Continued use of old Tubes

[onebigtrip]

Is there any possibility of damaging an amp by continuing to use tubes that are years and years old? I just bought my first Mesa (WOOT!! - its a Heartbreaker 2x12) but the dude that sold it to me told me he couldn't remember changing the tubes since he bought it, which was 6 years ago. So theres a chance that all of the tubes are a whopping 6 years old. This is my very first all-tube amp so im still learning, but the tone seems to sound good throughout the amp, but im getting what i think is some microphonic squeeling when i have the volume and the reverb up at high levels at the same time. Also, Im getting a very high-pitched sounding rattling when i play that i THINK might be coming from the power tubes....the sound is similar to a lightbulb if you put it up to your ear and shook it...only louder

Is there any way to tell how old tubes are, or what kind of condition they are in? I need to replace these tubes regardless, im sure, but until i have an extra $230 i want to be able to play this amp at high volumes....am i ok to do this?

also, does everyone here prefer mesa tubes? i can get discounts at my local shop on JJ tubes, so im wondering if i should shell out the extra cash for mesa tubes, or if JJ are any good.

Thanks in advance!!

 

[212Mavguy]

You might want to think about retubing, those symptoms sound like tubes that need replacing, the squealing sounds from your writing to be microphonic pre tube(s) and I have heard similar rattling in power tubes before. I had a look at a friend's HB, and the Mesa labeled preamp tubes were made by EI, those tend to become microphonic after a while. They have a long smooth plate similar in shape to a Telefunken 12ax7 smooth plate.

You will find as many opinions here about what to replace with as there are members... :wink: My philosophy has been to listen to the tubes, not so much the people, and collect a few hundred vintage used ones one or two at a time mostly from eBay. That gave me a lot of choices and really sharpened my ears for tone...

One of the nice things about this forum besides the civility of its members is that you can look at a member's posting history, guys like stokes, Monsta-tone, Timbre Wolf, Shredd6, and others have unusual and vast knowledge about tubes, especially the older ones no longer made that to my ears sound much better than the new production ones. In addition, some members have tech skills and are amp repairmen. peace.

 

[94Tremoverb]

The tubes being old (in years) by itself is no risk at all - tubes don't wear out just with age. But they could certainly be worn out, if the amp has been used a lot. Or, if it hasn't been used much they may be effectively almost brand new. *Faulty* tubes (power tubes particularly, and possibly rectifiers) can certainly damage an amp, but that's actually as likely to occur with really brand-new tubes as with older ones - in fact, if they've been run reasonably gently over six years they will have passed their 'burn in' period and are probably a good choice for reliability.

In other words, unless you know the history of the amp's use you really don't know - but I would certainly not change them just for the sake of it and throw them out. What I might certainly do is buy a new set and keep the old ones as spares - every tube amp owner needs spares, and at least you know these ones are working.

The tubes in my amps are all at least 25 years old by the way! - often more. Like 212Mavguy I much prefer old-production US or European-made tubes for tone *and* reliability, and they haven't been any made since the early 80s. You do need to buy them from a reputable vendor if you're going to pay premium prices for them though - the ones you commonly find on Ebay are often fine, but equally often mis-described either as "New Old Stock" when they are just old used tubes, as "tested" when they have simply been tried in some piece of equipment and just basically worked, or as matching when they are no more than the same brand. (Some sellers will also quote tube-tester results which are essentially meaningless for guitar amp power tubes in particular, although they can confirm matching.) If you get them cheap and can test them yourself, you can take more of a chance. Being used is not a problem either, as long as that is reflected in the description and price. Many old-production tubes will last tens or hundreds of thousands of hours.

If this doesn't sound like what you would want to do, stick to new tubes from recognised reselling companies (including Mesa) who test them properly and offer a warranty. JJs are good as new tubes go, but I've still had several fail right out of the box.

 

[elvis]

I agree with 94Trem - just want to add a bit of detail.

In general, preamp tubes are low power, and the circuits they are used in are designed so that they tend to survive even if the tube fails catastrophically. Also, as they are low power, preamp tubes can stay in spec for up to 10,000 hours, depending on how high quality they are.

Power tubes and rectifier tubes are a different story. Because of the high power they handle, they can (but don't usually) take big expensive pieces of the circuit with them when they go bad. So it's best to change them more often. They also degrade faster, so even if they don't explode, you will need to change them every couple of years (if you use them regularly) to keep them sounding good. NOTE: the AC mains fuse usually protects the circuit when power tubes go bad - make sure you have a correctly rated fuse installed, and a few spares handy!

Calendar age is also not a good measure of tube life. You want to look at operational hours. Tubes do not age significantly when the amp is turned off. So if you use the amp once a month, the tubes will last for years.

 

[stephen sawall]

I have power tubes that have been used for over 15 years that sound better than any new tubes I can find. I know people that have had the same tubes in there amps since the 60's that sound better than any new tube put in the amp.

Do you replace light bulbs because they are old ? I only replace them if they die or become dim. I do the same with tubes. Preamp tubes well be good longer than you well live in a lot of times.

New tubes that have not been burned in are very nasty sounding and harsh. Tubes past there time well sound dull / flat.

Does it only squeal when the reverb is turned up ? I would guess the problem is the tube driving the reverb is the problem.