Before choosing a switch-mode bench supply by default, it's worth knowing what you'd be giving up - because Vartech's transformer-based linear range (3005 B, 3010, 3020, 6005, 6010, plus the dual-output 3010-2 and 6005-2) still outperforms SMPS on the one thing linear regulation does best: clean, low-noise DC with no switching artefacts on the output.
Why Choose Linear Over SMPS at All?
A linear supply's output ripple and noise comes only from mains-frequency residue after a large transformer, rectifier and filter capacitor bank - typically single-digit millivolts RMS, with no switching-frequency noise at all. An SMPS supply, however well designed, always carries some residual switching-frequency ripple riding on its output. For most bench work this is irrelevant. It matters for audio circuit development and testing (switching noise is audible), RF and sensitive analogue/instrumentation circuits (switching harmonics can couple into a sensitive front-end), and any measurement where the power rail itself needs to be "quiet" rather than merely regulated.
The trade-off, stated plainly
The Single-Output Range: 3005 B, 3010, 3020, 6005, 6010
The 3005 B (0-30 V, 0-5 A) is the entry point, adding a distinctive Output Pause function that lets you dial in a voltage before connecting the load rather than exposing the circuit to whatever voltage the dial happened to be at. The 3010 (0-30 V, 0-10 A) and 3020 (0-30 V, 0-20 A) step up in current for heavier 30 V loads, with the 3020 adding preset V & I so a value can be set and recalled without live adjustment. The 6005 (0-60 V, 0-5 A) and 6010 (0-60 V, 0-10 A) mirror the same current progression at double the voltage ceiling. All five support series/parallel connection with a second unit for extending range beyond a single chassis.
The Dual-Output Range: 3010-2 and 6005-2
The 3010-2 (two independent 0-30 V/0-10 A channels) and 6005-2 (two independent 0-60 V/0-5 A channels) go further than simple dual-channel convenience - both support auto series/parallel tracking, meaning the two channels can be linked to move together as a single higher-voltage or higher-current source, or run fully independently. This is exactly the configuration op-amp circuits, bridge circuits and differential-signal testing need: two matched, independently-adjustable rails from one instrument rather than juggling two separate supplies.
Quick Reference by Use Case
- Entry-level bench work, education, service: 3005 B.
- Higher-current 30 V bench or industrial use: 3010 or 3020 (preset V & I).
- Higher-voltage bench or industrial use: 6005 or 6010 (preset V & I).
- Op-amp, bridge or differential circuit testing needing two tracked rails: 3010-2 or 6005-2.
- Audio, RF or noise-sensitive circuit work: any model in this range, over an equivalent-rated SMPS supply.
CIE Instruments is an authorised distributor for the full Vartech DC power supply range, including the 3010-2 and 6005-2 dual-output linear supplies. Contact us to confirm whether linear or SMPS regulation is the right fit for your circuit.