EL34s - again

[DownByLaw]

Hi all,

I retubed my clx with the New Sensor Mullard EL34s about 6 mos ago. I don't gig, play about 5-8 hours a week, generally at pretty healthy volume. Thought I had some dodgy preamp tubes, tone was deteriorating, (loss of body on treble strings, not as big sounding as usual, loss of detail in lower mids) so changed them out, but the amp still sounds flat and is distorting earlier than it used to. (went back to the other set of preamps since the new ones didn't seem to make a positive difference) Also it seems as thought the tone gets worse the longer I play. (even accounting for ear fatique) Is it possible for the power tubes to be giving up after such a short time? I have heard to change out the power tubes about twice a year, but does anyone else do this more often? Are the Mullards just not that robust? What would be a good choice for replacement that I might get a bit more life out of? (w/out going NOS) I'm not new to this, but I didn't think big bottles like these would wear out so fast.

Patrick

[suhr_rodney]

You didn't mention whether or not you biased the amp when you installed the new tubes, nor if you allow the amp to warm up and cool down by putting the amp in standby. With proper biasing and amp ettiquette, some report 500 hours as the expected lifespan for current production tubes... vs 2000 for NOS. Even so, you're somewhere around 200 hours. Try a pair of NOS Tesla's from Mike @ KCA. $150 but if they last 4x as long they will be cheaper in the long run. Not to mention, they will probably sound better, too.

[jlh]

You should consider JJ E34L or The new JJ KT77 power tubes for your amp, contact Dougs Tubes, He is the man, Great customer support and knowledge.
Your choice of tube types and manufacturer are critical to the tone, then of course bias and then preamp tube choice.
The power tubes mentioned above will make a big difference, the E34L's will give you a little later break up and tighter lows than the KT77's but the KT77's have a warmer feel with earlier break up.
Talk to Doug, dougs tubes on the web, he will take you there

[DownByLaw]

Yes, the amp was rebiased when the power tubes were replaced. (Jimmy Somma) Sounded great for the last 5 mos or so. Noticed today a lot of light popping, little bursts of static in the background. Does that sound like power or preamp? Has anyone else had less than stellar results with the Mullards? I have considered going NOS before, but quite expensive as I would need a quad.

Patrick