Tubes and how often do you replace

[dmccombe7]

Has probably been asked before but because I'm doing this from work i can't spend a lot of time searching.

How often do you change your tubes more specifically for me with a Genz Streamliner 600.
Currently used most days for a minimum 1hr with 6 hr sessions every 2 weeks.

Should it be time based or dependant on how often used.

Are there any signs of a tube failing that i should look out for.

Any advice welcome

Dave

[chris_b]

These are preamp tubes, replace them if they fail or if you want a different sound but they won't wear out like power valves and should last forever.

[franzbassist]

Preamp tubes should last for years, although their life span can be shortened by sudden changes in temperature, knocks and bumps etc... Assuming they are treated well, they should only need replacing when they become noisy or microphonic.

[Mr. Foxen]

Preamp valves totally do wear out, but not in a regular amount of time. Some just die, others keep going forever, some just start sounding rubbish.

[jwood662]

I haven't changed my power tubes in my SVT since 2003, used new old stock GE 6550s from Watford valves and haven't noticed any degredation in sound quality since. Which is good since they cost £50 each back then and they are now £100 and you need 6 of the buggers! Fingers crossed they last a bit longer!

[dmccombe7]

Thanks guys
Its put my mind at ease.

Basically when they do start going they will show signs of tone changes, microphonics which i think I've heard via guitarist Marshall whereby when he touched the amp or moved it it gave a pinging type of sound and eventually a squealing if that makes sense ? would that be right. ?

Otherwise they just fail.
Can you replace yourself as I've heard of bias settings need set up.

Dave

[franzbassist]

[quote name='dmccombe7' timestamp='1331123977' post='1567980']
Basically when they do start going they will show signs of tone changes, microphonics which i think I've heard via guitarist Marshall whereby when he touched the amp or moved it it gave a pinging type of sound and eventually a squealing if that makes sense ? would that be right. ?
[/quote]

Yep, that's the classic symptoms you describe.

[quote name='dmccombe7' timestamp='1331123977' post='1567980']
Can you replace yourself as I've heard of bias settings need set up.
[/quote]

Bias only applies to power stage valves. Preamp valves are just a case of swapping in and out. Simples.

[brensabre79]

That ping sounds like a microphonic valve to me.

You don't need to bias preamp valves, the power amp valves should be though

Edit: Haha beat me to it!

Edited March 7, 2012 by brensabre79

[dmccombe7]

Confirmed both of you are correct and have passed that test.
Take a beer this weekend as a winning prize.

Thanks for the advice its very much appreciated.

Dave

[brensabre79]

Cheers Dave,

One other thing to note if changing the valves in your Streamliner, Genz Benz 'design out' most of the valve characteristics from their pre-amp designs to avoid people suffering from variable quality of valves. So whilst changing faulty/worn valves may help, If you are going to buy a set of expensive NOS Mullards or something to improve the sound of your amp I doubt you will notice much (if any) benefit...

[dmccombe7]

The amps only a year old so looks like I'm being overly paranoid.
I now know what to look out for though.

Cheers Guys
Dave

[skankdelvar]

[quote name='Mr. Foxen' timestamp='1331118905' post='1567827']
Preamp valves totally do wear out, but not in a regular amount of time. Some just die, others keep going forever, some just start sounding rubbish.
[/quote]

Indeed. I just worked out that the pre-amp tubes have been in my Marshall since it left the factory.

39 years ago.

[clarkpegasus4001]

[quote name='skankdelvar' timestamp='1331261321' post='1570520']
Indeed. I just worked out that the pre-amp tubes have been in my Marshall since it left the factory.

39 years ago.
[/quote]

That does not suprise me at all. May I ask which model Marshall you have? is it a Marshall 100w?