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Post by bukowski on Sept 8, 2005 7:28:41 GMT -7
today while playing my mazerati it started to hum and a pair of el84s were starting to glow (the plates)these el84s are almost 2 years old and this amp sees daily action any ideas?
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Post by hdahs143 on Sept 8, 2005 10:29:23 GMT -7
I'm stunned you got 2 years out of a set of power tubes! It's definitely time for a new quad!
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Post by myles on Sept 8, 2005 10:31:08 GMT -7
today while playing my mazerati it started to hum and a pair of el84s were starting to glow (the plates)these el84s are almost 2 years old and this amp sees daily action any ideas? You are so overdue it is out of sight! On amps that see everyday service such as those on tour or amps that sit in the bedroom, I change the output sets every 300 hours of playing. You will hear the change immediately. You are WAY beyond the service life of these tubes in this amp. I use these in a #5 or #6 rating exclusively.... www.groovetubes.com/product.cfm?Product_ID=1687You can get these (JJ EL84S) from many sources but they may not have a GT rating. The Z amps are generally designed around a 5-6 rating. If you do order these off the GT site, in the comment section of any order put in a not that says #5 or #6 ONLY, and also mention you are a friend of mine (Myles). They will bring me the order to ask if there is anything special they need to do and I will hand trace a quad for you. This normally runs $10 extra per tube by the way. I will only do this for folks from this forum. If you get tubes elsewhere and are local and can come over on an evening or weekend I will trace anybodies tubes for you at n/c. You will be able to see how they actually match over the entire range, not just statically. There is nothing I can do about a mis-matched set of tubes but at least you will know why you have a bit more hum, why the amp runs hotter, and why you have a loss of sustain and dead spots on your fretboard.
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Post by mikekca on Sept 8, 2005 18:23:01 GMT -7
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Post by bukowski on Sept 9, 2005 7:49:10 GMT -7
Thanks Myles and Mike ,thats what I've been using the nos tesla from you mike (get all my tubes thru you)thats why I thought I could get a little more hours out of them .I popped the groove tubes #6 that came with the amp back in ,thanks for the offer myles and if I buy a set I'II definitly do that .I have a question How many hours (average )would I expect to get out of the tesla nos compared to the groove tubes ?I know thats a very broad question so many factors like how hard you play volume etc , thanks Jason
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Post by myles on Sept 9, 2005 9:04:23 GMT -7
Thanks Myles and Mike ,thats what I've been using the nos tesla from you mike (get all my tubes thru you)thats why I thought I could get a little more hours out of them .I popped the groove tubes #6 that came with the amp back in ,thanks for the offer myles and if I buy a set I'II definitly do that .I have a question How many hours (average )would I expect to get out of the tesla nos compared to the groove tubes ?I know thats a very broad question so many factors like how hard you play volume etc , thanks Jason In amps such as a Matchess DC30, Hot Cat, Z MAZ 38, Vox AC-30 .... quad output amps .... I change at 300 hours. On the Tesla it will be about the same as the JJ is also a very robust tube. You can go longer but you will notice a sonic improvement after 300 or so hours with fresh tubes. In a Mazerati or RxES with it's split load bias the amps tend to go about 400 hours.
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Post by bukowski on Oct 1, 2005 7:04:06 GMT -7
while I finally found the hum ,after changing the power tubes from nos tesla to the original goove #6 ,still hum ,then pulled the chasis (I love looking at the guts of my rati)changed the bugle boy 5ar4 back to sovtek, still hum , finally the ones I thought I would get more life out of v1 and v2 rca blackplates 5751 (found the hum ),so I put back the jj ec83 in the v2 pi and the ge 5751 in v1 no hum .With my tele I really think I'm a 5751 in v1 kind of guy and the ge 5751 are pretty affordable so me thinks I;m going to get some more of these ,also what I'm I doing when I put a 12ax7 in the phase inverter?sounds good to me will know for sure after tonights gig , thank Jason MAY YOU ALL BE WELL AND HAPPY
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Post by myles on Oct 4, 2005 18:25:19 GMT -7
Keep the 5751 in the PI. You can get some great ones at less cost than a lot of new 12AX7s from Mike at www.kcanostubes.com
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