Class D power amplifiers

[lovinthehd]

Once again your attempting to generate an argument with your reply about my attempts regarding digital chips, No where have I commented on that subject. I simple don't like Class "D" amplification. So I would suggest you except that fact and move on. March audio are a clone of Mola Mola. They gained a performance award from "What Hi FI" probable due to the large amount they spent on advertising.. That is the way "What Hi Fi" seem to operate. I think if I was shopping for a class "D" power amp my choice would be from Holton Electronic's in Tasmania. They do the full range class A, A/B and D. Together with pre-amps, Dac's and power conditioners. I've owned some of there A/B amps over the years, which are high level . Also another brand would be Elektra Audio, who specialize in high quality power amps. No class D.allowed. Arthur does not have a web site, but has a few retail outlets, plus direct selling via word of mouth. I have one of his 5 channel PA in my HT set-up. I only wish he would produce a line of Pre-amps to complement his range of PA's So now you can hunt down these websites and retail outlets and become an over night expert, on brands you know nothing about.

LOL you think I care that much about what gear you've been obsessed with or why? Glad you're supporting some local audio folk, tho....you need that down there.

ps I find it amusing you're posting in a dedicated class d thread, too.

pps Yes "excepting" the fact is what I'll do. LOL

 

[mono-bloc]

What I found interesting in the What Hi If review , is the fact they quote the output at 450 watts at 2 ohm's Means that the amplifier is rated with a power output of 450-watts per channel into 2Ω I have never seen that before. I would stand to be corrected but I would assume that equates to around 105 watts at 8 ohms. A two ohm load is almost impossible to most conventional A/B rigs let alone a class "D". Anyone got any thoughts on this would be welcomed. Maggie owners please step forward.

 

[lovinthehd]

What I found interesting in the What Hi If review , is the fact they quote the output at 450 watts at 2 ohm's Means that the amplifier is rated with a power output of 450-watts per channel into 2Ω I have never seen that before. I would stand to be corrected but I would assume that equates to around 105 watts at 8 ohms. A two ohm load is almost impossible to most conventional A/B rigs let alone a class "D". Anyone got any thoughts on this would be welcomed. Maggie owners please step forward.

Good grief, as bad as most what hii fi reviews, are in this case, of what? The manufacturer rated the amp at that spec or not?

 

[mono-bloc]

are in this case, of what? The manufacturer rated the amp at that spec or not?

Would someone care to translate this crap

 

[lovinthehd]

Would someone care to translate this crap

If you don't understand the language that doesn't surprise me. What amp is it and what does the manufacturer rate it for?

 

[PENG]

Would someone care to translate this crap

There may or may not be any truth at all in what What Hifi claimed, depending on context. When reviewers talked about amp output into a 2 ohm load, they generally refer to short term duration, most likely in ms, or may be up to a few seconds. Some speakers may have dips to 2 ohm or even less but it would be for a very narrow range, i.e. a very sharp and narrow dip, so most well designed amps can handle.

If What hifi mentioned a 2-ohm capable amp, they probably just meant the amp could deal with those sharp dips without shutting down, most likely not meant to be a so called "continuous" rating.

Case in point, even some (very few for sure) AVRs could pass a 1 ohm test. The Denon AVR-3805 was one of those, and I owned one. That one passed the following tests:

Note: Duration for the 2 and 1 ohm test were not specified, they might have talked about that elsewhere on their website but I am not sure and also not sure if they are still in business.

2 ohm, 1 kHz:
299.9W @0.9% (Front Channel)
311.6W @0.9% (Front Channel)

1 ohm, 1 kHz:
160.3 @0.8% (Front Channel)
169.6W @1% (Surround Channel)

If you are interested to see the full test results:

Report (milleraudioresearch.com)

 

[Mikado463]

There may or may not be any truth at all in what What Hifi claimed, depending on context. When reviewers talked about amp output into a 2 ohm load, they generally refer to short term duration, most likely in ms, or may be up to a few seconds. Some speakers may have dips to 2 ohm or even less but it would be for a very narrow range, i.e. a very sharp and narrow dip, so most well designed amps can handle.

If What hifi mentioned a 2-ohm capable amp, they probably just meant the amp could deal with those sharp dips without shutting down, most likely not meant to be a so called "continuous" rating.

Case in point, even some (very few for sure) AVRs could pass a 1 ohm test. The Denon AVR-3805 was one of those, and I owned one. That one passed the following tests:

Note: Duration for the 2 and 1 ohm test were not specified, they might have talked about that elsewhere on their website but I am not sure and also not sure if they are still in business.

2 ohm, 1 kHz:
299.9W @0.9% (Front Channel)
311.6W @0.9% (Front Channel)

1 ohm, 1 kHz:
160.3 @0.8% (Front Channel)
169.6W @1% (Surround Channel)

If you are interested to see the full test results:

Report (milleraudioresearch.com)

agreed, big difference between 'capable for a short duration' and continuous. Besides, show me a speaker with nominal 2 ohm rating.

 

[mono-bloc]

There may or may not be any truth at all in what What Hifi claimed, depending on context.

Unfortunately most publications rely on advertising for there survival, and they write complemented reviews on products that pay the most by way of advertising. What Hi Fi are no different, and will claim anything to retain the advertising dollar. But in this case they openly state, an output of 450-watts per channel into 2Ω. Implying this is what the amp being reviewed is capable of.. We are not talking about short dip's in signal, but as continues signal of 2 ohms. I agree with what you say, but this is not what was implied. Very few will play a continues 2 ohm load, and I discount AVR's as frankly most are rubbish regardless of cost. When they produce an AVR with a descent Toroidal power supply things might change. But that is a discussion for another day. As for speakers requiring a 2 ohm load One standard design was / is the Equinox Jupiter. I'm not sure if Rick is still in business. Or cause a great swag of Magnepan designed Speakers are built to maintain a 2 ohm load , Some dropping a lot lower . The Apogee Scintoilla is one such model, which does drop to point 85 of an ohm . It's known as the impossible speaker, and was reported to have destroyed a Krell 250a whilst trying! But I diversity from the subject. Of someone advertising a small class "D" amp being capable of maintaining a 2 ohm load. Regardless of how you read it.

 

[PENG]

Unfortunately most publications rely on advertising for there survival, and they write complemented reviews on products that pay the most by way of advertising. What Hi Fi are no different, and will claim anything to retain the advertising dollar. But in this case they openly state, an output of 450-watts per channel into 2Ω. Implying this is what the amp being reviewed is capable of.. We are not talking about short dip's in signal, but as continues signal of 2 ohms. I agree with what you say, but this is not what was implied. Very few will play a continues 2 ohm load, and I discount AVR's as frankly most are rubbish regardless of cost. When they produce an AVR with a descent Toroidal power supply things might change. But that is a discussion for another day. As for speakers requiring a 2 ohm load One standard design was / is the Equinox Jupiter. I'm not sure if Rick is still in business. Or cause a great swag of Magnepan designed Speakers are built to maintain a 2 ohm load , Some dropping a lot lower . The Apogee Scintoilla is one such model, which does drop to point 85 of an ohm . It's known as the impossible speaker, and was reported to have destroyed a Krell 250a whilst trying! But I diversity from the subject. Of someone advertising a small class "D" amp being capable of maintaining a 2 ohm load. Regardless of how you read it.

Which amp did they refer to again? That is rated down to 2 ohms, "continuous:? No doubt some power amps can do it, so it depends on which one they are talking about. For AVRs, I agree, none can do such a thing, never mind 2 ohms, they can't even be rated 4 ohms without caveats, at least none that I know of are rated 4 ohms on "continuous" basis with meaningful output watts (meaning something like 120 W 8 ohm, 120 W or more 4 ohm). Any AVR can be rated for say 120 W 8 ohm, 60 W 4 ohm though.

 

[panteragstk]

Which amp did they refer to again? That is rated down to 2 ohms, "continuous:? No doubt some power amps can do it, so it depends on which one they are talking about. For AVRs, I agree, none can do such a thing, never mind 2 ohms, they can't even be rated 4 ohms without caveats, at least none that I know of are rated 4 ohms on "continuous" basis with meaningful output watts (meaning something like 120 W 8 ohm, 120 W or more 4 ohm). Any AVR can be rated for say 120 W 8 ohm, 60 W 4 ohm though.

I don't know about "consumer" amps, but quite a few, if not all, "pro" amps that are class D that I've seen are rated down to 2ohms. My Crown XLS1500 is and I ran it with that load for some time. Granted, it wasn't a fan of having one channel at 2ohms and the other at 4ohms, but I can give it a break on that considering that's not exactly a normal use case.

It's been a solid amp for over a decade. I probably won't use anything else for subs unless I have a need for a plate amp.

For my speakers I've been using my AVR amps without complaint since I've owned AVRs. Once I do need an outboard amp I'll probably go the same route you and @ryanosaur went. Those prices are pretty great and I like the idea of not having to lug around a heavy amp. I've got plenty of heavy stuff already.

 

[PENG]

I don't know about "consumer" amps, but quite a few, if not all, "pro" amps that are class D that I've seen are rated down to 2ohms. My Crown XLS1500 is and I ran it with that load for some time. Granted, it wasn't a fan of having one channel at 2ohms and the other at 4ohms, but I can give it a break on that considering that's not exactly a normal use case.

It's been a solid amp for over a decade. I probably won't use anything else for subs unless I have a need for a plate amp.

For my speakers I've been using my AVR amps without complaint since I've owned AVRs. Once I do need an outboard amp I'll probably go the same route you and @ryanosaur went. Those prices are pretty great and I like the idea of not having to lug around a heavy amp. I've got plenty of heavy stuff already.

There are quite a few consumer amps that are rated for 2 ohms as well. That's why I said What Hifi could be right, or BS, depending on which specific amp (and under what conditions) they referred to.

A good example is the MC2KW monoblock, that weights 500 lbs for a pair and apparently for under £110,000.00. Each is rated 2000 W into 2, 4, and 8 Ohms ("continuous"):

McIntosh MC2KW Amplifier (mcintoshlabs.com)

I am not sure if their "continuous" means literally continuous, or for a maximum duration of X minutes or hours, not that it matters practically speaking.

 

[lovinthehd]

There are quite a few consumer amps that are rated for 2 ohms as well. That's why I said What Hifi could be right, or BS, depending on which specific amp (and under what conditions) they referred to.

A good example is the MC2KW monoblock, that weights 500 lbs for a pair and apparently for under £110,000.00. Each is rated 2000 W into 2, 4, and 8 Ohms ("continuous"):

McIntosh MC2KW Amplifier (mcintoshlabs.com)

I am not sure if their "continuous" means literally continuous, or for a maximum duration of X minutes or hours, not that it matters practically speaking.

Agree on the pro amps and Crown XLS series with @panteragstk, many are indeed rated for 2 ohm. I've got a variety of them mostly on sub duties, but they'll work on mains just fine as well. That ridiculous pair of amps isn't exactly a typical consumer amp otoh....and few consumer amps I've seen bother with a 2 ohm rating in any case, even when priced more in reality. Easier not to buy speakers that were designed with such a low impedance, too.

 

[PENG]

Agree on the pro amps and Crown XLS series with @panteragstk, many are indeed rated for 2 ohm. I've got a variety of them mostly on sub duties, but they'll work on mains just fine as well. That ridiculous pair of amps isn't exactly a typical consumer amp otoh....and few consumer amps I've seen bother with a 2 ohm rating in any case, even when priced more in reality. Easier not to buy speakers that were designed with such a low impedance, too.

Agreed, consumer amps with 2 ohm ratings are rare and are typically monoblocks. Parasound Halo JC1 is another example, one that is more affordable. There is an odd case, the Benchmark AHB2 has the following output ratings:

CONTINUOUS AVERAGE OUTPUT POWER
< 0.0003 % THD+N at full rated power, 20 Hz to 20 kHz

• 100 Watts per channel into 8 Ohms, both channels driven
• 130 Watts per channel into 6 Ohms, both channels driven
• 190 Watts per channel into 4 Ohms, both channels driven
• 240 Watts per channel into 3 Ohms, both channels driven

My point is simply that review magazine's claimed 2 ohm ratings such as the quoted 450 W should not be taken out of context, as some amps are indeed rated down to 2 ohms.

 

[mono-bloc]

On the question of output power, I have just spent time reading the long awaited report / review on there new Flagship, Move over Mephisto.. The Gryphon Apex twin channel power amp. It also comes in a mono-bloc version. The review comes from Soundstage Ultra, [ see link below] To say the thing is massive is an understatement . Apart from being huge it weighs in at 445 pounds or 550 pounds in it's timber crate.. But the point of this is it's listed full class "A" output range 210 watts per channel into 8 ohms 420 watts at 4 ohms 800 watts at 2 ohms and 1490 watts at 1 ohm. So if you have a spare 100 grand US, your welcome to get on the waiting list . Official announcements will be at this years Munich audio show. . Gryphon Audio Designs Apex Stereo Amplifier or https://www.soundstageultra.com/index.php/equipment-menu/1106-gryphon-audio-designs-apex-stereo-amplifier

 

[Golfx]

On the question of output power, I have just spent time reading the long awaited report / review on there new Flagship, Move over Mephisto.. The Gryphon Apex twin channel power amp. It also comes in a mono-bloc version. The review comes from Soundstage Ultra, [ see link below] To say the thing is massive is an understatement . Apart from being huge it weighs in at 445 pounds or 550 pounds in it's timber crate.. But the point of this is it's listed full class "A" output range 210 watts per channel into 8 ohms 420 watts at 4 ohms 800 watts at 2 ohms and 1490 watts at 1 ohm. So if you have a spare 100 grand US, your welcome to get on the waiting list . Official announcements will be at this years Munich audio show. . Gryphon Audio Designs Apex Stereo Amplifier or https://www.soundstageultra.com/index.php/equipment-menu/1106-gryphon-audio-designs-apex-stereo-amplifier

To me this seems like a 1960s triumph. 440+lbs! And delivers less wattage than a hypex ncore 1200. I also noticed from the review there were no bench measurements to at least testify to the wisdom of paying that much for 1960s tech. The buyers of this amp will not be using logic, blind comparisons or math when deciding this is their dream amp.

 

[}Fear_Inoculum{]

To me this seems like a 1960s triumph. 440+lbs! And delivers less wattage than a hypex ncore 1200. I also noticed from the review there were no bench measurements to at least testify to the wisdom of paying that much for 1960s tech. The buyers of this amp will not be using logic, blind comparisons or math when deciding this is their dream amp.

Agreed.

On top of that, I see that the reviewer is fully into the snake oil category with his cables. Using ~1500$ USD each XLR cables, and ~550$ USD power cables etc. The flowery language used to describe the sound of the amp is very impressive.........a fool and his money......