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I'm about to revalve my Hughes and kettner switchblade I'm a virgin at this so I'm after some advice. It has 2 12ax7's and 4 el34's. Can anyone suggest what tubes to go for and any tips for doing this.

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I'm about to revalve my Hughes and kettner switchblade I'm a virgin at this so I'm after some advice. It has 2 12ax7's and 4 el34's. Can anyone suggest what tubes to go for and any tips for doing this.

If you don't know exactly what you're doing then you should consider taking it to a tech to get it done as the potential to kill yourself is high.

Valve wise I like JJ tubes; but I use Marshall amps so I can't really comment on them in an H&K. Quite dark sounding and break up fairly quickly in the Marshall.

Also, I doubt you need to change your preamp valves (12ax7s). Preamp valves generally live longer than power valves.

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LameDrummer knows a fair bit about this i think. I think most people will advise you not to do this yourself though.

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If you don't know exactly what you're doing then you should consider taking it to a tech to get it done as the potential to kill yourself is high.

Valve wise I like JJ tubes; but I use Marshall amps so I can't really comment on them in an H&K. Quite dark sounding and break up fairly quickly in the Marshall.

Also, I doubt you need to change your preamp valves (12ax7s). Preamp valves generally live longer than power valves.

Might as well go the whole distance though. There's no sound quite like fresh valves. Razor sharp. Saves him going back to a tech in the near future if one does pop.

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I'm about to revalve my Hughes and kettner switchblade I'm a virgin at this so I'm after some advice. It has 2 12ax7's and 4 el34's. Can anyone suggest what tubes to go for and any tips for doing this.

There are so much choices of valve combinations out there and the choice of tubes depends on the sound you are looking for. Example for you. I like a nice warm full sound in my Mesa Boogies and Diezel so I use low gain 12AX7 and ecc81's in set positions. In the power sections I use Svetlana Winged c El34 or 6L6 valves. Lot of trial and error to get to that choice and it depends on the amp as well. I find this gives a nice full warm tone that doesn't get harsh or muddy. In a marshall amp I use Harma EL34 and 12AX7, this gives a lovely classic rock tone.

Never used an H&K amp so unsure about the bias requirements, but biasing an amp can either be simple and safe if it is something like a marshal DSL with external bias points or very dangerous if its like a Marshall JMP ( amp has to be opened out and on and adjustments made to internal trimmer).

You have to bias an amp when changing valves even with the same make as previously used. In fact you should really check the bias of an amp every few months to ensure the voltage to the tubes doesn't change over time. A lot of people might disagree, specially if it means a tech doing this but its just my personal opinion as I bias my own amps.

Don't poke around in your amp if your unsure what to do as the large caps in there hold lethal voltages, even if the amp hasn't been used for months. Just takes a hand to be an inch away from them and you can be zapped ( trust me, been there )

I would give Derek from Watford valves a call and tell him what amp you have and the kind of tone you want from it. He will advise best on a valve combo. Also dennis marshall is the man to use if you want an amp biased and serviced. I have his number if needed, he is the authorised Mesa tech in the UK as well as a damn good all round Amp man.

I think an amp like an H&K would be more suited to Harma preamp valves, mid gain ECC 83's or maybe high gain ones as its not a bright lower gain marshall, Possibly Winged C svetlana EL34's or maybe TAD or Groovetube EL34. Am not slating JJ valves but I find them to harsh and lacking in the midrange dept. They are a rebranded Ruby tube I think. Rubys were very unreliable valves.

Let me know if I can help in any way

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Cheers for your advice. The valves that came in it are really muddy and bassy I'm looking for something with a bit more bite and clarity. Another question one of the valves burns brighter and it looks like it has a wee lump on the filament bit what's that all about lol

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Cheers for your advice. The valves that came in it are really muddy and bassy I'm looking for something with a bit more bite and clarity. Another question one of the valves burns brighter and it looks like it has a wee lump on the filament bit what's that all about lol

In a word, its fucked! Lol

If its burning brighter and is an EL34, its got more voltage running through it than the others. Not biased correctly, or bias not maintained over time. Svetlana EL 34 will give you a tight bottom end with no flubby feel to it. Harma ECC83 preamp valves will give you a nice crisp tone as well. Check with Derek at watford valves though. Remember though, you could have the best suited valves in your amp but if its not biased correctly the valves could run too hot and burn up very quickly or they could be running too cold and sound very harsh

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Been reading up on your amp and it seems it has a self adjusting bias circuit, meaning you theoretically can just pop the new valves in. However am quite sceptical of these things due to lots of reasons with bias circuits and valves. I think it would possibly still best to have your amp checked by a tech as if one valve is burning brighter it could mean something in the amp could be causing that to happen. I could be wrong so what to do is buy valves and pop them in and if everything sounds cool and the valves aint redplating then your fine. If you still have a valve glowing brighter then get it to a tech.

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Sweet cheers for all your help man that doesn't sound too difficult without all the biasing nonsense lol I shall give this a blast after ive ordered some new valves and I'll post how much an arse I make of it once the electrical burns allow me to type ha ha

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