The discussion has to do with excessive heat problems. The more efficient the amp is the cooler it will run which is why Class D amps run cool due to pulse width modulation
which moves well over 90% of the current at a constant stream to the output. Class D amps have transfomers, transistors and power caps just as A/B and A amps but they run cooler since there is far less build up of wasted current not going to the output. Again, as I indicated in my conversations with Roger Sanders, His patented linear voltage regulator keeps the voltage stable and eliminates voltage flucuation which increases the efficiency of the amp so there is minimal wasted current which results in caps and transformers putting out very little heat resulting in his amp running just about as cool as class D amps because of higher efficiency. |
Efficiency of most class D amplifiers are among the specs if not at amplifier manufacturing web site hen at original vendor e.g. B&O web site.
For example, our amplifier, Musician III has efficiency of 92%.
Efficiency has nothing to do with the stability of the power supply (and sound quality, in principle) as Almarg pointed out. Where its important are two areas: a) your utility bill and b) the size and weight of your amplifier.
For example, we have 1300VA Transformer in PSU and efficiency is 92% then "effective transformer" is in essence 1300 x 0.92 = 1195VA
If we compare it with typical class A amplifier where efficiency is about 25% then it needs:
1195 VA / 0.25 = 4800 VA (real life) Transformer. What it does with such transformer its different matter but it adds weight to the amp; and multiple additional heatsinks add cost and weight as well.
Yet, many class A amplifiers are simply magnificent and many are simply ear-piercing machines.
Simon |
"I also don't question the possibility that the approach to voltage regulation, used in that design, (the Magtech), may be a significant contributor to its high efficiency and cool temperatures..Al" This statement Al acknowledges the very point I'm making. I had a two hour conversation with Roger Sander's three weeks ago on this very issue. Different designer's, as he explained, take different approaches to regulate voltage attempting to stabilize the voltage to improve the efficiency of the amp.
Some methods work better than others, and in some cases, according to Coda engineers I spoke to, voltage regulation can cause an amp to blow up if not done properly. Again, high heat dissipation in an amp causes the amp to get hot due to unstable, fluctuating voltage. The focus here is LINEAR VOLTAGE REGULATION. To say that power consumption creates heat is not accurate since its unstable flucuating voltage that causes the heat problem. If you take any high powered amp on the market that runs extremely hot, and install the Sanders linear regulator, the amp will run much cooler according to Roger which is why his design is patented so others cannot use it and keep it exclusive to the Magtech amp. |
I'm a bit confused but perhaps what Audiozen is trying to say re voltage "fluctuations" is that in an unregulated power supply the voltage must drop significantly in order for the transformer to produce current. Load the amplifier further and the voltage will drop further and the transformer will deliver more current than its rated value, potentially overheating it?
Al has it right though. Power dissipation, however that happens, is the producer of heat. The Magtech runs cool because its transistors have an extremely linear transconductance function and therefore do not require much bias to eliminate crossover distortion. Most of the heat produced in a Class AB amp is produced by the bias current. The sole purpose of the bias current is to eliminate distortion. Through the use of linear “Thermal Trak” transistors very little bias current is needed to eliminate distortion and the amplifier as a result runs cool. |
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08-10-12: Audiozen
I dare you to name any other class A/B amp on the market that does not have oveload clipping shut down circuits in the same price range as the Sanders Magtech. As I said previously, I don't doubt that the Magtech is an excellent amp. I also don't question the possibility that the approach to voltage regulation used in that design may be a significant contributor to its high efficiency and cool temperatures. 08-10-12: Audiozen
BALONEY..what a load of crap. Voltage fluxuation results in a volume of wasted current that decreases the available current to watts to the output since the voltage is unstable. The wasted fluxuating current holds up in the amp due to unstable voltage regulation which results in a higher volume of heat heat due to current delay in the amp. By stablizing the current with a linear regulator eliminates voltage fluxuation and there is no wasted or delayed current in the amp which results in lower heat since the total voltage is completely stable going to the output resulting in a cooler running amp. This statement is, to use your word, baloney. I say that as someone with multiple decades of experience designing advanced analog and digital circuits (not for audio), and having multiple degrees in electrical engineering. From the Magtech's description: Audiophiles would not consider using a source component that did not have regulated power supplies. So why use amplifiers with unregulated supplies?
The main problem is heat. Amplifiers operate at much higher voltages and currents than line level source components. These higher voltages and currents forces conventional regulator designs to waste large amounts of energy, which wastes expensive electricity and causes the amplifier to get very hot.
Also, many regulator designs radiate RF (Radio Frequency) energy when switching high currents and voltages. This RF gets into the amplifier's electronics and can cause instability, oscillation, and noise. As a result of these problems, modern power amplifiers do not use regulated power supplies and fail to take advantage of the benefits available from doing so.
Sanders has solved these problems by developing a voltage regulator that is essentially 100% efficient. There is no heat dissipated by the regulator system. There is no high-power/high-voltage switching that causes heat generation or RF problems.
The regulator in the Magtech amplifier maintains a stable voltage regardless of load or reasonable changes in the line voltage feeding the amplifier. It runs stone cold, produces zero RF energy, and is simple and reliable. What this statement is saying is NOT that voltage fluctuation due to lack of regulation causes other amplifiers to run hot. What it is saying is that voltage regulation is not provided in most other amplifiers because if it were, the regulator itself would cause the amplifier to run excessively hot, especially in the case of a conventional linear regulator (as I indicated in my previous post). Apparently you have misinterpreted this. Based on your tone, I suspect that further discussion of the matter would not be constructive, so you can have the last word. Others reading this thread can (and will) reach their own conclusions as to which viewpoint to believe. BTW, it is "fluctuation," not "fluxuation." -- Al |
BALONEY..what a load of crap. Voltage fluxuation results in a volume of wasted current that decreases the available current to watts to the output since the voltage is unstable. The wasted fluxuating current holds up in the amp due to unstable voltage regulation which results in a higher volume of heat heat due to current delay in the amp. By stablizing the current with a linear regulator eliminates voltage fluxuation and there is no wasted or delayed current in the amp which results in lower heat since the total voltage is completely stable going to the output resulting in a cooler running amp. The Sanders Magtech amp puts out 900 watts into 4ohms continuous and drives down to 1/3 ohms. The amp runs cool to lukewarm at all gain levels and has no overload shutdown clipping circuits since it is impossible to clip the amp due to full, stable voltage regulation and the amp idles at just over 30 watts. I dare you to name any other class A/B amp on the market that does not have oveload clipping shut down circuits in the same price range as the Sanders Magtech. Good luck finding one. |
What generates heat is not voltage or voltage fluctuation. It is power consumption, also referred to as power dissipation. In the case of an amplifier, the amount of power dissipated at any given instant is equal to the AC power going into the amp minus the power that is delivered to the speakers. Power at any given instant is equal to the product (multiplication) of voltage and current at that instant. Heatsink temperature is dependent on many variables, in addition to the amount of power that is dissipated. Those variables include the size, weight, and overall design of the heatsink. The amount of power dissipated by the amplifier is also dependent on a great many variables. One of the most significant variables is its class of operation (A, AB, D, etc.) See this Wikipedia writeup for further information on amplifier classes. The best and one of the most powerful amps on the market under $10K is the Sander's Magtech amp.... It has a patented linear voltage regulator that eliminates voltage switching and voltage fluxuation which is typical in most amps which is why they run hot. I have no knowledge of the Magtech's patented linear voltage regulator, but I don't doubt that the amp is an excellent one. In general, though, a linear regulator will be much less efficient, and dissipate much more power, than a switching power supply rated to provide a similar output. Amps that are luke warm to slighty warm is a good sign the designer did a good job regulating the voltage. Not true. As I indicated, there are a great many variables that affect heatsink temperature. In general, voltage regulation has no specific correlation with power consumption or heatsink temperature, and whatever relation might exist could be in either direction depending on the specific design. Regards, -- Al |
Baranowski..There is no spec listing with companies that manufacture amplifiers that specifies the percentage of wasted voltage. Amps that are very hot to the point you'll get second degree burns if you lay your hand on the heat fins for a short time period is an amp with poor voltage regulation. Amps that are luke warm to slighty warm is a good sign the designer did a good job regulating the voltage. One of the many things I like about the Sanders Magtech amp with full voltage regulation, is the top cover is a complete solid piece with no slits or cut open air vents that would allow dust and dirt to get into the amp. |
Is there a spec that show the efficiently? i am curious to know where my stands in comparison.
thanks,
Bill |
Bill..not giving bad advise at all. All amps do a good job but some better than others. The most important is how efficient is the amp you own. This is why Class D amps have made great strides during the past seven years because of their efficiency. The key benefit to stable voltage is there is no wasted current failing to leave the amplifier output. When the voltage is unstable, then you have the problem of the voltage constantly fluxuating and a percentage of current fails to leave the amp causing heat problems and less continuous output of watts at different ohm levels. This wasted voltage creates heat which is why internal heat sinks and external heat fins are necessary. |
I do have to admit that i do not know about the stable voltage thing... i do know that after hours and hours of movies the p5 is only "warm" to the touch. i do know that the multi mono amp design of the anthem is not typical for ss amps. The anthem have brought my b&w's to life. i hope i am not giving bad advise to others.
thanks,
Bill |
The Anthem Statement amps do not have stable voltage at all gain levels. Its a typical solid state design with fluxuating voltage with no full voltage regulation so the amp will run much hotter than the Sanders Magtech and has a much lower damping factor. |
What about an anthem statement p2? i love my p5...you could find one used? |
Stl114..do yourself a favor and give the Papa 802d what it really deserves. Lots of power!! The best and one of the most powerful amps on the market under $10K is the Sander's Magtech amp and it will drive the 802d's with such aplomb and majestic splendor that you will never look back. The amp will easily drive down to 1/3 ohms. The amp has a very large 3.0 kVA transformer. It has 20 Motorola 15 amp thermal-trax transistor's. It has a patented linear voltage regulator that eliminates voltage switching and voltage fluxuation which is typical in most amps which is why they run hot. The amp has no clipping protection circuits and will never clip no matter how hard you push it due to the voltage regulator. And the amp runs cool to lukewarm at all levels. The amp took two years to design by Roger Sanders and is built by Coda in California. Coda is the former engineering team from Threshold. The amp is warm, natural, very smooth and dynamic and it puts out 900 watts into 4ohms and weighs only 55 lbs. It only costs $5K!! Roger allows you to try the amp for thirty days and will return your money in full and he pays for the shipping both ways. Comes with a lifetime warranty. One of the hidden treasures in high end audio. |
Looking at Ajackson1's posted system he has the CAD 500MB mono amps, which are solid state and rated at 500 wpc into 8 ohms and double to 1000 wpc into a 4 ohm load. |
Ajackson1, Was that a tube or SS Cary? |
Another amp to consider is the Wyred SX-1000 mono blocks at 570 watts a channel. I have some power hungry speakers that demand a lot power like the B&W. I have the Wyred with the Joule tube preamp and its is a killer combination.
Good luck in your search. |
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Ajackson: What speakers do you have?
I am asking it because B&W802, referenced in original question, are very power hungry
Thank you
Mike |
I have owned the Spectron, Parasound and the Cary. I settled with the Cary. |
I don;t want to say a bad word regarding NuForce or any other amplifier in the world but you must be aware that your B&W802 need huge amount of power to utilize them FULLY.
I have had very similar story with my Watt/Puppy 8 and only when I bought Spectron I realized that my speakers are REALLY capable of.
I am extraordinary happy with my Spectron (and Wilsons) and cannot recommend it high enough !!!
Mike |
Nuforce Ref 9SEV3's play very nice with the Cary Preamps. An lot of bang for the buck. A bit more than your budget new but I think worth the stretch. Nuforce also has a policy for an in home trial.
Cheers! |
another (VERY) satisfied spectron owner here... excellent amp. to my ears, it just does everything right. i just got mine back from having it annodized black - looks as good as it sounds now! |
The Spectron has a good reputation and it seems many use it to power the 802's. With a 30 day trial period its going to be pretty hard to beat. I wanted to explore some other options as I hope this will be my last upgrade for a while (one can only hope!) |
I drive my B&W 802D by Spectron and very happy. Its much better then Parasound A21. Pass has many models and XA 0.5 series has excellent amplifiers - probably exceeding your budget...
Get amplifier of your interest into your system for a few days at least and listen. |
