tube fanatic
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Posts posted by tube fanatic
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It is a nice, simple, ultralinear design which should sound very nice.
The solid state diodes are used with the tube rectifier to form a hybrid bridge rectifier. Some designers prefer doing it that way, and it works fine whenever the current draw is on the low side.
I would enjoy seeing a picture of the underside of this amp.
Maynard
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11 hours ago, RANGE DOG said:
May have found my answer,
I think it was a language translation problem.
I believe it means, “ if you turn it off, do not turn it back on for 5 minutes,” to protect the tubes.
Thoughts?
The tubes will not be damaged if you turn the amp back on in less than 5 minutes. I’m guessing that they want the electrolytic caps to fully discharge before the next power up cycle. I would have to see a schematic and look at a few things to provide a better answer. I think they left out the word “not” in regard to #2 in the instructions.
Maynard
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I'll have to do my own fact checking on this when time permits. If true, it exposes more reasons to be skeptical about the stated reasons for doing research into pathogens having the sole purpose of destroying life:
Maynard
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The voice of doom speaks again:
As far as conspiracy theorists are concerned I, and many others, remain convinced that the virus was lab created and released with intent. However, we all wear masks when in any kind of public setting both for our own protection as well as others. No one, including those responsible for this situation, is assured of not getting sick.
Maynard
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Here are some thoughts from the top:
And here’s more cause for optimism:Maynard
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NJ has finally issued guidelines for school reopening, and students are not required to wear masks while teachers and visitors are. There is no protocol for what will happen if a student tests positive. Will the rest of the class, and teacher, be forced to go into a 14 day quarantine every time this happens? Teachers posting on the teachers’ union FB page are livid and have raised more than 200 questions and concerns which the state has somehow forgotten to address in their 100+ page document. Many are now considering submitting their retirement papers out of concerns for their personal safety as well the safety of their family members. Ultimately, there is going to be a severe teacher shortage here as many college students are seriously considering changing to a different career track.
Maynard
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My cousin’s husband is in the NYPD mounted unit and works in Manhattan. Talk about a dangerous level of exposure. One well aimed brick and he’s dead. The morale is extremely poor.
Maynard
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The video in this article is worth watching:
Maynard
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15 minutes ago, RandyH 000 said:
Definitely shoot for the new glasses -0.25 and add lenses that are the Transition type so as to darken when he goes out in the sun , as his eyesight will worsen if he doesnt also have sunglasses
The key issue is UV exposure so, if JL’s son is not bothered by brightness, going with Transitions is not necessary. Brightness does not make eyes get worse. In fact, recent studies on myopia progression in kids have shown that exposure to bright, outdoor light actually reduces myopia progression.
Maynard
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More than ever I believe this virus was engineered—
Maynard
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24 minutes ago, JL Sargent said:
I know we have some people here that are experts in vision/glasses. My son just left the eye doc. He was told he didn't need glasses, but he did get a prescription for corrective lenses at -0.25 for each eye. So he is slightly near sighted, right? Wouldn't that affect his ability to play baseball at the varsity level? Based on his sporting activities, he think he might need them. What do you think?
Yes, he is slightly myopic and his Rx is certainly minimal. If your son believes he needs to sharpen his acuity a bit, the Rx could be incorporated into a pair of protective glasses (which he should be using regardless) like Rec Specs. The lenses should be polycarbonate or Trivex for maximum safety. The latter has the advantage of better optical clarity, and doesn’t have the chromatic aberration issues of the former. Both offer uv protection. If the Rx doesn’t accomplish what your son desires, you can substitute plano (non Rx) lenses and just go for the safety.
Maynard
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This is how a local care facility has decided to allow residents to have visitors. To me, it looks like an animal shelter! They certainly could have found a better way to ensure distancing. How demoralizing...
Maynard
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I can’t resist posting this as it still brings tears to my eyes.
Maynard
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This is not a political thread. Rather, it is about the desire of some to remove the way many of us feel about our wonderful country. This article, which deals with the issue from a sports perspective, beautifully explains why doing so would slap the faces of all who have died protecting our freedoms.
https://fanbuzz.com/national/national-anthem-at-sports-events/
Maynard
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5 hours ago, tube fanatic said:
Just noted that CNN updated their article half an hour ago stating that the county was forced to drop their exemption. The link takes you to the updated article, not the original.
Maynard
Well, CNN updated the article yet again this morning! What is interesting to me is that the article is being rewritten each time and the prior article ceases to exist. This is just like the activities of the Ministry of Truth in Orwell’s 1984. So, unless a person prints articles as they originally appear there is no way to look at what was actually said.
Maynard
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Just noted that CNN updated their article half an hour ago stating that the county was forced to drop their exemption. The link takes you to the updated article, not the original.
Maynard
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10 hours ago, mungkiman said:
This country just set a record for the largest number of new Covid-19 cases in a day since this pandemic began.
USA! USA! USA!
Meanwhile, this Oregon county has chosen to allow certain individuals who do not have medical issues to ignore the state mandate for mask use. Why hasn’t the Governor put a stop to this immediately? The political side of the virus is winning out.
https://www.cnn.com/2020/06/24/us/oregon-county-people-of-color-mask-trnd/index.html
Maynard
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On 6/19/2020 at 7:29 PM, MyOwn said:
I hate it....How can you convey in a text your voice nuance?
My daughter has perfected the art! She yells at my wife all the time via texting and has refined it to an art form......
Maynard
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Very exciting indeed! However, the real takeaway here is that you and Dennis share listening taste in terms of the amp’s harmonic characteristics and its relationship to the speakers with which it is tested. One cannot assume that those characteristics will be universally appreciated just as some audiophiles find all tube amps to be unacceptable, and as we find SS amps to be unacceptable. One other question is whether it is necessary to build an amp as complex as yours to achieve a result which is equally pleasing. That, of course, is a question without an answer. A certainty is that there is no amp in existence (mine included) which will interface with all speakers and listener preferences.
Maynard
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One other thing Jeffrey. Do I remember correctly that you said Dennis discovered something was wrong with one or both of his speakers after you and the other listeners had gone home?
Maynard
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It looks fine. Using the separate power supply makes things much more forgiving as there are no AC issues which need to be dealt with in the amp chassis (other than the signal of course).
Maynard
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“There was a reason, many years ago, why the Engineers put in an extra grid, in the triode Finals tube, and NOW, as of THIS MONTH in 2019, we finally understand, have heard, and know why.
Why, because it allows the Finals tube to play better, than any triode .......in a similarly-excellent amp.”
Jeffrey, you are totally wrong. The engineers were searching for a cheap way to increase audio output power in radios so they could avoid having to use push pull triodes. It was believed that listeners could tolerate a somewhat higher level of distortion when listening to certain types of program material. It is well known that single ended pentodes or tetrodes without negative feedback can only produce low distortion at a fraction of their maximum power output. As I’ve explained before if the distortion of your KT88 amp is low (I would like to see some figures on that) it is because you are not pushing it to more than around 1 watt out. Also, how are you dealing with the issue of the amp’s high output impedance?Maynard
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Gorgeous!!! I really like your choice of knobs as well. Can you post a picture of the underside to show your construction technique?
Maynard
Rp150m or rp4000
in Talkin' Tubes
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Very nice work in there! Neat, simple, and great symmetry. I couldn’t buy the parts to build one for its retail cost (and mine would not look as nice). Enjoy!
Maynard