What products you'd like to see WiiM produce?
slartibartfast
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What is EM?
And I do EE as well... and computer engineering too. Professional background in physics.
So there.
Heck, I just had to bias a big Class A amp the other day... used brand new clip that had some oil in them.... SMOKE!
This particular one was done with dual Meanwell switching power supplies. A very unusual DIY amp.
So there.
Heck, I just had to bias a big Class A amp the other day... used brand new clip that had some oil in them.... SMOKE!
This particular one was done with dual Meanwell switching power supplies. A very unusual DIY amp.
EddNog
Senior Contributor
Perthaps, I should have used the term "Dynamic Range" as opposed to Peak vs RMS... since that implies the square root of 2.
Google "dynamic range of an NAD amplifier"
In my DIY F5m amp, we went with dual rail Meanwell 24V, 211W (709-LRS-200N2-24) power supplies even though the rated output for the design is 25wpc (class A). I also have a "classic" F5 amp with linear power supplies and big capacitor banks and a huge toroidal. Guess which one sounds more "dynamic"...
Not only that, but my back appreciates the change every time I pick up the amp.
Google "dynamic range of an NAD amplifier"
- Dynamic Headroom/Power: The ability to handle musical peaks (10 to 20 dB above average) by providing short-term bursts of power, such as the NAD 2200, which can deliver 400-800 watts.
In my DIY F5m amp, we went with dual rail Meanwell 24V, 211W (709-LRS-200N2-24) power supplies even though the rated output for the design is 25wpc (class A). I also have a "classic" F5 amp with linear power supplies and big capacitor banks and a huge toroidal. Guess which one sounds more "dynamic"...
Not only that, but my back appreciates the change every time I pick up the amp.
Shotgun Rico
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I was thinking Reed Richards and Tony Stark
slartibartfast
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So how do you get this higher peak power without a much higher power supply voltage? 6dB increase in power would need double the voltage.
Ay... read what I wrote... we went dual rail in the power supplies... we DOUBLED the voltage from 24VDC to 0 to +/- 24VDC. Double the number of parts.
And in this case, we didn't really increase the rated output into 8 ohms, we just kept doubling it down to 2 ohms ( likely more ). But then, what is rated power anyhow? It's just a measurement of power into a load with some distortion number. To achieve high numbers, specially short peaks that will draw some current, you need.... a more powerful power supply...
In reality, "rated RMS sustained power" is never a situation when the output at the amplifier is near Vcc. Imagine what kind of heat sinks you would need and you would have no overhead. Only Class A amps reach anything even half near like that kind of power draw from their power supplies. Class AB amps seldom draw that much from their supplies during operation... most of the time they put out 1 watt or so to the speakers. Unless you run something like a Magnepan which runs 10 watts ( 83 db/w). But when peaks hit, those numbers may shoot by 6 db or more.. 10 db for example on a closely miked drum kit... that will take your 1 watt to ~10 ( back of the envelope ). If you are playing the music louder, well, that can be a substantial increase in power... but, it's a short burst... so you don't run into heat problems. You might, however, run into clipping... but if it's short term clipping your tweeters will sound nasty but survive.
In my case, we spec'd the higher wattage power supplies... each runs 200 watts which is a lot more than the amp will use.. and this is a Class A design. More power, double the voltage than the original single linear power supply.
I specifically wrote that. I even specified the model number. The Meanwell switching power supplies cost $28 each at Mouser. Two of them, in an amp, meant 56 bucks for the BoM. Plus then we had more filtering behind them. How much is the power supply in the BoM for the WiiM Ultra Amp?
Then the output bias was dialed down so the output transistors don't run that hot, yet, they can swing more voltage in peaks and low impedance. The fact that this is a Class A amp with very large 4U heat sinks helps a lot... even so, it idles at 50C.
Do remember that there is nothing in an amp, unless it has some means of power limiting circuitry with some diodes somewhere, to keep it from running more power than rated. And if the output impedance lowers, the main constraints to how much power it can deliver are
(1) The ability of the power supply to keep Vcc steady under load -some amps can drive into 1 ohm.. some into a short.
(2) The ability of the output devices not to burn ( get a bigger heat sink )
(3) The hearing -as the distortion will likely go higher.
I also gave you the specs on the NAD monitor and PE amps. They were able to swing much more in dynamic peaks than their RMS... this was because their power supplies could really swing voltages. Now, I know those were linear power supplies, but the discussion noted the wide dynamic range in music from the RMS background to musical peaks... think drum kit, trumpet...
Those NAD amps of yore used dual voltage power supplies, they could switch for short bursts into the high voltage. Since the power dissipation of such a low burst is not a load into the power supply (think capacitor discharge) it didn't pose an issue with heat.
Do me a huge favor... stop the ad hominem, stop saying that I don't know what I'm "talking" about. I do. You could start by telling me where, in your opinion, I am wrong. Don't call me an "audiophile". Don't say that I got my physical facts incorrect. Tell me which physical facts I got incorrect. Be constructive about it.
If you want more power, start by running a more powerful power supply that can drive the amps into lower loads and can keep the voltage high when power demand increases. Only then, if you want more steady power delivery get bigger heatsinks and larger (or more) output devices.
Now, I realized that you were cagey when you said I know nothing about SMDS power supplies. It is true that I have not designed one, but I have worked with their schematics. So I know enough to be able to design with them.
This whole discussion started because I wrote that "IMHO, it's not the RMS power but the dynamic range added by more power and a heftier power supply." To handle dynamic peaks.
Then I was told that I "didn't understand" SMPS... which, IMHO, is irrelevant. As I noted in the beginning, you just need a more "heftier" power supply. Heftier: strong, solid, substantial, robust, tough. You think that all things being the same, a power supply of 400w with 48VDC is "heftier" than a 200w 24VDC power supply? It will drive low impedance loads better and hit higher peaks. You can still play with the biasing to control the heat, but it will do peaks better ( more operational overhead ).
In any event, I doubt those big Meanwell power supplies will make it into a product that costs under 1500 bucks at MSRP. So, I think we're gone past the idea of the post.
Perhaps installing some NC400 modules might make sense, but then you got a big MSRP. I doubt that WiiM will do Purify modules either as those are pretty expensive.
New WiiM product? multichannel processor.
And in this case, we didn't really increase the rated output into 8 ohms, we just kept doubling it down to 2 ohms ( likely more ). But then, what is rated power anyhow? It's just a measurement of power into a load with some distortion number. To achieve high numbers, specially short peaks that will draw some current, you need.... a more powerful power supply...
In reality, "rated RMS sustained power" is never a situation when the output at the amplifier is near Vcc. Imagine what kind of heat sinks you would need and you would have no overhead. Only Class A amps reach anything even half near like that kind of power draw from their power supplies. Class AB amps seldom draw that much from their supplies during operation... most of the time they put out 1 watt or so to the speakers. Unless you run something like a Magnepan which runs 10 watts ( 83 db/w). But when peaks hit, those numbers may shoot by 6 db or more.. 10 db for example on a closely miked drum kit... that will take your 1 watt to ~10 ( back of the envelope ). If you are playing the music louder, well, that can be a substantial increase in power... but, it's a short burst... so you don't run into heat problems. You might, however, run into clipping... but if it's short term clipping your tweeters will sound nasty but survive.
In my case, we spec'd the higher wattage power supplies... each runs 200 watts which is a lot more than the amp will use.. and this is a Class A design. More power, double the voltage than the original single linear power supply.
I specifically wrote that. I even specified the model number. The Meanwell switching power supplies cost $28 each at Mouser. Two of them, in an amp, meant 56 bucks for the BoM. Plus then we had more filtering behind them. How much is the power supply in the BoM for the WiiM Ultra Amp?
Then the output bias was dialed down so the output transistors don't run that hot, yet, they can swing more voltage in peaks and low impedance. The fact that this is a Class A amp with very large 4U heat sinks helps a lot... even so, it idles at 50C.
Do remember that there is nothing in an amp, unless it has some means of power limiting circuitry with some diodes somewhere, to keep it from running more power than rated. And if the output impedance lowers, the main constraints to how much power it can deliver are
(1) The ability of the power supply to keep Vcc steady under load -some amps can drive into 1 ohm.. some into a short.
(2) The ability of the output devices not to burn ( get a bigger heat sink )
(3) The hearing -as the distortion will likely go higher.
I also gave you the specs on the NAD monitor and PE amps. They were able to swing much more in dynamic peaks than their RMS... this was because their power supplies could really swing voltages. Now, I know those were linear power supplies, but the discussion noted the wide dynamic range in music from the RMS background to musical peaks... think drum kit, trumpet...
Those NAD amps of yore used dual voltage power supplies, they could switch for short bursts into the high voltage. Since the power dissipation of such a low burst is not a load into the power supply (think capacitor discharge) it didn't pose an issue with heat.
Do me a huge favor... stop the ad hominem, stop saying that I don't know what I'm "talking" about. I do. You could start by telling me where, in your opinion, I am wrong. Don't call me an "audiophile". Don't say that I got my physical facts incorrect. Tell me which physical facts I got incorrect. Be constructive about it.
If you want more power, start by running a more powerful power supply that can drive the amps into lower loads and can keep the voltage high when power demand increases. Only then, if you want more steady power delivery get bigger heatsinks and larger (or more) output devices.
Now, I realized that you were cagey when you said I know nothing about SMDS power supplies. It is true that I have not designed one, but I have worked with their schematics. So I know enough to be able to design with them.
This whole discussion started because I wrote that "IMHO, it's not the RMS power but the dynamic range added by more power and a heftier power supply." To handle dynamic peaks.
Then I was told that I "didn't understand" SMPS... which, IMHO, is irrelevant. As I noted in the beginning, you just need a more "heftier" power supply. Heftier: strong, solid, substantial, robust, tough. You think that all things being the same, a power supply of 400w with 48VDC is "heftier" than a 200w 24VDC power supply? It will drive low impedance loads better and hit higher peaks. You can still play with the biasing to control the heat, but it will do peaks better ( more operational overhead ).
In any event, I doubt those big Meanwell power supplies will make it into a product that costs under 1500 bucks at MSRP. So, I think we're gone past the idea of the post.
Perhaps installing some NC400 modules might make sense, but then you got a big MSRP. I doubt that WiiM will do Purify modules either as those are pretty expensive.
New WiiM product? multichannel processor.
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slartibartfast
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It is probably worth pointing out that an amplifier rated at 100W before clipping with an 8 ohm load is only rated at 100W while playing a sine wave. Playing pink noise with a crest factor of 13.59dB (standard pink noise from REW) brings the rating down to 8.8W before clipping 
The crest factor is - as you correctly stated - a property of the signal, not a restriction imposed by the amplifier. It's the best power output you can get for that signal.It is probably worth pointing out that an amplifier rated at 100W before clipping with an 8 ohm load is only rated at 100W while playing a sine wave. Playing pink noise with a crest factor of 13.59dB (standard pink noise from REW) brings the rating down to 8.8W before clipping
Depending on if the amp is voltage limited or current limited (weak PSU) the effects might show in the highs or in the lows earlier, but the thermal stress is definitely lower than during pure sine testing, this way or another.
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You're still ignoring the context, so I'm going to repeat it.
I'm not questioning or discussing any of your skills or designs and I'm not competing in any way.@Indydan had asked for 150 W or more from a successor of the WiiM Amp Ultra.
I reminded him that 150 W instead of 100 W equals a 1.76 dB increase in SPL. This is a simple fact and universally true.
You stepped in explaining to me that even though the rated RMS might be just 1.76db louder, the actual peaks might be +6db or more (emphasis by me).
Of course it is possible to design an amplifier with more increase in headroom than in RMS power. This is as true as it is trivial. It just needs a different desig. 150 W amps don't do that naturally just because they are 150 W amps.
If all you wanted to point out is that dynamic headroom is more relevant than RMS power, that's OK with me (I'd still reply that a 500 W amplifier with zero headroom beats a 100 W amplifier with 10 dB headroom).
All this discussion about how to design and adjust amplifiers or PSUs is just unrelated to what I stated, so I have no intention to continue the. No ad hominem argument here. SMPS have totally different requirements for their caps than linear power supplies. Just a fact.
If you could do me just one small favour, please explain why you don't want to be called an audiophile, when you've repeatedly called yourself so.
Here's a WiiM Ultra in its natural element. Sounding really good. One of the racks developed a bent coaster, so I took down a bunch of stuff, stacked some amps and a WiiM Ultra and a USB DAC/headphone amp as preamp...
The top speakers are the $100 Amazon Elac "burners" because I just turned on that amp for the first time with real speakers, not power resistors.
I'm using as source my galaxy phone into Tidal Connect.
Spanish Zarzuelas breaking the amp in... not a trace of harshness, huuuge soundstage, it's absolutely BEAUTIFUL music. This simple setup conveys the emotional impact of the music... you know, when you go to a concert some people sit there stiff while the music washes over them... while others... well, you can see their heads sway with the aural landscapes being presented to them....
Ataulfo Argenta doing La Leyenda Del Beso.... exceptional... ( we saw him live twice, last time was his last performance in the US ).
Thanks to WiiM... bit perfect playback.
I think I may not need a preamp in this set up after all.
Have fun.
BTW: Cream, Disreali Gears, Tidal HiFi, 24.96... Strange Brew... bit perfect. No remote but the rack is six feet from my left arm...
The top speakers are the $100 Amazon Elac "burners" because I just turned on that amp for the first time with real speakers, not power resistors.
I'm using as source my galaxy phone into Tidal Connect.
Spanish Zarzuelas breaking the amp in... not a trace of harshness, huuuge soundstage, it's absolutely BEAUTIFUL music. This simple setup conveys the emotional impact of the music... you know, when you go to a concert some people sit there stiff while the music washes over them... while others... well, you can see their heads sway with the aural landscapes being presented to them....
Ataulfo Argenta doing La Leyenda Del Beso.... exceptional... ( we saw him live twice, last time was his last performance in the US ).
Thanks to WiiM... bit perfect playback.
I think I may not need a preamp in this set up after all.
Have fun.
BTW: Cream, Disreali Gears, Tidal HiFi, 24.96... Strange Brew... bit perfect. No remote but the rack is six feet from my left arm...
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jlmsouth86
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Now that I've been having some issues with my internet signal lately, I would love a streamer that could have local files pre-saved on a streaming service, like a device with storage. I'm not sure how feasible this would be, but it would be an excellent idea if it could come to fruition.
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