All of the dc power supplies that are being discussed are variable both for volts and for watts but there is a difference in the absolute voltage control and the maximum amps control. When a given voltage is dialed in on the display (say 24 volts) the power supply will give exactly (+/- 2% accuracy on most units) that much voltage to the unit that will be powered.


On the other hand power supplies that have an amperage control works differently because the power supply can not be forced to provide more amps than the resistance of the circuit also known as electrical load. If a particular device needs 7 amps the power supply will not give it more even if the amp control is set at 10 amps maximum. Consider the selected amperage on the power supply display as a ceiling of output current. You can lower the amps that are provided and the corresponding new level will be displayed but you can’t increase the level that it will draw. In having amperage control, regardless of your voltage setting you can ensure a set temperature of your cutting device.


There are two primary power supply design types available. One is the traditional LINEAR Design and the other is a newer SWITCHING Design.

The LINEAR models will work for any application as long as the maximum power is not used on a continuous basis. The SWITCHING models are best nonsensitive electronic equipment like radios, RC cars and trains.

The benefits of the LINEAR power supply is that they are heavy duty units that can handle continuous use and produce very low line noise that can effect sensitive equipment. There design of using large DC transformers, heat sinks and fans causes them to be heavier and more costly than their switching power supplies. Because they are heavy duty, some may choose linear power supplies for cutting tools because if they are run at 80% below their rated values, can provide very high amperage to heat large gauge wires.

The main benefits of a SWITCHING power supply are that they are much lighter and less costly over their switching counterparts. Because these do produce a larger amount of electrical noise, they will not work for sensitive electronics but will work just fine for resistance wire applications. Because these units are smaller, less weight, and less expensive, they will also be suitable for Hot Wire Foam Cutting Devices.


Many of these power supplies come in DUAL VARIABLE configurations which mean the supply has two independent supplies within the cabinet and they can be used in INDEPENDENT, SERIES or PARALLEL operation which can provide either dual 0-30V @ 0-5A or one 0-60V @ 0-5A or one 0-30V @ 0-10A connection for the Mastech HY3005D-3 for example. Dual supplies have -2 after their model numbers.

Triple power supplies provide dual variable and a third FIXED output which is usually 5 volts at 3 amps.

One important deciding factor that you should use after selecting a Mastech power supply for purchase on the Internet is to find out if the seller has a technician available. Most sellers do not and if something goes wrong with your supply during the warranty period there could be a delay in replacing it if the seller is out of stock.


Stock levels fluctuate and many times out of stock conditions occur and the next replacement container ship could be months away. We have a full time technician available for Mastech and spare parts for them at the warranty center.

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