Tube Maintenance Question

[HANGAR18]

A question for anyone who might know... Will I get uneven "wear" out of the tubes if I set the power switch to the 50 watt setting and leave it there?

 

I'm thinking specifically about my Carvin V3, 100 watt 3 channel amp. I'm pretty sure that I read in the manual that when I switch the amp to the 50 watt setting, that only half the tubes are used. This has led me to wonder about when it comes time to change the tubes, will I have to change all of the tubes or just the ones that got used by having the amp set to 50 watts for its whole life? But on the other hand, a lot of tubes are sold in sets which are matched at the factory, so maybe I'd still have to change all the tubes at once regardless of whether they are all used or not.

 

 

 

The new living room photo.

 

 

I'm also thinking about selling one half stack but that would be a different thread.

[DetroitBlues]

If no power is going the half the tubes, I think those tubes won't need to be replaced as soon as the others.

[mars_hall]

Agreed

[ironmike]

a matched pair,or a matched quartet would be required .time on a pair of tubes will wear into a mismatch with the other pair, but, it might not be noticeable to the ear.no harm to the circuits though,so if it sounds good, it doesnt matter what the tubes measure at. just how they sound..

[t0aj15]

IIRC there are two ways to cut the power in tube amps. Most amps such as the Carvins simply cut the power in half by cutting out one of the tube pairs, which means to get even tube wear you need to switch tube pairs (inner pair-outer pair) occasionally to maintain even tube wear. Other amps like my Fender Super Sonic 100 simply lower the power to all four power tubes simultaneously which maintains even tube wear and negates the need for tube swapping. But don't take my word for it, instead talk to a tube tech. The guy at Eurotubes is pretty good at this type of info.

[HANGAR18]

Eureaka! The "RTFM" rule strikes again! I downloaded a copy of the manual online and here is what it had to say about the 100 watt/50 watt selector switch.

 

(Edit: Not for this amp but for the new PRS Archon amp)

 

Output Power (100 Watt ):

This control allows you to switch off two of the four

power tubes. This causes a volume decrease as well as gives you tonal variation.

For ideal operation, switch the impedance sett ing to ½ the normal value when

using the 50W sett ing. For example, when using the 100W sett ing going into an

8 Ohm cabinet, use the 8 Ohm impedance sett ing. When using the 50W setting,

switch the impedance selector to 4 Ohms

[HANGAR18]

I think what I will do is just set all of these amps to the 100 watt selector so that all the tubes can be heated equally. For some reason I don't think I will notice a difference because I never turn up the volume past half way anyhow.

[t0aj15]

 

Eureaka! The "RTFM" rule strikes again! I downloaded a copy of the manual online and here is what it had to say about the 100 watt/50 watt selector switch.

 

(Edit: Not for this amp but for the new PRS Archon amp)

 

Output Power (100 Watt ):

This control allows you to switch off two of the four

power tubes. This causes a volume decrease as well as gives you tonal variation.

For ideal operation, switch the impedance sett ing to ½ the normal value when

using the 50W sett ing. For example, when using the 100W sett ing going into an

8 Ohm cabinet, use the 8 Ohm impedance sett ing. When using the 50W setting,

switch the impedance selector to 4 Ohms

 

That is typical for amps that remove two tubes from the circuit.

[212Mavguy]

There's not very much difference in loudness with setting a 100 watt amp to half power, no matter how it's accomplished by the circuit. If your V3 has a serial effects loop, you can stick a Ceriatone K-lator or C-lator in the loop and use it to control the overall volume of the amp. It's incredible how good it sounds and how manageable it makes a monster amp behave on stage. You set the amp's master into the volume sweet spot that the amp likes and use the C-lator to take the volume back to decent levels without the tone changes that attenuators tend to impose, I've used the C-lator with great results on my 50 and 100 watt Dumble clones, as well as my Harry Joyce Custom 30. I got my second one on ebay used for 250 bucks plus shipping. My Steel String Singer Clone is insanely loud at a master setting of only 4, but adding the C-lator takes that painfully loud master volume setting to living room volume or less...

 

If your Carvin reduces power by taking two power tubes out of the circuit, those tubes taken out still have the heaters going all the time. If you like the 50 watt tone better than 100 watt just yank the pair of tubes that turn off, those will now be your matched spare pair.

 

My Dumble clones that have half power switches reduce the power by running the power tubes as triodes, not pentodes. The tone is a bit darker in the half power settings on triode/pentode half power switched amps. I much prefer to use a C-lator if the amp has a serial fx loop, it's no contest.

[tbonesullivan]

While no plate voltage is going to the tubes, the filaments are still getting power, and they will get hot. Not as hot as the tubes that are "on" but still hot. If you run it in 50 watt mode all the time, I would switch the inner and outer tube pairs once a year to get even wear.