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  1. dsavitsk

    "Millett Hybrid" redux: NuHybrid headphone amp, using the Korg Nutube

    Hfe on those is max 300. At the 10mA running through these, the base current will likely drag the voltage too much. A darlington (2N6426 perhaps?) might work.
  2. dsavitsk

    A very simple single-ended parafeed design

    Nice design :) I am a little concerned about the unbypassed cathode resistor - you are adding ~2500 Ohms to the plate resistance with it, which sort of defeats the point of the low Z tube. I have a write up of such designs which might prove useful...
  3. dsavitsk

    What's the best amp for HD800

    There is an ecp thread? I didn't even know. Do you have a link? I'm not trying to ignore anyone, I just haven't seen it. I am a fan of the headphone power amp concept - basically, for people with a DAC that has a volume control, or for people who are going to just drop the amp into a rack...
  4. dsavitsk

    Official New York Spring Meet Saturday June 11 2016

    I may make it if Todd picks me up on the way.
  5. dsavitsk

    Tube Amp Noise

    That sort of noise is consistent with something oscillating. If it just started recently and happens regardless of the tubes used, that suggests that a part has gone bad -- likely a capacitor somewhere.
  6. dsavitsk

    Iron transformer standoffs / platform / risers

    If you are investing this much effort, upgrade to the equivalent 300 series. You can remove the endbells and replace them with brackets. https://www.edcorusa.com/brackets
  7. dsavitsk

    Torpedo III Build Thread

    2006? You guys are a bunch of neophytes. As for the transformer - It would certainly not be the first noisy Edcor we've seen, but checking for DC offset is a good idea as a first step as replacing these is not trivial. The buzzing is mechanical? That should not translate into harsh sound. Are...
  8. dsavitsk

    Torpedo III Build Thread

    R3, D3, D4, and D5 form a voltage divider. D3-D5 will always drop a fixed (~225) voltage as they are Zener diodes, and that's what Zeners do. R3 drops the remaining voltage and limits the amount of current flowing through the diodes. That 225V biases the gate of Q1, and the source stays at a...
  9. dsavitsk

    Torpedo III Build Thread

    I will have the individual transformers for sale on my site. I just need to actually put them there. Give me a day.
  10. dsavitsk

    Torpedo III Build Thread

    I've got plenty more. No worries -- I'll drop them in the mail to Tom on Monday morning :)
  11. dsavitsk

    Torpedo III Build Thread

    The T3 is basically designed around the HD650s and HD800s because those are what I listen to. :)
  12. dsavitsk

    Torpedo III Build Thread

    I think I like the T3 better, but keep in mind I've not heard an L2 in a couple of years.
  13. dsavitsk

    Torpedo III Build Thread

    Oh goodness. T3 is probably a little sweeter sounding. Maybe a little warmer, and punchier, too. BD might be more neutral.
  14. dsavitsk

    Torpedo III Build Thread

    That looks like the right one. Caps should be at least 300V with min 10uF recommended. Sims with caps as small as 1u show that they transfer bass frequencies, but the phase is distorted which will make it sound like they don't. You might do OK with slightly smaller (8u? possibly 5u?) but I...
  15. dsavitsk

    Torpedo III Build Thread

    I have shipped the nickel transformers to Tom, but he won't have them for a couple more days. I think he is very close to being ready to accept orders, but the number of i's to dot and t's to cross is enormous. So I think it will just be a couple of days, but I know we've said that before...
  16. dsavitsk

    Torpedo III Build Thread

    Here's what Spice has to say about the circuit. TORPEDO3.pdf (188k. pdf file)
  17. dsavitsk

    Dsavitsk/Beezar Torpedo Build Thread

    If there are no more surprises, 2 weeks maybe.
  18. dsavitsk

    Dsavitsk/Beezar Torpedo Build Thread

    I do have L2 PCBs available and the new Cinemags will fit the boards (as will the Edcors) but frankly I'd build a T3 before an L2 unless one is a glutton for punishment. The L2 build process is non-trivial, and I like the T3 better anyway.
  19. dsavitsk

    Torpedo III Build Thread

    My comment to Tom about the Cinemags is that once he's heard them, he will have no interest in hearing the Edcors again. :)
  20. dsavitsk

    Dsavitsk/Beezar Torpedo Build Thread

    What we hope will be the final prototypes of the nickel OPTs should be here within the week. If all goes well with them, we will offer the T3 with either the Edcors or the Cinemags at different price points. I will also offer the Cinemags for sale on their own. As far as we know, they should...
  21. dsavitsk

    Dsavitsk/Beezar Torpedo Build Thread

    The only way to know is to try it.
  22. dsavitsk

    Dsavitsk/Beezar Torpedo Build Thread

    Just a little Torpedo update -- I have been testing the first prototype of the new output transformers. There are a few small tweaks to make and I'll be testing a second (and likely final) prototype in the next week or two, but thus far the results are extremely promising. By that I mean the...
  23. dsavitsk

    Dsavitsk/Beezar Torpedo Build Thread

    We are running it conservatively to ensure that noise and heat are minimized. In a sense, we are running it more conservatively than in the T1 as the B+ current is similar but the heater current is reduced. If you run a bit more current, nothing will be damaged (which I think is what you mean by...
  24. dsavitsk

    "I'm not dead yet!" ...A Balanced LTP/Jisbos Tube Hybrid

    Not to second guess your decisions, but I can't for the life of me figure out why you'd want to include the opamps.
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