Jump to content
aberdeen-music

Are valves easy to change?


Dan G
 Share

Recommended Posts

Its not bad at all, you dont have to get a pro

Its bit scary the first time opening up the amp but its simple.

Power and Pre amp valves just pull out on the DSL100 should be the same on the 50. there are metal clamps holding them in tight but you just pull them apart a little, i got someone to hold it whilst pulling it out its was easier

Then you just push the new one back in, there are pins on the bottom that can only slot in one way,

it should be the same as mine, oh also got told not to touch the glass of the valve so use a cloth or tissue

to push it back in.

was a bit of a bastard as just after replaced my Poweramp Valves the Pre-amp valves blew a week later

bastard ! was 80 for all 8 valves!

Link to comment
Share on other sites

it shouldnt be too hard to do yourself

the only problem could be biasing the valves (basically making sure they run at the best voltages for every individual valve - they are all slightly different)

i have no idea how to do it personally, but there should be guides on the net to explain how, i think i saw one from marshall somewhere but i cant remember where that was. or you could always ask over at www.harmony-central.com forums, the guys in the amp forum should be able to help you out

David

Link to comment
Share on other sites

Originally posted by Dan Atom:

...or do you have to get a pro to do it?

I just ordered some valves with the aim of changing them myself, or is that not a wise idea, as I don't really like playing about with stuff like amps.

I have a Marshall JCM2000 DSL-50Watt Head.

If you are not too sure, I'd be getting someone who knows what to do. I'd be worried about fucking the new valves, or worse the nice amp you have.....

Link to comment
Share on other sites

Guest redmeat

Biasing is not something you should try yourself unless you really know what you're doing and have the right equipment. Apparantly it can only be done properly using an oscilloscope.

Some people say it's okay if you use matched power valves. they are wrong. Though the individual valves in a pair are matched, different sets of pairs are not matched. The only company that does this is Groove Tubes (for a price) and you'd still have to have the amp rebiased to use them in the first place (though not for subsequent replacements).

Your amp could work if you do it yourself but the danger is that the output valves might run too cold (too low voltage) which would give a shitty, distorted sound, or too hot which would mean they'd burn out quickly or blow your amp up (like the guy above).

pre-amp valves are a different story - you can swap them at will though there are still issues with opening up your amp chassis - safety,warranty etc.

Link to comment
Share on other sites

Changing valves is a simple procedure.

Don't worry about lethal voltages. Unplug the amp and it'll be okay. You'll only be near the top of the chassis, the bit with the lethal voltages is underneath.

Take the top or the back of the amp off. Make sure the original valves are cool (i.e not been used in the last half hour). The power valves are the big ones (there should be two that look the same). Take these out. Replace with the ones you bought. They will only fit in one way due to the pins.

Don't worry about getting quad matched valves as you only need two, a matched pair will be fine. Don't worry about biasing, it's complicated and the amp will work fine without out being done. If you notice the amp sounds a little muddy or something in the future then it can possibly be done.

Link to comment
Share on other sites

Me, I would rather spend the cash on having Marshall service the amp. Even the price of the valves, labour and carriage for the boys in Milton Keynes will be worth a spot on, roaring amp, rather than a flabby, un-reliable POS. Just call them up, ask to be put through to their service department, and they will be able to quote you and will arrange a carrier to pick the amp up from you. A valve is not an electronic piece of equipment, so it cannot really be just replaced by unplugging the old and refitting the new.

Link to comment
Share on other sites

Originally posted by Dan Atom:

Goddamn y'al! thanks a lot for all the help - although so many mixed suggestions has confused me even more!

I wonder what Graeme C would say...?

I would say....I have re-valved a good few valve amps over the years and have never experienced a bias problem....thats not to say it cant happen.

G...

Link to comment
Share on other sites

Originally posted by GraemeC:

I would say....I have re-valved a good few valve amps over the years and have never experienced a bias problem....thats not to say it cant happen.

G...

Does that mean you think I could do it myself, I'm not *completely* stupid (although I do lack knowledge on said subject) and know that valves do 'pull out and plug in'...

I orderd 2 x SVETLANA EL34s

and (after much reading up) 4 x SOVTEK ECC83s

;)

Link to comment
Share on other sites

Originally posted by Dan Atom:

Does that mean you think I could do it myself, I'm not *completely* stupid (although I do lack knowledge on said subject) and know that valves do 'pull out and plug in'...

I orderd 2 x SVETLANA EL34s

and (after much reading up) 4 x SOVTEK ECC83s

;)

you shouldnt have a problem with that....if you stick jamseys got my number.

Link to comment
Share on other sites

Originally posted by Tav:

Hmm I dunno but valve amps have lethal voltages in them so I wouldn't go in. Once you turn them off there's still voltages lurking around.

yeah even on my valvestate when i unplug it from the mains and i accidentally touch the plug i get a fucking cracking shock.

man it hurts like a bitch but i reckon the DSL thingy would fuck you up real good. heh.

Link to comment
Share on other sites

ok, now am i the only person thinking... why?

and aren't Svetlana's what Marshall provide with their amps anyway? but they just rebrand them?

the old set that were in my Marshall for ten years are still in good condition... but the new ones tightened it up a bit.... but thats after TEN YEARS!!!

whats your reason behind the change Dan?

pretty curious?

Link to comment
Share on other sites

Look, all this electrocuting yourself bullshit isn't going to happen.

Just change them yourself. I've done it hundreds of times, no probs.

All this shipping it to Marshall stuff is a load of crap: it will be expensive and you'll not have your amp for a while.

Just take the top off, put the new valves and close the top. it will take all of 5 minutes.

The biasing stuff is bullshit as well, you're not really going to notice a difference, and putting in new valves will not blow up your amp.

Plus, valves are going to need changed more than once in 10 years for a gigging amp.

Craig

Link to comment
Share on other sites

Originally posted by Eriatarka:

ok, now am i the only person thinking... why?

and aren't Svetlana's what Marshall provide with their amps anyway? but they just rebrand them?

whats your reason behind the change Dan?

pretty curious?

Yes Marshall use Svetlanas.

My amp is broken (sort of).

When playing it sounds fine (cos the noise drowns out the problem), but when there is a guitar plugged in and not playing the noice from the amp sounds like rice crispies on clean, and a thunderstorm on overdrive.

The louder you turn up the master volume on the head, the worse the problem is. For gigs, it doesn't really matter butas for recording...

Everyone seemed to suggest it was the valves.

Link to comment
Share on other sites

Originally posted by Monk Rocker:

I'd get someone to take a look at it for you. You don't want to waste money relpacing the valves if that's not where the problem lies. I'm with Rob on this one, send it to Marshall.

I figured that I'll need to change valves at some point in the future so I thought that if the valves aren't the problem, then at least I have a spare set of valves which would be handy. But cheers anyway.

Link to comment
Share on other sites

Originally posted by craig deadenstereo:

Just take the top off,

Top?

Anyway, you'd be best just going for it.

The only problem I've had before (with re-valving marshalls) is the valves being so tight that I've had to remove the entire chassis to get any purchase on them.

Does it sound fucked up without a guitar plugged in?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...