Through-hole vs Surface Mount Components - which is better?

Hi-Fi enthusiasts have long obsessed over the effects that differing interconnects and loudspeaker cables have on the audio signals before they are converted into sound by the movement of the speaker cones. With this in mind, it is surprising how little thought is given to what is going on inside the boxes of electronics. You are probably aware that there are likely to be many hundreds of components within each unit. What might not be so obvious is that there are even more connections and possibly a few metres of copper tracks that the audio signals must negotiate. As the consumer, you have no influence on the effect these have on the sound. However, as the designers, we do - and we think long and hard about it!

Typically two types of component fixings are used – "through-hole" and "surface mount". Of the two, through-hole will be the one most familiar to everyone. Such a component has a body with wires. It is mounted on one side of a Printed Circuit Board (PCB) by bending its connecting wires, feeding them through the PCB and then soldering them in place on the opposite side of the board. Surface mount components are generally much smaller, and do not have any connecting wires. These components are designed to be mounted on the same side of the PCB as the copper track. The ends of the component are then soldered directly to the copper tracks.

Benefits and Disadvantages

Through-hole components are generally larger and can therefore dissipate of more power. Accordingly, components such as output devices and large capacitors will be through-hole devices. Physically bulky Items benefit from the added mechanical security of a through-hole arrangement. One disadvantage that is apparent when you look at the diagram above, is the need for wire leads. These leads can be of varying quality and create more junctions between the component body and the PCB. Through-hole components are easy to work with and lend themselves to prototyping. They are invariably what we start with in the early development stages.

Being smaller, surface mount components are not usually suited to high power applications, however, there are many applications where high power is not a priority. In these instances, surface mount brings beneficial improvements from higher tolerances, reduced numbers of junctions and, due to the higher density of circuit design, shorter PCB tracks.

Conclusion

So, rather than one method being better than the other, it is more a question of utilising the best technique for your needs. As a result, you will always find a mix of technologies in our products – but you can be assured that the decision is always driven by performance and not cost.