Basic valve amps 101

[BobArsecake]

Right, one of my valves has gone, and because I'm out of the loop and have forgotten I how to look after my amp, can put one EHX (or Sovtek) EL84 in with the others as replacement, or do I need a full set? I've replaced individual ones before but am anxious about the "required matching" on here;

http://www.hotroxuk.com/matched-valves- ... -el84.html

Bit of a Blobby nuisance if so.

Not at home right now but when I am I'm going to have it apart and see what I've got in there at the moment. I am embarrassed for my questions but I know you are all lovely and forgiving.

[Gabriel]

I've always read that you're supposed to use a matched set. No idea if that's true but I've always just followed that advice.

[NickS]

In an amp with pairs of output valves, one in the pair handles the positive-going half of the waveform and the other handles the negative- going half. If you want lowest distortion then the amount of amplification needs to match on each half; so that's why you use matched valves.

[Fran]

The rule book says if you support Leeds United you need to cover your Amp and yourself in petrol, stick your head inside it (or next to it) then light it. It solves everything.
Just kidding, or am I?
Swap the set Jon. Power Valves as far as i know need to be replaced as a set.

[George]

Yeah, new pair that are matched. They can have different tolerances so they will not bias equally in the same amp which can lead to all sorts of problems.

I recommend Hot Rox Uk. Very helpful.

http://www.hotroxuk.com/

[BobArsecake]

Just opened it up and they're all ehx anyway, but you reckon I should replace all four rather than just the one? Or at least two?That was my first idea, Fran but I didn't want to spoil my amp. Oh by the way, it's the ecc83s I have two marshall (courtesy of mike <3) and two that it came with.

[benecol]

So Mike sold you an amp with ropey valves? Typical.

I've been using these cats for valves - even with (very reasonable) shipping from the US and comedy tax, still about half the price of Watford Valves/Hotrox.

[Thomas]

^ Great site. I've bookmarked it.

[benecol]

Bought a reverb tank from them too - really recommend them.

[BobArsecake]

So Mike sold you an amp with ropey valves? Typical.

I've been using these cats for valves - even with (very reasonable) shipping from the US and comedy tax, still about half the price of Watford Valves/Hotrox.

Actually, he sent me them FOC! it's one of the EL84s that's stiffing me.

[benecol]

That's sabotage then.

[BobArsecake]

His are working like a treat still, touch wood.

[BobArsecake]

Four years on. Four more years! Four more years!

[Mike]

Glad to hear those Marshalls are still giving you some love, sorry about the EL84s crapping out - that's the worst part about owning an amp - the power valves going.

I think as people have said it's best for you swap at least the pair that the bad valve belongs to and maybe the others too. Nothing bad will happen if you just replace one with the same type, you just won't get the purest distortion sound or whatever.

Sounds like benecol had a good recommendation for a place to buy from (regardless of his misplaced accusations), I have to admit I only use hotrox. I had a bad ebay valve experience that put my 6100 in the Marshall repair workshop.

[UlricvonCatalyst]

While we're bandying reccomendations about, try Banzai. EU sellers, so no duties/customs delays.