Could I change the tubes in my Peavey classic 50 myself

3manstack

Im going to get a spare set of tubes shortly and was just wondering that when it comes time to fit them could I do it myself?

I have the Peavey Classic 50 410 Combo.

In my old fender hot rod I could access them quite easily but in this amp they seem quite well hidden.

Am I best to leave it to the professionals?

Thanks in adavnce for the advice

exhausted

changing them is easy. just unplug it and take as many panels etc. off as you have to. it's biasing the power tubes that is a little funky unless you understand what needs to be done.

but i really never got into amp technical stuff so i'll going to shut up now.

SomethingCreative

3manstack wrote:

Im going to get a spare set of tubes shortly and was just wondering that when it comes time to fit them could I do it myself?

I have the Peavey Classic 50 410 Combo.

In my old fender hot rod I could access them quite easily but in this amp they seem quite well hidden.

Am I best to leave it to the professionals?

Thanks in adavnce for the advice

i don't know but I just got a Peavey Classic 50 410 myself...don't they rock!?!

Pacomc79

3manstack wrote:

Im going to get a spare set of tubes shortly and was just wondering that when it comes time to fit them could I do it myself?

I have the Peavey Classic 50 410 Combo.

In my old fender hot rod I could access them quite easily but in this amp they seem quite well hidden.

Am I best to leave it to the professionals?

Thanks in adavnce for the advice

e-mail ted at http://www.webervst.com and ask. or talk to the guys at http://www.thetubestore.com

mccreadyisgod

Accessing the tubes is a lot easier than it first looks. There are just a couple panels that cover the tubes (that also serve to keep the tubes well-seated) that you'll have to locate and remove. The only real problem with it is that there isn't a lot of room to maneuver or see what you're doing, so lining the tube pins up can be kind of a bitch.

As far as biasing, you should be fine just swapping them tube-for-tube. Make sure you replace the power tubes (four EL-84's) with a matched quartet, all four at once. If you want to get anal about it, you can have it biased, but the plate voltages should be fine for a new set of tubes. It's not a bad idea to have your amp biased every few years (maybe every second or third power tube swap), but I don't believe it's necessary every time. Biasing should only be necessary if your amp goes out of bias (a sign of a serious problem) or if you change tube-type (like EL-84's to 6V6's).

All Those Yesterdays

mccreadyisgod wrote:

Accessing the tubes is a lot easier than it first looks. There are just a couple panels that cover the tubes (that also serve to keep the tubes well-seated) that you'll have to locate and remove. The only real problem with it is that there isn't a lot of room to maneuver or see what you're doing, so lining the tube pins up can be kind of a bitch.

As far as biasing, you should be fine just swapping them tube-for-tube. Make sure you replace the power tubes (four EL-84's) with a matched quartet, all four at once. If you want to get anal about it, you can have it biased, but the plate voltages should be fine for a new set of tubes. It's not a bad idea to have your amp biased every few years (maybe every second or third power tube swap), but I don't believe it's necessary every time. Biasing should only be necessary if your amp goes out of bias (a sign of a serious problem) or if you change tube-type (like EL-84's to 6V6's).

I know you still don't believe me, but even places like http://www.tubestore.com tells you to rebias Power Tube's each time you replace them. Each tube is different. Thru the tube store you can continue to by tubes from the same "groups" which means if you buy a set from a group at the tube store, and have the amp biased, you just continue to by from that group and don't need to rebiased the amp.

All Those Yesterdays

mccreadyisgod wrote:

Accessing the tubes is a lot easier than it first looks. There are just a couple panels that cover the tubes (that also serve to keep the tubes well-seated) that you'll have to locate and remove. The only real problem with it is that there isn't a lot of room to maneuver or see what you're doing, so lining the tube pins up can be kind of a bitch.

As far as biasing, you should be fine just swapping them tube-for-tube. Make sure you replace the power tubes (four EL-84's) with a matched quartet, all four at once. If you want to get anal about it, you can have it biased, but the plate voltages should be fine for a new set of tubes. It's not a bad idea to have your amp biased every few years (maybe every second or third power tube swap), but I don't believe it's necessary every time. Biasing should only be necessary if your amp goes out of bias (a sign of a serious problem) or if you change tube-type (like EL-84's to 6V6's).

This is qouted straight from the http://www.tubestore.com

9. What does it mean to "bias" the amplifier?
Just like the idle of your car may need adjusting when a major change is done to the engine, new power tubes need their idle (the "bias") adjusted to make sure the amp sounds as good as possible. Some amps do this automatically, but many do not - particularly in the world of guitar amps. Many tube amp owners are unaware of this simple regular service for their amp that will keep it sounding it's absolute best. The bias methods of amplifiers fall into several basic categories:
- fixed bias amplifiers
- cathode bias amplifiers
- adjustable bias amplifiers.
Each of these types is unique. Fixed bias amplifiers CAN'T be biased. These amps (for example, some Fender and Mesa Boogie models) are designed to run with tubes that have a specific current draw (see question 4) and should only use tubes that fall within a certain range. Fortunately, these amps are usually pretty forgiving and will work well with a pretty wide range of tubes. For the best results, specify the make and model of your amp in the "Comments" of your order and we will make sure you get the best tubes for your amp.
Cathode bias amplifiers shouldn't require any adjustments and will work with a wide range of tube plate currents, as the circuit is "self adjusting".
For adjustable bias amplifiers, the amp should be biased by a tech with experience with this procedure. It's not difficult, it doesn't take long, but if you don't know what you're doing you may hurt yourself (amps can give lethal electric shocks even when unplugged, and NO, we're not just saying that to scare you). Also, your amp may sound horrible or cause undue wear and tear on the tubes or power supply. Until you learn how to do it correctly by yourself, it's best to pay a technician a few dollars to do it for you.

If you look else where or read books it will tel you the same thing. Which is cool with the tubestore because you can then start buying "perfect pairs" which are all grouped by there individual current draw

mccreadyisgod

All Those Yesterdays wrote:

I know you still don't believe me, but even places like http://www.tubestore.com tells you to rebias Power Tube's each time you replace them. Each tube is different. Thru the tube store you can continue to by tubes from the same "groups" which means if you buy a set from a group at the tube store, and have the amp biased, you just continue to by from that group and don't need to rebiased the amp.

Well, lemme put it this way:

Biasing a tube amp is NEVER a bad idea, and can never hurt your amp. NOT biasing your tube amp CAN be a bad idea, and you can end up shortening tube life or doing damage to the circuitry. So, if you want to be 100% safe, biasing is a great idea. My opinion is, most tube amps run safely within a certain range (like the Tube Store says), so if you run the same tube type, you should be fine. Besides, the amp tech I work with (a really good guy, does a lot of Fender tweed work) has told me that biasing a Fender amp every time is a little redundant. I feel the Tube Store or (insert tube seller here) ideology is, "better safe than sorry." Like a quick-lube guy telling you that you really should change your automatic transmission fluid. It can't hurt, but it might not be necessary, nor worth the cost.

The better question to ask here is if the Peavey self-biases (many newer tube amps do). Of course, it might be just about impossible to find that out... Peavey's web site just says take it to an authorized repair center for any maintenance (a nod to the dealers to get them some extra $$$ on stupid things like re-tubing).

I'd try to find a good tube amp tech (an independant one, if possible) to ask these questions. Any good tube tech will have catalogs that will list an amp's needs and biasing options.

who's_pearljam?

If you're changing to a strange set of tubes, I think it's worth it to rebias, because the voltages will be different. Even the same manufacturers have different "hardness" factors for their tubes.(the point at which they break up and distort) If you buy the same matched voltage tubes after you change tubes you should be fine changing them, but I would rebias after you change them for the first time. If the amp is out of bias, it may break up too soon, or get a bunch of ugly overtones and harmonics.

If you're changing the set of tubes to sound better, I think it makes sense to tune up the amp to get the best sound.

3manstack

Wow, thanks for the cool advice, its like being back in science class again, heh heh.

Any suggestions as to where I could find out whether the Amp is self biasing?

mccreadyisgod said it might be fairly difficult to find that out, but any help is greatly appreciated.

All Those Yesterdays

3manstack wrote:

Wow, thanks for the cool advice, its like being back in science class again, heh heh.

Any suggestions as to where I could find out whether the Amp is self biasing?

mccreadyisgod said it might be fairly difficult to find that out, but any help is greatly appreciated.

I've found that Peaveys support web site, is very responsive, and usually get back to you extremely quick. Heck they got me schematics on some old late 70's tube bass amp that I never heard of in just a day or so. I thought that was impressive because I didn't even expect to get anything.