Transistor Guide 2017

Class AB amplifiers recently swept the board in the What Hi-Fi? 2016 Awards1 ‘Best Stereo Amplifier’ category:

What Hi-Fi? 2016 Awards: Best Stereo Amplifier

Rega Elicit-ROver £1,000 category
Rega Elex-R£700 – £1,000
Cambridge CXA60£300 – £700
Onkyo A-9010Under £300


We at Profusion were very proud to discover that the above all use Sanken Power Transistors in their output. This will come as no surprise to any engineer who has used Sanken power transistors, as they are designed for the best possible audio performance. Every transistor they offer has excellent linearity (hfe vs Ic), very low distortion and superb reliability. In general, the published figures are conservative, so expect better than rated performance.

To meet the more demanding applications, a number of additional technologies are employed.

Sanken’s proprietary LAPT and Base Island topology are used to prevent hot spots and current tunnelling (secondary breakdown). As a result, the transistors’ power ratings do not suffer with voltage, and they offer a wide area of safe operation.

Backthinning the wafer draws the heat away from the active junction more effectively, thus lowering the thermal impedance and increasing the power rating.

Thermal tracking diodes are included in the STD range, so that biasing can be thermally compensated, and distortion is minimised across the operating range.

For matching transistors to the right application, please see the table below.

2SC43822SA1668200V2A6025WInsulated package driver transistor
2SD23902SB1560150V10A30,000100WBest for budget amplifiers
2SC35192SA1386160V15A130130WGreat linearity for mid performance
STD03NSTD03P160V15A8,000160WThermal tracking and thin die technology – best for high fidelity amplifiers
2SC32632SA1294230V15A50130WBest for install and PA amplifiers
2SC6145A2SA2223A260V15A50160WHigh power, thin die technology – best for very high power class G & H designs
2SA32642SA1295230V17A50200WTwin fixing with internal copper slug

Value Added Services

For high end applications, Profusion can perform additional selection of transistors, to offer precise matching or higher voltage selections. For closer matched transistors, lower value emitter resistors can be used, which reduces output impedance.

Please contact us to discuss your requirements