Class D amp long term reliability

[Philbo King]

Around here a vertical hole is a mine shaft. In the midwest, it's a well. Don't know if either is significantly better or worse on average than a class D amp for reliability.

Crawling back into my cave now - Don

Mineshaft joke:
What chord is produced when a piano dumped down a mineshaft hits bottom?

A flat miner

 

[DonH56]

Mineshaft joke:
What chord is produced when a piano dumped down a mineshaft hits bottom?

A flat miner

I wanted to like that, but... I just couldn't.

 

[pseudoid]

Mineshaft joke:
[Q:]What chord is produced when a piano dumped down a mineshaft hits bottom?

[A:]A 3-note "tweet" just before the canary goes 2-D!
I liked @DonH56 reply better.

On Topic: I just pulled a 5-Channel Rotel powerAmp out of Service:
*Five ICEpower "Class D" internal (B&O) PCBs.
*Besides some internal dust accumulation, none of the e-caps show signs of bulging or leakage.
*It was in 24/7 duty since January 2011.
Would this - the fact that it has been rarely turned OFF and/or stored - indicate that a ClassD powerAmp just likes being left ON; to prevent the "voltage-free" capacitors from oxide layer deterioration?

 

[mhardy6647]

And a cave is just a hole turned sideways. Do with it what you need to do. Vertical or horizontal? That is the question.

 

[mhardy6647]

I guess I don't need to remind denizens of this forum that transistors operate using holes.

source: https://www.worldradiohistory.com/BOOKSHELF-ARH/Technology/GE-Books/GE-Transistor-Manual-1964.pdf

 

[pseudoid]

I guess I don't need to remind denizens of this forum that transistors operate using holes.
source: https://www.worldradiohistory.com/BOOKSHELF-ARH/Technology/GE-Books/GE-Transistor-Manual-1964.pdf

Is the moral of your reminder about the fact that there are must be some positive virtue to even a- hole?
We had a professor, charmingly called "P-hole"!

 

[mhardy6647]

Is the moral of your reminder about the fact that there are must be some positive virtue to even a- hole?
We had a professor, charmingly called "P-hole"!

Well, since this thread had taken a turn towards spelunkery...

PS When, as a UG, I took Intro Physics for non-physics majors*, it was taught by a his-and-hers pair of professors in the Physics Dep't named Gabor Domokos and Susan Kovesi-Domokos. Neither of them was high on the list of scintillating lecturers. We thus used to refer to them as "Dr. Comatose and Dr. Really Comatose."**
Oh, we were so witty in those days.

__________________
* Or, as it was widely referred to at my alma mater: Physics for Poets
** I mean, not in class...

 

[dlaloum]

[A:]A 3-note "tweet" just before the canary goes 2-D!
I liked @DonH56 reply better.

On Topic: I just pulled a 5-Channel Rotel powerAmp out of Service:
*Five ICEpower "Class D" internal (B&O) PCBs.
*Besides some internal dust accumulation, none of the e-caps show signs of bulging or leakage.
*It was in 24/7 duty since January 2011.
Would this - the fact that it has been rarely turned OFF and/or stored - indicate that a ClassD powerAmp just likes being left ON; to prevent the "voltage-free" capacitors from oxide layer deterioration?

I would posit that keeping electronics turned on seems to encourage longer life, the on/off cycle itself seems to be a major form of internal wear on a whole bunch of components - it isn't exclusive to Class-D.

My Class-D Crown XLS2500's have been on 24/7 since around 2013... and I purchased them second hand.... they seem quite intact and running "like new"
But then my Quad 606 and 707 amps, have had a similar regime since around 2000.... both were purchased used, the 606 had a refurb around 2005 - mostly to match its input sensitivity to the 707 - the 606 is a late 80's model, the 707 90's... - they are perfectly happy soldiering on too!

There is a degree of give and take needed - additional cost of keeping them on when "idling" - vs the cost of replacement or refurbishment....

 

[theREALdotnet]

Well, since this thread had taken a turn towards spelunkery...

 

[Platypus20]

Before I bought my pair of AHB2s, I looked at NAD, Bel Cantro and Elac amps, all class D, my concern was reliability, my C-J amp had run for 25+ yrs without a hiccup, but I sold it in a moment of weakness. The Class D amps I had actually seen and heard, all failed within the first year. So I wanted an amp with a dealer network and at least a phone number to call. All of the failed amps, were bought off the web, the first one sound great, the others bought them, then 7-9 months later they started to die. I do not know who the manufacturer was, but they could get no service or repairs, they ended up in the landfill. It encouraging to hear they can actually be reliable. I’m hoping I’ll never new new amps, but it’s nice to know there are other viable options.

 

[Deleted member 21219]

Before I bought my pair of AHB2s, I looked at NAD, Bel Cantro and Elac amps, all class D, my concern was reliability, my C-J amp had run for 25+ yrs without a hiccup, but I sold it in a moment of weakness. The Class D amps I had actually seen and heard, all failed within the first year. So I wanted an amp with a dealer network and at least a phone number to call. All of the failed amps, were bought off the web, the first one sound great, the others bought them, then 7-9 months later they started to die. I do not know who the manufacturer was, but they could get no service or repairs, they ended up in the landfill. It encouraging to hear they can actually be reliable. I’m hoping I’ll never new new amps, but it’s nice to know there are other viable options.

Any product (or any topology) is only as good as the professional insight and integrity of the manufacturer. Class D can be as good or as bad as someone makes it. As you have seen, an accurate assessment of professional insight and integrity can be very difficult to come by before purchase. That is exceedingly unfortunate.

Jim

 

[Blumlein 88]

I have a couple class D amps over 20 years old. One is only sometimes used, but was used for a decade daily. I also have one in daily use for the last 15 years. Ice power amps at least seem pretty good.

 

[EJ3]

This conversation is getting deep. And troglodytic.

Possibly: comparative more troglodytic or superlative most troglodytic?

 

[manisandher]

Many years ago, I used to run a pair of PS Audio HCA-2 amps for biamping. One of them failed (total PCB burnout) after a short while. I never bothered repairing it, as in my view, the HCA-2 is a truly awful sounding amp. Put me off class D for many years.

But it's a 'Stereophile Class A' component, which even @Kal Rubinson liked the sound of, so what do I know?

My brother still has the other (still working) HCA-2, but hardly ever uses it. I can understand why...

Mani.

 

[JSmith]

the HCA-2 is a truly awful sounding amp

I'm not surprised tbh;

PS Audio HCA-2 power amplifier Measurements

Sidebar 2: Measurements The PS Audio HCA-2 inverted absolute polarity, and its balanced and unbalanced inputs featured almost identical voltage gains: 30.2dB and 30.4dB, respectively, into 8 ohms, both of these on the high side. As a result, it took only 1V or so to drive the amplifier to...

www.stereophile.com

But it's a 'Stereophile Class A' component, which even @Kal Rubinson liked the sound of

@John Atkinson wasn't too impressed, though diplomatic;

I was disappointed with the PS Audio HCA-2's measured performance, particularly regarding its lack of high-frequency linearity. This behavior suggests that the amplifier circuit has limited open-loop bandwidth, which conventional engineering practice suggest could be coped with by applying more loop negative feedback. The resultant improvement in high-frequency linearity would be achieved at the expense of overall voltage gain; as the HCA-2 has around 6dB more gain than is strictly necessary, it might be thought that applying the same 6dB of loop feedback would radically improve the amplifier's measured performance (footnote 1).

However, it is not my job to second-guess designers. As PS Audio's Paul McGowan is one of the more careful listeners around, he presumably decided that increasing the amount of negative feedback to improve the measurements did not make the sound better, and perhaps made it worse. But I'd certainly expect the HCA-2's measured problems to have audible consequences. Perhaps it was the presence of added high-frequency harmonic content that gave Kal Rubinson the impression that the HCA-2 pushed the soundstage forward, though he didn't find its presentation "glaring." Certainly more auditioning is called for if we are to confirm the HCA-2's Class A rating in "Recommended Components."

JSmith

 

[hearone]

Yes, they confuse a bunch of people by re-publishing old reviews. Note the dates.

View attachment 147400

Wish I had kept my NS-1000M. Sad. Replaced after about 15+ years with Thiel 3.6 tower. Kept them in storage for a few years, but finally let them go in a divorce.

 

[Xcaliber]

FWIW, my SVS PB12-ISD has the class D plate amp, bought it in 2004 and it has been running almost daily for 20 years now, all the vibration from the room shaking bass didn't shake it apart either, the woofer dust cap fell off not long ago, probably due for replacement but the class D plate amp keep on working and refused to die.

 

[Xcaliber]

Just for experiment, My Apollon 1ET7040 case went from 105F down to 86F using the lowest fan setting from my laptop pad cooler, that's close to 20 degree drop. Measured the Apollon front, bottom, and top section with an infrared temperature gun, i figured since these Hypex/Purify amps are using convection heat transfer via the case, keeping it as cool as possible may be able to prolong the life of amp?

These laptop cooling pads are cheap, like $20~30 from Amazon, most of them are very quiet, anywhere between 25dB to 35dB depending on the fan speed and mode, and it cools both my AVR and the Apollon at the same time when I stacked them together.

Amazon.com

Amazon.com

 

[Doodski]

Just for experiment, My Apollon 1ET7040 case went from 105F down to 86F using the lowest fan setting from my laptop pad cooler, that's close to 20 degree drop. Measured the Apollon front, bottom, and top section with an infrared temperature gun, i figured since these Hypex/Purify amps are using convection heat transfer via the case, keeping it as cool as possible may be able to prolong the life of amp?

Everything benefits when you are able to operate your gear cooler.

 

[Xcaliber]

Everything benefits when you are able to operate your gear cooler.

it's a cheap insurance and the fans are very quiet so it wouldn't hurt. My 10yr old Denon x4000 AVR in the living room still run like a champ and it is cooled by two 140mm 18dB USB fans sat on top of the AVR since day 1. I use the same USB fan to cool my RT-AC5300 router and saw a 30 degree temperature drop as well. lol