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tube fanatic

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Posts posted by tube fanatic

  1. 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

  2. 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

  3. Before you consider other amps I need to ask some questions.  Have you tried both impedance taps?  In some systems one tap can provide a very different sound from the other.  With a different amp is the sound radically different?  And, does the LM-34 sound well with different speakers?  Another option to try, which is not costly, is to try swamping resistors to smooth out the speaker impedance variations:

     

    https://www.zuaudio.com/diy/loading25r

     


    Maynard

  4. (Mod edit: personal commentary removed),  If you have had a corneal transplant, know someone who has had a transplant, or is going to have one, this information is relevant.  
     

    https://www.aao.org/editors-choice/two-cases-of-corneal-transplant-rejection-after-co

     

    No discussion please as the thread will probably be locked immediately if there is.  

    (Mod edit: Author's conclusion: 

    Clinical significance

    This study is the first evidence of a temporal association between corneal transplant rejection after COVID-19 mRNA vaccination and the first case reports of DMEK rejection following any immunization. Patients need to be informed of the symptoms and signs of rejection that require immediate medical attention. Clinicians and patients should be aware of this potential risk and consider vaccination before planned nonurgent keratoplasties. In those who already have corneal transplants, it may be beneficial to either increase the frequency of existing steroid regimens or avoid reducing treatment around the time of vaccination. When patients present with signs of transplant rejection, physicians should inquire about a history of vaccination and report temporal associations to the relevant agencies. As both patients were successfully treated with topical corticosteroids, the findings in this paper should not deter administration of the COVID-19 vaccination, because early recognition and prompt treatment of rejection can yield positive outcomes)

     

    Maynard

    • Like 1
  5. 8 hours ago, Jazzmaster Jake said:

    Unless I’m wrong, It doesn’t seam anybody has tried to build this yet. So i’m gonna five it a go since i have many of the parts needed floating in “extras” boxes around here.

     

    The only issue is i don’t need to build a Stereo unit, as i only need a mono-block amp for a mono bedroom rig. 

     

    So to make a mono-block version, what change to the hearter resistor R15 to only feed one valve. Are there any other alterations I should make that I’m not noticing to the power supply?

     

    thanks much,

    Jake


    The easiest solution is to use the second 50L6 (or any other 50V/0.15A) tube as a filament ballast so you can leave R15 as specified to reduce under chassis heat.  With only one channel, plate and filament voltages will run a little higher since the p/s won’t be loaded down as much, but it will be ok.  If you happen to have an 820 ohm/10 watt resistor you can use that in place of R13/14.  Feel free to PM with other questions.  It may take me a few days to respond though.

     

    I now use full time, single speaker, mono with a RB-51 series 2 near a room corner and the combination is pure bliss to my ears.

     

     

    Maynard

  6. Many details would be useful:  room size, listening level, distance from speakers when listening, type of music, and lots more.  I have set guys up with ridiculously low powered amps which practically blew them out of the room.  Your budget opens up many options like the Decware Zen Triode.  It provides more than enough power for any “reasonable” listening level in my opinion.  The lifetime guarantee is very appealing as is its being built in the US.

     

    If you are electronically experienced, and can build your own, I can provide you with a link to my most successful SET design which works great with LaScalas.

     

    Maynard

    • Like 1
  7. 2 hours ago, seti said:

     

     

    I have had many amps up to two watts. They do not all sound great. They need to be extremely well designed and the power supply is of the utmost importance. I don't have any EE in my background but I've noticed the better the power supply the better the SET amp. They also need a bit more refining. I built a 1625 triode amp and it sounded ok at first but not as nice as my 2a3/45 amp. My friend had me tweak the driver stage many times and it just went from an ok amp to great. I have several rebuilt PP amps EL37 7591 EL84 6L6 50CA10 2a3 but they just don't sound as good. The PP EL84 fisher is the best I've heard so far with the PP EL37 not far behind. What about higher powered SET amps 300b 211 845 ? I'd like to try a SET DC 300b/50 amp. However I think we are going to do a compactron 6HS5 SET amp next.  The best amplifier with horns I've ever heard was a Eimac 75tl which was a bit higher power but that build is not for the faint of heart. Perhaps it is topology and execution that are of the most important.

     

     

     

     

     

     

     

     


    The question is what constitutes a better power supply for SETs.  If the ripple is sufficiently low to prevent any hum, all is well.  The DC current draw is almost constant in SETs, so regulation is often unimportant.  Of greatest importance is choosing an operating point which promotes the best linearity so distortion remains very low.  

     

    Maynard

  8. Forgive me for asking, but isn’t the above discussion political?  If not, can we have a discussion about the movement to end abortions in this country while funding them elsewhere?

     

    Maynard

  9. 3 hours ago, Iteachstem said:

    Unfortunately, this cannot be further from the truth.  Educators are discriminated against for having education and experience.  Most districts now will only offer you up to 5 years of experience.  So, if you want to change districts, and have more than 5 years experience, you will take a pay cut, and potentially a huge one.  It's very bad for people who want to move out of a state or have to move due to their significant other's job relocation.

     

    For example, If I have 20 years and a masters + I will earn around $75,000 in my district.  Now, if I wanted to move to another district, even though it's a higher paying district, I will start at year 5.... which translated anywhere from a $10,000 to $17,000 pay cut.( this is just looking at the surrounding districts..... if I moved further away from the city or to another state, the differences could be even more dramatic.)

     

    It's not like my friends in the corporate world, where one transitioned from an engineer at Mobil to BP and actually enjoyed a pay raise as well as moving expense, etc.

     

    I'm not trying to cry poor me, as this is the profession for which I chose to remain employed. However, I hope I can educate some people as to what teachers experience throughout their employment in the wonderful world of education!


    This is so true.  My wife is a retired special ed teacher who worked in one of the lowest paying districts in the county.  She was stuck as a move to a higher paying district would have resulted in a pay cut.  The district prefers to hire a new, inexperienced, person to paying a seasoned professional what they are worth.  
     

    Maynard

    • Like 3
  10. I have never used air conditioning and my listening rooms have often hit 90F during the summer.  It has never been an issue.  Considering the fact that electrolytic caps are typically rated for at least 85C it is not likely that they will be damaged if run on the hotter side for a few hours.  Resistors are even more heat resistant.  And remember that the under chassis temperatures will be lower.

     

    Maynard

  11. 3 hours ago, Kalifornian said:

     If you can trust a 16 year old with car and all the decisions and responsibility that comes with it then you can trust them with a vaccine.   


    I don’t share your optimistic view of a 16 year old’s responsibility level when driving.  
     

    https://www.myimprov.com/top-ca-teenage-driving-statistics/

     

    1 hour ago, mungkiman said:

    Imagine your 12 year old getting seriously ill or dying because you didn't let them get a vaccine. Insanity...

     


    Would your 12 year old child know that they had a serious adverse reaction to a vaccine, or adjuvant, as an infant which precludes their taking a coronavirus vaccine?  And what about informed consent?  Do you really believe a kid that age is capable of that?  Here, parental permission is needed to instill drops for tonometry or pupil dilation during an eye examination if they are under 18.  Same for fitting contact lenses.  I see a big difference between the latter circumstances and the former.  In my family kids are told not to accept any medical intervention without their parents being advised.  To me, this is good sense!

     

     

    Maynard

    • Like 1
  12. [EDIT BY Moderator: People will have to get their information from sources they feel provide them the most useful information] Nothing on Coronavirus will be allowed on this Forum, it is too politically intertwined to be of any use]

  13. 7 hours ago, RandyH001 said:

    State and Federal Authority to Mandate Covid 19 Vaccination  / 

    Congressional Research Service -

    Informing the Legislative Debate since 1914 -

    https://crsreports.congress.gov/product/pdf/R/R46745

    A truly frightening glimpse into what is likely to happen.  It seems that where trillions of dollars are concerned the warnings issued by many respected scientists worldwide will not be considered.  What if some of their concerns turn out to be true?  Can our medical system handle millions of sick people?  I seriously doubt it.

     

    [Political link removed]

     

     

    Maynard

  14. Dr. Tess Lawrie speaks out against suppression of treatments which were saving lives:

     

    https://www.thedesertreview.com/opinion/letters_to_editor/dr-tess-lawrie-the-conscience-of-medicine/article_ff673eca-ac2d-11eb-adaa-ab952b1d2661.html

     

    In my years of being tied to the medical community I have never seen such reluctance and refusal to try treatments which are being used successfully by those in the front lines.  
     

     

    Maynard

    • Sad 1
  15. 3 hours ago, Shakeydeal said:

    I weighed my options and decided I'll take my chances with the virus. The odds are waaaaaaay in my favor. And all the vaccinated people need not worry about me. They are vaccinated.

     

    Not saying I'll never get it, just don't see that it's necessary.

     

     


    Yes, but when proof of vaccination is required for forum participation you will be very sorry.....😄

     

    Maynard

    • Haha 1
  16. Today’s observation at 2 very busy stores:

     

    Supermarket—-              98% wearing masks.  Those without getting “the look.”

     

    Farm supply place—.     98% without masks.  Those with masks getting “the look.”

     

    (for the pedantic folks participating in this thread, the quoted percentage is approximate)

     

     

    Maynard

    • Haha 1
  17. 2 hours ago, Deang said:

     

    This is true. That is how science is supposed to work. So when you say the kinds of things he has said, there should be peer reviewed papers, with supporting evidence, submitted to reputable journals. There is nothing. He is just another once brilliant guy who has gone off the rails, and now stands on the rooftop waving his arms around.


    I appreciate your reliance on peer reviewed papers.  Unfortunately, even that is not always worthwhile as some have been found to be written by ghost writers, or contain fabricated data.  There is little integrity where money is concerned.  Here are some thoughts by the editor of the Lancet, certainly a respected journal.

     

    https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)60696-1/fulltext

     

    As to the excellent article you linked about how vaccines work, it supports the concern voiced by some that incomplete eradication of the spike proteins by the immune system could cause all kinds of problems down the road and may explain the “long haulers.”

     

    Maynard

     

     

  18. 1 hour ago, Deang said:


    Dr.’s are human beings who are also susceptible to misinformation and being misled. 
     

    Would corporations and governments really conspire to poison and kill off the human race? Have they have grown tired of our labor and profits?

     

    There will always be some who have strong responses to immunizations. This is nothing new, and neither is using the genetic material from a host as an antigen to provoke an immune response. 


    The sources I cite are not representing conspiracy theorists.  Rather, they are credentialed scientists who have legitimate concerns.  In a normal vaccine approval process many questions would be answered before the product hits the market.  It has now been shown that the real issue is the inflammatory process triggered by the spike proteins which get into the lymphatic system and wind up being distributed systemically and show up in the spleen.  So questioning the possibility that the vaccines, which turn our bodies into spike protein factories, could result in vascular and organ damage over time makes sense.  It has been shown that pulmonary arteries are damaged by them, as one example.  
     

    I have been tied to the medical community for decades (mostly in ophthalmology) and have attended many medical conferences at which prominent doctors gathered to examine patients with unusual pathologies to discuss various treatments to try.  Never did I encounter a situation in which a “mainstream view” was the only one considered acceptable.  It was always, “we need to investigate this or try that.”  Sadly, that attitude has been totally absent with coronavirus resulting in serious deficits which have cost countless lives.

     

     

    Maynard

  19. 5 minutes ago, Deang said:

    The information in that letter has been debunked and the Dr. discredited. He’s been talking nonsense for almost a year. 


    That has been the unfortunate side of the “science” all along- anyone who disagreed with the mainstream view has been “debunked and discredited.”  Such an attitude has cost lives during this crisis.  The questions raised in the letter from those doctors are quite valid.

     

     

    Maynard

    • Like 1
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