) as well as safety advantage for switching the actual mains power off.
Only when the device takes a long time to stabilize with temperature it might be a good idea to only power a device off when not needed for quite some time.

 

[amirm]

These are real handy:

I suggest getting the dual laser ones so that you know when you have them at the right distance for spot measurements (the two laser spots converge).

 

[Deleted member 9685]

@solderdude I read most consumer-grade SMPSs are not designed to be plugged in and out frequently. When they are plugged in, current inrush happens. The lifespan of SMPS can decrease greatly by making it experience current inrush often.

 

[Deleted member 9685]

The amplifier enclosure is divided into the upper half and the lower half. I opened the upper half and touched the main capacitors with my right finger.
My right finger also felt the temperatures of my armpit and my chest.

While there is no sound, the two main capacitors were slightly cooler than my armpit or my torso or my tongue.
I think the temperature of the main capacitors is below 37 degrees celcius.

The plastic power supply enclosure is cold to touch with my fingers.

You can see the pictures of my amp and its power supply above.