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Post by orangeghia on Jan 2, 2008 21:48:26 GMT -7
After some time, I'm afraid that I will have to part with my ghia head. Mostly because it is simply too much volume for my needs, but, I did mention in previous posts that I was experiencing a dislike with the treble frequencies.
While putting up my amp for sale , I received an email from an interested party, who seems to think the treble problem was from a construction flaw, rather then speakers tubes etc.
Here is a exerpt from the message:
"These amps have an intrinsic design flaw. When you blow a power tube one common result i the Ghia is that the joint connecting the conjunctive filter heats up , often to the point of breaking the solder joint to the filter. That would be an explanation for the harsh treble of the amp. A friend of mine experienced this first hand and was told by those close to the Z Forum that it is a problem with the Ghia design. So open her up and see if anything looks disconnected...that could explain it."
What do you ghia owners think? Could my own amp be flawed?
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Post by benttop (Steve) on Jan 2, 2008 22:06:19 GMT -7
"Flawed" is a pretty obnoxious way of saying that when tube amps have tubes go bad, it can damage circuitry. If that's a flaw, then I'd say all tube amps share it.
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Post by bluzman on Jan 2, 2008 23:14:38 GMT -7
**Posted in the Ghia Section Too**
I don't think the use of a conjunctive filter in the Ghia should be considered a design flaw. The CF can obviously fail if your power tubes fail, but before EL84s fail, from my experience, I can hear it and replace them before they go. I think Dr. Z described it to me a few years ago something like this: When a power tube fails sometimes there is a flyback and it can cause the soldered joint to heat up. I do know the value of the Ceramic Cap is .0022uf and the resistor should be a 5 watt 10K. The addition of the CF is actually a good thing. You CAN hear the difference. The Doc didn't develop the CF; it is something that has been used in tube technology from way back.
I own two Carmen Ghia heads. I used to have a third one, but she was blonde and like many blondes she ran off. One of the Ghias that I bought used had a tube failure weeks after I bought it and I had to replace the CF. It took more time to remove and re-install the chassis than the actual electronic repair!
Hope it helps some.
PaulT
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Post by benttop (Steve) on Jan 3, 2008 6:44:36 GMT -7
I've had several amps over the years that had the output tranny short circuit when the power tubes went bad. Now THAT should be called a design flaw if anything. But it's a fairly common occurrence on most Marshall amps and many Fenders.
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