
Originally Posted by
The Dunster
You did well with the guitar. They did a lot of work on it - and it would have taken a bit of time as well. The fact they don't provide measurements of changes they make and so on though still gives me the impression that they are not serious about what they do.
The acoustic is a Solid Mahogany Maton Mini. I only use it for noodling on the lounge while I watch TV - so nothing too speical or serious about it.
With respect to valve amps I have had them for over 40 years.
Tubes do not die over time only through usage. Power tubes depending on plate voltages used can last 5000hrs for very good ones not pushed too hard - but average is around 1000hrs and a few hundred hours for Chinese types pushed hard - if you are lucky.
Pre-amp / input tubles like 12ax7, 12au7 or other dual triodes can last for 10,000hrs even longer.
I'm guessing your problem is very simple.
1. You need to check / adjust the bias
2. You have dust or corrosion in the tube sockets.
3. You might have a failed Cap - but 99/100 times a visual inspection will answer that for you. Looking for bulging or crack in severe cases.
One thing you don;t want to do though is run the head without a speaker connected. The reason is that the output transformers need to be coupled / connected to a load / speaker. So if you do run the head without a load long enough you will eventually burn out the output transformers - that is an expensive problem.