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Post by billyguitar on Feb 15, 2006 16:29:55 GMT -7
Came home from work and had a song idea in my head so I fired up my Maz 38 and started working on it. After a while there was a small pop and the volume went way down and got thin sounding. I looked at the tubes and wiggled the preamp tubes. The amp started sputtering and popping more and then the two output tubes on the preamp tube side started glowing orange. I shut it down quick. I went and got the screwgun and took the top panel off and replaced all of the original Groove Tube output tubes with a matched quad of JJs that I had bought from Charlie Kittelson @ Vacuum Tube Valley. Apparently it was one of those tubes because I just played it for a half hour and no more noises. What's amazing to me is how much better the amp sounds. Much more solid midrange and the highs are sweeter. I thought the amp wasn't sounding as good as it should but I had no idea. I don't remember it sounding this good when it was new! I've retubed lots of amps over the years and never heard such an improvement, but this is the first EL-84 amp I've used for my main amp.
Questions for ya'll:
1) Is it common for EL-84s to fail in that manner?
2) Has anyone else noticed a big improvent when retubing?
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Post by bluzsteel on Feb 16, 2006 6:33:17 GMT -7
I think tubes should burn a orange color some times a bit of blue florescence in the orange is not necessarily bad , hot cherry red is bad, Ive never had two go out , and a match set can really change your tone
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Post by myles on Mar 1, 2006 21:04:30 GMT -7
You want to change your output set on these amps about twice a year if you play four or five times a week.
In concert we change output tubes every 300 hours at the most.
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Post by real.sladdi on Mar 3, 2006 0:34:58 GMT -7
Hello guys, regards from Germany!
Have a question concerning output tubes: Dr.Z recommends GT EL84 with a rating of 5-6. As far as I know this is a special GT rating. If I have other Tubes than GT what is the value to look at compared to the GT rating? Thanx in advance.
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Post by bluzsteel on Mar 3, 2006 7:03:13 GMT -7
if they are not rated with a number just make sure they are matched
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Post by LittleBlindShakey on Mar 3, 2006 8:43:56 GMT -7
After reading the various posts on this topic I called Myles yesterday and we spoke briefly. In short I went out yesterday and purchased a matched quad set of GT EL84S with a #5 rating for about $50 (#6 was stock in the amp). Put them in my Maz 38 Sr and it put the snap back into my amp. I like the change and for $50 what a deal.
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Post by espennor on Mar 3, 2006 9:13:36 GMT -7
My Maz 38 sr sounded thin and weak with the original tubes. I replaced all pre and output tubes with NOS tubes. Now it sounds great, and it compares even with my brother DC-30. EL 34 based, British sounding amps, like AC-30 and Dr.Z etc.. are more sensible to what kind of tubes you put in them, than eks Fender 6L6 or 6V6, bassman, twin or whatever...
I even got a few different tubes for the V1 position, to get different sounds.
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Post by real.sladdi on Mar 3, 2006 10:40:33 GMT -7
I even got a few different tubes for the V1 position, to get different sounds. Maybe I should experiment a little bit too... but actually my MAZ Sr. sounds great with the stock tubes - and with a 1x12" Tonker and/ or a 1x12" G12H30. BTW: Which one in my MAZ Sr. NR Head is V1 when looking at the back? There are actually 5 Preamp sockets: the first one on the left is empty, the next two are JJ's (V1 and V2?), then another empty socket and the next is a Sovtek 12AX7 LPS (V3?).
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Post by billyguitar on Mar 3, 2006 11:18:17 GMT -7
NR amps have less tubes because you don't need reverb drive and recovery, but I think you understand that. Tubes are numbered thusly; V1 is the tube furthest from the output tubes. In discussions where tubes are mentioned as V1 etc you'll have to be aware if the author is talking about a reverb or non-reverb amp.
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Post by myles on Mar 3, 2006 11:46:15 GMT -7
Hello guys, regards from Germany! Have a question concerning output tubes: Dr.Z recommends GT EL84 with a rating of 5-6. As far as I know this is a special GT rating. If I have other Tubes than GT what is the value to look at compared to the GT rating? Thanx in advance. Just make sure your vendor at least statically matches the tubes to within 10% each other. That means if on a given tester a tube has 30mA of output, the other tube should be within 3mA of the first tube. 20% is considered "industrial match" but 10% is the outside figure I will accept (or else the hum goes up and life goes down and there are other issues). If somebody uses a Maxi Matcher, you are looking for a "range" of 35-45 on that device for a mid rated EL84. I like 38-42 or so on this test device for most Z EL34 amps. Mike at KCA has one of these as does Bob Pletka at Eurotubes, the folks at Tubedepot have one and Doug Preston has one. In the UK ... there is a GT factory outside of London and there is also Watford Valves over there that does really nice work.
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Post by real.sladdi on Mar 3, 2006 14:48:22 GMT -7
And in Germany we have T.A.D. (Tube Amp Doctor); they were Ruby Tubes dealer for many years and do their own matching and distribution now - so I'm sure I will find some good stuff there too... Thanx guys for all the useful information! Myles, we were talking about my GT Soul-o 45 a while ago - maybe you remember? But it got replaced by the MAZ Sr. soon after... So now I'm a proud member of the big happy Z-family...
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Post by myles on Mar 3, 2006 16:52:12 GMT -7
And in Germany we have T.A.D. (Tube Amp Doctor); they were Ruby Tubes dealer for many years and do their own matching and distribution now - so I'm sure I will find some good stuff there too... Thanx guys for all the useful information! Myles, we were talking about my GT Soul-o 45 a while ago - maybe you remember? But it got replaced by the MAZ Sr. soon after... So now I'm a proud member of the big happy Z-family... The MAZ Sr is a killer amp and really versatile. I love my own S-45 and a few months ago we built up about six of them on special request for a few folks. I would never part with mine with my mod in it but it is a very different amp than a MAZ Sr. I am glad I have both amps.
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Post by real.sladdi on Mar 4, 2006 1:57:46 GMT -7
No doubt about that! The Soul-o is a great amp too. But there's another great sounding SF Super Reverb in my basement... too many good ones for my budget and one had to go...
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