Originally Posted by
Simon Barden
Glad you're happy with the changes. It can be a real let-down when you splash out on some reportedly extra special valves only to find you liked the old one's better. Done it myself several times!
Pre-amp valves last for ages so you won't need to buy any more for the Marshall for many years (except for an early failure). It's the power valves that need replacing, but even they can last for many, many years if the amp isn't used that much and is always driving into the correct load impedance.