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Post by slincoln on Nov 28, 2005 20:56:17 GMT -7
I've owned a Rt 66 that I bought new from Mike in '99. My question is, how do I know when I need to change my EF86, or for that matter, my 12Ax7? I changed power tubes (to GT KT66's) about a year ago, for tonal purposes, but I've not changed anything else. Are there telltale symptoms of tonal/performance degradation that would signal it's time for a change? I have noticed, if I hit the amp with my Klon Centaur, which has a pronounced upper end wallop, that I'm noticing a really strained, screeching sound (sounds like this could be a speaker). Mind you, I don't want to pop new tubes in there just for the heck of it, or because it seems like a long enough time has passed that I should. Thanks in advance.
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Post by myles on Nov 29, 2005 8:55:35 GMT -7
I've owned a Rt 66 that I bought new from Mike in '99. My question is, how do I know when I need to change my EF86, or for that matter, my 12Ax7? I changed power tubes (to GT KT66's) about a year ago, for tonal purposes, but I've not changed anything else. Are there telltale symptoms of tonal/performance degradation that would signal it's time for a change? I have noticed, if I hit the amp with my Klon Centaur, which has a pronounced upper end wallop, that I'm noticing a really strained, screeching sound (sounds like this could be a speaker). Mind you, I don't want to pop new tubes in there just for the heck of it, or because it seems like a long enough time has passed that I should. Thanks in advance. For the most part, preamp tubes last years. The exception is the phase inverter which is a very hard worked tube in many amps. I change the PI when I change the output tubes in most cases. The EF86 .... could last for years but if a current production one it may go physically microphonic long before it begins to wear at all. This can happen (microphonics) in as little as a few turn on and turn off cycles. If you have an NOS EF86 you will probably find that it will last a very long time. I get my EF86's for my own amps and those of my clients from Mike at www.kcanostubes.com It is a good idea to have a spare on hand as this is the main tone and gain stage in your particular amp .... the heart of the amp in some ways of looking at things. A good NOS EF86 is not all that pricy considering how long they last and the tone benefits. A GREAT EF-86 may cost about what a good set of preamp tubes would cost in a common amp with multiple 12AX7s.
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