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Post by rogdent on Jan 1, 2019 21:39:27 GMT -7
Hey everybody, its been quite some time since I've been on the forum but I am having a issue with my 03 Mazerati v2. The last couple times I've played through this amp it acts just fine and sounds great for about 10 minutes. After that it starts to hiss and the volume cuts out. I thought it was probably the power tubes because the last time I had a problem like this Nashville Amp Repair just put tubes in it and it been great for years and many gigs since then. After changing the tubes it worked for about ten minutes or so and the volume cut out again. This time I looked at the tubes and the 2 power tubes to the left, if you were to be facing the front of the amp, were extra bright and the 2 on the right of them were not lite up at all. Any ideas as to what could be going on would be great. I will be taking it to an amp tech but with the depth of knowledge here I may be able to give him a place to start looking or and idea possibly.
Thanks in advance,
Roger
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Post by purpletele on Jan 1, 2019 23:01:30 GMT -7
Roger,
Just talking out loud it would seem that there is too much current going to the tubes for some reason.
The fact that it works and then stops after 10 minutes is curious. If there was too much current then that should pop a fuse rather than allowing the Power tubes to red plate.
That is an interesting set of symptoms, I wonder if there is a filter capacitor that is failing and causing a large draw of current.
I will be curious to see if Dr. Z sees this and has an idea
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Post by premiumplus (Dave) on Jan 3, 2019 19:48:13 GMT -7
To find out if it's the tubes or the amp, take note of which side the power tubes run hot on, and then remove them and swap them with the two tubes from the other side. If the same tubes still get hot, in other words if the problem moves with the tubes, then you can safely assume it is those two tubes running hot on their own. If the problem stays in the same place in the amp, that is if the same tube sockets make the other tubes run hot, then you may very well have an amp problem. Hopefully the problem will follow the tubes, and a fresh quad will put you back in business. Let us know how it works out for you, good luck!
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Post by rogdent on Jan 3, 2019 22:31:19 GMT -7
That's a great idea Dave! Kinda upset I didn't think of that. Just like swapping spark plugs chasing a misfire. I'm going to give that a try when I get back home tomorrow, and yes I'll let you know how it goes. Thanks again!!
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Post by doctorice on Jan 4, 2019 5:44:11 GMT -7
If you can't sort it out, you can always send the amp to Dr Z's repair team. May cost a little more, with shipping, but guaranteed to be "factory fresh" (chassis, that is) when it returns.
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Post by T-R☼CK ♫ on Jan 4, 2019 9:40:45 GMT -7
If it's not tubes, I'm guessing screen grid resistor. Don't ask why I say this...
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Post by premiumplus (Dave) on Jan 4, 2019 14:08:50 GMT -7
If it's not tubes, I'm guessing screen grid resistor. Don't ask why I say this... That would be my first check too, if the problem stays with the socket(s). I can smell it from here.
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Post by rogdent on Jan 9, 2019 13:30:54 GMT -7
Looks like it's not the tubes. After switching the tubes around it did the same as before. So off to the amp tech we go.
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