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tube fanatic

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  1. Many of the power supply and other questions were previously raised by former forum member xxJPMxx in the original thread, and answers were provided.  
     

    If the amps are constructed as mono units with the specified parts, the only voltage reference really needed is the plate to cathode voltage of the 6Y6.  We can safely assume that the other voltages will follow.  The reference point for specified electrode voltages in manufacturer tube data is always to the cathode in tubes having one.  
     

    In the original thread, John Lumley posted his power supply variant which some may find interesting and informative.  And, former forum member wdecho posted his FFT measurement of the amp which is interesting as well.

     

    I agree with Henry that his build thread should be kept on the non-technical side.  His implementation has worked very successfully and anyone emulating his work should expect to obtain similar results.  
     

    I suggest starting a new thread for improvements to the original design for those more technically inclined.  Suggesting changes to the design based on calculations without experiencing the original is analogous to a chef wanting to improve a recipe without tasting the original form.  
     

    Maynard


     


     

     

    • Like 3
    • Thanks 1
  2. Since Henry mentioned Deckert’s Zen Triode, prospective builders of their first tube amp may enjoy watching Deckert actually build one.  Be sure to watch all 12 videos.  Seeing a point to point build in real time gives a somewhat different perspective from seeing still photos.

     

    https://www.youtube.com/watch?v=n1ENOdYN6iA

     

    Henry, if you think this will dilute the thread, I will delete it.  Let me know.

     

    Maynard

    • Like 2
  3. 8 hours ago, henry4841 said:

     

    If you want a visual image of me think bald, 20lbs overweight, 73 year old man in coveralls. 

    Henry, it is unfortunate that we live so far apart.  We could sit on the porch of the general store reminiscing about the good ol’ days.  I am also a bald old timer, but 50# underweight.  A local farmer offered me a job as a human scarecrow.  If I had time, I would take him up on it!

     

    Maynard

    • Like 2
    • Haha 2
  4. 22 hours ago, Curious_George said:

    When I get around to building one of these, I'm going to redo the driver circuit and use a 12AV7. I don't need the gain of the 6SJ7 pentode since I always use a preamp. 

    Nick, how are you planning on configuring the 12AV7?  Getting around 21V rms from one section to fully drive the 6Y6 as used in the Sweetie will bring the distortion of the 12AV7 into the 5% range.  This is not a bad thing in my opinion.  You could set up the 6SJ7 for minimum gain to allow use of your preamp and minimize driver distortion if desired.

     

    Maynard

  5. Hey folks!  It has been a while so Henry twisted my arm to say hello.

     

    The plate curves of the 6Y6 are very similar to those of the 2A3.  The former have the distinct advantage of being inexpensive and abundant, and don’t have the DHT filament issues to deal with.  It is a wonderful tube all around.

     

    I have taken a break from amp design and building for now due to a number of old radio restoration projects which have accumulated due to the move 6 months ago.

     

    Hope everyone is well.

     

    Maynard

    • Like 8
    • Thanks 2
  6. 8 minutes ago, wuzzzer said:

    What's the point of posting this?


    Educational.  There are many “experts” claiming that one type of mask is vastly superior to another.  This study found little difference between two popular types.  
     

    Maynard

  7. 6 hours ago, joessportster said:

     


    Joe, Travis will not be happy that you posted this!  I am waiting for his response to my questioning why he believes the patents have anything to do with anti-vaxxers and conspiracy theorists.  They do prove quite well that COVID was lab engineered for a very specific purpose.

     

    Maynard

    • Like 1
  8. 28 minutes ago, dwilawyer said:

    Now we are back into the stuff seen on the anti-vaxx/conspiracy sites. Oh my gosh, the answer was in the patents all along. That was in all of the videos deleated by social media/video platforms as quackery.

     

    .  


     

     

     


    Travis, if you get the chance, PM or email me with your reasoning that the patents enumerated in the video have anything to do with anti-vaxx beliefs or conspiracy theories.  What social media sites say is quackery means nothing, and YouTube would have deleted the video if it was not valid.  Fuellmich, the attorney, appears to be highly respected as well.  The patents cited are pure science and were granted to our own government agencies, Fauci, Baric, Moderna, et al.  

     

    Maynard

  9. 34 minutes ago, Jeff Matthews said:

    Same with the J&J vaccine.  Listen to how surprised and disappointed the medical community is to find this out after giving the vaccine to so many people.  They didn't say, "We knew this before we started giving it.  It's been studied for years." 

     

    What else will they find out?

     

    When 2 or 3 people die from eating tainted ice cream or lettuce, they pull the products from the market immediately.  Not so with the vaccines.

     

     

     


    And here is the disclosure Pfizer made to Japan’s ministry of health.  Scroll down to the section in English on organ distribution which reveals how we have been told lies about the vaccine remaining in the injection site:

     

    https://trialsitenews.com/wp-content/uploads/2021/06/Pfizer-report_Japanese-government.pdf

     

    In case, you didn’t see it, look at the thread I started on patents and download the links before they are deleted.  You will be shocked what the patents say.


    Maynard

    • Like 1
  10. 8 hours ago, Jeff Matthews said:

    CDC admits the vaccine kills some people (though they aren't for sure why and don't fully concede causation).  Same with other serious side effects, such as clots and heart issues.  The numbers reported are, of course, very small.  But the same is true for the underlying illness.  

     

    I have a hard time sitting there submitting to an injection when, right before they push the plunger, they say, "Now, this could possibly kill you or damage your heart."  What am I supposed to do?  "Duh... Ok..."  

     

    There's a small chance Covid could kill me or mess me up good.  I'm not going to stand in line to get purposefully infected.  

     

    There's a small chance the vaccine could also kill me or mess me up good.  Likewise, I'm not running to stand in line to see if it does.

     

    FDA has only approved these for emergency use.  I don't even want any of the drugs they've approved for everyday use, let alone ones they limit to emergencies.  There is no available data concerning long-term effects.

     


    Jeff, I applaud you for stating your feelings and I am surprised your post was not deleted for presenting a view which is not mainstream.
     

    This video explains how mRNA vaccines work and I have read multiple studies which support the mechanism presented and the resulting vascular damage.  

     

    https://www.bitchute.com/video/uD98ksu0PzQg/

     

    And we know that FDA approval means nothing!

     

    Maynard

     

     

    • Like 2
  11. On 8/14/2021 at 2:22 PM, artto said:

    Here's my dumb question of the day. I'm pretty sure the answer is as usual......"it depends"

     

    With that in mind I'd like to hear some arguments for and against, why, and why not (as in don't bother, or why solid state regulation would be preferred) using vacuum tubes for voltage regulation in tube power amps. More specifically, in SET amps. And even more specifically Decware Super Zen Triode 25th Anniversary Edition (Model SE 84UFO25).

     

    Fire Away!!!!!!  🤩


     

    Voltage regulation in SETs is unnecessary due to the near constant dc current draw under all operating conditions.  Of course VR tubes are pretty to look at in a dark room!  Deckert is using the option of different voltage drops among some of them to change the plate voltage of the driver which, of course, changes the distortion characteristics to tailor the sound to suit.  This could more easily be done other ways but that would not have the “coolness” factor of the VR tubes.  Only you can decide if it is worth the extra cost.

     

    Maynard

    • Like 1
  12. 9 hours ago, Jazzmaster Jake said:

    Would there be any pitfalls in swapping output transformers with Hammond 1627SEA? Same impedence on the primary (2.5k). Primary inductance is 20H vs the approximate 10H of the 125ese.

    I’ll attach the link to hammonds info below. As it is, I see the spec sheet for the 125ESE warns to use this series use the 1627-1640 trannies for “HI-FI” 20-20khz output.

     

    http://www.hammondmfg.com/1627.htm

     

    cheers,

    Jake


    It would be fine to use the 1627 although it may not be much better than the 125ESE in this application.  The bandwidth of the latter is extremely wide due to being operated at such a tiny fraction of its output power rating.  Personally, I would build the Millie as shown and keep the size and weight down.

     

    Look at George Anderson’s measurement of the 125CSE to gain some insight about transformer bandwidth as a function of output power:

     

    http://tubelab.com/articles/component-testing/budget-output-transformers/

     

     

    Maynard

  13. Those who can live with less power can achieve 2A3 performance with a triode strapped 6Y6 which can usually be found NOS for around $4.00. The curves are very similar.  And, of course, a pair could be used in parallel for a little more “oomph.”  
     

    Maynard

    • Like 1
  14. 11 hours ago, mr clean said:

    The wife had cataract surgery. They really talk it up but the wife now has dry eye, and still wears glasses. I’m sure every case is different but she told me she would not have had it done. Not yet anyway.


    Is your wife still using post surgery drops? They can sometimes worsen an existing dry eye condition.  Did the ophthalmologist recommend a trial with cyclosporine? The latter is often very helpful in dry eye patients.

     

    Maynard

    • Like 2
  15. Zen, are you saying that the American Academy of Ophthalmology is spreading disinformation?  I sincerely hope not.  If you believe that a general practitioner knows as much about ocular conditions as an ophthalmologist then I wish you luck!  
     

    Maynard 

    • Like 1
  16. 1 hour ago, Ronald Marshall said:

    I think your article is more provocative than informative. Many people who have been vaccinated can become depressed after reading, even if they are doing well. In any case, yes, you need to be careful and think carefully, but I am sure that those who have already decided on this do not regret it.


    Well, if a person who has had corneal grafts develops symptoms and sees their family doc who is clueless and loses their sight as a result I imagine they will be more depressed!  Knowing the possibility would likely result in their seeing an ophthalmologist instead and saving their eyes.

     

    Maynard

  17. 4 hours ago, AndreG. said:

     Our eyes, like ourselves, are lazy things. Once you give them support of lenses, they will get used to it, this can (not must) lead to them geting weaker faster. 


    Wearing glasses cannot cause them to get weaker faster.  The brain can get accustomed to the level of clarity which glasses or contact lenses allow.  If you try to take that away after a length of time a person can feel “blind” although nothing has changed.  This is seen across all age groups and with correction for myopia, hyperopia, and astigmatism.

     

    Maynard

    • Thanks 1
  18. 5 hours ago, parlophone1 said:

    However, you should wear glasses for one other reason and that is you could loose your sight much more rapidly then without them. At lest that is how my optometrist explained to me.


    This is not correct.  Failing to wear corrective lenses will not cause eyes to change more rapidly.  
     

    Maynard

    • Like 2
  19. 15 hours ago, danielg said:

      

     

    Oh interesting point about the tube rolling @tube fanatic. A few days ago I ordered two fairly cheap JJ Tesla tubes to replace my two 12AU7 input tubes let's see if I'd be able to feel any difference.

    This "magic" is certainly something which interests me, currently the listening is very fatiguing but not engaging. I listen mainly to jazz, ambient, classical/avant-garde, folk/blues, African, Latin. I do however come from a DJing background and would sometime enjoy disco/ house/ techno with a good volume. 

    I sit about 2.6m from the speakers and the speakers are spaced 2.6m apart. They are fairly close to the wall and toed in, and about 50cm from the side walls (see picture).IMG_8141.jp2


    Before considering ordering a single ended amp it is worth measuring how much power you will need to satisfy your loudest listening levels.  When the time comes I can point you to a very simple method which takes about 2 minutes using a cheap multimeter.  Do post your impressions after the tube swap.

     

    Maynard

  20. Well, I have never found that tube rolling produces significant changes in sound although others may disagree.  As far as single ended amps go,  they are the only type I design and use.  I find that SEPs and SETs offer a “magic” which I don’t experience with push-pull types.  If your listening levels allow the use of low power amps, then they may be the route to the kind of sound you are looking for.  
     

    How far from the speakers do you sit and how large is your room?  What type of music do you listen to?

     

    Maynard

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