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Posted by Greg (220.127.116.11) on July 22, 2002 at 20:43:47:
In Reply to: Re: Hartke amp problem posted by email@example.com on July 02, 2002 at 09:08:37:
: Adam, I've experienced these symptoms before. If you have changed the tube and the fuzz is still present, you probably have to replace some transistors in the power section of the amp. It's not difficult, but patience is required. First, go surfing to the Samson / Hartke website and download the manual for the head if you don't already have it. In there you will see the electronic schematics for your amp. There will be 3 main components. The preamp, the amp and a transformer or two. The preamp will likely have the tube nearby, you're looking for 4 to 6 transistors about the size of a quarter. My amp was a Peavey, but the basic operation of an amp is the same. In my case, there were 6 transistors in a row, and they were stamped Motorola 45B33 or something like that. Take a volt meter and probe the transistors with the amp off (obviously, unless you like afros) the value should be the same for all of them. You most likely won't find the troublemaker(s) if the problem is intermittent. It sounds to me like you have some bad power transistors that are acting up when warm. You should rewire your 410 cab to 4 ohms if it not already at that load. The Hartke will work less hard at 4 ohms and you won't have to turn it up as much as you would at 8 ohms. I'm also going to throw in my 2 cents here and suggest you purchase a 400 or 600 watt power amp to drive your cabinet and to just use the Hartke as a preamp "soundshaper". I love the sound of the Hartke, but quite honestly it just doesn't have the gonads to gig or play with a band every week. More available power won't tax the equipment and it will last forever if cared for.
: It sounds like it might just be the tube - A gassy tube would act exactly like this. Even though it happens withy the tube control off, I'd try replacing it.
: Good Luck,
: : I have a Hartke model 2000 bass amp and a Hartke 410TP cabinet. Both are about
: : 4-5 years old. Recently, the amp has been giving off a fuzzbox-style distortion after about 5 minutes of playing. It goes away if you turn the amp off and back on again, but it always comes back within a few minutes. I don't think it's the tube, because it still happens if you turn the solid state control all the way up and the tube control to off. There are also no abnormalities in the speaker cones, as far as I can tell. It does, however, look like the head has been dropped (damn roommates). Anyway, any insight you could give would be greatly appreciated.
: : Thanks,
: : Adam Steele
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