switching power supply runs cooler

[walters]

Does a switching power supply make a high voltage 500V or 700vs run cooler? so the power amp Tubes don't need a Fan?

Why would a switching power supply make a high voltage circuit run cooler and not cause alot of HEAT?

 

[yeechyan]

Based on the equation P = VI, with higher voltage, transmitting the same power requires lower current. Lower current makes it run cooler, which is why the power transmission lines are using high voltage to supply the electrical energy.

 

[walters]

so are all Switching power supplys very low current output?

 

[leftyretro]

Does a switching power supply make a high voltage 500V or 700vs run cooler? so the power amp Tubes don't need a Fan?

Why would a switching power supply make a high voltage circuit run cooler and not cause alot of HEAT?

I think your post is mixing up two different things.

A switching power supply will generate less heat then a linear power supply simply because it's more efficient.

A tube power amp circuit will generate the same amount of heat no matter what kind of power supply is generating the voltage and current for it to utilize.

A tube amp will require some kind of cooling if it's maximum plate dissipation power specification is exceeded without external cooling. The plate dissipation of a specific tube amp is determined by it's operating point of plate voltage Vs bias voltage, class of operation, and duty cycle.

Lefty

 

[walters]

A switching power supply will generate less heat then a linear power supply simply because it's more efficient.

1.) why does a switch power supply generate less heat?

The plate dissipation of a specific tube amp is determined by it's operating point of plate voltage Vs bias voltage, class of operation, and duty cycle

2.) duty cycle of what? what duty cycle?

 

[leftyretro]

A switching power supply will generate less heat then a linear power supply simply because it's more efficient.

1.) why does a switch power supply generate less heat?

The plate dissipation of a specific tube amp is determined by it's operating point of plate voltage Vs bias voltage, class of operation, and duty cycle

2.) duty cycle of what? what duty cycle?

1) A linear power supply regulates by dissipating the difference of input voltage Vs desired regulated voltage by voltage drop across the series pass transistor, dissipated as heat. Simple and effective but not efficient. A SMPS uses a switching transistor that is either full on or full off pumping just enough energy into an inductor to maintain the desired regulated output voltage, much more efficient.

2) Some modes of operation like Class C can run the tube amp at much higher voltage and current because they only work in pulses, like sending Morse code or pulsed radar output. The tube may be only conducting current for 10% or less of the time.

Lefty

 

[Kral]

walters,
The dissipation of a series linear regulator is equal to (Vin-Vout)Il,
Where
Vin is the input (unregulated) voltage
Vout is the output (Regulated) voltage
Il is the load current.
.
The dissipation (Pd) of a switching regulator consists of 4 components.
Let d = the duty cycle = On time/(On time + Off time)
Let Vs = the voltage drop across the pass element (transistor) when it is fully on.
Let Ilk = the (leakage) current thru the pass element when it is fully off
Let Tson = switching time of the pass element when turning on.
Let Tsoff = switching time of the pass element when it is turning off
Let Ild = the steady-state load current
Let vp = the instantaneous voltage across the pass element
Let ip = the instantaneous current thru the pass element
Then
Pd = dVsIld + (1-d)(Vin-Vout)Ilk + ∫(vp)(ip)dt Integrated over the turn-on switching time + ∫(vp)(ip)dt Integrated over the turn-off switching time. Ideally, Vs, Ilk, Switching times are all zero, so the dissipation is zero. In real life, these quantities are not zero, but the total dissipation due to the 4 components of dissipation is much less than the dissipation of a linear regulator.
Regards,
Kral