Yaqin Tube Valve Amplifiers

Supply voltage

The first thing any buyer in the UK should note is that all examples of these amps that I’ve seen were desgined for 220Vac – not the 230Vac+10%-6% supply that we enjoy. This means that the expected voltages in the circuit (heater voltage for instance) are sometimes too high. In the case of the MC-5881A and MC-84L that I trialled the voltages were so high that the power supply smoothing caps were well over maximum rated voltage.

Import duty

Another thing to note is that importing them from Hong-Kong is expensive both in terms of agreed postage and the subsequent (and somewhat unpredictable) customs duty. Expect to pay ~£35 duty on these items. Prices offered by UK ’suppliers’ (some irony intended) are generally very high and I’ve had no response from them on how they modified them to ensure safety when sold and operated in the UK on 230Vac – my guess is they haven’t done a thing.

Appearance

One other general complaint I have is the use of very bright, usually blue, LEDs for the power indicators. These are so bright they light up a darkened room and, in my opinion, detract from the gentle warm glow of the valves. In all cases I have either tamed them with a (higher value) series resistor or replaced them with standard LEDs.