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  1. trainbuftony

    Vintage tube amp THD

    Ask him to test it at full power and give you a relevant number. Even if it's 1% that's still an excellent amplifier. I'm sure be is a professional and knows exactly what he's doing. Measuring it at a low enough level to get .o2% thd is all the proof I need that he knows what he's doing...
  2. trainbuftony

    Vintage tube amp THD

    It seems like the person doing the measurements knew precisely what power level to test at in order to get the lowest THD. Testing it at full rated power will produce a number that actually means something. Most any tube amp can make excellent distortion numbers when you keep the output at...
  3. trainbuftony

    Simple, high quality tube amp designs for the modern era?

    It's a great idea, but we are individuals living in a free society where one of the only acceptable ways to differentiate ourselves from others is to buy different stuff than them. The fact is, tube amps are so dirt simple that virtually anyone who wants to can assemble a good running amplifier...
  4. trainbuftony

    Weber WS1 in a Dynaco ST70 without modification?

    Yes, that is their intended purpose
  5. trainbuftony

    Weber WS1 in a Dynaco ST70 without modification?

    You could always wire in 2x diodes instead of the tube rectifier, make sure the DC voltage doesn't exceede the rating of the first cap on startup. Rebias the output stage and call it done. You'll no longer have a "soft start" but that will be the case with the webber too. Many many classic...
  6. trainbuftony

    Scott LC-21 Phono Section Question - Resistors

    Order them again, or call mouser and let them know about it, perhaps they'll send the right parts if they determine it was their error...
  7. trainbuftony

    Output Transformer without Common, Identification

    F Field coil runs on DC, so no output transformer tap needed. It may get its dc current by acting as a power supply choke or it may be shunted across a power supply. They never used power from an opt, that would have been AC.
  8. trainbuftony

    Output Transformer without Common, Identification

    The speaker winding will have a low dc resistance generally speaking a 4 ohm tap will read 1/10th of that. .3-.6 ohms. The full 16 ohm secondary may read as high as 1.5 ohms but usually lower. On the primary end, you should have equal turns on either side of a center tap. The DC resistance...
  9. trainbuftony

    PrimaLuna EVO and Tube Rolling

    If you find your system weak on bass try an equalizer. They're literally built to adjust individual frequency bands. Changing tubes may cause you to perceive more or less bass, but there's no guarantees. You can buy a used equalizer for about the same price as a single tube. The equalizer...
  10. trainbuftony

    PrimaLuna EVO and Tube Rolling

    That's not what I'm saying at all. What I'm saying is that I've seen enough evidence on my end to suggest that we need to keep our fallable ears and imaginative minds in check by measuring things from time to time so that we can know that we're traveling in the right direction. I've personally...
  11. trainbuftony

    PrimaLuna EVO and Tube Rolling

    There, I fixed it for you. Until you own and use the test equipment you can't really contextualize how hilarious it is when people claim improvement by ear. Once you've seen the reality of these "improvements" you can't unsee it. So you lead the horse to water...
  12. trainbuftony

    PrimaLuna EVO and Tube Rolling

    To be 100% clear, sound quality can easily be measured and quantified. For under $1000 a person can set themselves up to measure the performance of tube amplifiers then when a change is made you can compare what you measured before the change to what you measured afterwards to see if an...
  13. trainbuftony

    PrimaLuna EVO and Tube Rolling

    I'd be concerned that the power transformer designed for EL34s is not likely to have the extra capacity on the heater supply to feed those tubes on a long term basis. (they draw more current) The bias surely will not be optimal. If you're not prepared to modify the amp to alleviate these...
  14. trainbuftony

    Started a new Point to Point tube amp build - Analog Ethos Legendarium

    I was thinking it was a push pull mono amp with a very appropriately sized transformer mounted top side. Never heard push pull 300bs so it looked nice. Single ended 300b, I've personally heard/seen enough of to know its not for me. The case work, fit and finish look nice. Have fun
  15. trainbuftony

    PrimaLuna EVO and Tube Rolling

    Often, they don't. There's nothing different about anything, many power tubes use the same pin out, if the builder selects the cathode resistor or sets the bias such that the amp will work and bias up with any power tube in it from that series. Better amplifiers will give you a means of...
  16. trainbuftony

    12 Volt Tubes

    Yes and if you open the field to sweep tubes, there's really no need to spend goofy money on power tubes. Find yourself a box of sweep tubes and you can have cheap fun for a good long time! There's really no shortage of vacuum tubes out there that will make great audio amplifiers. They just...
  17. trainbuftony

    Started a new Point to Point tube amp build - Analog Ethos Legendarium

    Looks nice! You have two for stereo I presume?
  18. trainbuftony

    Question: Where to find good replacement for 60uf-450V axial Capacitor ???

    I second the recommendation of using a pair of F&t 33uf x500v caps in parallel. Alternatively you could use 3x 22Uf in parallel. You could also just drop a 47uf in there and it would probably not make one bit of difference in the end.
  19. trainbuftony

    Removing labels on Heathkit amps and transformers

    Sometimes I wrap the ends of a razor in masking tape to space it up above the work like a little plane. That may allow you to scrape without scraping off paint.
  20. trainbuftony

    Another ID these mono amps.

    Waterside decals is correct. That and the mirrored construction lends me to believe that they're homebrew by a seasoned "brewmaster" rather than a commercial product or prototype.
  21. trainbuftony

    Bad Chinese translations make the world go round

    Dr pepper has a flavor too. Anyone want to take a guess at what Dr pepper is supposed to taste like? Delicious prunes! It was also originally recommended to drink it warm or cold. Fascinating.
  22. trainbuftony

    Bad Chinese translations make the world go round

    Half a liter of the good stuff. Yes I'm aware they remove the cocaine and ship it separately these days... The flavor is Coca, and a little nutmeg.
  23. trainbuftony

    Bad Chinese translations make the world go round

    I do still have it. I drove it 250 miles on Saturday. It's not an FJ40. It's an fj55 station wagon. A restored original sold a few years ago for 130k. I paid 2.6k for mine, and sat on it 2 decades. Needless to say, It's not for sale.
  24. trainbuftony

    Bad Chinese translations make the world go round

    Suggar unfortunately is not what made original Coca-Cola the "real thing" It was the blow. Before cocaine was illegal, it was an ingredient in Coca-Cola. +1for real Mexican coke. I recently gave up caffeine as a daily habit. If I drink a "Medio litro" it may as well have cocaine in it, because...
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