Questions You Should Know about Class D Amplifier Price

I’ve had a Stellar P3 for 4 months. I connected the power supplies for 4 source components to it and got improvements across the board on sound quality. My power amp is Primare A.60 (class D) rated at 300watts. As an experiment last month I swopped the power supply of one of the (little-used) components for that of the power amp. I fully expected to get warning changes of colour of the blue LED on the P3 as the total power requirement (adding figures from specs of the sources and the power amp) is well over 400watts. No problems at all, even when I turned the volume way beyond anything I would ever listen at - the power blue LED stayed unblinkingly blue!
To answer your question the changes in sound quality I noticed were in general small in all the areas mentioned above, however there was a very noticeable reduction in high-treble rawness and congestion. As a result I could play music at a higher volume without distortion and experience a higher dynamic range - the music became more exciting.
When I bought the P3 I regarded it as a no-brainer cost-effective way of improving the sound obtainable from system sources but now I think it’s an inexpensive must-buy for complete systems. For the great majority of systems I’d guess the P3 300watt rating is sufficient.

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I have M700s powered by a “mere” Stellar P3. They, along with everything else in the system except the subwoofer and the turntable motor, are run off of the P3’s regen outlets. The system, including the P3, never strains at all, and I’m super happy with the sound I’m getting, but I have to admit I haven’t tried it with the M700s getting their power elsewhere. I just plugged it all in together and started listening. That was almost 4 weeks ago now.

I bought the M and P15 at the same time. however I did connect M to my old TAD Power Purifier for a few days to break in. When I switched to P15, the overall improvement was significant. Later I added a AQ Thunder cord from the wall to the P15 and the improvement was again significant.

I think all PS Audio gears work great together and their power plants will bring out their best performance.

Yes indeed adifferentpaul that is the direction I’m considering. I would love a pair of BHK 300’s but financially it isn’t possible now. Not that the M’s are cheap or affordable by any means but compared to the BHK 300’s they are. I know a lot of people take the BHK 250 route which I have no doubt is a phenomenal amplifier but I’m sticking to the mono blocks due to current set up and cable cost. Reading that the m’s were voice matched to the same setup I’m using and the positive reviews that both press and forum members are writing its hard to be patient when I’m looking for that next sonic upgrade!

I was fairly skeptical that I would hear any difference when adding the Stellar P3 to my SGCD and M700s. I picked up the P3 at a good price from a forum member, so it was also well broken in. Imagine my surprise when I plugged everything in and there was an obvious difference. It was kind of like a lot of the background sound suddenly took a step forward. I don’t really understand why it would make that much of a difference, but I’m a believer.

To put it in perspective, I was skeptical that power cords would make a difference but swapped out the stock cords on the SGCD and M700s with some AQ NRG4 power cords that I found on sale at half price. Could not hear any difference in SQ at all.

After buying the M700s I thought things were as good as they could get. A little over two years later the Ms came out. Reading what others were saying about the improvements, and being offered 30 days risk free in home audition and a generous trade, I went for them. First, you must let them burn in a couple hundred hours or more. They aren’t kidding about that. My stereo is in the basement. I turned on the radio and let it play softly 24/7. After that I settled in for some serious listening. If you like the M700s, you will love the Ms. They are, simply put, more musically engaging in every way. The imaging, the sound stage, the bass; everything is better. I haven’t changed tubes, as others here have and really don’t feel incline to. I suppose it’s always nice to have that option. If you can swing them I doubt you’d part with them after 30 days. You can even A/B them with your M700s. Even before the Ms burned in, I thought then sounded better than the M700s and never took them back out of the system. Good luck!

After slogging around posts it seems this one is as good as any to fire off a few questions. With regards to the Stellar P3:

I was considering purchasing linear power supplies for a modem and ethernet switch when I realized plugging into the regenerator is essentially the same. Why stop there? I plugged the power strip that has all associated internet components, computer and HDMI switch into an unused receptacle. I do not detect any SQ loss and have eliminated remaining ground loop issues (oh that demon is relentless in this apartment building that mixes knob and tube with modern circuit breakers, distribution bonded to a water pipe instead of building ground and don’t get me started with the cable provider, but I digress). Reality is building power is as dirty as it gets and I’ve very few options when it comes to choosing a circuit to use. Is using the P3 as a source for powering mentioned equipment taboo?

Second P3 question. I am using regen power (not filtered) on preamp/DAC, phono preamp, and a pair of M’s without sending the P3 into yellow or red state. Specs for M’s state 600w minimum at 8 ohm, times 2. The P3 sustains 300w as I understand. I have everything in my system connected and this baby doesn’t even notice. And speakers are not what anyone would consider efficient at 87db and yet I can turn it up past the point of neighbors pounding on the door. Wonderful for me but I’m not understanding how is this possible?

I appreciate your feedback in advance. Please understand I went from low end AVR quality music to where I am now during COVID. Not a lifelong audiophile by any means. Just someone who appreciates listening to music.

Two possibilities:
1)You are not playing music loud enough to use enough power to trip the P3.
2) You have the M’s connected to the “High Current” outlets on the P3.
Also, the 600W minimum at 8 ohms is actually a minimum maximum value, that if you push the amp that hard, it will deliver a minimum of 600 watts at it’s maximum output into 8 ohms. But the amp is not normally trying to use (or pump out) anywhere near 600 watts of power per channel. My M700’s, for instance, use 21 watts per amp when fully on (according to my P12 regenerator).

Recently I bought a preamp and a pair of class d monoblock amplifiers to replace my ageing class a/ab amplifier. They were about two years old when I bought them and I’m quite happy with the sound so no regret soundwise.  One of the monoblocks makes a slight static noise through the speaker at switch on but is good after that. It annoyed me so I made enquiries through a well respected technician to inspect and repair. Now here is the big WARNING to potential purchasers of class d amplifiers. They are, on the whole, irreparable.  If something is wrong then more than likely the whole class d module will need to be replaced. My amplifiers are American made with Australian distributer but to get a new module I will need to deal with the American company and the module is quite expensive almost the price of a new amp. You might be lucky and the problem might be the electronics ancillary to the class d module. Just a warning to would be class d amplifier buyers.

Class D involves SMD to work as components have to be very close proximity, these devices are tiny and not many techs have the equipment or the expertise.   You are better to buy a brand new module and know it’s perfect from day one, as repairs can sometimes introduce other issues.  I’ve been dealing with SMD since the late 90s,   When they went to SMD from through the hole the size and cost reduced,  this made it not feasible to repair items on circuit board (pcb) level,  it was more reliable to just order a brand new pcb and replaced it, even if basic components like resistors went open!   
When I went to update, I had a member here who had a nc400,  when it ended up in my rig, one of the modules took out the 30A main circuit breaker to the house,  upon inspection something that went wrong destroyed 1/3 of the pcb.  This wasn’t repairable, the traces were totally gone, luckily Bruno agreed to send a replacement free of charge at his cost.  Generally SMD components are super reliable, it’s the implementation that can let it down.  Unfortunately it’s the way to go with any product,  and standard class A, A/B audio amplifiers won’t be any different,  it’s to cut cost and reduce realestate .

So much for renewable resources. But there is a glimmer of hope, not so much for the environment, but at least for the consumer. If one buys a product in australia it is covered by the new consumer protection laws. As I understand the new laws, if I buy a product, notwithstanding any sellers product warranties, there is a assumption by any informed consumer that a product should perform as expected commensurate with the cost and function of the product. So from my understanding if I buy an amplifier for say $ I would expect it to last at least 5 or possibly 10 years trouble free.  If it does not than it should be repaired at no cost to the consumer dispute it being well out of sellers warranty period. I don’t know how or if this works in practice but it is a step in the right direction. More consumers should start to insist on their rights especially in this expensive hifi hobby.

5 hours ago, fjs said:

Recently I bought a preamp and a pair of class d monoblock amplifiers to replace my ageing class a/ab amplifier. They were about two years old when I bought them and I’m quite happy with the sound so no regret soundwise.  One of the monoblocks makes a slight static noise through the speaker at switch on but is good after that. It annoyed me so I made enquiries through a well respected technician to inspect and repair. Now here is the big WARNING to potential purchasers of class d amplifiers. They are, on the whole, irreparable.  If something is wrong then more than likely the whole class d module will need to be replaced. My amplifiers are American made with Australian distributer but to get a new module I will need to deal with the American company and the module is quite expensive almost the price of a new amp. You might be lucky and the problem might be the electronics ancillary to the class d module. Just a warning to would be class d amplifier buyers.

I had a problem with my Class D amp just after 2 years owning it. Was a dual mono amp but in one chassis.

It would not always turn on with one channel. Might take multiple turn ons. Went through a few seconds check on turn on and one channel would not start.

It was taking longer and longer as time went on.

to the supplier and they said I would need another PSU.

Took it to a local tech and he found it was a capacitor in one the power supplies. Replaced that one in both and it was good to go.

So could be something similar happened to yours?

One test possibly you could try yourself if its modular, could be to swap the power supplies over and see if it then happens to the other one?

ADDED: Mine was a NCore with 2 NC500 modules with dual SMPSA700 Power Supplies.

Seems it has happened to a few others too.

Edited June 2, by rocky500

5 hours ago, DavidH71 said:

components

7 hours ago, BugPowderDust said:

I wouldn't disagree.  

The same situation is apparent when you get your car serviced too. They fire up the EBC software, figure out what is bung and it's just a swap of parts / modules to fix. It's going to be rarer and rarer in the future to find a capable mechanic that can fault find without the computer telling them where to look.

in some industries that’s been going on since SMD was introduce,  that’s all we do apart from replacing blown fuses…..   the product has a 100s of service codes, every one will tell you what to expect and why it’s not happening,  go to that part of the the product where the suspected faulty component is and swap it out so the code doesn’t show and the thing boots up normally, if it does it’s fixed. You’re lucky to get a multimeter to use, in fact some of the diagnostics, the voltages in test modes are on display via the same touch panel.   Now the product even tell us from a remote location,  if it’s access able on line and have the ability to reset the code remotely to get the client up and running.  Not only that we can push new version firmware /software patches onto the product and the client will never know!

Edited June 2, by Addicted to music

7 hours ago, fjs said:

So much for renewable resources. But there is a glimmer of hope, not so much for the environment, but at least for the consumer. If one buys a product in australia it is covered by the new consumer protection laws. As I understand the new laws, if I buy a product, notwithstanding any sellers product warranties, there is a assumption by any informed consumer that a product should perform as expected commensurate with the cost and function of the product. So from my understanding if I buy an amplifier for say $ I would expect it to last at least 5 or possibly 10 years trouble free.  If it does not than it should be repaired at no cost to the consumer dispute it being well out of sellers warranty period. I don’t know how or if this works in practice but it is a step in the right direction. More consumers should start to insist on their rights especially in this expensive hifi hobby.

About 8yrs ago I tried that with an iPhone- it was randomly switching itself off and also draining the battery completely flat overnight. 
I took it to an Apple store and they said it’s outside of warranty, we can repair at your cost. 
I mentioned that in the USA this was a known problem with this model and Apple exchanged them at no cost, in Australia they said it doesn’t apply. 
I contacted the ACCC and they said the expected use date was covered by Apple’s warranty. 
You might find that the ACCC has a very different view of a usable timeframe. 
Also, the CG has exceptions for one off sales (I.e 2nd hand) and for sales via auction sites. 
Copied from ACCC webpage ; / CG exceptions :

•bought as a one-off from a private seller, for example at a garage sale or fete (but you do have rights to full title, undisturbed possession and no unknown debts or extra charges)

Goto AISP to know more.

•bought at auction where the auctioneer acted as an agent for the owner (but you do have rights to full title, undisturbed possession and no unknown debts or extra charges)
 

In these cases, I expect you would have to go back to the importer/distributor. 
 

and the ACCC also say the CG doesn’t apply if ;

•got what you asked for but simply changed your mind, found it cheaper somewhere else, decided you did not like the purchase or had no use for it.

•misused a product in any way that caused the problem

•knew of or were made aware of the faults before you bought the product.  

The 2nd item I believe would cover @andyr concerns.  If the Retailer/Distributor was able to show that the unit had been misused (either unintentionally or intentionally) e.g. outside of its design speculations then they are legally able to charge you with costs of investigation (costs agreed upfront) and such items as shipping (if incurred by them). 

10 hours ago, bob_m_54 said:

I reckon that because of this, there should be a new Trade Qualification to reflect the situation.. Electronics Mechanic, in stead of Electronics Technician..

It makes a mockery of the Technical Trades Qualifications, and is an insult to all the highly skilled technical trades like "Nail Technicians", "Eyelash & Eyebrow Technicians"  etc...

I concur fully Bob.  This cycle has been going on for decades.  I recall as a youngster the TV repairman visiting home to fix the tele that had gone on the fritz.  He ripped the back off, swapped a few valves and pronounced it dead enough to warrant going to the workshop where the real technicians fixed things to component level.  When I entered the technical arena the home TV repair guys were known as valve jockeys.  Today all those decades later we have card jockeys. 

The knowledge to diagnose to component level is almost a lost skill.  Not many of us real techs left to service the industry.  So if you're unlucky to have a bit of gear that's only a few years old and spare cards are still available you might be able to get it "fixed" with a card swap if one is even available and you can be assured it probably gonna cost a packet. 

I get to see a fair bit of gear through the workshop were the customer has exhausted just about all possible avenues to get something repaired.  Most things are repairable if the part is generic or if it's a specialised component still available.  The sad part is most repair shops are either incapable or can't be bothered diagnosing to component level.

As for some comments re SMD work.  I have all of the tools and microscope to undertake this work. Yes it can be fiddly and I can see why some techs avoid it.   

1 hour ago, Ihearmusic said:

Anyway, diagnostic skills are lacking in a lot of industries because folks are no longer payed to think for  them self.

Learning is spoon fed these days. Book knowledge is what matters to pass exams.

The industry groups are primarily responsible for this fiasco.   It started a few decades ago when industry leaders pressured the TAFEs into shortening the length of formal training in exchange for increased workplace learning.   All very well in theory but many businesses exploited loopholes in the competency assessment process and workplace competencies were getting awarded where insufficient evidence existed.  To add to the woes many states based TAFE funding on successful competency assessments in the formal learning environment which at first seemed like a good idea, BUT in order for RTOs and TAFEs not to miss out on funding the assessment criteria was changed that allowed a student as many attempts at achieving competency at it took to finally jag the magic pass mark.

Unlike the days of old when if a student failed (not allowed to use that term these days) the student had to plead their case for a second attempt at an assessment which was often more difficult or required addition work to be done in order to pass the subject or module; these days students are never failed per se.  They are deemed "not yet competent" which often means they can simply have as many attempts at the SAME assessment as they please until they finally pass.

In the TAFE system most theory assessments are done on-line whereby the student simply selects the correct response by picking A, B, C or D from a set of clues; or in some cases matching statements by dropping the appropriate responses into boxes.

On written assessments such as recording lab work results plagiarism isn't uncommon.

Unfortunately most TAFE assessments check only memory not application.  We need more scenario type questions which check the student's ability to apply knowledge in a practical situation rather than simply memorising facts and processes.  Understanding the how and why doesn't seem to to be deemed important these days so when a student is faced with anything but a classic text book problem they have difficulty applying basic knowledge and skills outside of the box.  The classic situation of "Computer says no..." 

One only has to look back at the Gonski review recommendations to see the system has been failing for years.  Yet still all these years later Australia still has one of the poorest literacy and numeracy scores in the developed world, and it's getting worse.    Australia was once a smart and innovative country which morphed into the "lucky country" and is now rapidly heading down the path to become the dumb country of guess and giggle thinking.  Of the bright students and minds we have they are getting cherry picked by employers in other countries to develop and grow their industries and technologies rather than our own.   

Totally agree with monkeyboi re the tafe system. It is indeed a sad decline of a system that did work well to one that Is now designed to look as though it is doing something other than keeping kids off the streets until they are 18. In principal I have no objection to modular construction and replacement of boards or modules that are faulty. The problem comes when the spare parts industry has a monopoly on particular parts and charge exorbitant prices. The car industry is a major offender as is the hifi industry. I remember reading several years ago that if one attempted to build a $ car from spare parts it would cost $. I’m not a big fan of increasing government regulations but some industries need regulating and self regulation is not an option when monopolies exist.

On 2/6/22 at 9:01 PM, Monkeyboi said:

Computer says ABS sensor is faulty.  Dealer just wants to replace sensor.  Mate who is a mechanic has seen this before.  Puts car up on hoist and blows compressed air around sensor and dislodges a build up of dust from the brake pads.  Problem fixed and hasn't missed a beat since.  Quote from the dealer to replace sensor around $500.  Cost from mate to diagnose and fix the problem - a beer at quitting time. 

thats because  the client is paying for it…..  it’s either you agreed to have it replaced at $500,  or not or have it looked at somewhere else.    Another scam is fuel injection clean,  again the client is paying for it!   And usually with dealers like this,  walk and go to another dealer!  Hence the horror stories coming out of one brand is typical of the monopoly they want to represent, and they have the worst track record in repairs and production in a time like now .

There are industries like mind that actually makes you diagnose the fault at the lowest cost….  The reprographics industry is one where you pay every time you press that go button, that $0.75 for every sheet of print that we charge covers toner and service that includes spare parts.   Therefore we are under pressure to keep costs down to a minimum to survive, some parts are not cheap, to replaced one of the wear and tear item that last 5M prints is $4k to us,  it can go at 500k or 6M, some parts only last 10% while others last 200%..  There are severe time constants where they market SLA and to be up and running in 4-5hrs.   Apart from the refrigeration industry,  and some aviation companies I don’t believe the demand and expectation to have a product up and running in 4hrs is ever possible, more times it’s not!   When you get the jobs you’re usually busy at a call, you can’t attend another until you have the present one up and running!  That’s why component level on board repair is now dismissed, as I said earlier, replacing it ensures there are no other issues and it’s cost effective and time efficient, it also saves costs in tools,  just saying!   

6 hours ago, Addicted to music said:

thats because  the client is paying for it…..  it’s either you agreed to have it replaced at $500,  or not or have it looked at somewhere else.    Another scam is fuel injection clean,  again the client is paying for it!   And usually with dealers like this,  walk and go to another dealer!  Hence the horror stories coming out of one brand is typical of the monopoly they want to represent, and they have the worst track record in repairs and production in a time like now .

There are industries like mind that actually makes you diagnose the fault at the lowest cost….  The reprographics industry is one where you pay every time you press that go button, that $0.75 for every sheet of print that we charge covers toner and service that includes spare parts.   Therefore we are under pressure to keep costs down to a minimum to survive, some parts are not cheap, to replaced one of the wear and tear item that last 5M prints is $4k to us,  it can go at 500k or 6M, some parts only last 10% while others last 200%..  There are severe time constants where they market SLA and to be up and running in 4-5hrs.   Apart from the refrigeration industry,  and some aviation companies I don’t believe the demand and expectation to have a product up and running in 4hrs is ever possible, more times it’s not!   When you get the jobs you’re usually busy at a call, you can’t attend another until you have the present one up and running!  That’s why component level on board repair is now dismissed, as I said earlier, replacing it ensures there are no other issues and it’s cost effective and time efficient, it also saves costs in tools,  just saying!   

I hear you.  In the hi-fi repair industry not everything is a board swap.  In the case of gear over 10 years old there's no legal requirement for the manufacturer to supply spares at all let alone entire boards.  I've had lots of gear through my workshop only requiring minimal component replacement.  Of course no one has a crystal ball to foresee any and all possible future failures but keeping up to date with service bulletins helps, plus over time some makes and models are prone to certain failures due to poor design or component choices.

Lots of expensive 4k monitors are now starting to go out of warranty.  As Gomer Pyle would say "surprise, surprise, surprise" failed low ESR electrolytic caps in the SMPS are the usual culprits.  Why condemn a $ monitor to verge collection when it's under an hours labour and a few bucks of parts?  As a society we have become so conditioned to treat everything as disposable we do it out of habit.      

Class D designs have pretty much defined the point where a skilled tech can no longer reliably repair a piece of electronics. No matter the quality of eyesight or soldering skills the vast majority of class D amp faults are going to be best sorted by a complete board replacement. (ignoring non amp circuit related issues within the amp chassis such as PS, dodgy sockets etc, there is always the possibility a Class D amp fault is not the actual main board).

The price of the replacement parts is for me not the concern (although in many cases they may well be expensive, but then the labour component of the repair will be minimal)..

The real problem with Class D in the medium term will be the simple lack of parts.  Whatever class D board is popular today will be unavailable in 5 years or less.

In a simple power amp design my guess is that they might be able to upgraded/repaired with some newer module/board. All good.

Not sure what happens with a fancier design incorporating a bunch of other DSP functions etc.

One thing I'm fairly sure of  is there wont be a future version of the current love of 40 - 50 year old HiFi components.

Cars are similar of course, as mentioned above.

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