Spectron vs Parasound vs Cary vs ?

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

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.

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

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.

Nice beat down Al.

+1