How long do rectifier tubes last?

[LivewireBlanco]

I just acquired a Marshall 1974x made in '05 and it appears to have all original tubes. I'm going to go ahead and replace the preamp and power amp, but should I replace the rectifier tube as well?

[MKB]

Generally the longest lasting tube in an amp is the rectifier tube, I wouldn't replace it unless you are having issues with it, especially if it is a quality NOS like a RCA or GE. Those tend to last for decades.

[surfnorthwest]

Generally the longest lasting tube in an amp is the rectifier tube, I wouldn't replace it unless you are having issues with it, especially if it is a quality NOS like a RCA or GE. Those tend to last for decades.

+1

None of my amps have a rectifier but the ones that did I never had to replace them. Here is some good information

WHAT THE HECK IS A RECTIFIER TUBE????

All of our Marshall and VOX tube amps require DC (direct current) to work. However, as you know, the power we get from the wall is AC (alternating current). So, a device known as a rectifier is utilized within the power supply of an amp and its job is solely to convert AC into DC - hence the name "rectifier." In most modern tube amps a solid-state device known as a diode does this “rectification”. However, a few "older" amps use a tube as their rectifying device and we happen to distribute four (4) of 'em! They are the Vox AC30 (GZ34 rectifier tube) AC15 ( 5Y3 rectifier tube), the re-issue JTM45 (GZ34) and the 1962 Bluesbreaker combo (also aGZ34).

Now, as the guitar's signal never actually passes through this part of the amp's circuit, one would think that a rectifier tube has no direct effect on the sound of the amplifier… well, that's the theory anyway! The truth however is different. The thing is, the rectifier tube has a direct bearing on the power supply tube for the other tubes and, due to its relative inefficiency (compared to a solid-state rectifier), it can and will “sag” when the demand for power is higher than it can handle. And, as it happens, a lot of players like the sound and feel that results from this "inefficiency." To hear and feel this "sag" in action, plug into a JTM45 or a 1962, crank the thing up and then start attacking those strings! Believe me, once you've experienced this "sag" in action, you'll fully understand why it is so named. I hope this information helps. Be careful out there, wherever you are…

[MKB]

One more item about rectifier tubes; it's best to go with NOS if at all possible as the Chinese and Russian reissues have a reputation of spotty quality. The problem is if your rectifier fails in a shorted condition, it will kill your power transformer in a hurry. Some manufacturers of current amps want the tonal characteristics of rectifier tubes but are worried about the quality, so they make a simple circuit modification that prevents the power transformer from blowing (basically adding a solid state diode in series with each of the sections of the tube). This modification is easy and cheap, doesn't alter the sound of the amp, and is good insurance against tube failures.

[LivewireBlanco]

So let me get this straight, ya'll would suggest that I not replace the rectifier tube unless it goes out. Even if it's been 5 years?

[SteveD]

If your amp is working OK, leave it alone.

[LivewireBlanco]

If your amp is working OK, leave it alone.

Spoken from the Godfather himself! I will take thy word as law! No changy the rectifier if it works!

[slowpokerhino]

What are the signs that the rectifier needs changing?

[LivewireBlanco]

Either the transformer blows up :scared or it won't make any sound. Evidently they work, or they don't.

[musicman]

The Vox Custom Classic series has big issues with the rectifier tube and many people recommend replacing it with a Weber Copper Cap solid state device.
I don't know if similar issues affect other makes/models but there is a lot of discussion on the Plexi Palace Vox pages.

[surfnorthwest]

many people recommend replacing it with a Weber Copper Cap solid state device.

+1 IMO the SS is a better way to go, I agree.

[LivewireBlanco]

I dig the tube sag. I'm not much for the aggresive sound of the SS. The VM fulfills the SS role in my amp arsenal, but for leads I just really love that tube rectifier.