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Post by Eddie on Jul 2, 2008 20:32:54 GMT -7
I've read in more than one place that the phase inverter tube should be replaced whenever the power tubes are replaced. Seems wierd to me. If the PI is a good balanced one, why replace it?
Eddie
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Post by Deleted on Jul 3, 2008 13:52:05 GMT -7
Cuz' Myles says so is good enough for me!
It is really a part of the power section of the amp. Also is a very hard working tube. Replacing it with the power tubes would allow your vender to match the rise times between the PI and power tubes.
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Post by Eddie on Jul 3, 2008 19:01:02 GMT -7
Ah! I see...
I read through Myles tube info pdf and didn't see that but I didn't search all of his posts here. Thanks, doc001.
Eddie
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Post by Deleted on Jul 3, 2008 21:07:27 GMT -7
I hope I'm not misquoting him.
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Post by Phil (aka Phil) on Jul 4, 2008 6:17:02 GMT -7
I think Myles' advice was to replace the inverter tubes every other power tube change. I think changing it every time you replace the power tubes is a little overkill and probably not necessary.
Myles?
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Post by myles on Jul 15, 2008 11:28:31 GMT -7
Depends on the amp in many cases. 6L6's are harder to drive than EL84's as an example and some amps have a pre or post master volume come into play. On my big 6L6 amps such as my Tone-Master or Twin Reverbs I do change the PI when I change the output sets ... but I can get 4000+ hours out of a set of good 6L6s. On El34 amps I check the phase inverter when I am looking at the output tubes and maybe change it every other cycle. On some EL84 amps I check and change when necessary and this really varies .... some folks like to change EL84 sets every 10 shows ... about 30 hours ... and this is nothing to the PI. NOTE: None of this applies to a Carmen Ghia. A Carmen Ghia has a fixed bias phase inverter and about the only amp on the planet that has this. So ... it's PI is under almost no stress at all and runs cool. It is easy to know exactly when the phase inverter needs to be changed on a Carmen Ghia. It is a visual trick: Look in the back of the amp at the phase inverter .... if it is broken and has jagged edges and there is broken glass on the bottom of the head or cab then the phase inverter needs to be replaced Remember .... on top of all that, an NOS 5751 to meet mil-spec had to withstand 600Gs of shaking force and the two sides had to be balanced pretty closely to each other as standard design practice. One more factor to consider.
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Post by Deleted on Jul 18, 2008 14:43:46 GMT -7
Depends on the amp in many cases. 6L6's are harder to drive than EL84's as an example and some amps have a pre or post master volume come into play. On my big 6L6 amps such as my Tone-Master or Twin Reverbs I do change the PI when I change the output sets ... but I can get 4000+ hours out of a set of good 6L6s. On El34 amps I check the phase inverter when I am looking at the output tubes and maybe change it every other cycle. On some EL84 amps I check and change when necessary and this really varies .... some folks like to change EL84 sets every 10 shows ... about 30 hours ... and this is nothing to the PI. NOTE: None of this applies to a Carmen Ghia. A Carmen Ghia has a fixed bias phase inverter and about the only amp on the planet that has this. So ... it's PI is under almost no stress at all and runs cool. It is easy to know exactly when the phase inverter needs to be changed on a Carmen Ghia. It is a visual trick: Look in the back of the amp at the phase inverter .... if it is broken and has jagged edges and there is broken glass on the bottom of the head or cab then the phase inverter needs to be replaced Remember .... on top of all that, an NOS 5751 to meet mil-spec had to withstand 600Gs of shaking force and the two sides had to be balanced pretty closely to each other as standard design practice. One more factor to consider. Hey Myles, Thank you for chiming in here and sharing your information. It's cool that you are so willing to help out. I apologize if I miss quoted you. I was just trying to help out a Z bro. No harm intended. I don't always remember things as easily as I would like. They say the memory is the first thing to go.
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Post by myles on Jul 21, 2008 10:49:43 GMT -7
Depends on the amp in many cases. 6L6's are harder to drive than EL84's as an example and some amps have a pre or post master volume come into play. On my big 6L6 amps such as my Tone-Master or Twin Reverbs I do change the PI when I change the output sets ... but I can get 4000+ hours out of a set of good 6L6s. On El34 amps I check the phase inverter when I am looking at the output tubes and maybe change it every other cycle. On some EL84 amps I check and change when necessary and this really varies .... some folks like to change EL84 sets every 10 shows ... about 30 hours ... and this is nothing to the PI. NOTE: None of this applies to a Carmen Ghia. A Carmen Ghia has a fixed bias phase inverter and about the only amp on the planet that has this. So ... it's PI is under almost no stress at all and runs cool. It is easy to know exactly when the phase inverter needs to be changed on a Carmen Ghia. It is a visual trick: Look in the back of the amp at the phase inverter .... if it is broken and has jagged edges and there is broken glass on the bottom of the head or cab then the phase inverter needs to be replaced Remember .... on top of all that, an NOS 5751 to meet mil-spec had to withstand 600Gs of shaking force and the two sides had to be balanced pretty closely to each other as standard design practice. One more factor to consider. Hey Myles, Thank you for chiming in here and sharing your information. It's cool that you are so willing to help out. I apologize if I miss quoted you. I was just trying to help out a Z bro. No harm intended. I don't always remember things as easily as I would like. They say the memory is the first thing to go. As they say here in So Cal .... no-problem-o I misquote myself all the time !!!!
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Post by Deleted on Jul 21, 2008 16:10:11 GMT -7
Hey Myles, Thank you for chiming in here and sharing your information. It's cool that you are so willing to help out. I apologize if I miss quoted you. I was just trying to help out a Z bro. No harm intended. I don't always remember things as easily as I would like. They say the memory is the first thing to go. As they say here in So Cal .... no-problem-o I misquote myself all the time !!!! Cool
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Post by deaconblues on Jul 22, 2008 12:22:55 GMT -7
So, Myles, how long would you expect a set of EL84s to last in the Ghia?
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