viren bakhshi
Well-Known Member
Hi,
Just to allay any fears about valve amps, before you get carried away.
Yes, valve amps do operate at voltages much higher than seen in solid-state amps. Power supplies at 300 VDC are pretty common. So, safety precautions while working on an amp are essential.
Any manufacturer worth his salt knows this, and will protect the user to the utmost. The amplifier chassis should be fully insulated, and properly grounded against any internal failure. Wood chassis serve here admirably. All high voltage supplies should have bleeder resistors in them, to discharge all voltages when the amp is switched off. This happens within minutes. So, opening a chassis, say, 5 minutes after switching off, and unplugging from the mains, is safe. But, please confirm from the manufacturer before you do! And, the glass envelope of a valve is a perfect insulator too - you will never get a shock touching a valve glass body.
Its mainly the power valves that get really hot. So, some caution around them is advised. However, they do not get as hot as an incandescent light bulb - so use the same amount of care.
Valve circuits are relatively simple and straightforward. A well designed amp should give decades of service.
Regards,
Viren
Just to allay any fears about valve amps, before you get carried away.
Yes, valve amps do operate at voltages much higher than seen in solid-state amps. Power supplies at 300 VDC are pretty common. So, safety precautions while working on an amp are essential.
Any manufacturer worth his salt knows this, and will protect the user to the utmost. The amplifier chassis should be fully insulated, and properly grounded against any internal failure. Wood chassis serve here admirably. All high voltage supplies should have bleeder resistors in them, to discharge all voltages when the amp is switched off. This happens within minutes. So, opening a chassis, say, 5 minutes after switching off, and unplugging from the mains, is safe. But, please confirm from the manufacturer before you do! And, the glass envelope of a valve is a perfect insulator too - you will never get a shock touching a valve glass body.
Its mainly the power valves that get really hot. So, some caution around them is advised. However, they do not get as hot as an incandescent light bulb - so use the same amount of care.
Valve circuits are relatively simple and straightforward. A well designed amp should give decades of service.
Regards,
Viren
