When do Tube Amps Wear Out?

WTF someone has been giving you bad information. Who said the amps "decay"?!?

I have a Little-Dot I+ and it's going strong, but I also have a Little-Dot II+ from 2006 and a Little-Dot II++ from 2007. Both are still working great and still sound just as good as the day I bought them.

The only thing that really "wears out" are the tubes, and even then, only after a very long time. I've had one pair of EF92 tubes that developed a slight hiss after literally using them for years. I don't even know if that was a result of the tube dieing or maybe I just mishandled it or something. But tubes are cheap and having a selection of tubes to choose from is half the fun anyway.

Some food for thought - I use my Little-Dot II++ as a pre-amp and have two stereo power amplifiers for my speakers. One is a Yamaha P2201 made in 1976 and the other is a Yamaha M-2 made in 1979 (both ~240wpc into 8 ohms). Both of those are still going strong after 30-35 years.
Edited by GotNoRice - 8/30/11 at 4:41am

I think whoever told you that greatly exaggerated. Don't worry about it, I've been using the same tubes for the last 1000 hours or so and their still going strong as ever. Eventually the tubes will need replaced but they are very cheap so don't worry about it. You can pick up a very nice set of matched tubes for about $10-20 off ebay when they go. So stop worrying and start listening to the music!

If you take care of the amp you can will it to your grandkids.

I have a pair of 50 year old tube amps. Some of the tubes in them are original, some have worn out and been replaced. Both amps work fine.

Headphone amps are quite similar to guitar amps and the components do wear out.

Pull up a datasheet on a capacitor at Mouser or Digikey. You'll find the mean time before failure (MTBF) listed in terms of hours. Nothing lasts forever.

Failure does not mean it won't turn on or go up in flames. It usually means that the part goes out of spec and that it no longer operates at the value specified in the circuit. This is tricky to hear because the parts slowly change value over time. But if you recap an old set (and preferably get the old resistors out, too, since they drift) it'll sound different when plugged back in.

The only parts that keep their value over time are wirewound resistors, transformers,mica caps, and the air gap capacitors used for tuning radios. Everything else degrades.

This is also why I'm a fan of point-to-point construction for tube gear. If you need to replace parts on a PCB, you have to unsolder the jacks, switch, power supply, and other stuff to get the board out. Once out, it's easy to lift pads, damage traces, and have other problems with the PCB. Those can be tough to fix. Further, replacement parts don't always match up with the PCB holes and sometimes space is an issue.

Point-to-point will let you get a bad part out and replaced in a few minutes, no disassembly. If a wire is damaged, a new one goes in just as fast. If you want to put in bigger parts, no problem. It costs more to build that way, but it will hold up forever and can always be repaired.

Hi Uncle Erik, do you have any examples of point-to-point constructed amps? Thanks.

 

Yes, amps from Eddie Current, Woo Audio and the DNA Sonett are all point-to-point. There might be others, but those three manufacturers use it and you'll find internal photos of them.

I'll have to look back to see if I have photos of my ProAc clone crossovers. I used two individual solder lugs for each part and then wired it up. I had to drill about 40 holes to mount the solder lugs. In all, it took a couple hours more than stuffing a PCB. But it turned out well and they're really solid.

Very well stated Erik...completely agree with you.

All the Decware amps are point to point and there are also pictures on Decware site.

Bottlehead's too.

 

 

No amp wears out! Just replace parts! ;)

 

Mapletree amps by Dr. Lloyd are point to point.

And so is Lafigaro 339. I bet we can keep this list going for quite a while ;)

It is?

The only photo I could find is this:



I don't know if that's the right amp, but it certainly has a PCB inside.