What are the different types of power supplies?
Switch-mode power supplies (SMPS) and linear power supplies (LPS) are the main power supply typologies.
Within the LPS category there are a few different sub-categories: capacitive, CLC, and LC choke input.
Capacitive power supplies use only capacitive filtering and don’t have any chokes.
Capacitor – choke – capacitor (CLC) power supplies have a capacitor as the first filter component followed by a choke and then additional capacitor filters.
Choke input (LC) power supplies have a choke as the first filtering component followed by capacitive filters.
The CLC and LC typologies can also have additional choke/capacitor stages, such as CLCLC or LCLC configurations for even better filtering and more constant current.
What are the advantages of switch-mode power supplies?
Switch-mode power supplies (SMPS) were engineered to be efficient, small, and lightweight. This is why they are so popular in modern digital electronics.
SMPS create “pulses” of energy to meet the current requirements of each moment by switching from zero to full power. The peaks and valleys created by the intermittent pulses are filtered out to create a flat DC output.
Modern SMPS can produce incredibly low noise (ripple) and measurably clean power.
What are the disadvantages of switch-mode power supplies?
SMPS dump “hash” noise into the ground and radiate EMI/RFI noise. This noise can inductively corrupt the analog signal in any component or cable that is improperly shielded or can find its way into sensitive components through their ground.
What are the advantages of capacitive power supplies?
Capacitive power supplies are the lowest cost, most efficient, smallest, and lightest of all LPS typologies.
What are the disadvantages of capacitive power supplies?
Capacitive power supplies were created as a lower cost, smaller, lighter alternative to use in high-value tube electronics in place of the larger, heavier, less efficient, and more expensive CL and CLC power supplies.
Later they became popular used in the first solid-state electronics which were marketed as a lower cost smaller size alternative to the tube electronics of their day.
Capacitive power supplies can be very clean but lack the constant current and AC filtering of power supplies with chokes. They tend to lag and overshoot on dynamic passages as the capacitors discharge and recharge. And they are more susceptible to AC line noise.
The constant charging and discharging of capacitive power supplies results in a false sense of PRAT and the music distorting out of time and out of tune during dynamic passages.
Sadly, the majority of modern high-end audio components use capacitive power supplies.
What are the advantages of CLC power supplies?
CLC power supplies have similar efficiency to a capacitive power supply with the added constant current and AC filtering of a choke.
CLC power supplies were engineered as a higher performance alternative to capacitive power supplies and a higher efficiency, smaller size, lower weight, and lower cost alternative to an LC choke input power supply.
A very nice compromise.
What are the disadvantages of a CLC power supply?
CLC power supplies lack some of the performance of an LC choke input power supply. Slightly less high impedance to AC, slightly less more impedance to DC, slightly less constant current, slightly more heat, and slightly less durability.
All-in-all CLC power supplies are an excellent compromise, which is why they are one of the most popular power supply typologies used in modern high-end tube electronics.
What are the advantages of an LC choke input power supply?
In the early 1900’s Western Electric and Bell Labs engineered the ultimate power supply typology with a massive choke before the first capacitor.
It was used for laboratory test equipment, military applications, telecommunication, recording studios, and the finest home audio electronics.
An LC choke input power supply has the highest impedance to AC, the lowest impedance to DC, the lowest heat, and the most longevity of any power supply typology.
Unless the laws of physics have changed it is still the ultimate power supply typology.
What are the disadvantages of an LC choke input power supply?
LC choke input power supplies are the largest, heaviest, least efficient, and most expensive power supply typology with a massive choke and a power transformer that needs to be 50% larger than a capacitive or CLC power supply of the same current output.
Though historically popular among tube enthusiasts, because of their excessive size, weight, and cost, they are rarely used in any modern high-end audio components.
Can a power supply provide constant current without a choke?
Yes. Many companies add solid-state constant current circuits to their capacitive power supplies to improve their performance. Though they provide a somewhat constant current, they don’t compare with the performance of a choke input power supply.
Constant current circuits have double the ripple at the first capacitor, double the heat at the rectifier, use a power transformer that is 2/3 the size, and are nowhere near as durable as a choke input power supply. Another compromise that saves size, weight, and cost.